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#1 of 18 OFFLINE   EricB

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Posted April 09 2007 - 05:59 PM

If two different speakers had an identical response curve, would they sound identical as well, in the same room?

Just a thought.

#2 of 18 OFFLINE   SHS

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Posted April 09 2007 - 11:16 PM

I'll take a stab at this. There are a few other variables besides the speaker itself.
1) The room would have to be completely symmetrical.
2) Doors, windows, walls/ceiling/floor of different stiffness/construction, openings in all of above, items in the room, all have to be considered.
3) You would have to be placed equidistant from the speakers.
4) the speakers would have to be placed symmetrically in a mirrored placed in the room.
5) Your hearing would have to be identical in the left and right.
6) Airflow in the room
7) Speaker cables identical and connected well

Then they should sound and actually reproduce identically (within the accuracy specs of the amp/source/speaker of course) with the same db and frequency emanating from them.

......variables!!!
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#3 of 18 OFFLINE   Tony Genovese

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Posted April 10 2007 - 12:17 AM

Quote:
Originally Posted by EricB
If two different speakers had an identical response curve, would they sound identical as well, in the same room?

Just a thought.
No. The other aspect that you need to consider is dispersion.

#4 of 18 OFFLINE   Marc LaPalme

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Posted April 10 2007 - 01:05 AM

every speaker is different. unless they are the exact same speaker they will sound differently.

#5 of 18 OFFLINE   Tony Genovese

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Posted April 10 2007 - 01:12 AM

Quote:
Originally Posted by Marc LaPalme
every speaker is different. unless they are the exact same speaker they will sound differently.
And even if they are the exact same speaker, if the manufacturer doesn't match the speaker to tight tolerances, they will sound differently.

#6 of 18 OFFLINE   MaxL

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Posted April 10 2007 - 01:49 AM

sorry scott, but i sort of disagree with your list.

if we have 2 matching fronts, we have two speakers with matching response curves. while you are absolutely correct that those considerations you listed will affect the sound we hear, most of them will affect it about equally as that sound gets from the speakers to our ears. if you were correct, anyone in an asymetrical room with anything but perfect room acoustics would need a team of acoustic technicians to set up two stereo speakers to sound the same. i think most of us can agree that our matching speakers do sound the same, especially if they are of decent quality/ craftsmanship. (yes, cheap speakers whose cones are inconsistently manufactured may display discoloration between two of the same drivers.)

there is a simple test for this. take a mono recording or listen to a stereo recording in mono. the signal sent to the speakers will be identical. is the sound the same from both speakers? the stereo image should present everything coming from dead center, no sounds favoring stage right or left. again, room considerations may affect your soundstage, but not really speaker coloration unless there are extreme in-room factors (or you have super-human hearing powers).

this method would also be the easy way to test the OP theory. here's my response to that:

1) let's assume that the response curves are actually the same. (many graphs are created using somewhat different methodology, and therefore represent different facts).

2) a response curve, however it's made, tells us about quantity of sound not quality. we know this speaker puts out a sound this loud from this distance at this frequency given a signal of this much power. we may make inferences about overall sound based on the curve, such as a slow rolloff at 17khz might make for a warm overall sound. but the curve can't tell us about distortion anywhere, tightness, strain, openness, detail, clarity, muddiness, voicing of any description, etc.

3) rather than room considerations, it is the other physical diffferences in the speakers themselves that will make them sound different. the cabinet materials, shape and size, the drivers, the cone/ dome size and materials, surround materials and stiffness, etc. all have affects on the sound we hear. in an anechoic chamber two different speakers with identical freq. resp. curves will sound different assuming some of these other variables are different.

the short answer to th OP then is no, almost definitely not. but as the saying goes, even a blind zombie finds a brain every now and then. it could happen, but luck would have about as much to do with it as matching freq resp curves IMO.
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#7 of 18 OFFLINE   SHS

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Posted April 10 2007 - 05:43 AM

I guess it is one of those arguments that could go around and around. I see your point but I think you are referring to similar sound not "identical" sound.

All of those variables and more will effect the sound from one extreme to the other. I agree that you will not hear most of them, however, they do have an effect. The accumulation of these effects begin to be noticeable. Just like if you have one speaker too close to a wall or corner, it most likely won't be too noticeable until you hit volume levels that cause reverberation or coloration of the sound.

I humbly bow to the experience of others here though, they have much more than theory to draw from.
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#8 of 18 OFFLINE   MaxL

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Posted April 10 2007 - 02:31 PM

i won't claim to be an expert... but i will claim to be rightPosted Image .

by your definition of identical sound, no two speakers anywhere have ever sounded identical. this is, if nothing else, due to the constantly changing magnetic fields moving around and through the planet as well as the gravity of the sun, moon and other celestial bodies that pull on the magnets and coils in our speaker drivers. no, even your average college campus wouldn't be able to measure these effects in a meaningful way, but I know they're there!

the reasons i listed for speakers sounding different actually cause speakers to sound different, regardless of room acoustics. what you have talked about are reasons why the same speakers may sound different in a real room. as i said already:
Quote:
...you are absolutely correct that those considerations you listed will affect the sound we hear...

the point is, this is not one of those questions that is a matter of opinion. there's no around and around. this is a theoretical question. the part of the question that specified "in the same room" i read as a room that does not affect either speaker differently. it's a yes or no question. the answer is no, they would not sound the same. of course somewhere around 1% or less of the time that answer would be wrong because the speakers would sound the same and that would be a fluke. what i have tried to do is list the some of the top reasons why that answer is likely to be no.

i am fully capable of being wrong too.... ask my wife. Posted Image
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#9 of 18 OFFLINE   Jacob C

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Posted April 10 2007 - 02:48 PM

there are lots of factors, many of them mentioned above.
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#10 of 18 OFFLINE   SHS

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Posted April 10 2007 - 03:37 PM

I would be willing to bet that with most well built speakers that are not made to be left or right biased you would not be able to pick out the difference by listening in a blind test. ie; swapping speakers back and forth. Admittedly there would be some speakers that some people could tell the difference with just listening, those of more acute hearing and tone sensitivity.

Now, measuring the differences is a different discussion altogether.

The question was "would they sound identical as well". My EX-wife says I think I'm always right.....hmmmmm, maybe hence EX.

My answer be YES, most of the time, with a few caveats.Posted Image
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#11 of 18 OFFLINE   JohnRice

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Posted April 10 2007 - 04:30 PM

Do you guys really think all aspects of sound reproduction can be boiled down to a line on a piece of paper? That if that line is the same for two different speakers, they will sound exactly the same every time( under the same listening conditions), or even 9 times out of 10, even if they have significantly different design principles?

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#12 of 18 OFFLINE   EricB

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Posted April 10 2007 - 05:17 PM

Interesting ideas guys.

Anyway, the question came to mind because as I understand, everything that we hear can be translated / equated to corresponding frequencies, which is (roughly) represented by the response curve. (As a side note, the spectrum analyzer used by the fbi to identify voices comes to mind. Posted Image)

Isn't it that these qualities that we use to describe speakers (warmth, brightness, laidback, forward, etc) can be attributed to variations within this response curve?

But as you guys have pointed out, it seems that what we 'hear' cannot be entirely represented by a response chart.

#13 of 18 OFFLINE   SHS

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Posted April 10 2007 - 10:15 PM

Quote:
Originally Posted by JohnRice
Do you guys really think all aspects of sound reproduction can be boiled down to a line on a piece of paper? That if that line is the same for two different speakers, they will sound exactly the same every time( under the same listening conditions), or even 9 times out of 10, even if they have significantly different design principles?

Absolutely YES, or no or, I'll get back to you on that! Let me draw a line and study it for awhile, would that line be straight or green errr I mean with a pencil or verticle......or....wait a minute, who's talking about lines here?Posted Image

John you are raining on our little parade here!!!Posted Image

Hey, I've been in Ft Lauderdale working all week, nothing can get me riled....too much pretty things to admire.Posted Image Life is golden.
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#14 of 18 OFFLINE   MaxL

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Posted April 11 2007 - 12:32 AM

Quote:
Originally Posted by JohnRice
Do you guys really think all aspects of sound reproduction can be boiled down to a line on a piece of paper? That if that line is the same for two different speakers, they will sound exactly the same every time( under the same listening conditions), or even 9 times out of 10, even if they have significantly different design principles?

no, i do not think sound can be boiled down to a line on a piece of paper. to quote myself:
Quote:
a response curve, however it's made, tells us about quantity of sound not quality. we know this speaker puts out a sound this loud from this distance at this frequency given a signal of this much power. we may make inferences about overall sound based on the curve....

scott, you:
Quote:
I would be willing to bet that with most well built speakers that are not made to be left or right biased you would not be able to pick out the difference by listening in a blind test. ie; swapping speakers back and forth.
me:
Quote:
i think most of us can agree that our matching speakers do sound the same, especially if they are of decent quality/ craftsmanship.
so you're agreeing with me now. good. we're all on te same page - i'm rightPosted Image .

Quote:
Anyway, the question came to mind because as I understand, everything that we hear can be translated / equated to corresponding frequencies, which is (roughly) represented by the response curve. (As a side note, the spectrum analyzer used by the fbi to identify voices comes to mind. )

in theory all sound can be translated to numbers: hence digital recording. but a freq resp graph is not nearly so detailed. first off, there's the line and what it represents. generally if that line is smooth, we can assume that the line was made by taking points from samples at given frequencies, plotting them and then connecting the dots with a smooth line. if it is a zigzag line it is probably made the same way but connecting the dots with straight lines. the more jagged the line, the more samples (and points) along the way. i'm not going to pretend that i know much about how the fbi uses a spectrum analyzer except to say this: it is going to be comparing patterns of known sounds that happen in time. time is not a variable in a freq resp curve, but it does play into the sound of a speaker, the sound we hear.

Quote:
Isn't it that these qualities that we use to describe speakers (warmth, brightness, laidback, forward, etc) can be attributed to variations within this response curve?
as i've already mentioned, we can infer from a resp curve a likely overall sound based on peaks, valleys and rolloffs, but that is a very imprecise science and even experts would be fooled regularly if they had to guess (and it would be a guess). also these terms are widely seen as subjective, what sounds bright or warm to me may be neutral to someone else.

Quote:
But as you guys have pointed out, it seems that what we 'hear' cannot be entirely represented by a response chart.
yes, yes... you agree with me too... Posted Image
HT: Marantz SR8000, PSB Alpha B fronts, Alpha C center, CSW Newton S200 surrounds, Martin Logan Dynamo Sub, Marantz DVD, Sony CRT TV

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#15 of 18 OFFLINE   RickiRed

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Posted April 11 2007 - 04:09 AM

Quote:
Originally Posted by EricB
If two different speakers had an identical response curve, would they sound identical as well, in the same room?

Just a thought.

Too many variables........Are the materials of the speakers the same? Who is listening to the speakers.................... But to answer the question, NO!
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#16 of 18 OFFLINE   SHS

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Posted April 11 2007 - 06:58 AM

hmmmphhhh! Then I guess we have nothing else to disagree about! darn, NEXT SUBJECT!!Posted Image
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#17 of 18 OFFLINE   EricB

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Posted April 11 2007 - 07:29 AM

Well, just before we end this one, a little something more. Posted Image

My original question was under the assumption that the complete responses of the two speakers were exactly the same, including every minute spike, peaks, dips, etc, and not just a 'summation response curve.'

I'm still a bit confused though.. I mean, a certain frequency can never sound any different under any circumstances, right?

And about dispersion, as mentioned above, I'm not really sure what factor governs this, but if you're seated say.. at the sweet spot, does it still matter?
If it does, is it because the effect of the reflection points would be different then?

#18 of 18 OFFLINE   MaxL

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Posted April 11 2007 - 09:15 AM

no, a given frequency can sound different. i suppose if all you were listening to were sine waves and test tones, maybe, but i'm still not convinced they would sound the same. but listening to real sounds, voices and instruments, time, attack and decay all play a part in the final sound we hear. these may be very subtle things and not everyone would notice all of them, certainly not if you were doing an a/b comparisson. but the problem, and i sort of assume the original intention of the question is what if you were to listen to these two speakers at the same time.

our ears, like most of our senses, are designed to pick up on change and notice difference, it's a survival mechanism we've inherited through evolution (i assume you believe in evolution, otherwise god just make's the best speakers and they are all available at walmart and sound best while eating domino's pizza and watching the 700 club or your favorite bush speech on education). so, while we may not consciously be able to identify how the speakers sound different, our hearing would be affected in that certain sounds would appear to come more from one speaker than the other. this is because our brain-ear hearing system works by assigning every sound we hear an original source sound fragment and then associating the rest of the sound fragments that go with it to that sound. there's an explanation of all this at aperion's educational section.

there are just so many parts of sound reproduction beyond frequency and volume, which is what the resp curve tells us about. in the interest of the hypothetical, lets imagine two speakers that are dead flat in response. not a blip in the line from 20hz to 20khz. now, lets imagine we're testing these two speakers in a field in central illinois. there's nothing for miles for the sound to bounce off of except you, the amp and the cd player. now you put in bohemian rhapsody, set the playback to mono and... not the same sound. why... all of the reasons i've already mentioned in my original response and earlier in this one.

and yes, dispersion can play a role in the real world or my hypothetical scenario. even if there's nothing for the sound to bounce off of, we can perceive the difference between wide and narrow sound stages from individual speakers.

if the reason every dip, spike, peak, etc is identical is because they are the same speaker, then, yes, they will sound the same.
HT: Marantz SR8000, PSB Alpha B fronts, Alpha C center, CSW Newton S200 surrounds, Martin Logan Dynamo Sub, Marantz DVD, Sony CRT TV

Stereos include vintage Sony receivers/amps into vintage AR and KEF speakers.


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