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RE: setting up a listening room

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David Aiken

In Reply to: RE: setting up a listening room posted by temporarymadness@aol.com on August 10, 2007 at 17:21:17

1) so how far do you sit away from your speakers? are they near-field or midfield?

A bit under 8'. Technically, that's going to be far field, even for 2 way monitors.

2) what do you mean "short wall placement"? does that just mean the shorter walls are to your left and right (when sitting)? or does SWP mean that the desk is just a shorter distance away from the wall? sorry, i just wanna make sure i'm understanding correctly.

Short wall placement is having the short wall behind the speakers. Long wall placement is speakers is having the long wall behind them. Most people do short wall placements. Some of us crazies like long wall placements.

3) can you give me a few quick, easy tips on junk placement and absorption?

Well, a lot depends on what the junk is and whether it absorbs or reflects. Soft things tend to absorb so things like old rolled up carpets may have some absorption value. Hard surfaces tend to reflect. If you've got a lot of hard surfaces, angling them randomly so they don't all have flat surfaces facing in the same direction is best. That way you'll get some scattering of reflections. Keeping absorption close to joins between 2 room surfaces (corners, floor/wall and wall/ceiling junctions), similar to bass traps or at early reflection points are good ideas.

4) what are cheap substitutions for accoustic panels?

Look in the FAQ for Jon Risch's DIY acoustic treatment instructions for reliable DIY approaches. Things that can be found around the house that can be used to some effect are rugs and carpets, old cotton-filled matresses like futons or foam mattresses, several thicknesses of blankets, thick curtains and the like. Books are also useful for absorption. None of them are as good as the proper item, even DIY panels are usually considerably better than any of the substitutes but the substitutes can have a positive effect if used in moderation. Too much absorption within a narrow frequency bandwidth is most definitely bad and to be avoided.

David Aiken

Follow Ups:

Curious... - clio09 10:31:28 08/12/07 (16)
when you say 8' away is that distance measured from tweeter to listening position? I have Spendor 1/2e speakers and sit about that distance away as measured to the tweeter. I had considered this near field. Am I mistaken?
- RE: Curious... - David Aiken 18:12:01 08/12/07 (15)
  Yes, that's tweeter to ear and that is into the far field. The true near field probably extends no further than 4' or so�it's confined to an area very close to the speaker. How close depends on speaker design to some degree. What we audiophiles tend to call "near field listening" isn't a particularly accurate usage of a technical term.
  
  David Aiken
  - Thanks for the clarification... - clio09 18:54:18 08/12/07 (14)
    if you could look at this post and possibly give me some recommendations I would appreciate. I like the Audio Physic method for speaker placement, but am wondering if this would work best in this scenario considering the equilateral triangle between speakers and listening position will be about 8'. I'm considering short wall placement, but only if long wall will not be feasible.
    - New listening room (Open in New Window)
    - RE: Thanks for the clarification... - David Aiken 15:01:32 08/13/07 (13)
      I read that post and passed on responding at the time. I have no experience of the 8th Nerve treatments or the theory behind them.
      
      I'm also unconvinced of the virtues of the equilateral triangle. Audio Physic say that a 72 degree angle at the listening position is preferred by listeners and I'd guess the angle at my chair is probably around 65 degrees or a bit more, but probably not quite as wide as 72 degrees. I could try to work it out but I haven't. I don't think an equilateral triangle is something you need to slavishly consider.
      
      I've said it before and I'll say it again: I think most formula based methods will give good results if the room proportions suit the formula. Some room proportions simply don't go with some formulae or rules. The smaller the room, the more likely problems are to occur. The closer the room becomes to a square or to a very narrow rectangle, the more likely problems are to occur. Some approaches work better at the square end of the scale, some at the long rectangle end of the scale.
      
      Some people prefer long wall placement and some prefer short wall placement. Each produces a different effect. I don't think either one has any intrinsic benefits over the other but one may definitely work better than the other in a given room and it's not only room proportions that make the difference. Things like doorways and windows, whether you can obtain a more symmetrical placement one way or the other, furniture that can't be moved�lots of things can make a difference and the room is not always a blank slate that we can write on how we will.
      
      I'd give the long wall placement a go and see how you go. At 11'5" the short wall is probably a little shorter than I'd like but it may work for you. Definitely try it. All you have to lose is a little time and effort and, at the worst, you'll find that you don't like it and perhaps a little more about what you like and don't like in the process. That kind of information is always useful.
      
      David Aiken
      - RE: Thanks for the clarification... - clio09 17:34:41 08/13/07 (12)
        
        In Reply to: RE: Thanks for the clarification... posted by David Aiken on August 13, 2007 at 15:01:32
        
        I think I will experiment with long wall first and if I encounter any issues give short wall a try.
        
        How would one go about calculating the 72 degree angle? I find that Nathan Loyer at Eight Nerve also does not suggest the equilateral triangle and instead recommends that the distance between the speakers (tweeter to tweeter) equal 20% - 30% of the distance between the speakers and listening position.
        
        RE: Thanks for the clarification... - David Aiken 18:23:36 08/13/07 (11)
        
        In Reply to: RE: Thanks for the clarification... posted by clio09 on August 13, 2007 at 17:34:41
        
        How to calculate the 72 degree angle: use Tan36 degrees. Tan 36 degrees = (.5 x distance between tweeters) divided by (distance from plane of speakers to listening position). The value of this is 0.726.
        
        Let's take my case. My ears are roughly 1.99 metres in front of the speaker plane so let's call it 2 metres for simplicity. That means that half the distance between the tweeters will be (0.726 x 2) metres or 1.452 metres. The distance between the tweeters will be twice that or 2.9 metres. In my case it's actually 2.6 metres which puts my angle at a bit over 66 degrees as I said.
        
        Nathan Lloyd's suggestion that "the distance between the speakers (tweeter to tweeter) equal 20% - 30% of the distance between the speakers and listening position" is going to demant a short wall placement. You're talking about a sine of around .1 to.15 which translates to an angle of 11.5 degrees to 17.2 degrees if the distance between speakers and listening position is a straight line drawn from the speaker to the listening position. If you're talking about the distance to the plane of the speakers, then the angles are a little narrower. You aren't going to get a wide soundstage with that sort of placement, in fact you'll get a very narrow one. I think that's one of the most extreme recommendations I've ever seen. Put the speakers much closer together and you may as well go back to mono. You're definitely not going to do his sort of setup in a long wall placement. It's most definitely a short wall placement approach.
        
        David Aiken
        
        I made an error in the formula from Eighth Nerve... - clio09 18:50:23 08/13/07 (10)
        
        In Reply to: RE: Thanks for the clarification... posted by David Aiken on August 13, 2007 at 18:23:36
        
        that should have read 70% - 80%. Ex.: If the listening position is 10' from the tweeter then the speakers should be 7' - 8' apart.
        
        I'll try the 72 degree configuration as well. Thanks for your help.
        
        Oops... - David Aiken 23:26:28 08/13/07 (9)
        
        In Reply to: RE: I made an error in the formula from Eighth Nerve... posted by clio09 on August 13, 2007 at 18:50:23
        
        That makes more sense. Still, that comes out at around the 40-45 degree mark, still a bit narrower than 60 degrees and probably narrower than a lot of people would like. I'd also say it's still a short wall placementrather than a long wall placement.
        
        Does he give any reasons for that recommendation?
        
        David Aiken
        
        RE: Oops... - clio09 07:43:05 08/14/07 (8)
        
        In Reply to: RE: Oops... posted by David Aiken on August 13, 2007 at 23:26:28
        
        Only that Nathan feels it sounds better. I have provided a link below to an article in 6Moons that discussed the earlier model Eighth Nerve products, as well as more of Nathan's speaker placement philosophy.
        
        Also, here are a couple of comments from Robert Greene on my speakers:
        
        "Because of their deliberate beaminess, the SP1/2s have to be pointed at the listener if their full potential neutrality is to be appreciated."
        
        So it appears significant toe-in (Or is it toe-out? I get confused as to which is which sometimes) is recommended.
        
        Also, another comment that if you could clarify I would appreciate:
        
        "Incidentally, I should add that the SP1/2s should be placed widely apart, in something along the lines of the theoretical Blumlein position (90 degrees apart, from the listener's viewpoint)."
        
        Lastly, I tried using your formula but not sure I used it correctly. Given the following measurements what would the 72 degree angle equate to in distance between the speaker tweeters?
        
        Distance between tweeters = 84"
        Distance from listening position to plane of speakers = 78"
        
        Eighth Nerve (Open in New Window)
        
        RE: Oops... - David Aiken 21:05:08 08/14/07 (7)
        
        In Reply to: RE: Oops... posted by clio09 on August 14, 2007 at 07:43:05
        
        The reason for using the tangent of 36 degrees is because we're dealing with 2 sides of the right angled triangle that connects 1 speaker, the listener, and the mid-point of a line drawn between the speakers. The side of that triangle connecting the mid-point of the line between the speakers to the listener bisects the 72 degree angle so you've got 36 degrees on either side of that line.
        
        The tan of 36 degrees is 0.726. The distance from the speaker plane to the listener is 78" so the distance from the speaker to the midpoint will be 56" (78" x 0.726) and that makes the total distance between the speakers 112".
        
        -----------------------------------------------
        
        I haven't got any experience with Spendors but I do have my Dynaudio Contour 1.3 SEs pointed directly at me. If the on axis response is flat there shouldn't be a problem and it may actually help. Pointing the speakers directly at the listener means that the early reflections are going to come from a fair degree off axis. Since the top end usually rolls off some as you move off axis, that takes some of the energy out of the early reflection. The early reflection would still be off axis if the speakers were pointed straight ahead (no toe in) but they become more off axis as you increase the toe in by angling the speakers more towards the listener. Different speaker designers have different views on what the most desirable listening axis is, and your views don't necessarily have to coincide with those of the designer. In my view toe in is something that you adjust to suit your ears and the room.
        
        David Aiken
        
        That is the number I came up with as well... - clio09 10:56:57 08/15/07 (6)
        
        In Reply to: RE: Oops... posted by David Aiken on August 14, 2007 at 21:05:08
        
        which means the speakers will need to be a little more than 9' apart, leaving them about 4' from the side walls. Not bad I suppose and hopefully with the toe in will minimize side wall reflections. I would also have to test the center image to see how it sounds. I've never had these speakers that far out before.
        
        A couple more things. The 78" I referenced was measured from my listening position to the front of the plane at the mid-point between the speakers, not the distance from the listening position to the tweeter. Is this the correct measurement? Now the last question. According to Robert Greene the Spendors should be placed 90 degrees apart, from the listener's viewpoint. Does this equate to Tan45 degrees?
        
        Looks like I have some fun stuff ahead of me with my new room. Thanks for your help.
        
        RE: That is the number I came up with as well... - David Aiken 23:45:18 08/15/07 (5)
        
        In Reply to: RE: That is the number I came up with as well... posted by clio09 on August 15, 2007 at 10:56:57
        
        Unfortunately the Audio Physic setup documents on Immedia's site aren't all that precise on some things. They say that most people prefer a 72 degree angle, talk about placement at the focal point of an ellipse which all 4 walls contact tangentially, and use a grid which shows placement at quarter and three quarter width points. There's no guarantee that the focal points will give a 72 degree placement with the listening position�that angle will be determined by room dimensions if you use the focal points. As I said previously, I use the quarter and three quarter points and that gives roughly a 66 degree angle in my room�the angle here is also going to be determined by your room dimensions. I have tried the focal point placement and found it too far apart in my room. I haven't worked out what the angle was there but it would have been less than 90 degrees. 90 degrees is going to be a very wide placement and I would think you would run into problems.
        
        You asked:
        
        "The 78" I referenced was measured from my listening position to the front of the plane at the mid-point between the speakers, not the distance from the listening position to the tweeter. Is this the correct measurement?"
        
        Yes, from the speaker plane to the listening position
        
        "Now the last question. According to Robert Greene the Spendors should be placed 90 degrees apart, from the listener's viewpoint. Does this equate to Tan45 degrees?"
        
        Yes, but the Tan of 45 degrees is 1 so the calculation gets very easy. What you want is a speaker to speaker distance that is exactly twice the speaker plane to listening position distance in order to get the 90 degree angle.
        
        David Aiken
        
        I calculated Tan45 and came to the same conclusion... - clio09 07:01:04 08/16/07 (4)
        
        In Reply to: RE: That is the number I came up with as well... posted by David Aiken on August 15, 2007 at 23:45:18
        
        which is that the speakers would be placed too far apart (13'). I think the 17.5' x 11.5' room (the walls do meet tangentially) would make for a nice elliptical set-up. I have read the Immedia instructions before and will try to set the speakers up according to that method. I think what I'll do is start with the speakers 7' apart and then move them out further from there until the center image collapses. Then see after setting them up for depth (5' - 6' into the room) and toe in if I like what I hear. If I get to the 72 degree angle great, if not I'm sure whatever I come up with will be better than what I have now.
        
        RE: I calculated Tan45 and came to the same conclusion... - David Aiken 19:05:25 08/16/07 (3)
        
        In Reply to: RE: I calculated Tan45 and came to the same conclusion... posted by clio09 on August 16, 2007 at 07:01:04
        
        "I think what I'll do is start with the speakers 7' apart and then move them out further from there until the center image collapses."
        
        When I put my speakers further apart, at the focal points of the ellipse, what I found was that the centre image didn't collapse as I expected, but that I started to get a gap in the soundstage between each speaker and the centre, so I ended up with some sound coming from the centre and other sounds coming from an area centred on each speaker. Very strange, and not at all what I expected.
        David Aiken
        
        I'll keep that in mind as I experiment with the distance. (nt) - clio09 19:33:14 08/16/07 (2)
        
        In Reply to: RE: I calculated Tan45 and came to the same conclusion... posted by David Aiken on August 16, 2007 at 19:05:25
        
        nt
        
        New news from the mobile speaker room - David Aiken 13:45:35 08/18/07 (1)
        
        In Reply to: RE: I'll keep that in mind as I experiment with the distance. (nt) posted by clio09 on August 16, 2007 at 19:33:14
        
        In a fit of craziness, last night I dug out the tape measure and metre steel rule and moved my speakers back to the focal points of the ellipse. It's probably close to 3 years since I last had them there.
        
        I didn't notice any problems that might not be recording related, and I quite liked the result. The room has changed a fair bit in that time due to the addition of 2 pairs of DIY acoustic panels at early reflection points and that has probably helped.
        
        The soundstage has changed. With speakers at the quarter/three quarter points I routinely get a soundstage that extends to the outer side of each speaker. At the focal points, that only happened on a few tracks last night. Instead the soundstage didn't quite seem to extend as far as the speakers a lot of the time, but it was still probably the same width as before since the speakers are now further apart, and it's still a very wide sound stage. The depth of the soundstage seems a little deeper and images maybe a little less holographic and a little more rounded but quite precise. The height of some sources, especially voices, seemed higher on a lot of material and that's a plus for me. I didn't notice a down side but I only played about 3 discs before going to bed around midnight.
        
        Given that the only real difference between my first attempt at this placement and now is the room treatment at early reflection points and that placement at the focii puts the speakers closer to the side walls, I think side reflections may have been the cause of the soundstage issues the first time around. Interestingly, on one disc the soundstage did seem to group into 2 areas around each speaker and the centre image but this did not occur on the other discs and I didn't get the feel of a break in the soundstage between each speaker and the central image area. That disc was obviously mixed that way so perhaps what was happening last time was that due to the exaggeration of that mixing choice by early reflection issues.
        
        David Aiken
        
        Well now you've gone and thrown a wrench in it... - clio09 07:21:50 08/19/07 (0)
        
        In Reply to: RE: New news from the mobile speaker room posted by David Aiken on August 18, 2007 at 13:45:35
        
        I had pretty well settled on a set-up that used the quarter/3 quarters points and have the speaker no more than 8' apart. Even though this would not give me the 72 degrees or even the 90 degrees that Greene recommended, it was going to minimize side wall reflections. I can move the speakers further apart as I do have some 4' x 2' x 2" fiberglass panels to use for the side wall reflections, so maybe I should experiment both ways and see what happens. I'm somewhat of a set it and forget it kind of guy so tis would be a little out of character for me.
        
        At 8' apart the speaker/listening position distances would be close to an equilateral triangle, which I'm not striving for, but it just turns out that way. One thing about the wider placement of the speakers at the focal points and beyond is that the distance between the tweeters will exceed the distance from tweeter to listening position. I've never had placement like this before. I'm wondering how this will affect the sound. I guess there is only one way to find out.
RE: setting up a listening room - temporarymadness@aol.com 07:48:40 08/12/07 (1)
ok, let's say i just wanted to get batts/bails of fiberglass in all my corners to start. i don't completely understand how unfaced/paper out/paper in all enters into it. i mean, the John guy says to alternate, but why is this? and do those rules apply to my room? or do i just want all one way or all the other?
also, i'm not completely sure i understand how he's making the accoustic panels. is he just putting fiberglass and polyester batting in a wooden frame and then wrapping the whole thing in burlap?
also, is 8' the standard listening position for near-fields?
thanks
-chris

Edits: 08/12/07 08/12/07 08/12/07 08/12/07
- RE: setting up a listening room - David Aiken 18:36:35 08/12/07 (0)
  I'm not the best guy to ask about Jon's designs because I happen to be in Australia and it's hard to find some of the products he refers to which are apparently relatively common in the US. We probably have them but under different names. In any event I prefer to use polyester rather than Jon and Ethan's recommended fibreglass because of my background in health and safety. Fibreglass can present a health risk and I'd rather not use it myself in a DIY project. I don't have the same concerns about using commercially made products based on fibreglass which are intended for domestic usage�the manufacturer should have ensured their safety. I simply don't have the sort of environment that would allow me to safely work with fibreglass at home so I prefer not to.
  
  Do those rules apply to your room? Which rules are you talking about? If you're talking about the number of traps and panels recommended, then most probably yes but that recommendation is what's required to reach optimal results. You can certainly get good results with fewer panels and traps than that but it does take quite a bit of absorption, and by that I mean true wide band absorption, to really get the best results in a room. As with most things you've got a law of diminishing returns so installing half the recommendation will get you more than half the benefit of the full recommendation.
  
  If, on the other hand, the 'rules' you're talking about refer to construction details, then you're talking about something that applies to the trap or panel design, not your room. You can build traps and panels in other ways�I think Ethan has some different DIY designs on his site. If you're going to build your own traps and panels, then pick a reliable design and follow it. Each design takes into account the products being recommended in the parts list and chopping and changing things may or may not work as well as following the instructions precisely, or as closely as you can if you choose to make variations as I did in not using fibreglass.
  
  For the panels he's putting the fibreglass in a wooden frame, wrapping that in polyester to prevent fibreglass fibre leakage, and then covering the whole thing as tightly as possible with burlap.
  
  David Aiken

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