The Objectives of a Loudspeaker in a Small Room

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graaf said:
Re: soongsc

listening rooms seem to be acoustically not so diverse, they are quite standarized, that is - quite typical
after all they are in most cases our living rooms
"living room" has functions and architects are supposed to take those functions into account when they work
it has to be not to small and not to big and to have proportions most suitable for all of its functions to be best realized
typical sizes, typical proportions, and not very diverse acoustics because it is a function of furnishing and decor - typical furniture, carpets, curtains etc.
"living rooms" of typical size and with typical furnishing and decor (that is most of them) are very similar from the point of view of fundamental acoustical characteristics i. e. the RT60

if I'm wrong than correct me, comments welcome! :)
Bear in mind that different locations in the world have different considerations during decoration and furnishing. Not many people do much to cover concrete walls here, whereas in places like the US, wall are already more absorbent. Listeing to speakers in HiFi shows hosted in hotels here, lots most equipment on display really are worth only 1/10th of what the asking price is IMO. I'm sure the room is probably at least 80% responsible for this.

gedlee said:



Well, I think that you are wrong. My listening room is anything but typical and its NOT a living room.

This is the whole point of this thread. Are we trying to squeeze some speakers into our wifes living rooms and call it a "sound system"? (I'm not.) Or are we trying to find the ideal solution for really exceptional sound reproduction (again as I am). Because if our "goals" are not the same then its highly unlikely that our approachs or our results will be comparable.

As I have said before, if you are limited in what you can do (because of space or whatever) then I sorry for you - I wish you the best. But this stuff is my life and I take it very seriously. When I discuss things here it is from this "extremist" point of view and you have to keep that in mind. I am seeking "the very best that can be achieved". If I have to knock out a few walls to do that then so be it - I've done that before. But basically its just easier to start from scratch with a new room and design it right from the ground up (I do that a lot.). Thats what I specialize in. (I don't install Bose cubes in living rooms.)
The title makes me think of designing loudspeakers for small rooms in general. Or am I mistaken?

gedlee said:



I am sorry, but I have drawn many conclusions in this regard thank you. To me its not "diversified opinions". You will find that most "experts" agree (Floyd Toole and I agree on virtually everything - some minor differences, but on the whole we see eye to eye.)

There is no way to standardize the rooms, but there is a way to make virtually any room acceptable to excellent. Its all a matter of design, but you have to know what to do. Much of the "diversified opinions" out there are simply incorrect. Granted, sorting out the "wheat from the chaff" can be a difficult thing to do , but read some of the classic texts, like Kutruff, or Floyd Tooles stuff and you will come to understand the realities.

If you ask the room designers why a certain pair of speakers sound terrible in a room they designed, they will point to the equipment, and vice versa. :D Well, maybe a few will tell the buyer that they are out of their mind.:angel:
 
Re: soongsc

>Bear in mind that different locations in the world have different
>considerations during decoration and furnishing

ok, it's true but all that differences are negligible from the point of view of loudspeaker designer in the sense that they can be fixed easily even without specialized "acoustical treatment"
natural acoustics of a living room (as opposed to e.g. natural acoustics of a bathroom) should be sufficient

>Listeing to speakers in HiFi shows hosted in hotels here, lots
>most equipment on display really are worth only 1/10th of what
>the asking price is IMO. I'm sure the room is probably at least
>80% responsible for this

well, I understand that domestic hi-fi equipment is supposed to be used at home in our domestic environment and to sound good in that typical environment rather than our houses are supposed to be built around home hi-fi
that would be turning things upside-down

louspeakers that sound good only in a room built/arranged around them?
it seems to be a strange idea for me

surely loudspeakers should be carefully matched with a given room but that is mainly problem of bass response of loudspeakers the bass response of which is optimized for "flat" in an anechoic environment

the main cause of horrible sound at the hi-fi shows is IMHO marketing strategy of hi-fi dealers who want to display all of their priciest/most precious audio-gear at the same time in the same room, probably "to impress" ;)
the often horrible sound at the shows is mainly because of total lack of synergy between the elements of the presented audio systems and of "too bass heavy speakers in too small rooms"

I seriously believe that it is not a question of a bad room. I visit HiFi Shows organized at the same hotel for years and I didn't notice a problem of a "bad room" like "there is always bad sound in room 213", "everything sounds bad in that room" etc.
One audio system sounds good in the room and other sounds bad.
IMHO it proves that finally not the room is to blame.
 
The big problem with ambiophonics is that it is pretty much DIY - although it should not be a problem for us:)

Decoders available now are the following:
TACT now have crossfed/crosstalk cancellation option
the RACE algorhytm on the ambiophonics site
the Yamaha YSS901 DSP chip - this is what I prefer
the DSP inside the Creative Playworks PS2000 toy speaker (not kidding)
.
.

Ambience generation can be done with most of the older Yamaha, JVC acoustics processors or with a pc. As correctly said on the ambiophonics site, the more ambience channels the better.

I totally believe now that hi-fi is not depends on minuscule detail improvements, but solely on 2 things: psychoacoustical consistency and soundfield completeness.


BTW I have to diagree with Mg Geddes. Harmonic distortion of drivers are eminently audible with crosstalk cancellation. The distortion component can not hide in the recorded ambience like in stereo if you use XTC.
 
Re: fcserei

>I totally believe now that hi-fi is not depends on minuscule
>detail improvements, but solely on 2 things: psychoacoustical
>consistency and soundfield completeness

Amen Amen!

that is so very well said!

thank You so much for the answer :)

BTW I didn't know that Tact has crosstalk cancellation option
Could it be they took ambiophonics into account when designing their equipment or is it just a coincidence?
 
fcserei said:
The big problem with ambiophonics is that it is pretty much DIY - although it should not be a problem for us:)

Decoders available now are the following:
TACT now have crossfed/crosstalk cancellation option
the RACE algorhytm on the ambiophonics site
the Yamaha YSS901 DSP chip - this is what I prefer
the DSP inside the Creative Playworks PS2000 toy speaker (not kidding)
.
.

Ambience generation can be done with most of the older Yamaha, JVC acoustics processors or with a pc. As correctly said on the ambiophonics site, the more ambience channels the better.

I totally believe now that hi-fi is not depends on minuscule detail improvements, but solely on 2 things: psychoacoustical consistency and soundfield completeness.


BTW I have to diagree with Mg Geddes. Harmonic distortion of drivers are eminently audible with crosstalk cancellation. The distortion component can not hide in the recorded ambience like in stereo if you use XTC.

This is one side of the camp that I am not convinced about. I beleive minuscule detail preservation is also very important, which normally is lost if the ambient part is not handled correctly. Additionally, interaction of the recorded ambient information mixed with the stored energy in speakers mess things even more.

Speaker location and speaker distance should all be considered in the decoder to properly reveal the recorded data, how many ambience channels can these decoders handle?
 
Have you tried Angelo Farina's plug ins for binaural playback through loudspeakers (Ambiphonics) or its reverse - stereo via headphones? As I understand 2x2 impulses are measured by microphones in my ears at listening position (speakers close togather, 10deg) and then Kirkeby linearisation is performed. How algorithm knows my speaker transfer function? Kirkeby makes so strong correction - it doesn't use any frequency dependant windowing. Overcorrected speaker may be not the ideal one.
 
graaf said:
Re: soongsc

louspeakers that sound good only in a room built/arranged around them?
it seems to be a strange idea for me

surely loudspeakers should be carefully matched with a given room but that is mainly problem of bass response of loudspeakers the bass response of which is optimized for "flat" in an anechoic environment


I started this tread to discuss small "listening" rooms, not "living" rooms. Perhaps I should have been clearer in the tilte, but I know what my initial interest was and I have been to that point ever since. Perhaps a thread on "Sound systems in living rooms" would be appropriate, but certainly not my interest.

The loudspeaker design does have to be carefully matched to the listening room - but what listening room? As a designer I had to pick something so I decided to pick a "well designed room". It seemed a little absurd to design loudspeakers for a "badly designed room" even though such spaces abound. And its far more than a problem with bass response as the room affects imaging, bass, everything.

Just because speakers are targeted at a "well design room" does not mean that they are bad in a badly designed room. Thats a false assumption. As I have said before, a bad room tends to degrade the sound a good loudspeakers while a good room accentuates them. In general a good set of loudspeakers will still sound good in a poor room, but they will not be as good as they could be in a well designed room. You guys seem to go to the extremes, ignoring the grays of reality.
 
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gedlee said:
In general a good set of loudspeakers will still sound good in a poor room, but they will not be as good as they could be in a well designed room.

Can't argue with that! And it's amazing what great room can do for ordinary speakers. Of course some rooms are so bad they ovewhelm even good systems - but I'm thinking of aircraft hangers and hockey rinks that I've had to mix in - certainly not "small rooms", those.

The title of thread does seem a bit misleading. "The Objectves of a Loudspeaker in a (small) Dedicated Listening Room" might be more in line with what Mr. Earl has in mind.
 
Re: Gedlee

>I started this tread to discuss small "listening" rooms,
>not "living" rooms.
>As a designer I had to pick something so I decided to pick
>a "well designed room".

I undestrand but cannot a living room be a "well designed listening room" as well?
Is it that difficult?
Perhaps we really should discuss the question of "a well designed room" as Soongsc already suggested.
As an expert with a clear concepct of "a well designed room" i.e. with defined expectations as to the room appropiate for Your Summa loudspeakers perhaps You could clarify the subject for us :)

What are the main characteristics of a "well designed listening room" according to Your concept and in what aspects it differs significantly from a "typical living room"?

>And its far more than a problem with bass response as the
>room affects imaging, bass, everything.

Could You elaborate a little on how it affects those other aspects? What do You precisely mean by "everything"? Can You give some examples please? I'm asking for examples as they are easiest to understand for nonexperts.

>Just because speakers are targeted at a "well design room"
>does not mean that they are bad in a badly designed room.
>Thats a false assumption

I agree.
So in the end loudspeaker design that produces loudspeakers that sound good in a living room and better or much better in a living room turned into "well designed listening room" is possible, isn't it?
Separate design rules for loudspeakers dedicated for "a living room " and for "well designed listening room" are not necessary - or are they?

and may I ask You again (it seems that those questions have been overlooked):
what about that unusual Stereolith thing?

and what about those "diversified opinions"?
I mean the results of Toole's research on early lateral reflections and Your position regarding that question
It seems to me that we have an example of "diversified opinion" here. Is it "minor" or is it just a misunderstanding?
 
graaf said:
Re: Gedlee

I undestrand but cannot a living room be a "well designed listening room" as well?
Is it that difficult?
Perhaps we really should discuss the question of "a well designed room" as Soongsc already suggested.
As an expert with a clear concepct of "a well designed room" i.e. with defined expectations as to the room appropiate for Your Summa loudspeakers perhaps You could clarify the subject for us :)

What are the main characteristics of a "well designed listening room" according to Your concept and in what aspects it differs significantly from a "typical living room"?


Well it is pretty difficult to place room objects, dampers, etc. in a manner that is pleasing to everyone.

IMO the room behind the speakers needs to be dead with no diffracting or refelcting objects nearby. These objects set up early diffraction and reflections and obsure the image - this alone dictates a lot of problems. The speakers should be symetrical to the listener - as well as can be achieved in the room. Then the nearest walls where the first sidewall reflections occur should have a diffuser (I build a special kind here) and this is usually a problem on top of the above requirements. The ceiling reflection must be disipated, the same with the floor. Then the listener must be near the center of the room away from reflecting boundaries. And finally the room from the listener position back should be without any sound absorption at all.

Now get all of this into your "living room" and you are a wizard!!!


>And its far more than a problem with bass response as the
>room affects imaging, bass, everything.

>Could You elaborate a little on how it affects those other aspects? What do You precisely mean by "everything"? Can You give some examples please? I'm asking for examples as they are easiest to understand for nonexperts.<

To me there are two things in audio reproduction that are paramount to good perception - tembre or coloration and image. Both of these are stongly influencd by the room, its early reflections, etc. In the low frequencies the room totally dominates the situation. SInce the main speakers need to be placed to achieve good imaging and low coloration, we cannot control the room base with the loactions of these. Thus I recommend the use of several subs - as does just about everybody these days since it works so well. Place them around the room - random almost works as well as strategic placement. Putting one off of the floor helps too.

>So in the end loudspeaker design that produces loudspeakers that sound good in a living room and better or much better in a living room turned into "well designed listening room" is possible, isn't it?<

Of course - and this is what I believe that the ESP line achieves. Its just that I like to talk about the ideal - its far more interesting.

>Separate design rules for loudspeakers dedicated for "a living room " and for "well designed listening room" are not necessary - or are they?<

There are situations where this could be the case, such as a very dead room. The high directionality of the ESPs would likely sound somewhat less spatious in a dead room than a wide directivity speaker. But I would never design nor recommend a dead room, so to me this is not an issue. But it could be to others I suppose.

>and may I ask You again (it seems that those questions have been overlooked):
what about that unusual Stereolith thing?<

This just isn't something that I have looked into.

>and what about those "diversified opinions"?

I mean the results of Toole's research on early lateral reflections and Your position regarding that question
It seems to me that we have an example of "diversified opinion" here. Is it "minor" or is it just a misunderstanding? <

I do not believe that Toole ever said that very early lateral reflections (<10 ms.) are a "good thing". If you know of a statement of his that claims that I'd like to read it.


Earl

[
 
posted by gedlee: "Thus I recommend the use of several subs - as does just about everybody these days since it works so well. Place them around the room - random almost works as well as strategic placement."

Hi Earl,

How about placing several stereo subs ?, put all the left channel subs in the left of the listener and the right channel subs on the right ?

Hartono
 
119th AES Convention, NY, October, 2005 - Tutorial

T1 - The Acoustics and Psychoacoustics of Loudspeakers in Small Rooms: A Review Presenter: Floyd Toole, Harman International Industries, Inc. - Northridge, CA, USA


Toole has concluded that normal reflections in a typical small living room seem not to interfere with perception of the recorded space. He has also determined that early lateral reflections (<50ms) have a beneficial effect on intelligibility similar to raising the dialog level, and that the reflection pattern is more important than reverberation.
 
Re: Gedlee

>I do not believe that Toole ever said that very early lateral
>reflections (<10 ms.) are a "good thing". If you know of a
>statement of his that claims that I'd like to read it.


Unfortunately only an abstract of his presentation is available to me:
http://www.linkwitzlab.com/Acoustics and Psychoacoustics of Loudspeakers in Small Rooms.doc

>>"A certain amount of the right kind of reflected sound appears to enhance the music listening experience and, interestingly enough, to improve speech intelligibility."
Toole has concluded that normal reflections in a typical small living room seem not to interfere with perception of the recorded space. He has also determined that early lateral reflections (<50ms) have a beneficial effect on intelligibility similar to raising the dialog level, and that the reflection pattern is more important than reverberation.
This has led to Toole’s recommendation that too many or too few reflections can be a problem. In particular, acoustic absorption, diffusion, and reflection must be broadband, ideally starting below 200Hz. He pointed out that the typical 1½ or 2½ sound panel most often affixed to walls works only at relatively high frequencies, and acts to effectively turn down the tweeter with no effect on the midrange or upper bass, thus unbalancing the sound<<

This seems to be consistent with Moulton position. Therefore I ask.
Is anything wrong with that asbtract? Is any misinformation there?
 
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