Theoretical question - differences between speaker systems

[johnnm]

When one speaker is "better" than another, or more detailed, or has "more air", or "more presence", or even if an instrument section appears to be in a slightly different space than when heard with another speaker...are these observations solely a function of the speaker's frequency response?

In other words, if two speakers have an identical frequency response, and are placed in the same spot in the same room, will they sound identical?

 

[Sir.Byrd]

Nope. Many more characteristics to deal with, such as dispersion, for example.

 

[Negotiableterms]

Hmmm... now what was that old measurement that everyone used to focus on before the modern era.... what was that?

Oh yeah! Distortion. There were different kinds, too: THD, IM... there were probably others, too.

 

[Soundthought]

The only way 2 sets of speakers will sound the same, is if they're the same physically identical speakers.

But, any one pair of those same speakers will sound (behave) differently, in different acoustic environments


Regards,
John

 

[TerryO]

When one speaker is "better" than another, or more detailed, or has "more air", or "more presence", or even if an instrument section appears to be in a slightly different space than when heard with another speaker...are these observations solely a function of the speaker's frequency response?

In other words, if two speakers have an identical frequency response, and are placed in the same spot in the same room, will they sound identical?

John,
If this isn't a troll, I'll answer your question: "if two speakers have an identical frequency response, and are placed in the same spot in the same room, will they sound identical?"

Based on an exact interpretation of your statement, the answer is: Yes, they would sound the same.

Best Regards,
TerryO

 

[Zilch]

Other things being equal, "Yes...." :tongue:

 

[lab]

No two speakers are absolutely identical...kinda like snowflakes, only it takes an overdriven amp to melt a speaker!

 

[dnewma04]

A non-overdriven amp can also melt a speaker.

 

[johnnm]

Not a troll - just curious.

Thanks for the replies. I forgot the baffle construction could add dispersion effects. And I do realize the improbability of ever finding two speakers with exactly identical frequency responses.

 

[Blast]

The OP said "speaker system" (not individual driver). Does everyone still stand by their answers?

 

[toddalin]

When one speaker is "better" than another, or more detailed, or has "more air", or "more presence", or even if an instrument section appears to be in a slightly different space than when heard with another speaker...are these observations solely a function of the speaker's frequency response?

In other words, if two speakers have an identical frequency response, and are placed in the same spot in the same room, will they sound identical?

No, not necessarily.

They could have different imaging characteristics so the placement of instruments across the sound stage varies a bit. One set may sound "wider" than the other.

Also, if the speakers are not phased the same (one out of phase in one pair but not the other), they may sound the same individually, but not in the pair.

 

[TerryO]

No, not necessarily.

They could have different imaging characteristics so the placement of instruments across the sound stage varies a bit. One set may sound "wider" than the other.

Also, if the speakers are not phased the same (one out of phase in one pair but not the other), they may sound the same individually, but not in the pair.

That's right!
Another thing to imagine is, that if someone forgot to hook up the speaker cables on the second pair, they wouldn't "sound" alike either.

So, is it your contention is that drivers wired out of phase will measure exactly the same as those with "correct" phase and that there would be no dips or peaks in the Frequency Response? What exactly is the correct phase relationship between drivers in a speaker?

Best Regards,
TerryO

 

[Zilch]

The OP said "speaker system" (not individual driver). Does everyone still stand by their answers?

I believe I understood that. While on-axis frequency response is a significant indicator of loudspeaker performance, it is not the only one, and thus, is not comprehensively definitive. A metric comprising multiple response measurements such as that described by Toole & Olive gets us closer, but there remain other factors, some of which we don't yet even know how to accurately assess.... :yes:

 

[shimniok]

I was under the impression, perhaps wrongly, that phase response has an impact on imaging/soundstage. If so, two speakers with same freq response yet different phase response, would sound a little different... ?

 

[TerryO]

The OP said "speaker system" (not individual driver). Does everyone still stand by their answers?

Actually what he said was:

"In other words, if two speakers have an identical frequency response, and are placed in the same spot in the same room, will they sound identical?"

I'm sorry, I thought I read "speakers" not drivers. When I finally learn to read I'll be more careful.
:tears:

FYI: There is not one mention of "speaker system" in the original posting, although that was my understanding from the start.

And yes, I believe that with identical frequency response measurements they will indeed sound the same.

Best Regards,
TerryO

 

[Zilch]

And yes, I believe that with identical frequency response measurements they will indeed sound the same.

At best, they might sound similar in an anechoic space, but in a room, they'd have to be very much the identical speaker to sound the same, whereas the question, as framed, implicitly presumes different ones.... :yes:

 

[TerryO]

At best, they might sound similar in an anechoic space, but in a room, they'd have to be very much the identical speaker to sound the same, whereas the question, as framed, implicitly presumes different ones.... :yes:

As the OP said identical FR, I took him at his word. Identical means the same. Once you've taken careful, meaningful measurements both in the horizontal plane and the vertical and they are identical, I think that it would take a very special person to hear any differences.

As there was no mention as to the probability of two different speakers having the same FR, I just gave my opinion on what the outcome would be with two sets of speakers with identical measured frequency response.

Best Regards,
TerryO

 

[Zilch]

O.K., if we then take it that "frequency response" does not mean a single on-axis measurement, rather, a definitive sample of perhaps hundreds of measurements with infinite resolution taken in spherical planes at representative radii, all being identical, I submit that it would still be slam-dunk simple to tell whether a silk vs. titanium dome tweeter was playing the VHF.

Somehow, however, it seems doubtful OP was postulating such a scenario.... :tongue:

 

[GordonW]

Several FAMILIES of factors that would ALSO have to be identical, for the speakers to even have a chance of sounding alike:

-Frequency response- on and off axis response curves, extension on top and bottom end.

-Transient response- group delay in the bass, resonant modes (and their die-down times) of the individual drivers, damping ratios in the crossovers, enclosure damping/resonance, driver time alignment (difference in path lengths to the listener between all drivers in the system) and so on.

-Dispersion characteristics- monopole vs. dipole, baffle width (baffle step effects), driver diameters vs. frequency range (lobing in individual drivers), driver center-to-center spacing vs. frequency of crossover (lobing from adjacent drivers), driver location on baffle (diffraction effects)

Without EVERY ONE of those parameters matching exactly, there's very little chance of the speakers sounding "identical", even if their on-axis response matched. And even if all these matched, as Zilch mentioned, there are still whole fields of research devoted to other aspects of performance and design, many of which we know very little about to this point.

Regards,
Gordon.

 

[Negotiableterms]

If you pumped in a sine wave, and the speaker gave you back a square wave, the frequency response could be identical and they'd still sound very different. I suppose this is just a special case of Zilch's case, and all I'm doing is making the silk v. titanium difference larger and more theoretical in style.

Even if we narrow the concept of "speaker" in the OP down to "driver", there's still tons of other factors involved. Frequency response just isn't the only measurement that matters. And even if we go down to "driver", we still get into the mysteries of cabinets, height, etc, etc, etc...