Cool Dave! Were there any conclusions drawn we should know about or is that testing yet to be? Taking the room and perception more into the equation has got to have some answers.
Dan
Dan
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CD systems are generally flat power over only part of the range. Still, many studies have shown that flat power is too bright.
Lipshitz and Vanderkooy did a study where they varied the power response into a room via a side firing dipole sitting on top of a conventional speaker. That way they could manipulate power response without messing up axial response. They still found flat power, even with flat on axis response, sounded too bright.
David S.
BTW, I'm still not buying the 'it's just direct sound and power response'-argument. That would mean your hearing doesn't discriminate between the timbre of early and later reflections - as long as it all adds up flat. I don't think our brain has such long steady-state integration time.
It probably makes sense below about 500 hz, but I deem it highly unlikely. I wish it were as easy as you are implying Dave, but I'm not sold yet!
It probably makes sense below about 500 hz, but I deem it highly unlikely. I wish it were as easy as you are implying Dave, but I'm not sold yet!
Hi Michael,
Great and scary paper....the sadly point is that our PC based measurements are flawed. Looks like we can't do without a real anechoic room.
A dumb question about CMP possible compensation :
with bare drivers (small in front of the wave length, not for tweeters then), the CMP has very small delay, so the created distortion is immediate. Can we consider it as any linear distorsion, then could it be possible of using EQ for partially addressing it ? 😕
Salmi ended up designing a system with a short line array so that he could reduce the sound bouncing off the floor in front of the system.
He called his measuring approach the Weighted Gating Technique (WGT).
"If the WGT curve is good (as flat as possible), the loudspeaker sounds good."
"If the WGT curve looks bad, the speaker might sound good with some particular program material but there are always signal (usually broadband) with which it sound bad."
"If a loudspeaker sounds "muddy" or if it exhibits "lack of clarity", the WGT curve shows a bad ripple in some frequency region. This kind of ripple is especially disturbing in the mid frequency region." (Such a ripple usually stems from a strong early reflection.)
Design wise I think it says that the ideal speaker would be very flat in anechoic measurements, have some kind of special midrange directivity to reduce floor bounce energy and have a woofer system that dealt with room boundaries to gave flat and extended bass response in the room.
David S.
Here's the papers Dave was speaking of:
AES E-Library: Listening Room Influence on Loudspeaker Sound Quality and Ways of Minimizing It
AES E-Library: A New, Psychoacoustically More Correct Way of Measuring Loudspeaker Frequency Responses
Thanks again Dave!
Dan
AES E-Library: Listening Room Influence on Loudspeaker Sound Quality and Ways of Minimizing It
AES E-Library: A New, Psychoacoustically More Correct Way of Measuring Loudspeaker Frequency Responses
Thanks again Dave!
Dan
Brighter than a conventional dome two way? Is it merely the kind of brightness that can be fixed with EQ?
Footnote:
... since reflections are by and large the "bad guy" in this discussion, therefore home music room should be as dead as possible. I'd bet you can get more mileage out of room absorbent than trying to squeeze the last bit of directivity-control out of the treble driver.
From eyeballing lots of pictures on this website, I'd say few set-ups have much chance of sounding good because they are hard-surfaced everywhere. Certainly not many old-tyme wall-to-wall carpets with thick felt underlayers.
Granted, that is modern home decor, but it isn't good for sound. The more dead the room the better and let the speakers make the sound. Even thinking Toole-wise, making a room as dead as you can still leaves more than ample reverberant sound.
Paraphrasing Hamlet, the problem lies not in the speakers but in our rooms.
Small hint: you can tuck the absorbent stuff, like Tectum replacing wallboard or sheets of fiberglass board, almost anywhere in the room or under couches and behind cabinets and hidden in curtains, etc. Try valenced wall-to-wall heavy or heat-insulated curtains hanging a few inches off the wall.
... since reflections are by and large the "bad guy" in this discussion, therefore home music room should be as dead as possible. I'd bet you can get more mileage out of room absorbent than trying to squeeze the last bit of directivity-control out of the treble driver.
From eyeballing lots of pictures on this website, I'd say few set-ups have much chance of sounding good because they are hard-surfaced everywhere. Certainly not many old-tyme wall-to-wall carpets with thick felt underlayers.
Granted, that is modern home decor, but it isn't good for sound. The more dead the room the better and let the speakers make the sound. Even thinking Toole-wise, making a room as dead as you can still leaves more than ample reverberant sound.
Paraphrasing Hamlet, the problem lies not in the speakers but in our rooms.
Small hint: you can tuck the absorbent stuff, like Tectum replacing wallboard or sheets of fiberglass board, almost anywhere in the room or under couches and behind cabinets and hidden in curtains, etc. Try valenced wall-to-wall heavy or heat-insulated curtains hanging a few inches off the wall.
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Sure sound absorption can certainly improve the sound of a system, but it's garbage in garbage out - it's been my experience that if a system doesn't sound good to start with, no amount of room treatment is going make it sound good, and conversely if a system at it's root sounds good to start with, a bare room isn't make it sound all that bad.
The goal is to not deaden the room completely, but to make it
such that the reflections arrive at a certain period after the direct
sound and that their character is close to the original sound.
If you remove the reflections completely, your brain will not be
able to locate the phantom image.
In my experience, loudspeakers that beam have their image in front
of the speakers., whereas loudspeakers that have good directivity
form their image behind the speakers. This second kind are also
less fatiguing because the brain does not have to work hard to locate
the source.
I've read Linkwitz say that in an anechoic chamber, the phantom image
forms in your head between your ears, just like when you listen to headphones,
because there simply isn't any reflected sound for the brain to use to
locate the image.
such that the reflections arrive at a certain period after the direct
sound and that their character is close to the original sound.
If you remove the reflections completely, your brain will not be
able to locate the phantom image.
In my experience, loudspeakers that beam have their image in front
of the speakers., whereas loudspeakers that have good directivity
form their image behind the speakers. This second kind are also
less fatiguing because the brain does not have to work hard to locate
the source.
I've read Linkwitz say that in an anechoic chamber, the phantom image
forms in your head between your ears, just like when you listen to headphones,
because there simply isn't any reflected sound for the brain to use to
locate the image.
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We audionuts just don't pay enough attention to our rooms, that's for sure.
I'm in the process of doing acoustic treatment now, and the results are very satisfying.
Being a "live sound guy" for years I can tell you that the room makes a HUGE difference. You learn that real quick when touring the same sound rig into many different venues. It can completely change the sound of the system.
Anecdote: Years ago I was touring with a jazz combo and a small P.A. It was crap, I didn't like it. When we got back to town for a show, all my buddies wanted to come hear the show but I was embarrassed about low quality of the sound system. After the show they all told me I was nuts. "It sounds great". Indeed it did. Why? A 100+ year old theater all built of wood. Marvelous acoustics. System completely transformed.
That was just one of many experiences like that. The room acoustics really do matter.
I'm in the process of doing acoustic treatment now, and the results are very satisfying.
Being a "live sound guy" for years I can tell you that the room makes a HUGE difference. You learn that real quick when touring the same sound rig into many different venues. It can completely change the sound of the system.
Anecdote: Years ago I was touring with a jazz combo and a small P.A. It was crap, I didn't like it. When we got back to town for a show, all my buddies wanted to come hear the show but I was embarrassed about low quality of the sound system. After the show they all told me I was nuts. "It sounds great". Indeed it did. Why? A 100+ year old theater all built of wood. Marvelous acoustics. System completely transformed.
That was just one of many experiences like that. The room acoustics really do matter.
Hey Pano Nut
Who are you calling a nut?
Just because I resemble that remark doesn't mean the rest of the, er, Nuts here qualify!
Who are you calling a nut?
Just because I resemble that remark doesn't mean the rest of the, er, Nuts here qualify!
Ra7,
Although I believe that a room that's too absorbent will sound dead, how much treatment is required for that effect to take place? It seems from many photos of 'audiophiles' in general, be it this site or the many others, most have next to no treatment at all. Also, since i'm just beginning to work with my acoustic treatment I'm not sure how costly/how much square footage of coverage it takes to achieve that 'overly' absorbent effect.
I'm not arguing with you, I just find that remarks like this while completely correct and true might often get misread or misunderstood by others who then think "I don't want a dead room!" not realizing that a dead room (Anechoic) is quite difficult to achieve.
Though, that talk about 'sound in your head' - I really like that effect :S
JR,
Although I believe that a room that's too absorbent will sound dead, how much treatment is required for that effect to take place? It seems from many photos of 'audiophiles' in general, be it this site or the many others, most have next to no treatment at all. Also, since i'm just beginning to work with my acoustic treatment I'm not sure how costly/how much square footage of coverage it takes to achieve that 'overly' absorbent effect.
I'm not arguing with you, I just find that remarks like this while completely correct and true might often get misread or misunderstood by others who then think "I don't want a dead room!" not realizing that a dead room (Anechoic) is quite difficult to achieve.
Though, that talk about 'sound in your head' - I really like that effect :S
JR,
from RA7
"....
If you remove the reflections completely, your brain will not be
able to locate the phantom image.
...."
While I agree you do not want to remove all reflections completely (which is not practical anyway), your above statement is absolutley incorrect.
-Tom
"....
If you remove the reflections completely, your brain will not be
able to locate the phantom image.
...."
While I agree you do not want to remove all reflections completely (which is not practical anyway), your above statement is absolutley incorrect.
-Tom
Rooms do make an enormous impact. I fully agree, after experiencing the old amphitheaters of the Roman empire (the ruins that are left) it's insane how easily one can be heard from a 'huge' distance by a speaker who isn't screaming their head off just due to positioning.
Jr,
Well, the brain will be able to locate it, but the location will be in your head between your ears.
Talking strictly about the phantom image, not the sound coming from the left or right speaker.
Sorry that I have to say that: You are still wrong. The phantom image does NOT need any reflections. It is as present (somewhere betwen the speakers or deeper into the room) in the anechoic chamber as well as in any untreated room.
You will have to lead me to Linkwitz' statement to make me believe he said that.
Rudolf
My room gets pretty good marks for sonics, yet would fall into your set. It is large & has a non-box shape.
dave
Ok.... I will have to find it online. He certainly said it in front of 150 people at BAF this year. I'm sure it must be online somewhere.
I'm saying the phantom image is present even without reflections, but it moves closer and closer to your head as the reflected information is reduced and it moves into your head when there are no reflections.
Btw, if you have experienced this in an anechoic chamber and know for sure that there is an phantom image between the speakers, then please do share that experience. I'd like to state that I have not experienced this personally, but I'm willing to believe the explanation behind it.
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