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Old 21st June 2007, 04:27 PM   #1201
Variac is offline Variac  United States
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Certainly a larger room is better, and physics enters into things.
In this thread, I guess Lynn is the one to decide if his listening space is large enough for certain designs. There are a lot of people with HT rooms, so clearly its not an insurmountable issue for many. DIY Audio is an international site, not a USA site. It was started in Australia and has members all over the world. My impression is that generally the amount of space available to our typical member is smaller than that discussed.

BUT:
Let's not continue discussions of the "morality" of too big an audio room, and how many big rooms are in what areas of the world. We really aren't able to know all the facts, but clearly some are able to have them and for some it is a matter of priorities.

SO:
We should freely discuss optimal room sizes for various speaker types, and how smaller rooms can compromise them, but please: not the immediately above issues

I live in a flat in San Francisco, and I won't ever have the greatest audio due to space constraints, but still am fascinated by audio generally, even if I can't take advantage of all I read here, and it's good to know which speakers work the best in which spaces. And I still enjoy music on my sub-optimal, but quite satisfying setup.



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Old 21st June 2007, 04:36 PM   #1202
gedlee is online now gedlee  United States
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Wise approach.

You can't decide what compromises to make in small spaces if you don't know what the ideal is. As I have said, I seek the ideal, thats my goal and point of view. If this does not apply to you and your situation in particular then I appologize - but it works for me.
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Old 21st June 2007, 05:24 PM   #1203
Teh is offline Teh  United States
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You know, I'd like for Lynn to weigh in on this issue.

Lynn, how much influence, on the system you're designing, does the size of your listening room impact how you're accomplishing your goals?

I ask because this thing is gonna be pretty big! So, based upon the drivers, the efficiency and physical size, I'm guessing you must have a pretty large room you're filling with sound?
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Old 21st June 2007, 07:37 PM   #1204
DDF is offline DDF  Canada
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Default Directionality

Ken Kantor poularized the philosophy of removing early room reflections, and IME, placing a speaker along the long wall performed best, set up to Ken's old yard sticks. It maintained the most acurate tonality from recording to recording, and minimized imaging vagueness. It also provided the best presentation of HRTF/crossfeed encoded material that I ever heard, with sharp images moving fluidly and contiguously from 20' left of left, through the speaker plane, to 20' right of right, for recording encoded as such. Speakers were 6' from each side wall. Not to advocate HRTF crossfeed, but it illustrated to me that pushing out the side wall maintains extremely cohesive and wide imaging, while favouring tonal accuracy.

This room was a rare treat. For most of us, we need to deal with that first reflection, and thats my current situation. I'm surprised the discussion hasn't included use a good side wall absorber, at the first reflection points. Given the absorption these offer down to 500 Hz or better, I would think they largely alleviate the need to go to a highly directional speaker.

The difficulty with these sorts of comparisons is that its impossible to A/B this scenario, a highly directional speaker vs a more common wide dispersion design+side wall absorber, and then make any conclusions based on directionality alone.
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Old 21st June 2007, 08:12 PM   #1205
Pano is offline Pano  United States
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Having followed this entire crazy thread I can say "too big!" For me - that is. The sketches and ideas that Lynn and others have come up with are much too big for my tiny cottage by the sea.


But the designs are still fascinating and full of great information. Just because I'll never build Lynn's "Beyonds" for my living room doesn't mean that the way they turn out isn't interesting.

Shootz, I'll never own a jumbo jet, but getting the chance to brainstorm with the experts on the design of one would still be fun. Even though it won't fit in my driveway.
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Old 21st June 2007, 08:48 PM   #1206
Variac is offline Variac  United States
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I'm still convinced that Lynn's work will pay off in less ambitious (smaller) versions. Just changing his max output requirement would make a huge difference in the final size I think.

It is obvious to me that my partially open baffle speakers are in too small a room, but they still sound very good. Actually the room's volume isn't small, it is just too narrow- no room for space behind the couch

Lynn must be at a doctor's appointment....
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Old 21st June 2007, 08:55 PM   #1207
gedlee is online now gedlee  United States
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Default Re: Directionality

Quote:
Originally posted by DDF


I'm surprised the discussion hasn't included use a good side wall absorber, at the first reflection points. Given the absorption these offer down to 500 Hz or better, I would think they largely alleviate the need to go to a highly directional speaker.


I use a sort of side absorber/diffuser, but I prefer not to use any more absorption than necessary - people tend to over do it with absorbers. And it is diffciult to get good absorption down to 500 Hz. or so, A simple thin absorber isn't going to do that. The really difficult reflections are the floor and ceiling. I use ceiling baffles to break up that reflection and a 3 in thick rug right at the floor bounce. But to the sides and behind the listener I use no absorption at all - I want as much reverb here as possible.

But I still don't think that side absorbers changes the need for directionality as it is more than just the first reflections that are at issue. Its all the reflection in the first 10 ms, and, if you measure it out, thats about the first 20 or 30 in a small room. The first 2-3 ms. is critical for imaging - I even make sure that there is nothing that can diffract (different than reflect) the sound within several feet of the speakers. But the first 15 ms. is critical for coloration and directional sources makes a very big difference in the levels of the reflections in this time frame.
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Old 21st June 2007, 08:59 PM   #1208
gedlee is online now gedlee  United States
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At Ai we are really enthusiastic about our smaller ESP12 and ESP 10. The ESP 10 is about 1/10 the size of the ESP15 (Summa) but with a very comparable performance. Very directional, efficient and high output - now that should be appealing to you guys with small spaces. All three system have the same waveguide, plug and compression driver, only the waveguide mouth is a bit scaled down on the smaller models - but not that much.
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Old 21st June 2007, 09:15 PM   #1209
chrisb is offline chrisb  Canada
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Quote:
Originally posted by gedlee
At Ai we are really enthusiastic about our smaller ESP12 and ESP 10. The ESP 10 is about 1/10 the size of the ESP15 (Summa) but with a very comparable performance. Very directional, efficient and high output - now that should be appealing to you guys with small spaces. All three system have the same waveguide, plug and compression driver, only the waveguide mouth is a bit scaled down on the smaller models - but not that much.

Do you have a URL for the new products yet? I vaguely remember seeing something a while back (could it have been a year?) on the Summa, but neglected to cache the page.
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Old 21st June 2007, 10:45 PM   #1210
DDF is offline DDF  Canada
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Default Re: Re: Directionality

Quote:
Originally posted by gedlee



I use a sort of side absorber/diffuser, but I prefer not to use any more absorption than necessary - people tend to over do it with absorbers. And it is diffciult to get good absorption down to 500 Hz. or so, A simple thin absorber isn't going to do that. The really difficult reflections are the floor and ceiling. I use ceiling baffles to break up that reflection and a 3 in thick rug right at the floor bounce. But to the sides and behind the listener I use no absorption at all - I want as much reverb here as possible.

But I still don't think that side absorbers changes the need for directionality as it is more than just the first reflections that are at issue. Its all the reflection in the first 10 ms, and, if you measure it out, thats about the first 20 or 30 in a small room. The first 2-3 ms. is critical for imaging - I even make sure that there is nothing that can diffract (different than reflect) the sound within several feet of the speakers. But the first 15 ms. is critical for coloration and directional sources makes a very big difference in the levels of the reflections in this time frame.

The absorbers I have in mind are the resonating dissipative style, using peg board, frame and lossy material to provide a good broad band absorption. They're definitely DIY, but simple enough to build, unless flush with cash. They really work well. The absorption only needs to be 7 to 10 dB to not impact image shift (from Queen & Olive).

I can't visualize having 10 to 20 discrete reflections within 10 ms (drawing it out in a 16x13 room), with a broad absorber at the sides, with the following caveats.

I'm neglecting the first vertical refelction here of course. I really agree with controlling the first ceiling reflection. In that wide room, the ceiling was acoustic tile. Not the prettiest looking room, but it sounded wonderful, the room colouration was very low. Early vertical reflections affect timbre, but vertical reflections delayed by even 10 ms can affect image height (from an old JASA paper). Break them up and pad them down a bit.

I'm also neglecting the front wall which I feel is an absolute necessity to providing adequate depth cues, to reinforce frequency dependant and level ones (ie further back = less high end and quieter).

On the floor reflection, I'm philosophically more on the fence. If you want the effect to be one where the performers are in your room, I believe that the floor bounce is an aid in that mirage. Floor reflections also only affect image shift if the envelope is greater than several seconds (Kantor) so I think they aren't a terrible problem. The old Snells on the other hand were tonally wonderful by eradicating the floor from the equation. Pick your favoured illussion and design accordingly.

With the side absorption and some ceiling control, its still fairly easy to maintain a healthy RT60 (no carpet),

I focus on tonality when dealing with the room, but I know there are many that experiment at length with room boundaries and imaging. Hopefully they can share their practical experiences here.
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