And out of the west came the thundering hoofbeats of the comb filter.

This may prove to be the most complex and controversial topic ever.

To start: The main problem with most systems is that you have to be in the room to listen to them.

Just imagine all the complex, crazy, and varying acoustic effects you have on the sound of the room when you are in it vs. when your gear is playing to an empty room.

That's why "live in the next room" is easier to achieve when you aren't in the room than when you are.

Try this...get a good mic and digital recorder, and place the mic in your usual listening position, then leave the room while you record some music.

Then, play that back on another system and you'll get an idea of much different your system sounds when you are not in the room.

It's amazing.

So, the best place to really hear what your gear can do is to be in the room next to the room with your Hi Fi rig in it.

Then, any chair is fine!

I guess if you are going to insist on being in the same room as your gear, then at least get a "fast back" chair, as they create less "sonic turbulence" than square back chairs.

I call it "Chairodynamics."

Some diagrams:

I use a dimpled Love Sac as my listening chair for this very reason.

Check the sound chairodynamic flow diagrams comparing a smooth Love Sac to a dimpled Love Sac:

The differences are not trivial.

Then, when I sit in the chair, I make sure I get it scrunched into the most chairodynamic shape, too.

You'll find bean bag chairs very amenable to achieving the most chairodynamic shape of all, the "streamlined half body."

Diagram:

As you can see, the "streamlined half body" chair is second to none.

Here is a pic of a "streamlined half body" chair in action:

Caution is called for, because, as you can see, the experience can be rather overwhelming.

One last thing:

Avoid, at all cost, any square backed chair for listening use. That has the least efficient chairodynamics of any shape, with nearly 100% "resistance to good sound."

Here is a diagram of "resistance to good sound" that chairs inflict on your system:

As you can see, even a terrific chair has up to 5% "resistance to good sound," but square backed chairs completely eliminate 100% of any good sound produced by your gear.

We can keep talking about this as we go, but your point is well made, "chairodynamics" and "resistance to good sound" are important sonic seating considerations!

We can talk about acoustically streamlined listening helmets later.

Regarding the guy in the chair,i take it wearing different color socks have a certain "effect" on the sound ?

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How does the back of your listening chair effect the quality of sound?

Reflective chair and couch backs have a huge effect. As Clay said, the main issue is comb filtering. This article on my company's site shows hi-res measurements of exactly what you're asking:

http://www.realtraps.com/rfz.htm

See especially the last section.

--Ethan

Good to see that you're still dropping by, Ethan. I knew that if you were, you wouldn't let him down.

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How does the back of your listening chair effect the quality of sound?

Reflective chair and couch backs have a huge effect. As Clay said, the main issue is comb filtering. This article on my company's site shows hi-res measurements of exactly what you're asking:

http://www.realtraps.com/rfz.htm

See especially the last section.

--Ethan

Hi,

I agree, a little, but I still can't get past the hyperbole.

"Huge?"

To me, "huge" would be like you wouldn't be able to tell you were listening to the same artist.

"Huge" is a 33 1/3 running at 45.

Anyway, I looked at the graphs. They look alot alike.

I bet by sitting on the couch, you'd have an equally "huge" effect.

Question: When you measured the effect of the batting the second time, had you taken the batting off in between?

If so, I can't believe there wasn't a "huge" difference generated by the new positioning of all that batting.

Giving too much credit to comb filtering takes us perilously close to Heraclitus and his river.

Remember, the question was also about hearing things differently when he moved his head. That act alone, with no chair in the room, could also have a "huge" impact.

Huge! Cup your hands behind your ears as if you were holding a pair of headphones onto your ears and listen to your system. I would think a high-back chair would have much the same effect if it's above shoulder level.

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Huge! Cup your hands behind your ears as if you were holding a pair of headphones onto your ears and listen to your system. I would think a high-back chair would have much the same effect if it's above shoulder level.

A high back chair = hands cupped over ears?

I don't hear that big an effect.

I think my brain just says, "Yup, that's still John Prine..."

Maybe we are a bunch of princesses being kept awake by a pea under our seat cushions.

I honestly go from system to system and there may be "noticeable" differences, but I can still tell who the artist is, ya know?

It makes me wonder what the increments are of the differences we fuss over.

Then again, maybe it is "huge" and that last glass of 2002 Twomey vino made up for it today.

Cheers, amigos. I mean this only in the spirit of discussion.

Well, no, I doubt that it would make as much difference as cupping your hands. I'm just saying that it would probably have a similar effect that would be better left out of the listening thang. I mean, we are the anal retentive types who obsess over this sort of stuff. I remember somebody mentioning that they take their glasses off to avoid sound reflections.

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Well, no, I doubt that it would make as much difference as cupping your hands. I'm just saying that it would probably have a similar effect that would be better left out of the listening thang. I mean, we are the anal retentive types who obsess over this sort of stuff. I remember somebody mentioning that they take their glasses off to avoid sound reflections.

But what if they listen to live music while wearing their glases?

Then, wouldn't sound reproduced in such a way that they thought it sounded good with their glasses off sound "hugely" different to a guest?

That's messin' with nature, that is.

Maybe audiophiles should only play symphonic recordings while listening in evening wear in order to more closely match live conditions.

Hmmmmm.....

I bet poor Wes Phillips' head causes all kinds of trouble.

You think he has a hat made of dampened material that he wears while auditioning gear?

Maybe an "audio grade cap?"

I think we should invent "Listeningwear" and help hobbysists standardize conditions!

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I bet poor Wes Phillips' head causes all kinds of trouble.

You think he has a hat made of dampened material that he wears while auditioning gear?

Ah, but his head is optimally shaped for acoustics and is well damped.

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Hmmmmm.....

I bet poor Wes Phillips' head causes all kinds of trouble.

You think he has a hat made of dampened material that he wears while auditioning gear?

Maybe an "audio grade cap?"

I think we should invent "Listeningwear" and help hobbysists standardize conditions!

How soon they forget...

But Jeff, that hat was only rated "one star" by both "Fedoraphile" and "The Absolute Headpiece."

This changes everything.

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Huge! Cup your hands behind your ears as if you were holding a pair of headphones onto your ears and listen to your system. I would think a high-back chair would have much the same effect if it's above shoulder level.

Exactly, and it's so easy to try! As the original poster observed, "I can definitly hear a difference between sitting back and sitting forward."

To me the effect is huge, as is the improvement after adding the absorbing backing.

--Ethan

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"Huge" is a 33 1/3 running at 45.

LOL, okay, maybe not quite that huge.

> When you measured the effect of the batting the second time, had you taken the batting off in between? <

Not sure what you're asking. I did four tests, and showed only the first and last.

> Remember, the question was also about hearing things differently when he moved his head. That act alone, with no chair in the room, could also have a "huge" impact. <

Yes, small movements do make a huge change too, all by themselves. Due to comb filtering of course!

--Ethan

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"Huge" is a 33 1/3 running at 45.

LOL, okay, maybe not quite that huge.

> When you measured the effect of the batting the second time, had you taken the batting off in between? <

Not sure what you're asking. I did four tests, and showed only the first and last.

> Remember, the question was also about hearing things differently when he moved his head. That act alone, with no chair in the room, could also have a "huge" impact. <

Yes, small movements do make a huge change too, all by themselves. Due to comb filtering of course!

--Ethan

Hi, Ethan!

The batting question was whether or not you had removed and then replaced the cushioning between measurements. Changing the material's position alone may have an impact that shows up as well.

I certainly do believe in comb filtering, but there are days when my little brain gets caught in the infinite spiral of its effects.

Cheers, and I'm glad you're here.

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The batting question was whether or not you had removed and then replaced the cushioning between measurements.

I'm really sorry, but I still don't understand the question. I did four tests:

1. Measure the couch alone
2. Measure the couch with my "cat" blanket
3. Measure the couch with batting only
4. Measure the couch with batting plus a thick cover

Nothing else changed between measurements, including the microphone placement.

--Ethan

Threads like this one come up again and again, and they're always interesting to me because they demonstrate how much my attitudes differ from those some of my fellow audiophiles. I'm inclined to toss out the question whether I'm alone in my approach or whether others here share it.

In over forty years of seeking to enhance my enjoyment of music with good audio gear, the closest I've come to a "listening room" is the headphone set-up sitting next to me in the library. My best system lives in a large room with pretty good acoustical characteristics, but more importantly it is a room where people are likely to congregate, where they can enjoy music with a cup of coffee or a glass of wine. My headphone set-up is very good, but I much prefer listening to music on my main system in a room where the art and the decor add to the pleasure of the music.

There is a "best seat", but the sound is very good almost anywhere in the room. I determine the "sweet spot" with ears that have lots of experience listening to gear. I wouldn't consider setting up microphones and using electronic measurements to tell me whether I ought to like what I'm hearing.

Am I all alone, or are there any others out there who invite their best music playing equipment into the rest of their lives instead of putting it in a padded cell?

By the way, Ethan, you're probably aware that I think your participation in this forum is strictly an exercise in marketing/advertising/sales but, that notwithstanding, anyone with a cat blanket on his couch can't be all bad.

Clay,

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By the way, Ethan, you're probably aware that I think your participation in this forum is strictly an exercise in marketing/advertising/sales but, that notwithstanding, anyone with a cat blanket on his couch can't be all bad.

Well, my cat Bear thanks you.

As for my participation here (and in other forums), that's not really true or fair. I've been talking up the importance of room acoustics and treatment since the late 1970s, many years before I ever thought to go into this business. I've been doing this since before there was an Internet as we know it, when the main online gathering place was the MIDI & Music forum at CompuServe where I was a moderator. My 1995 article describing bass traps in Electronic Musician magazine opened a lot of people's eyes to the importance of room acoustics. Indeed, I'm in this business now because I truly believe in it, not the other way around.

Maybe someday magazines like Stereophile will have full page ads for acoustic treatment, and companies selling speaker cable and other wire products will be relegated to little ads in the classifieds section. If that ever happens - and I'm not optimistic! - my job will be done and I'll retire.

--Ethan

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I think your participation in this forum is strictly an exercise in marketing/advertising/sales

Not to beat this to death, but here's another point I need to make: Even though I'm in the business of selling acoustic treatment, I still maintain my Acoustics FAQ which explains DIY acoustic treatment, and I still visit many forums every day to answer the same questions I answer for pay as a consultant. I believe so strongly in the importance of room acoustics and treatment that I'd rather someone DIY or buy from a competitor than go without.

--Ethan

I, for one, greatly appreciate your willingness to help and your contributions. I wish more manufacturers were willing to engage us enthusiasts in this fashion.

I always enjoy your posts, Ethan. And, your passion for what you do comes across in your demeanor.

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I think that the comb-filter responses here don't apply because of the absorbing properties of almost all chair backs greatly reduce delayed reflection effects to make them a non-issue.

In my tests the measuring microphone was exactly where your ears would be. Why do you think your ears won't receive the exact same comb filtered response the microphone picks up?

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And from Alton Everest's Master Handbook of Acoustics Chapter 17 Comb-Filter Effects, "Comb-Filtering is a steady state phenomenon. It has limited application to music and speech, which are highly transient phenomena."

Maybe you misunderstood the intent and context of that remark? I have the 4th edition, so if you have the same tell me the page number that's from and I'll comment further. Or at least which figure it's near. I just skimmed through that chapter and nothing I saw implied comb filtering is not damaging.

One factor that reduces the audibility of comb filtering is the response at each ear is often different. So nulls at one ear are partially countered by not being present in the other. But with a nearby couch back both ears will receive more or less the same skewed response unless you tilt your head to one side.

More to the point, this is really easy to prove to yourself! Try what I did, first with a bare reflecting couch and then with thick absorption in place. If you listen carefully I'll be surprised if you don't come to the same conclusion I did - comb filtering harms imaging and clarity.

--Ethan

Or sit on a bench or something else without a back. Then have someone stand directly behind you. There is an obvious change in sound.

I don't know if this is due to comb filtering or not, but there is a difference.

What little measuring I have done with an SPL meter convinced me of the sensitivity to proximity when taking measurements. I could set the meter on a tripod at the listening position and walk around the meter from a distance of several feet while test tones were being played and watch the meter fluctuate until I stopped. The meter would react to my being to the side, back or even when placing my hand a couple of feet on top of it.

Exactly!

Pretty wild, huh?