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In Reply to: RE: Questions to ponder posted by unclestu on April 21, 2015 at 21:45:29
Uncle Stu,Having cork rather than other materials to hand, I tried a variant that supports your experience. Took a 5' length of cork with an 11" width and hung it down the side facing the sound-stage of each speaker anchored by a pile of tiles on top so that it screens the inside front edge of the tweeter/ mid-range/ with a 2" overhang along the front edge before being anchored at the bottom by the speaker base. The sound-stage, already wide, did not further expand this way but the image focus tightened up appreciably. Your idea of delaying the point at which the sound-waves of each channel conflict in order to minimize the resulting degradation of sound quality is outstanding.
DG
Edits: 04/24/15 04/24/15 04/25/15Follow Ups:
The soundstage width is not affected by the goings on in the center, but it does cut the distortion I mentioned in the middle. The effect is exactly what you hear: a much tighter center focus and much better detail.
Our French audiophile ( Sorry i keep forgetting how to spell his name)
just screwed a couple of woof panels together and reports some success. I like to be able to adjust the angle so you add brackets or even make a small wooden base into the panels from the bottom.
Uncle Stu,
Please advise whether each panel width that works effectively is 12" or 18"?
With many thanks,
DG
The key is simply blocking the line of sight between channels. If your speakers have very little toe in, the skinnier panel width is OK.In most cases, 12 inches is usually enough. Thickness is immaterial, of course, although a little absorbent material on the back is better as it will absorb some of the reflected sound off the back wall. You can simply buy 6 foot by 12 inch shelving and use that.
While your application works, some sound waves will bleed around the barrier and still meet and clash in the center, so the panels are preferred and will even give greater sonic gains.
Lighter panels are easier to move around too, if you have a TV set in the center. You can make a a sort of T shaped base so it becomes very easy to play with the angles, which makes a major sound difference.
Remember the panels must be taller than your tweeter height in order to have a greater sound stage height. Six inches would be great, although I have used 7 foot high panels with great success
Edits: 04/25/15
Stu,
Many thanks for this remarkable tweak and your help.
Found that the best configuration for the channel separators with my Vienna Acoustic Maestro Grands and room layout is at an angle of about 105 degrees 18 inches to the inside front of each speaker as depicted in the attached photograph.
I share your experience of the vertically expanded sound-stage (that happily also makes the widescreen sound behind more authentic) and the enhanced image definition that makes all sounds dense and even the smallest sounds stand out. What's even more important and takes me by surprise is the striking and highly desirable increase in the purity of sound; had always heard improvements of that nature in the past after removing a layer of digital corruption...
As you can see, made my own 12" x 48" channel separators with plywood base, each covered with cork and front-faced with a panel of acrylic P-99 non-glare plastic to reflect the sound waves to the listener. Lot of work but permanent fixtures deserve it.
DG
Hey Ginge, I tried this tweak too, but with 2 covered roxul panels in a V. Immediately heard better imaging, but by the sounds of it, not as dramatic as a reflective surface.
Want another revelation? deaden that back wall.
I know you've heard that before & been resistant to try, but it does look like a dedicated room.
I bought a pack of 5 roxul panels for 40 bucks and some "speaker" cloth for $20. Covered them using a glue gun, they look pretty good. Huge improvements in clarity. Never will go back to a "live" room again.
Is there a window on the left? and do you have any room treatments behind the listener?
PS I'm on board with the toe in. The only times I've liked no toe in has been in large rooms, where the speakers are far from the side walls. Still think toe-in almost always snaps in the imaging.
jhrld,Many thanks for sharing your experience with Roxul boards. Since mine is a sitting room (not dedicated listening room), will first have to overcome resistance to the impact in terms of aesthetics. Suspect that the utility of boards on the back wall behind speakers diminishes substantially after introducing 'channel-separator' panels that block most of the rear inward-leaking sound-waves. Stu's tweak takes work that is amply rewarded by an unexpected and marked improvement in sound purity and image definition.
Yes, there are a pair of 4' x 6' sliding French windows to the listener's left on which there are a set of 4 x 40mm Marigo Audio Black Super Dots @$79.00 per set for a total of $165.00 ($158 + $7 USPS PM); a brilliant acoustical invention of Ron Hedrich to dampen glass at the first reflection point so leaving unrestricted access to both the light and view unlike conventional fabric/ board solutions.
Have you considered soldering a new lead from each driver terminal to an externally mounted cross-over in a maple/ bamboo enclosure to reportedly create a significant improvement in clarity (a tweak slowly ascending my list...)?
DG
Edits: 05/24/15 05/24/15
moving the crossover outboard frees your inductors from the magnetic fields of the speakers and vice versa.
The wooden cabinets further reduce magnetic interaction. While it is not "audiophile" in appearance, the lightest, most porous wood, seems to give the best performance. I was rather surprised when I used balsa ( i had some pieces left over from model work). It had the most open top end compared to the more commonly used woods ( maple, etc.)
On the other hand, taking the experience with instrument makers ( luthiers).walnut/ oak have good bass, rosewood has a great midrange, maple: good top end. I still prefer spruce for an all 'round response. I would assume that the more plain jane woods can be dressed up with a thin inlay or purfling ( you can buy premade purfling from luthier suppliers). Just run a table saw shallow cut close to the edge the width of the purfling.
Of course YMMV and FWIW.
Stu,
Thank you. Forgot about spruce which is the most appealing and finishing off cross-over enclosures with decorative edges to achieve a professional look never even occurred to me...
Incidentally, when making channel-separators again, would make them 15" wide and 60" tall to more effectively block wave-leakage.
DG
DG and stu,
do you think it might be worth a try to cover the back sides of the roxul
panels I'm using for wave leakage with thin wood?
Some frequencies might penetrate the roxul, but are these the frequencies we need to keep separate?
Also, I'm thinking they might be more effective where DG has them, rather than a V in front of the rack. Guess I need to make bases.
jhrlrd,
Channel-separators need a reflective surface facing the sides of the speakers to swiftly redirect the sideways-leaking sound-waves towards the listening position and a base to hold them vertically as you say. In my case each panel is held vertically to the top of a 17.5" plywood circle by four 4" angle brackets. The back side of each panel is intended to absorb/ block sound-waves reflecting back off the back wall behind the speakers; personally used cork but Roxul presumably is effective and plan to test acoustic felt. Be interesting to read Stu's comment re. Roxul...
Test the V-layout against my open format and you may not hear much between them so your final selection may come down to other considerations. Good luck with Stu's excellent tweak!
DG
That's a lot more distance than I would use but then I never have done the set up with as much toe in as you use. Main thing is that it works, plus makes using the remotes a bit easier.....8^)
Stu,
An unobstructed sound-stage is important to those such as myself who want to visualize the orchestra or artists performing in their imagination - something that's quite impossible with the dominance of the central V-channel separators. That's why I started by draping cork over the side of the speakers themselves and graduated after testing to the inner-side location. The three impressive sound benefits are heard equally well using either location so it's a matter of personal preference.
The tow-in reflects a triangular configuration of speakers and listening position each of which are separated by eight feet.
DG
Hmmm...Not sure if I am understanding you correctly. Are you saying with the dividers you are not getting a wider three dimensional soundstage?
That has not been my experience at all. I get a very wide accurate soundstage with great depth. The caveat is that it all depends on the recordings themselves. That can be a major issue. I have long pursued recordings for which the recordings sets ups are known. Mercury, some RCA's, Some Decca's. Audio Quest recordings are also documented and actual pictures of the recording sessions are often published in their liner notes.
For such documented recordings I can hear the microphone positioning, which in my mind, reflects a neutrality in presentation. This of course does not apply to every recording on every label. The more multi miked the recordings, the greater the sonic " confusion" in terms of imaging, particularly with pop recordings.
In the pop world the Phil Spector "Wall of Sound" is a good example. Spector keeps the vocals usually in correct polarity in order to get that sharp central imaging, but then inverts polarity on the background instruments, causing them to sound a bit blurry but very expansive and with a wide soundstage.
Same thing happens with many artists doing duets. The Michael Crawford album has him singing with some great operatic singers (Barbara Bonney).
Bonney has perfect pitch and she doesn't sound quite as good as Crawford because Crawford in in one polarity and she is in another.
Polarity has been the bane of my listening and it literally took me a decade to be able to recognize upon hearing. The vast majority of the CD seem to be inverted for some odd reason. My DDG's and Philips also....Very frustrating until I put polarity switches on my Phono and picked up a DAC with the switch.
YMMV and FWIW
Stu,
This is what I, perhaps mistakenly, understand as the explanation for the dominant benefits:
1. The improvement in solid, detail imaging is caused by the reflection of the sideways-leaking sound waves forward so that they hit the listener's ear instantaneously with direct sound waves with the concentrated force of matched timing.
2. The expansion in sound stage height is attributable to the re-direction of some of the sound waves that leak inwards/sideways off each speaker being heard after reflecting off the top rather than mid-areas of the channel separator.
3. The marked increase in sound purity follows the removal of corrupt turbulence when the sound waves from each speaker are prevented from leaking sideways and meeting centrally before reaching the listener's ears.
You are correct that the whole sound stage is expanded in width but to me it's the least striking of the improvements and not one for which I can offer an explanation. Perhaps you can? As you say, the whole polarity issue is infuriating with CDPs; with servers the software setting is made once per album and then it's no longer an issue.
Hope that more inmates will grab the plywood/ L-joints and build their own panels to enjoy the many benefits of your tweak.
Thank you again.
DG
Even prior to my panels, I had great soundstage width. The panels basically sharpened the imaging within the soundstage and added a great amount of depth. This additional sharpness makes the extreme width information much more audible, in the sense that it is very nicely presented, with greater resolution of fine detail.
Incidentally, I prefer the panels even taller ( I can't in my room as I have low ceilings). You can experiment with placing a short stool under the panels or even placing an open CD case on the top. (I know, I know..... all that work.....). This way certain pieces, particularly choir pieces (thinking Cantate Domino) achieve a truly ethereal quality.
In a way, I guess we are simulating a headphone. Still, I believe the brain beats the sound waves attempting to combine and produce the center image. The brain does a better job at recombining the left-right data. Our mechanical transducers can not simply be made so precise.
Still the interesting thing is the fact that we can actually channel the sound to our advantage, and increase our enjoyment. The thing that freaks me out is that all this information was always in the musical data in the first place...
Not being able to leave well enough alone, I had a very old, tall, three-section room divider that I decided to put to work.
Being aware that the openings allow "leakage," I like it better than the previous room tune-type arrangement.
Stu,Yes, your tweak demonstrates how the brain constructs an internal sound-stage from the sound-waves heard from the speakers and channel-separators. In placing my head in the conventional external sound-stage between/ behind the speakers, the only music left there is above four feet after leaking over the panels from the speakers. There's zero reproduced-sound beneath.
Racks/ other obstructions of convenience against the central back-wall have previously paid a sonic price for disrupting the flow of leaking sound-waves. Now audiophiles can have their central racks, listen to their music free of that disruption and enjoy the other improvements.
DG
Edits: 05/20/15 05/20/15
Hi Dryginger,
WHat you say make me think to a...horn wich keep the sound in it's throat as long as possible...
Aupiho,
Please note that this is an exercise in traffic 're-direction' to prevent the cause of ongoing sound-wave crashes...
DG
20+ years ago I made some pseudo "room tunes," consisting of a frame, cloth and a piece of foil-faced (one side) fiberglass insulation within. I also made bases, but never attached them.
Put them in service as shown in the picture. Marked improvements on most fronts. Since I like the sound as they are, I am in no rush to experiment further.
Many thanks for this idea.
Place the foil side forward for best result.BTW, Looks great !!!
Edits: 04/26/15
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