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RE: Simulating impact of TV in middle (primarily, size change)

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In Reply to: RE: Simulating impact of TV in middle (primarily, size change) posted by JBen on April 21, 2012 at 22:50:28

I'd be curious in seeing a photo of your speakers/panel from your listening seat, with a mirror at the first reflection points on the front wall. The reason for that is that I'm trying to figure out what's happening here. I'm guessing that the TV is blocking the first reflection points between the speakers, which is going to have the effect of making the room acoustically deeper. It should do that very roughly to the point at which the wavelength of the sound is the size of the TV, below that frequency, it's going to start diffracting around the TV and in the bass it will be as if the TV isn't there. So that could be one reason why a larger TV works better.

I think this is of interest not just to people who have to accommodate TV's, but in general. I've been using my office video monitor down here to achieve some interaural crosstalk cancellation -- speakers behind the monitor and arranged so that they're mostly occluded from the opposite ear -- and it works, the effect is a lot like what you get from an ambiophonics barrier. I'm planning to try the same thing upstairs with my full-sized system, in that case, the monitor will be on a roll-around computer cart in front of me. I was originally doing that just because it occurred to me that I could do my office work in front of the big speakers, and then it occurred to me that rather than being a compromise, maybe I could make it into an asset. I don't think I'd want to listen facing an ambiophonics barrier, but looking at a monitor while I listen is something I like to do.

Follow Ups:

RE: Simulating impact of TV in middle (primarily, size change) - JBen 17:22:21 04/22/12 (35)
I promised my wife not to publish pictures until I am finished tidying things up to "her minimum requirements". In changing the corner "treatment', I made an ugly mess. On top of that, the pretty poplar LWingies "drove" to my friend's house at noon for a surface refinish. Right after we sanded them, it rained heavily and humidity became a concern, so we left it there until next weekend. I'll see if I can modify a drawing for your purposes this evening. The pictures should still be useful later on.

So, I came back home and just finished reinstalling the "old" prototype LWingies pieces. I am now warming up the gear to the tune of Patricia Barber's Companion hdcd. Its bass is so strong that it cooks things up quicker.

As I read your post I agree that we may have opportunities to help. If you can test a few things, it may help to define a wider range of options beyond what I've seen so far.

Relative to the last lines in your first paragraph, something else must be at work here. For all intents and purposes, the TV vanishes at pretty much ALL frequencies, just like the MMGs and the equipment rack do. They are all virtually transparent.

Forex, right now Patricia is singing center, right "behind" the TV. The band spreads in layers and pretty solid positions left to right, from outside the side walls. The wall 4' behind them is also "not there" sonically. The "visual focusing", the eyes being dragged along by the ears, now extends at least 5' further back, sometimes more with other material. The actual perception of overall depth is deeper still. (A few organ recordings can almost recreate a small chapel outside the apartment.)

The audience and nightclub ambiance is rich in positional detail all over the soundstage. There's clinking glass and silverware being handled, with some glass also resonating to the band's sounds. You can almost see the waiters going about the place. Applause, laughter and even whispers are also 3d sonic items. It is all a seamless sonic holography; side to side, front to back, and without a single aural hint that neither the MMG's, the TV or the equipment are there. The definition of "center" does not apply unless Patricia is singing. She is front of the rest and they are all in distinct positions both, directly behind her, and to her sides.

As I write this, another typical phenomena is constantly evident. If allowed, the eyes easily re-focus to each location on the soundstage. The drum array in Black Magic Woman is now playing...end of the disc. As I "looked" at each and every drum and element across the stage, this text on the TV went out of focus and then was sort of blotted off from mind. In fact, I've been enjoying the music so much all along that I started the post with the first song...and the disc just ended.

(Ok, now switching to Don Grusin's "The Hang", hang on...LOL) Brewed some coffee along the way, sorry for the delay : - ))

I don't think you would have to worry, this is not like ambiophonics. In fact, 3D HDTV has a long ways to go before something like what Maggies can do sonically in stereo can be done visually with TV.

Anyway, right now there is a rather solid saxophone hailing from outside the room and it is reminding me that this system's imaging capabilities did not happen all at once. At first, it was accidental. Later, it was more deliberate. Also, I am a beneficiary of the late Al Sekela's discoveries. He was dealing with a large console projection TV between his Maggies...tall order!

I'll see what I can summarize for your use. I just replied to a post by Norman and I am hoping his current setup can be used to try a few variations.

[Oh, the music now running is Julia Fischer on the fiddle. Imaging is just fine...but it is the violin textures that grab my attention and do not easily let go of it. Still, it helps that the violin is very stable, solid and cohesive from top to bottom, one foot behind the TV.]
- RE: Simulating impact of TV in middle (primarily, size change) - josh358 08:00:10 04/23/12 (34)
  Was looking at my room yesterday, frustrated by how hopeless it is. Whereas the room I'm in now is pretty much perfect, mwahahahaha. I mean, do we really need a library? (Carefully putting poison in other wine glass . . . )
  
  The crosstalk cancellation down here on my computer speakers was just something I hit on, as I tried putting them at different places on my desk. For a long time, I had them on either side of the monitor, then I found that they sounded better about 1-1/2 feet behind and slightly blocked, then later realized that I had created an ambio crosstalk barrier when I was experimenting with those. So since I'd already decided to move my computer work into the listening room (this was before the Mini Maggies, if I'd heard them at the time, they're so good that I would have just left the computer in my home office and gotten a pair of them), I began to wonder whether I could use the monitor as an ambio barrier. Before that, I was thinking, OK, this is something I'll pull in front of me when I'm working and push off to the side for serious listening, but who knows? It may actually improve the sound rather than hurting it. And I've learned that I do like to surf while I'm listening, I ended up doing a lot of that on the projector (always kind of guilty that I was using up time on the bulb).
  
  I envy you your perfect imaging. It's hard to see how I'm going to arrange for that in this room. The best setup has me sitting in the fireplace, which is ridiculous. The sideways setup is more practical, it's what I used to use, but it may not work with the IVa's, we'll have to see (the woofer panels have to be against the wall in split configuration). The setup I really want to use is still the one with the speakers in front of the fireplace, but that would mean more construction and after two years of renovations I'm really burnt out on construction!
  - RE: Simulating impact of TV in middle (primarily, size change) - Satie 10:34:29 04/24/12 (27)
    Josh, you are absolutely on top of the issue. The TV in JBen's setup is blocking the center reflections. I used the same trick with my center double rack, which had the front of the rack 3.5-4 ft from the front wall and the speakers were aimed to have the front of the rack in the null. So my normal equidistant setup had a bit of the ambiosonic effect.
    
    When doing the HK/Limage setup, the front of the rack was the cause of the weird effects. So I tried various ways of taking it out. I hung a throw in front of the rack and it did the trick to stop the effects and deepen the back of the orchestra to natural image layer structure. However, it made for a higher freq balance and had overemphsized details. I ended up experimenting with side panels of fuzzy blankets stretched over foamboard panels placed beside the double rack and pulled forward to various extents. I found a good balance with the "sideburns" panels jutting in front of the rack by about 10-12". That left only reflections off the far end of the rack front for each speaker, most of which was trapped by the other wing and had a shallow angle so what escaped would only come back to the ear after reflecting off the walls.
    
    I think JBen needs to work out the geometry of the reflections, which IIRC are blocked by his TV at the center. When he extends the TV he may get reflections off the front of the TV because of the toe in of his speakers allowing some reflections of the other speaker's front output off of the far end of the TV. meaning that the right speaker reflects off the left side of the larger TV since the far end is not inside the null.
    
    .
    - RE: Simulating impact of TV in middle (primarily, size change) - JBen 18:40:24 04/24/12 (26)
      Satie, I already posted a frequency sweep pair that shows how little change there is with & without the TV, earlier in this thread. If you have, and can post, what happened at your end when you tried in the past, then we may enlarge the pool of data. That's only a portion of the picture but a more objective one.
      
      Still, let me see if this, in terms of mere perceptions, helps to better portray the differences to your experiance.
      
      Taking the TV away here shows that there is no "real" audio quality loss vs when the TV was in, perhaps quite the contrary. Imaging changes, yes. Take that TV away and the most significant change is that the center moves away, backward. It also loses substance. It still has depth and some layering but it is like a somewhat compressed sandwich in the center. It will not be in line with the sides' frontal edges. In many cases, whatever sound projects directly behind, outside the room, loses definition in comparison to having the TV in place.
      
      In addition, with no TV, the back of the soundstage is lowered to, more often, be at the same level as all else forward. With the TV in, the soundstage tends to progressively raise as it gets deeper. Not always, just more often. Anyway, I grew up having access to the upper deck of a concert hall, mostly during rehearsals. The progressive raise towards the back of soundstage is closer to that experience. That higher level also enhanced the ability to perceive locations on the stage. Which is probably why I am so pleased with the imaging I get.
      
      A surprising, VERY SURPRISING thing when I first removed TV years ago: from "side-to-side", the elements on the soundstage remained in very much the same place (as in "spread"). This was totally unexpected. I have test music selections that are very specific as to side-to-side location and I could not believe that they all showed virtually the same phenomena, TV or not. Thus, I cannot expect other people to believe it easily.
      
      In any event, I ended my original post with this line: "If anyone is interested in testing in this manner, let me know and I'll add details on how to further optimize that test for a particular room/setup."
      
      This was because the draft became far too long. So, I left the option open (planning to do a final posting with a few examples). I was including a few key things. One of them is related to some of what you just said:
      -- begin paste
      3. The equipment and TV have to be between the Maggies, with the frontal plane of TV or gypsum (mock-up) flush with or slightly recessed from the Maggies'plane, not well behind and never forward.
      -- One can adjust a bit by having the frontal plane of the TV/rack somewhat behind the plane of the Maggies' center. Frontal center imaging will move away from you but it may just be fine. Sound quality suffers by degrees as one approaches a certain point backward but, frankly, that point will be up to your perceptions. In any event, the angle of toe-in is related; you can experiment. Overall, with "tweeter-in" you have less wiggle room than with "tweeter-out". Since I use tweeter-in, I have less leeway.
      -- The most important point is that the Maggies should not "see" the back of the TV or mock up. (This may not be practical if using MMGs that are slanted to any of the factory angles. You can always try; it did not work for me but there are lots of variables).
      ---end paste
      
      There is more, quite more items of detail, I just need to clean it up and perhaps illustrate a little. Still, in the end, this is not a scientific endeavor, just a practical approach to provide options. The basics don't need rocket science. Even as the details do count to maximize, I've seen enough cases where, as imperfectly as done, it was way better than it was before.
      - RE: Simulating impact of TV in middle (primarily, size change) - Satie 01:37:58 04/25/12 (25)
        
        In Reply to: RE: Simulating impact of TV in middle (primarily, size change) posted by JBen on April 24, 2012 at 18:40:24
        
        Ah..
        
        Same exact observation of the receding center soundstage with the HK/Limage setup with the front of the rack exposed as your observation without the TV. Since I have not tried to arrange things in the equidistant arc setup in any other way but with the null aimed at the rack front I don't know what would come out in my equivalent of "without the TV". It allways seemed a better idea to keep the speaker output from bouncing off the rack front so I just avoided setups where that would happen.
        
        In one of the "near Rooze" setups I did recently I had not managed to get the wall bounce spot to the right place without the back of the speaker "showing" so I put a board of styrofoam to block direct radiation from the back of the speaker from reaching me. It had a similar effect to what you describe going from "no TV" to "TV in correct place". I also get that raised back end of the soundstage when things are right.
        
        So I think we have the right analysis of what is happening and can sum it up with a simple statement "reflections from the center of the front wall (or TV, or equipment rack) are destructive of imaging in the center of the soundstage. This is because they are early reflections and are not psycoacoustically separable from the direct radiation."
        
        RE: Simulating impact of TV in middle (primarily, size change) - MG-bert 16:25:48 05/30/12 (0)
        
        In Reply to: RE: Simulating impact of TV in middle (primarily, size change) posted by Satie on April 25, 2012 at 01:37:58
        
        @Satie:
        
        When I tried a Rooze setup in my acoustics lab (aka the shed) I loved the imaging but hated the frequency imbalance which I think is due to comb filtering. With the success of my First Reflection Traps, it occurs to me that they can be modified to address the center reflection in a Rooze. Of course, I'll have to rename them Second Reflection Traps, since the first reflection is necessary. Another experiment to add to the list...
        
        MG-bert
        
        RE: Simulating impact of TV in middle (primarily, size change) - josh358 14:48:37 04/25/12 (22)
        
        In Reply to: RE: Simulating impact of TV in middle (primarily, size change) posted by Satie on April 25, 2012 at 01:37:58
        
        We may not want to admit it, but room reflections are a kind of artificial reverb, and act according to the same rules you use when you program a reverb unit in the studio. The delay of a first reflection corresponds to predelay on a reverb, and is one of the key factors the brain uses to determine the size of an acoustical space. So if the front wall first reflection is suppressed, the sound will tend to move forward. That, I think, is what's happening in JBen's case. The monitor is in the dipole null, so there aren't any short-term reflections off the front of it. But it blocks the front wall first reflections down to the frequency at which wavelength becomes comparable to the TV size. (There will be some diffraction around the edges of the TV in the transitional zone, which can in theory be minimized by curving the edges.)
        
        I think the U-shape to which JBen refers is probably caused by corner reflections. His monitor evens out the apparent depth of the acoustical space.
        
        I've noticed with my own system that the image depth seems to follow the contours of what's behind it. It's almost like a sonar image. It's behind the wall, in what I take is a compromise between the wall first reflection and the first reflection (or artificial reverb predelay) on the recording. I'm not really sure why this should be so, since we're hearing first reflections essentially from one part of the wall, but the brain can apparently glean enough information from the reflections to form a fairly detailed impression of the acoustical space. (I don't think it's my vision interfering, since it doesn't go away when I close my eyes and others have reported the same effect in my setup without being prompted.)
        
        RE: Simulating impact of TV in middle (primarily, size change) - Satie 23:38:27 04/25/12 (3)
        
        In Reply to: RE: Simulating impact of TV in middle (primarily, size change) posted by josh358 on April 25, 2012 at 14:48:37
        
        I don't think it is the corners at all. The transition from U shape to more uniform flat front is accompanied by a transition in FR and absolute HF SPL. HF reaching the seat is higher with absorption on the front of the rack.
        
        I think the issue is cancellation of some output at random high frequencies that vary according to the phase of the reflections. Most of the front wall reflections at the center have too flat an angle of incidence and reflect to the sidewalls, so the portion that arrives at your seat is from the edges of the center region. If the rack is close to the null and is densely populated then it will block the front wall reflections without adding any of its own.
        
        When I put the absorbent "sideburns" on the rack, I found a gradual reduction in weird effects and some increase in HF volume. Pulling the "sideburns" to jut forward about 10" in front of the rack gave the best balance of backstage detail and did not overly emphasize HF as did blocking the entire front of the rack. I think that is because of the short reflections from the center of the rack - which geometry dictates would shoot to the far ear and beyond by a bit - still come through with the "sideburns" but not with the full blocking of the front.
        
        With the HK/Limage setup the front of my rack is illuminated heavily. .
        
        RE: Simulating impact of TV in middle (primarily, size change) - josh358 05:28:58 04/26/12 (2)
        
        In Reply to: RE: Simulating impact of TV in middle (primarily, size change) posted by Satie on April 25, 2012 at 23:38:27
        
        "I think the issue is cancellation of some output at random high frequencies that vary according to the phase of the reflections. Most of the front wall reflections at the center have too flat an angle of incidence and reflect to the sidewalls, so the portion that arrives at your seat is from the edges of the center region. If the rack is close to the null and is densely populated then it will block the front wall reflections without adding any of its own."
        
        I think what you get from a corner that causes a "U" shape is a second reflection with a very short predelay -- dual bounce from the front wall to the sidewall to you. Of course, this is dependent on the geometry of a particular installation. But the predelay can be very short, depending on the room -- shorter than the main first reflections from the center of the front wall, so short enough to bend the acoustical space. This is just a guess, I haven't verified it. But I noticed for example in my room that when I face the fireplace wall, I get a much deeper soundstage on the right, where it opens into the hall, and a bit of a wrap-around effect on the left, where there's a corner. And when I reverse myself and face the shoebox side of the same room, I get a more typical wrap-around effect on both sides.
        
        I think the selective comb filter cancellation of some frequencies to which you refer is an important part of the means by which we gauge delay. If you take a single, unsmoothed mic measurement in a real room, the comb filtering is horrific. And yet we don't much hear it. It's removed from timbre by our perceptual filters, and instead, the brain apparently uses it to measure delay. For that reason, comb filtering of early reflections is essentially equivalent to predelay. In apes, the pinnae also have comb filtering with characteristic filter spectra that we use to judge spatial location. And somehow the neural net manages to make sense out of that filtration, different for each ear, and the combing from the reflections, and the IID's and ITD's, to get a sense of location and space, and to recover something very like the anechoic timbre of the sound.
        
        Which front wall reflections make it to your ear is going to be dependent on frequency, you transition from wave mechanics to ray tracing. Just like in a speaker. So there are frequencies at which the entire wall contributes, and frequencies at which the wall acts more like a mirror. In practice, I find that objects in the front that are significantly above or below ear level don't seem to have much of an effect on the sound, I think that's in the region of cancellation at high frequencies and at low frequencies the wave is just going to diffract around the object, it might as well not be there. When I was experimenting with my fireplace, I tried putting plexiglass in front of it to block up the opening, and while I could hear it, it was a minor effect.
        
        I think the distance of the speakers from your rack probably makes a difference as well because of geometric ray tracing.
        
        RE: Simulating impact of TV in middle (primarily, size change) - Satie 19:41:06 04/26/12 (1)
        
        In Reply to: RE: Simulating impact of TV in middle (primarily, size change) posted by josh358 on April 26, 2012 at 05:28:58
        
        "I think what you get from a corner that causes a "U" shape is a second reflection with a very short predelay -- dual bounce from the front wall to the sidewall to you. Of course, this is dependent on the geometry of a particular installation. But the predelay can be very short, depending on the room -- shorter than the main first reflections from the center of the front wall, so short enough to bend the acoustical space. This is just a guess, I haven't verified it. But I noticed for example in my room that when I face the fireplace wall, I get a much deeper soundstage on the right, where it opens into the hall, and a bit of a wrap-around effect on the left, where there's a corner. And when I reverse myself and face the shoebox side of the same room, I get a more typical wrap-around effect on both sides. "
        That is similar to my observations and is why I used the span of my room so that the Tympani had little room left for anything to sneak around the sidewalls. Just a 1' vertical slot in my normal Equidistant setup. That gives you good (not excellent) depth and a flat fronted soundstage so long as the null is aimed at the front of the rack. The mid/tweeter is aimed at the bookcases, and is hopefully dispersed that way. Thus the early reflections are somewhat diffused and partially absorbed. The double bounced reflections only come out the slot and those can't be short, they would be 15' and up.
        Further, in the ED setup, the bounce of mids off the sidewalls from the front output is more than 10' longer in path than the direct radiation, and the bounceoff the bass panels is a very shallow angle and hits the sidewalls behind the seat.
        The HK setup is shown in the pic in the light color as the panels in the middle of the sidewalls.
        
        Edits: 04/26/12
        
        RE: Simulating impact of TV in middle (primarily, size change) - josh358 18:53:33 04/27/12 (0)
        
        In Reply to: RE: Simulating impact of TV in middle (primarily, size change) posted by Satie on April 26, 2012 at 19:41:06
        
        Have you tried something similar to the HK setup with the panels brought back into the time aligned configuration you use when they're in the front of the room? In my room, the MMG's sound better when they're brought forward in the room as they are in the HK arrangement, though pushing them off to the side gives me too much of a midbass boost. But while the MMG's image nicely when they're parallel to the front wall, I find that it dulls transients too much, so I end up with them toed in, listening on axis. Of course, the IV's tweeter doesn't beam in the highs to the extent that the broader MMG tweeters do.
        
        RE: Simulating impact of TV in middle (primarily, size change) - JBen 16:55:02 04/25/12 (17)
        
        In Reply to: RE: Simulating impact of TV in middle (primarily, size change) posted by josh358 on April 25, 2012 at 14:48:37
        
        I've had whale of a long day so I'll probably crash down as I write and not wake up until tomorrow...which will another long one.
        On the difraction around the TV, I am sure there is some, there has to be. I have not caught any significant impact on the sound yet, that could not also be caused by the materials. This is when I've compared various materials at the edges of TV. I tried cloth of variuos kinds, curved wood, sharper edged wood stick, a frame made of 1/2" pipe. The most significant, and detrimental, change was using A/C pipe insulation, the surrond foam type. Where things really change is when one softens the edges of the Maggies. Dynamic impact suffers the most.
        The U image I have not figured out yet what causes it. Even with nothing in the middle, at home, it is not as bad as I've heard elsewhere. The effort to remove/relocate everything in the middle for a day took almost 2 days and left me with a backache. Then it was a bit anticlimatic. "Oh, ok, so I like it even less, but hell I knew that!" A friend who helped me said "that's why I don't like my partner's Martin Logans". He was right about that; but those poor MLs were not well set up in any way, shape or fashion (a dealer's job for someone who was looking for "style" first).
        
        I don't think your vision is interfering, either. The brain does make a lot of compensation, and interpretation. On top of that, the Maggies give it a lot to chew on. I usually warn that the Maggies are most observant of what behind them. (They really want symmetry back there, which is hard to do in our typical rooms.) What I mention less often, for being less critical: they also "see" the rest of the room in front of them. If my wife allowed it, I would center the sofa. Ten feet away from them and they still react to its position by slight shifting imaging balance.
        To the brain, it means that some recordings will feel short of space on the right side, vs the left. If you see one of my room drawings you may notice slightly more soundstage to the left side. The fix is moving the sofa. The poor man's remedy it to "erase" the offending segment with sheets of polyfiber, because he can't afford a divorce LOL!
        
        Edits: 04/25/12
        
        RE: Simulating impact of TV in middle (primarily, size change) - josh358 18:58:04 04/25/12 (16)
        
        In Reply to: RE: Simulating impact of TV in middle (primarily, size change) posted by JBen on April 25, 2012 at 16:55:02
        
        Wendell likes to listen in the dark, to avoid vision from interfering with the imaging. He told me that it makes a difference whether he listens in a dark room, or with his eyes closed! Which makes sense when you consider that our brains integrate every sensory input.
        
        I think several things can cause the "U" image effect. But I'm not sure what they all are. With Maggies, though, I usually find that it's the corners/side walls, at least it doesn't seem to happen if I put them along a long wall. When I listen facing my fireplace, I get a great sense of depth on the right, where the long hall is, but on the left, where there's a corner, the sound tends to wrap around -- not terrible since it's way off to the side, but I do hear it. When I face the other way in the room, so I'm facing a plain wall with walls on either side (plus windows but I flush them out with plexiglass and a narrow beam), the image is much better but it does wrap some at the sides.
        
        Wish I had the luxury to worry about what's behind, but in that room, I'm pretty much sitting against a surface. Eventually, I'll have to put some absorption behind my head.
        
        RE: Simulating impact of TV in middle (primarily, size change) - JBen 17:58:22 04/26/12 (11)
        
        In Reply to: RE: Simulating impact of TV in middle (primarily, size change) posted by josh358 on April 25, 2012 at 18:58:04
        
        Earlier today I forgot to reply to this particualar post.
        I had originally planned to spend last evening trying to configure as similar a situation to yours as I could. That way I could, perhaps, figure out something to help with the challenge. It was a good thing that I was too tired to do it. The reason is that I am a moron by nature.
        I thought that I had no real way to emulate that open hallway of yours, other than by heavy damping. BUT OF COURSE I DO!
        All I have to do is think in reverse. The left MMG has a door right next to it. And guess what? Leaving it open rolls out additional imaging impression on that side, like you seem to perceive on the right side. I normally close it for listening because I have no matching one on the right side. Things get unbalanced a little if I do. I already have a slight bias in that direction due to the sofa.
        Which, suddenly, brings up a possibilty. Nowadays, I have far more absorption material at hand than when I tried to balance for the door with damping on the right side. Hmmm, I may be a beneficiary of the excersise, as well. I hope that I get Saturday "free" to play with my toys.
        Anyway, on Wendell's observation, I also agree. Closing eyes is no good. More with SACD (the TV is off) than with Red Book via PC, I tend to dim the room. Imaging is more enjoyable because the eyes have less impediment to refocus as told by the ears. They can't focus on anything when closed, I guess. With the extra stereo imaging that some SACDs display, the experience gets a really nice boost.
        
        Edits: 04/26/12
        
        RE: Simulating impact of TV in middle (primarily, size change) - josh358 19:01:31 04/27/12 (10)
        
        In Reply to: RE: Simulating impact of TV in middle (primarily, size change) posted by JBen on April 26, 2012 at 17:58:22
        
        It works totally differently if you do it on the left than if you do it on the right. :-)
        
        Seriously, I wish I knew how to bottle that extra space and apply it to my walls, but if you just absorb the reflected sound I think you'll get less depth than you'd get with the door. As far as I can tell, we're using artificial reverb to create that sense of depth. There's reverb on the record, and you might think that if you eliminated the room reflections entirely it would create a space the size of the original recording venue. But in practice, if you put a pair of dipoles outside, that doesn't happen, the depth shrivels up. My best guess as to why this happens is that the ear doesn't interpret reflections as depth cues if they come from the same direction as the loudspeaker. They have to be IIRC 10 degrees separated. So to get good depth with two-channel stereo, you have to have a delayed reflection coming from another angle. You might have more luck with diffusion.
        
        RE: Simulating impact of TV in middle (primarily, size change) - JBen 20:46:34 04/27/12 (9)
        
        In Reply to: RE: Simulating impact of TV in middle (primarily, size change) posted by josh358 on April 27, 2012 at 19:01:31
        
        To tell you the truth, it did not work the first time I tried, very long ago. Two things are different now. (And then, there is an observation that gives hope.)
        
        One is that the objective is not the same. In those days I was merely checking out solutions for the right side "problem". I had resisted the obvious, that I had to create a corner truncation to match the structural one on the left. I kept that door, which is next to the MMG closed; it was not the issue. Now, I would do the same but trying to match the spaciousness that the door open on the left side brings about.
        
        The other difference is that I used light material then. I did not have all that much at the time. However, I now have piled up several types of materials that I bought along the years to experiment with. I would have had more had I not given some of it away, the pricey commercial stuff. I did it largely, because not much absorption was not really needed. Burlap, which is really not much absorption, does the trick when I need it.
        
        The hope mentioned earlier is this. With a double layer burlap on the corners that I am now testing, the sides' imaging started behaving in the same direction as the door open effect. Not as pronounced but they mimic some of it. I had forgotten this until you described your experience. It triggered the recollection.
        
        Except, that I really never took it to the next level: that perhaps this experiment on your behalf would allow me to keep the door open. So, let me make a clarification, I say absorption when in reality it will probably be a mix of commonly available household materials. Some to absorb more, and others to diffuse rather than absorb.
        
        RE: Simulating impact of TV in middle (primarily, size change) - josh358 06:38:37 04/28/12 (8)
        
        In Reply to: RE: Simulating impact of TV in middle (primarily, size change) posted by JBen on April 27, 2012 at 20:46:34
        
        If you want to play with diffusion, you can make a good QRD or skyline diffuser out of Home Depot styrofoam. Then it can always be recreated in wood if it has a good effect (I think you'll probably be able to hear a subtle sonic signature from the styro -- though maybe not, since it's diffusing the sound).
        
        I was just upstairs looking at my listening room. What hit me again (it's always more obvious when you're in the room than when you're thinking about it or looking at a drawing) was that the best course would be a couple of bookcases with transparent doors to flush the wall out to the front of the fireplace. Transparent to keep the room from getting too claustro. I'm tempted to give up the closet (really don't want to knock a new hole in the wall, now that the renovations are done -- of course I've already thought of a million other things I wish I'd done too). The only thing is, I set up the closet to house noisy equipment like the computer. I could put the computer back in my home office but the cable conduit I ran goes into the closet, so I'd still have to get there if I changed everything.
        
        RE: Simulating impact of TV in middle (primarily, size change) - JBen 07:14:36 04/28/12 (7)
        
        In Reply to: RE: Simulating impact of TV in middle (primarily, size change) posted by josh358 on April 28, 2012 at 06:38:37
        
        It will rain heavily; that means that the other plans had to be set aside. So, your project is on. Right now I am trying to solve a minor issue while at the same time I also plan for the test. I only have 3 hours, which is a bit limiting but perhaps I can continue on Sunday.
        At this point, I think I will:
        - Listen/measure at standard imaging settings
        - Listen/measure at standard imaging settings plus door on MMG side open
        - Listen/measure as above while testing various right wall combos
        - Listen/measure as the above but with simulated chimney hole of sorts, LOL.
        I hate styro's effect on sound here but I may have to cut some of what I still have in the storage to scale the chimney hole. How large is it? I can still aprox, based on your pix and relative to my 12' wide room... yours being 13'. Given so many other variables, it may not be critical. It's a bit of a stretch anyway but then again, who knows what it may still show.
        
        Edits: 04/28/12 04/28/12
        
        RE: Simulating impact of TV in middle (primarily, size change) - josh358 08:34:08 04/28/12 (6)
        
        In Reply to: RE: Simulating impact of TV in middle (primarily, size change) posted by JBen on April 28, 2012 at 07:14:36
        
        I just measured, the fireplace opening is 34" x 26". I did try putting a sheet of plexiglass in front of it when I was experimenting, and while the difference was audible, it didn't seem to have much of an effect on the main problem I was having in the room, that it was bunching up at the mantle.
        
        As far as I can tell, the sense of depth depends on the contours of whatever is on the wall. Sort of like sonar. I'm not entirely sure why this should be the case, since the first reflection is just from one part of the wall. I guess we can interpret the later reverberation, but man, the amount of brain power required to do that is mind boggling, since you have to take about a zillion things into account.
        
        RE: Simulating impact of TV in middle (primarily, size change) - JBen 21:56:30 04/29/12 (1)
        
        In Reply to: RE: Simulating impact of TV in middle (primarily, size change) posted by josh358 on April 28, 2012 at 08:34:08
        
        Gruesomely long afternoon into late evening. I did sort of an about face. Tore apart the room and changed it to have bare walls behind MMGs, like your room. The covered corners were never needed for good imaging here. I tried more combinations in one day than I remember ever doing. It kept raining but I took advantage of pauses to measure.
        Summary (remember that this is still, largely, relative to my room/setup):
        1. On balancing for your hallway (the left door open, in my case)
        A. Today, the door open (with no counteraction on the other side)yielded a change in L/R balance that could easily be missed by many! With bare walls behind, the image behaviors that I describe in my previous post for "the door open next to the left MMG" are much less severe. The previous post was about what happened yesterday, when I still had the corners covered with burlap. Today I remembered that you have no damping in there, that's why I had to break things apart here and make them bare. The difference is remarkable, IN THIS CONTEXT.
        B. Ironically, after much swapping materials back and forth, it was absorption that really did the trick. A rather thin layer of it in a similar shape to the door but flat on the wall, on the opposite side.
        C. In this manner, balanced imaging was achieved that essentially matched my standard imaging settings. Other sound characteristics could be called equal or better than I get on standard imaging settings. I could not compare any of this in the "enhanced imagings settings". In any event, never did I feel I was getting a "flawed delivery", just slightly different.
        D. This difference in behaviour mentioned in "A" was a major revelation to me and has implications for my own consideration. Somehow, I hit on a combo that I had never tried before. This, despite the fact that I had done somthing like "B" before.
        2. Completing the HOLE story. (the hole plus the treatment above)
        A. The smallest "fireplace hole" had to be 33x28. However, this hole could not cause a major problem. Neither could any larger size to over 33x60. These all cause a loss of bass but still leaves more bass than the average MMG.
        B. When the hole was reduced under 33x37, no major imaging artifacts ensued. Somewhat different sound, yes, but in the "quite acceptable" and still delightful range.
        I can't say that the "fixing agent" agent was the TV/rack. I am pretty sure that it is the larger part of the reason it all worked here, even if I can't afford to remove it all to prove it. Also, these truncated corners may have played a role. The good thing is that you can try with your MMGs first and see where it leads.
        More to follow but it may take a day or two. I'll be too busy but I have to find time to draw stuff. Also, the charts are unavailable for now. I had to isolate that PC totally from the network and can't access them just now. In the meantime. the room, as drawn in the link below, has changed little. The positions are the same, minus "fireplace hole" behind the center rack and minus absorption in the shape of the door opposite the one on the left.
        
        Sorry for typos, I am entering "zombie mode" this late in the night but wanted to provide some info.
        http://www.nicx.com/ClientSets/JBen/JBen-MMG%20Room%20early% (Open in New Window)
        
        Edits: 04/29/12
        
        RE: Simulating impact of TV in middle (primarily, size change) - josh358 07:47:23 04/30/12 (0)
        
        In Reply to: RE: Simulating impact of TV in middle (primarily, size change) posted by JBen on April 29, 2012 at 21:56:30
        
        Ineresting. Truth is, I hadn't given much thought to balancing the left and right parts of the soundstage because I was having so much trouble with the mantle! But I did wonder if I could do something about the corner on the left. I've never liked what corners do to dipole sound and I've been wondering whether those truncated corners you have would improve things, or whether it would make more sense to use a bit of absorption or diffusion on the corner bounce.
        
        I think I'm past the window on MMG experimentation, because while they're a lot easier to move than the IVa's I'm too eager to hear the IVa's! Listening room is now ready for them but I have to cut some sheet vinyl flooring that I'm putting in another room so that's currently occupying the floor. I think I'll be cutting it today, if I can manage to weight down the wrinkles it got while it was rolled up. Then I'm going to start putting up the full account of the Magnepan trip and once that's done, build my HTPC and test the IVa's. Not sure what direction they'll be in, I'm going to have to try it every which way to see what works. Which should keep me happy for the next few months. :-)
        
        I think I'll try them with my chair in the fireplace first to get a baseline, because I know that works best in this room. Then see if I can get the same effect facing the fireplace or, if necessary, facing across it, the way I used to. I'll probably get some big pieces of styrofoam to experiment with, e.g., to see if my bookshelf idea would work. Also to see what I could do with some QRD diffusers on either side of the fireplace.
        
        I don't want to get too crazy about it, too, since I'm planning to move in the not-too-distant future and my new place will have only two requirements: high speed Internet, and a bigger listening room!
        
        RE: Simulating impact of TV in middle (primarily, size change) - JBen 13:38:49 04/29/12 (3)
        
        In Reply to: RE: Simulating impact of TV in middle (primarily, size change) posted by josh358 on April 28, 2012 at 08:34:08
        
        Hi Josh,
        
        Nothing went the way I wanted on Saturday. It rained heavily , it thundered, the airport 30 miles away changed the flight pattern to cope ... and to keep our ambient noise levels too high.
        
        Despite this, I got a few things out of the way. Among them, I retested with the door open at the side of the left MMG. Upon listening, this confirmed that, aside from the delightful extra imaging, it causes a significant imaging balance shift. No surprise, it always did. However, this time I did a frequency sweep. The sweep, as can often be the case, did not reveal a major shift in frequency. Also, this time around I was able to pin down a couple of music examples where the imaging phenomena can be easily defined. It will serve to compare with what will happen as the tests continue. So far, so good.
        
        Then I was briefly able to open the back door behind the MMGs (not yet a "chimney simulation"), listen and then measure. That open door caused a change in sound character that could not be called "bad" in the short period I was able to listen. Surprisingly, soundstage imaging hardly changed though it obviously became more affected in the center. Still, altogether it was the same height, width and layering as normal. Frequency response DID measure much more different than with the door next to the MMGs open, largely below 300hz. Yet, the music that I was able to play in this brief period did not appear to suffer much for it.
        
        Next, and barely beating the arriving wave of heavy rain, I was able to listen with both doors open. The main difference heard was that AGAIN, the door on the left side shifts everything. Your hallway has to have a similar effect at your end. It may not be a perfect comparison but at least I know that if this gets "somewhat cured" in testing here, there's more hope for you.
        
        The next round of attempts begins shortly.
        
        RE: Simulating impact of TV in middle (primarily, size change) - josh358 08:03:14 04/30/12 (2)
        
        In Reply to: RE: Simulating impact of TV in middle (primarily, size change) posted by JBen on April 29, 2012 at 13:38:49
        
        I haven't really noticed any image shift with the open hallway on my right. I'm not quite sure why this is but I'd guess it's because the speakers are far enough away from the walls (at least 5') so that the reflections are all out of the image shift window, which is pretty much within the first 10 ms. The only exception to that would be the sidewall first reflections and in my room, those are way behind the opening.
        
        RE: Simulating impact of TV in middle (primarily, size change) - JBen 17:12:30 04/30/12 (1)
        
        In Reply to: RE: Simulating impact of TV in middle (primarily, size change) posted by josh358 on April 30, 2012 at 08:03:14
        
        Still trying to get to start putting things together.
        
        In the meantime, after reading Mart's first impressions on his new 20.7, I am thinking radical thoughts. Like buying a pair of 20.7s and moving to live at the nearby park. Right now I am trying to figure out how many solar panels I can tent around them and still have power to move them. Cooking is optional...
        
        ...Sterno, anyone?
        
        Anyway, poorish for now... There was some shift of imaging elements here with the door open and the corners bare. It was just not nearly as much as when I had the corner walls covered. No one would know unless familiar with the the normal positionings on the soundstage.
        
        Then, adding the light absorption in the shape of the door, but directly on the other side, corrected the minor shifts. That was uncanny.
        
        One other notable thing. Normally, I can turn my head to "look at" the imaging presented from the outer sides of the MMGs, and from any place behind the plane of the MMGs, for that matter. Soundstage elements that are perceived behind this plane or, at times, slightly forward of it, can be "looked at" by turning the head to them. Neither walls, MMGs, TV or rack matter...but being behind that plane does. It is a boundary of sorts for solidity and stability.
        
        The rest of the room, with some recordings, can have perceived surround & directionality from the wall sides next to you, behind you and even over you. However, it is "ghost" imaging. You only perceive it while looking at the system straight ahead. It vanishes the minute you turn your head to look at it.
        
        Well, I said all this because the segment of the imaging that appears so engagingly improved into the room when one opens the door, cannot be looked at. It vanishes when you look at it, as if it were on my side of the boundary. Yet, it is behind that plane. It breaks the "rules"!
        
        The same thing happened with imaging coming from the absorption "door" on the opposite side, when present.
        
        I have to revisit this for my own benefit later.
        
        RE: Simulating impact of TV in middle (primarily, size change) - josh358 17:35:04 04/30/12 (0)
        
        In Reply to: RE: Simulating impact of TV in middle (primarily, size change) posted by JBen on April 30, 2012 at 17:12:30
        
        That's interesting. I don't remember noticing that when I was listening, but I don't recall turning my head to look at anything -- not intentionally, anyway.
        There's gotta be a way we can bottle 20.7's for people like us with small rooms! I mean, if the Mini Maggies bottle 3.7's for people with desks . . .
        It's the bass that's the issue, no reason you couldn't make a tall, narrow true ribbon tweeter line source for the mids and highs. I mean, you could always use a sub, but it just doesn't sound the same. Maybe a dipole sub like Davey made . . . wouldn't be a line source, but I imagine it would blend better than a box.
        
        Edits: 04/30/12
        
        RE: Simulating impact of TV in middle (primarily, size change) - JBen 05:59:45 04/26/12 (3)
        
        In Reply to: RE: Simulating impact of TV in middle (primarily, size change) posted by josh358 on April 25, 2012 at 18:58:04
        
        Josh & Satie,
        
        I was reading Satie's post and remembering about related observations on the U effect. I am not sure about the corners causing it, either, at least, not alone. Bear in mind that I never made a major point of studying the U, more like observing when it happened. However, it did eventually, become part of the justification for me to see what happened when I removed everything in the center, at home, for one day. I never got a major U at home that day. The worst of the center stage depression still left some depth in the middle where layering, even if compressed, could be perceived. Not my cup of tea but at least it showed some floating center elements, if a bit too ethereal.
        
        Contrast this with the first time I conciously heard the U with planars, which was on my first exposure to 3.6s at the dealer. I've mentioned the incident, long ago, including that we cured the problem by dragging in a cart with TV & equipment. But what we then cured was a rather severe U. The center was devoid of depth and was just wall splatter.
        
        The dealer's room corners were deliberately "truncated" with light cloth absorption. Mine are truncated, one of them is structural, the other I made to match. Covered or not, at home they were not able to cause as severe a U.
        
        Things that had stuck in my mind from that first 3.6 day were how "too damped" the room seemed and, particularly, the heavier cloth art they had at the center back. So, at home, during the day with no stuff in the center, I tried it by hanging various heavy cloths behind, in the same relative area. It made things worse but not to the degree that I expected. That left me wondering, was it the overall room damping at the dealer? Perhaps the room height? A combination of things?
        
        Well, the next bad case of the U that I heard was when I was in Tampa one day for business. I had some free time, kicked up Craigslist. Pair of LFT-8 locally on sale. I had heard the 8b a few times earlier, but not yet the older version. I called, he was moving but we agreed to an audition. The gent was a British national attached to MacDill AFB, contractor duty. Remarkably, centuries earlier, as an AF ROTC cadet in training at MacDill, I had been a guest of an exchange officer from the RAF. Back then, he and I had two pleasant evenings listening to his rather nice system.
        
        The coincidence helped. He was more willing to trust the stranger, help along and also fill in with details. The room was a bit of a mess and we decided to move some boxes to the back. This left the room sides clear. The wall fixtures had been packed for the move, bare walls. The decent audio gear on the floor to one side had been warmed up and ready before I arrived. We sat to listen, went through a few of his CDs. The U promptly reared its ugly face. We both agreed.
        
        He said he did not have it in the past, when the equipment rack was in the middle and there were fixture on the walls. Since the rack was packed for the move, we stacked a couple of boxes in there. The U was gone and soundstage imaging was more even. The overall sound and imaging were still not great but, given the naked walls, it was to be expected.
        
        So, I looked around more closely. Carpeted, like all else (dealer, my home and others). The room was taller than mine, about 9'+, which is closer to our dealer's room. In all, 13x22x...9nish, the realtor specs did not say. Mine is 12x25x8, though irregular at the back. This was a clean rectangle, like our dealer's, but with typical corners. He said he did use plants of some sort at the corners behind the LFTs, in normal times.
        
        All of this, kind of threw my hyphothesis off. Ok, then, I thought, maybe it did have to do with height. Or maybe with having irregularity at the back of a room. Or, maybe something else I missed. I say all of this so that we can all keep observing.
        
        BTW, at the dealer, they took off the heavy damping center art from all Maggie rooms at some point later. The corner treatment remains. In recent years they have also tended to show Maggies with the equipment rack in the middle, just behind the plane, not too backwards or close to the wall. This is how the 3.7s and 1.7s have been set up each time I've been there in recent times. (For box speakers, they appear to keep the rack at the room sides.) They also display the Mini's on a desk with, by default, a laptop PC open to normal screen angles.
        
        RE: Simulating impact of TV in middle (primarily, size change) - Satie 01:28:43 04/27/12 (1)
        
        In Reply to: RE: Simulating impact of TV in middle (primarily, size change) posted by JBen on April 26, 2012 at 05:59:45
        
        I had to experiment with what affects the center image because of the truely weird effects that I had with the hk/Limage setup (see light blue colored speaker marker on the drawing). I did move the Vandersteens - now functioning as absorbers into various spots around the corners with no effect on the center. But when I covered the front of the rack with an absorber the center image of the piano in piano concertos stopped being ethereal and weak and became more like the image I am used to. The backstage images became much more specific and far more solid.
        
        The monstrous close miked piano delivered into your lap in the HK/Limage setup without absorbing the rack reflections went back to being a piano in the proper place and in another recording the orchestra portion behind the central piano was improved a great deal. The incredible stretching of the front of the orchestra without the absorbers was truncated a little with them, but the overall soundstage other than the center was unchanged no matter what I did to repair the center image.
        
        Right now, I am still working on the basic positioning of the speakers for the Rooze arrangement. But doing that with the nearly 5 foot wide Tympani is really not an easy thing.
        Post with drawing (Open in New Window)
        
        RE: Simulating impact of TV in middle (primarily, size change) - josh358 19:27:09 04/27/12 (0)
        
        In Reply to: RE: Simulating impact of TV in middle (primarily, size change) posted by Satie on April 27, 2012 at 01:28:43
        
        I can readily believe that, after my unfortunate experience with the fireplace.
        
        RE: Simulating impact of TV in middle (primarily, size change) - josh358 06:49:53 04/26/12 (0)
        
        In Reply to: RE: Simulating impact of TV in middle (primarily, size change) posted by JBen on April 26, 2012 at 05:59:45
        
        I think that the U effect can be caused by more than one thing. I think there may also be more than one kind of U effect. There's one kind in which the sound seems to begin at the speakers, then arch back in a U. And another in which the soundstage sort of wraps around at the sides, but is way beyond the walls. That latter is the one I get in my room when I face away from the fireplace. The former is what I first heard on a friend's KLH-9's years ago. They were well out in a big room and along the long wall (but with a mantle behind them). This may have had something to do with the fact that they were so beamy, or maybe to the fact that they weren't in mirrored pairs, they didn't know to do that back then so both had their tweeters on the same side.
        
        Also, I think I read somewhere once that distortion can cause sound to appear to emanate from a speaker, not sure if that's true. But for me, Maggies always disappear, and as far as I can tell from my limited experience, the sound doesn't wrap if there isn't a nearby corner or sidewall -- though I've been limited in my opportunities to hear them set up that way.
        
        Not sure about height, either. I haven't had much of an opportunity to experiment, most of my Maggie listening has been in two rooms.
        
        The problem I think with general descriptions of rooms is that you don't see the actual geometry. I like this illustration on Linkwitz's site, because it drives home that what we're actually listening to isn't one but a whole bunch of speakers. And the ear uses the delay and angle and relative intensity of those reflected speakers to determine the distance of the mirror, and so the size of the room. So what we hear is going to be very dependent upon specifics of geometry. For example, depending on toe-in, you might not hear the reflected speaker at the side at all, because you'll be in the dipole null. You will eventually hear a reflection there, but it will be a second reflection from somewhere else in the room. So there will be a longer delay and the brain will conclude that the wall is farther away, just as it would if you saw the second reflection in the mirror and noticed that the reflected speaker was smaller.
        Room reflections (Open in New Window)
        
        RE: Simulating impact of TV in middle (primarily, size change) - JBen 02:56:33 04/25/12 (0)
        
        In Reply to: RE: Simulating impact of TV in middle (primarily, size change) posted by Satie on April 25, 2012 at 01:37:58
        
        Sounds on the right track to me. I'd probably want to qualify with some observations later but one thing is clear to me so far, whatever the back of the Maggies "see" behind them, they act upon the most actively to. Also, the tweeter's dispersion is quite more ample than I suspected, on these older MMGs. (The Mini's sure are.)
        
        I am working a long day since 2am and I am going to be wreck later on. So, let me include another segment for you to ponder on the matter because I may be off the air for quite a while today.
        
        Bear in mind that it is really raw draft. I think that here I wanted to add the perceived role of the minimum distance mentioned but never got fully there.
        -- begin paste
        4. Generally, as long as one respects the TOP half of the Maggies:
        -- the equipment rack/stand can even span the distance between both Maggies if it is open at the back. This may vary room to room. [(The back opening does need to be partially muffled (see later)]
        -- each side of the TV should not be closer to each Maggie by less than a distance equal to the width of the Maggies. So, in my case, that's 14"+. (Newer MMGs are 15" wide.) {rem to recheck: there is a safety margin of sorts that may relate to "perhaps" the actual radiating area being more improtant to min. distance)
        -- when modded with wider frames or wings, it also matters but I have no clear idea yet to what extent. I did have to add a couple more inches of space on each side to generally compensate for 5.5" in LWingies on each side. Not doing so, affected full soundstage continuity side to side. Since I had no side space to separate the MMGs further, I bought a TV that was less wide...but that's me pretending to be a perfectionist, which I am not.
        -- a wider spread (more distance from the stuff in the middle to the edge of each Maggie) may also work well. Yet, it appears that at a certain point it only improves the center solidity... not necessarily the continuos RECTANGULAR soundstage side to side. The same happens as the center "isle" becomes relatively smaller (like with a narrow equipment rack and, is present, a small flat TV.
        -- HOWEVER, on what I mention in the previous paragraph, stronger power amplifiers (rem: as in power-supply note) seem to be able to somewhat compensate in these cases. In other words, to an extent, a powerful amp seems to be able to "stitch" stage segments together more seamlessly than weaker ones. It is part of what I, for now, conceptualize a "sustaining the imaging" category of things and it is not just amps that help. It is also why the "basics" included earlier are so important.
        -- end paste
  - RE: Simulating impact of TV in middle (primarily, size change) - JBen 11:44:33 04/23/12 (5)
    Last night I started looking for your old pixes to refresh my mind and relate them to the subject at hand. I struck out, probably because how tired I was. If you can point to them, I'll be able to see what can transpose from my perspective.
    
    As far as I remember, your fireplace would not be an issue as long as it is centered. It needs to be taken into account but it should be relatively easy to manage. This is assuming that we put a "something-in-the-middle" large enough and then condition its rear. I may be able to test for some of this.
    
    One day I left the sliding glass door behind the equipment partially open by accident. The sound changed, of course. I was not really "listening" but noticed 2 things. Imaging stayed symmetrically balanced, though in somewhat different in positions. The other was that the sound did not offend. The ambient noise from outside (crowd in the nearby park) was too loud to really judge SQ.
    
    Last night I thought that I should repeat this when it is more quiet outside, this time by design and while listening. It would annoy my neighbors, so it would have to be brief. I've got to plan for it and probably do it on Wednesday evening. The aim would be to see what I need to do behind the equipment to retain good sound and imaging. To be sure, a fireplace is still reflective, not a "black hole" like the open sliding door would be. I may have to put some reflective stuff outside and also block the top half of the door to get pseudo-fireplace hole.
    
    OTOH, it is that exit to the right that could be a real challenge. But, perhaps I was just not creative enough the previous time. I think I may be able to replicate some of its effect by grabbing every bit of absoption material that I can get and laying it on the right side wall. I am dead meat if my wife catches me. : - ))
    
    In the meantime, over at the other room, keep this in mind. A judicious amount of absoption behind the monitor can do wonders. I mean it like hanging a small towel at the back, not as a block of absoption stuff. It all depends on other variables so it is hard to know without testing. While we tend to think in terms of "killing reflections" it seems to be also a kind of "pattern disruption" or something. I hope it makes sense.
    - RE: Simulating impact of TV in middle (primarily, size change) - josh358 12:37:43 04/23/12 (4)
      The apartment where I had my 1-D's had a row of windows all along the wall, the kind that swing out. So one day I tried putting my speakers in front of them and opening them all up. I didn't know much about dipoles then (they were my first) and I figured the reflected rear wave could only be a problem.
      
      Truth is, I don't remember at this point what it sounded like, but I ended up with my speakers on opposite sides of the mantle. And that worked, so I thought it would here as well, but it was a disaster:
      
      What happens is that the sound bunches up and seems to emanate from the mantle. And no matter where I moved them, it still had that problem. I tried covering the fireplace with a sheet of plexiglas, but that didn't fix it. On the other hand, when I tried sitting in the fireplace and listening to the opposite wall, which just has a couple of windows in it, I got a big, vivid image. Even when I reversed the speakers so I was listening to them from the same side.
      
      The only thing I can think at this point is that to make the mantle side work, I'd have to flush it out on either side. I could make cabinets and then gain some storage space. But there's a closet door on the right side (it was taped up when I took this photo, you can see the blue tape above the right of the speaker), and since I'd need access to it I'd have to move the door to the hall side -- which of course would make quite a mess.
      
      Also, the IVa woofers want to be against a wall when you use them in split configuration, and as you can see, there's an opening on the right. It does no harm to the image, in fact, it makes it bigger on that side, but it would reduce the bass output from the RH speakers and put them out of balance. Ideally, what I'd like is to have the mid-tweeter panels about as far forward as the MMG's are (just past the opening), and the woofers behind them, against the left and (nonexistent) right walls.
      - RE: Simulating impact of TV in middle (primarily, size change) - JBen 19:43:03 04/23/12 (3)
        
        In Reply to: RE: Simulating impact of TV in middle (primarily, size change) posted by josh358 on April 23, 2012 at 12:37:43
        
        Josh, it really is a tough one. I have to take a look at the Ts again, to visualize what you mention against that backdrop. What's the room width? Also, how much does that top portion over the fireplace jut out, where what looks like cabinets are?
        
        RE: Simulating impact of TV in middle (primarily, size change) - josh358 06:48:18 04/24/12 (2)
        
        In Reply to: RE: Simulating impact of TV in middle (primarily, size change) posted by JBen on April 23, 2012 at 19:43:03
        
        The room is about 13' wide, and the cabinet/mantle come forward about a foot.
        The real solution would be to knock down that wall at the right, the original room is actually bigger but they chopped 1/3 of it off to make an extra bedroom. But one of the construction guys told me that wall is now providing structural support for the house . . . don't ask me how, since it doesn't have real studs in it, it's just plaster, lathe, and some boards.
        Here's how I had it before the renovations, I had the speakers firing sideways, across the fireplace. But that's harder to do with the IVa's in split configuration, I'd have to bring the mid/tweeters out to the middle of the fireplace.
        
        With screen slid into viewing position in front of window, you can see why I have to use the IVa's in split configuration rather than with the panels joined together:
        
        (Here's the same part of the room after the renovations -- slight improvement, no?)
        
        Edits: 04/24/12
        
        RE: Simulating impact of TV in middle (primarily, size change) - JBen 00:53:39 04/25/12 (1)
        
        In Reply to: RE: Simulating impact of TV in middle (primarily, size change) posted by josh358 on April 24, 2012 at 06:48:18
        
        Josh, am I looking at the same room from different perspectives? I have a hard time believing so because of the way the old floors line up.
        
        RE: Simulating impact of TV in middle (primarily, size change) - josh358 06:09:28 04/25/12 (0)
        
        In Reply to: RE: Simulating impact of TV in middle (primarily, size change) posted by JBen on April 25, 2012 at 00:53:39
        
        Yep, all the same room, taken at different times. The three photos are all of the same wall -- right hand part, left and center, left, respectively. And the red fireplace on the right in the topmost photo is what I was facing when I took the panorama in the original post.
        
        In the final, post-renovation photo, there are some structural differences in the structure that can be confusing -- old outlet removed from the baseboard and replaced by a new one in the wall, quarter round molding in place along the floor, boxes over the steam pipes at the left and on the ceiling (I thought about putting a motorized screen in the box along the ceiling but then decided to turn everything 90 degrees).

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