Building the ultimate acoustically friendly room - ideas/suggestions?

china · « **Reply #20 on:** 21 Mar 2007, 01:02 am »

Hello My Friends,

Here is another site that might be of interest. www.supersoundproofing.org or www.supersoundproofing.com

I think that the .com is for the forum. Both the home page and forum have very good information and the products that are offered are most reasonable in cost.

As always, all the best. From China

Ethan Winer · « **Reply #21 on:** 21 Mar 2007, 05:25 pm »

George,

> Ignore the mess <

LOL, yeah, and get all those speaker cables straightened out too.

I'm hoping to use your final photos for our Stereophile ad.

--Ethan

Ethan Winer · « **Reply #22 on:** 21 Mar 2007, 05:28 pm »

Quote from: Daygloworange on 20 Mar 2007, 05:34 pm

Your tastes are only going to be as good as what you've been exposed to.

That's a great point. It's tough sometimes for me to explain this to a customer without offending them. A well-treated truly neutral room is almost an acquired taste that many people have never even heard before. Most people are so used to the ambience it's difficult for them to distinguish between "different" and "better."

--Ethan

Ethan Winer · « **Reply #23 on:** 21 Mar 2007, 05:37 pm »

Hey Bryan,

First, please get that violin bow out of your nose, okay? It's driving me crazy!

(I'm kidding!)

BTW, Bryan, will you be at the HES show in NYC in May?

> I agree that IF you flatten out the poly's, they don't help much with comb filtering. <

It's more than that. A poly's depth is connected to its width. Yes, you could put several narrow/shallow ones adjacent on a wall, but then for every convex surface you have another that's concave where the panels meet. So the focusing from the concave junctions negate any advantage from the convex parts.

> As for 'real' diffusion, I suppose that's somewhat of a correct term. The poly's are more 'dispersion' as they scatter evenly and not randomly. <

Jeff Szymanski once posted a really good technical explanation of why QRD diffusors reduce comb filtering much more effectively than polys. I think it was at the Sound on Sound forum, but the last time I looked for it I couldn't find it. Understand that I have heard larger / deeper polys (and smaller / deeper ones too). I agree they're better than a flat wall, but even when ideally shaped they're not as good as a QRD diffusor. I don't care how high in frequency they may deflect too, you still get some of that boxy sound off the surface.

--Ethan

bpape · « **Reply #24 on:** 21 Mar 2007, 06:33 pm »

Personal preference Ethan. I like both of them but at different places in the room and with different requirements.

Also, when you do multiple smaller poly's, there is no concave surface. In fact, the tapered cavity that results at the intersection actually can cause some absorbtion at higher frequencies due to pure cancellation - just like in a QRD well. I will agree that it's a different sound and feel between a poly and a QRD. To each their own.

Bryan.

P.S. As soon as I get it cleaned out, I'll remove the bow

John Casler · « **Reply #25 on:** 21 Mar 2007, 08:12 pm »

Quote from: Ethan Winer on 21 Mar 2007, 05:28 pm

Quote from: Daygloworange on 20 Mar 2007, 05:34 pm
Your tastes are only going to be as good as what you've been exposed to.

That's a great point. It's tough sometimes for me to explain this to a customer without offending them. A well-treated truly neutral room is almost an acquired taste that many people have never even heard before. Most people are so used to the ambience it's difficult for them to distinguish between "different" and "better."

--Ethan

You can say that again!

A friend once told me, my amp or cables didn't have the right "decay".

After hearing his system, it turns out the "decay" he was refering to, was "echo distortion" from his room.

95bcwh · « **Reply #26 on:** 21 Mar 2007, 08:37 pm »

I just went to a local dealer store and saw that they're using this:

what's the difference between this "skyline" diffusor and the one Ethan offers??

zybar · « **Reply #27 on:** 21 Mar 2007, 10:39 pm »

Quote from: Ethan Winer on 21 Mar 2007, 05:25 pm

George,

> Ignore the mess <

LOL, yeah, and get all those speaker cables straightened out too.

I'm hoping to use your final photos for our Stereophile ad.

--Ethan

Cables are a mess due to trying a couple of different items - things will be cleaned up and mounted very soon.

George

JLM · « **Reply #28 on:** 21 Mar 2007, 11:16 pm »

The QRD diffusors that 95bcwh imaged makes for an easy DIY project. The plans are here:

http://pmerecords.com/Diffusor.cfm

I'm waiting for time, cash, and warm weather before trying to build a set. I'm considering using 2x4s and making three of them 3 ft x 6 ft with a 1 inch frame to mount on the front wall and at the front end of each side wall. (but they'll weigh about 160 pounds each with paint).

bpape · « **Reply #29 on:** 22 Mar 2007, 12:38 am »

Ethans are 2d as in they scatter side to side and in time. The skylines are 3d as they scatter in width, height, and time. However, the 2d will provide more inherent absorbtion due to cancellation in the wells.

Bryan

Ethan Winer · « **Reply #30 on:** 22 Mar 2007, 05:02 pm »

Bryan,

> Personal preference Ethan. <

Okay, fair enough.

I had another thought this morning, and one of these days I'll test this theory:

Let's say you have an optimally sized poly centered precisely behind the listening position. Sound from the loudspeakers whizzes past your ears, hits the poly, and some of it reflects back at you. The comb filtering at each ear will be identical, so the peak and null depths and frequencies at each ear will also be the same. The comb filtering will be less than a flat wall, of course, but it's still present.

Now, replace the poly with a QRD well diffusor. Each well has a different depth, and in the case of the RealTraps Diffusor the wells are 1-1/2 inches wide. The different well depths reflect with different delay times, which is one reason a QRD is able to reduce comb filtering. Further, whatever is reflected will be different for each ear. So now each ear receives a different comb filtered response, creating less of that swishy sound.

I know from experience that a QRD sounds better (IMO) than a poly. But do you think the above makes sense to help explain why?

--Ethan

bpape · « **Reply #31 on:** 22 Mar 2007, 05:22 pm »

In theory, that sounds good like a plausible explaination. Now, what happens if we take that poly and push it off to one side say 2"? Theory goes out the window. Also, in theory, the chair shouldn't be centered in the width anyway so a centered poly would react differently on each side, refletion paths would be different both in location and in time.

Bryan

Ethan Winer · « **Reply #32 on:** 22 Mar 2007, 05:26 pm »

John,

> A friend once told me, my amp or cables didn't have the right "decay". After hearing his system, it turns out the "decay" he was refering to, was "echo distortion" from his room. <

LOL. I once sat in on a loudspeaker audition for a pair of really expensive audiophile speakers. Like $60,000 per pair or some such. The editor of a very famous audiophile magazine was there, as was a regular reviewer for the same magazine. I had sent ahead eight MondoTraps on stands for the reviewer to use for the month he had those speakers. They were also testing two very expensive power amps ($12k and $18k), switching between them. One of the power amps was so badly designed it blew up because they forgot to power down the amp before unplugging the RCA input connection. Sheesh. But that's another story.

Anyway, at one point the famous editor commented that the current power amp had less bass "overhang" than the other power amp which had since self-destructed. I looked at him incredulously, and explained that any overhang he heard was due to the square room we were listening in. He nodded and said, "Yeah, okay, I guess so."

--Ethan

Ethan Winer · « **Reply #33 on:** 22 Mar 2007, 05:32 pm »

Bryan,

> so a centered poly would react differently on each side, refletion paths would be different both in location and in time. <

Could be, but I'm still thinking a QRD will be "more different" at each ear. Not sure. Need to test more.

I still say a QRD sounds a lot better than a poly.

So, are you now selling polys?

--Ethan

Kevin Haskins · « **Reply #34 on:** 22 Mar 2007, 06:40 pm »

Quote from: Ethan Winer on 22 Mar 2007, 05:26 pm

John,

> A friend once told me, my amp or cables didn't have the right "decay". After hearing his system, it turns out the "decay" he was refering to, was "echo distortion" from his room. <

LOL. I once sat in on a loudspeaker audition for a pair of really expensive audiophile speakers. Like $60,000 per pair or some such. The editor of a very famous audiophile magazine was there, as was a regular reviewer for the same magazine. I had sent ahead eight MondoTraps on stands for the reviewer to use for the month he had those speakers. They were also testing two very expensive power amps ($12k and $18k), switching between them. One of the power amps was so badly designed it blew up because they forgot to power down the amp before unplugging the RCA input connection. Sheesh. But that's another story.

Anyway, at one point the famous editor commented that the current power amp had less bass "overhang" than the other power amp which had since self-destructed. I looked at him incredulously, and explained that any overhang he heard was due to the square room we were listening in. He nodded and said, "Yeah, okay, I guess so."

--Ethan

I'd say it was probably due to his cables. If you suspend them too far off the floor you get excessive "overhang" down low.

bpape · « **Reply #35 on:** 22 Mar 2007, 07:18 pm »

Selling? No. Do I put them in a lot of rooms as DIY's? Yup. I'm comfortable with what the BBC uses in their rooms...

Seriously, both have their place. As I said before, at a reflection point on the walls or ceiling, a poly makes no sense at all. In those positions, a 2D or 3D QRD makes a lot more sense and will certainly sound much better. Again, it's a matter of preference on the sound. Either can sound good or sound bad IMO.

Bryan

Ethan Winer · « **Reply #36 on:** 23 Mar 2007, 09:15 pm »

Quote from: bpape on 22 Mar 2007, 07:18 pm

I'm comfortable with what the BBC uses in their rooms...

LOL, okay, this is my last post on this. (Yeah, right...)

I'm sure the BBC uses those in rooms much larger than most living rooms.

--Ethan

zybar · « **Reply #37 on:** 25 Mar 2007, 07:37 pm »

Ok, I have the back of the room cleaned up and the RealTraps Tri-Corner Traps, Mondo Traps, and Diffusors are all mounted. I now have the following RealTraps products installed behind me:

(2) Tri-Corner Traps
(2) Mondo Traps
(3) Diffusors
(1) MiniTrap

Here are some pictures:

A couple looking straight back at my listening spot:

Back left of the room:

Back right of the room:

Next up, I will be cleaning up the front of the room and moving some things around. I will also be ordering a Mondo Trap (HF version) to go on the front wall in place of the current MiniTrap.

George

bpape · « **Reply #38 on:** 25 Mar 2007, 07:40 pm »

Nice looking room George. Ethan's diffusors look really slick against the wall color.

Bryan

zybar · « **Reply #39 on:** 25 Mar 2007, 07:41 pm »

Quote from: bpape on 25 Mar 2007, 07:40 pm

Nice looking room George. Ethan's diffusors look really slick against the wall color.

Bryan

Thanks Bryan.

George