LF Driver Size vs. Soundstage Size: Related? How should we be choosing subwoofer (s)?

[benanders]

Is there a relationship between LF driver size and soundstage size?
If so, what is the nature of the relationship?

D (Direct relationship)
I (Inverse relationship)
F (Flawed-by-design reasoning to this query)

I brought this up in another thread (maybe not-so-relevant there on second thought), and resubmit here in survey form based on communicated interest from another member.

I’ve been curious for some time about a purported negative relationship

(I typed “negative relationship”; I should have typed “inverse relationship” …)

between driver size and soundstage: smaller drivers generating a more expansive soundstage, as it relates to LF.

The flip side of this would be the argument of lower visceral impact from multiple small drivers of equal surface area to a large driver(s), again for LF.

Seems relevant enough with things veering towards subwoofers.

It’s been suggested here and elsewhere that LF is particularly important in how we perceive soundstage size/width/etc.
If there’s accuracy to that, we should be particularly considerate of woofer size in the sub(s) we choose, if there’s also a relationship between driver size and soundstage size.
Is there a relationship? And if so, are we choosing LF driver size(s) accordingly
Thanks for considering.

 

[benanders]

Reserved, just in case

 

[Chrispy]

I can't think of why the bass response capabilities would affect soundstage particularly, but the term soundstage is one of the most abused in audiophilia, too. I'd think its mostly about the recording and your speakers/room in general rather than the contribution of better low end response.....

 

[benanders]

I can't think of why the bass response capabilities would affect soundstage particularly, but the term soundstage is one of the most abused in audiophilia, too. I'd think it’s mostly about the recording and your speakers/room in general rather than the contribution of better low end response.....

Soundstage being a perception that’s hard to define, let alone measure (?), keeps me skeptical of any relationship (or at least any ability to fit perimeters around a relationship) with driver characteristics, too. Ignorance equals not knowing, which encumbers my supposing…

But leaving everything up to “recording and speakers/room in general” is not very specific, is it?

Many if not most mechanical variables could play some role in our perceptions of speaker characteristics. So is there basis for the bass when it comes to *cough cough* soundstage?

 

[Chrispy]

Soundstage being a perception that’s hard to define, let alone measure (?), keeps me skeptical of any relationship (or at least any ability to fit perimeters around a relationship) with driver characteristics, too. Ignorance equals not knowing, which encumbers my supposing…

But leaving everything up to “recording and speakers/room in general” is not very specific, is it?

Many if not most mechanical variables could play some role in our perceptions of speaker characteristics. So is there basis for the bass when it comes to *cough cough* soundstage?

But is it actually "soundstage" or are you redefining that for your own convenience?

 

[benanders]

But is it actually "soundstage" or are you redefining that for your own convenience?

Not sure I understand your angle here.

I meant soundstage. There doesn’t appear to be a concise universal definition, so not sure how I’d be redefining the term for convenience or otherwise.

It’s a term generally not dismissed among those who evaluate speaker design / performance, as a characteristic of how we perceive a speaker’s playback.

 

[Chrispy]

Not sure I understand your angle here.

I meant soundstage. There doesn’t appear to be a concise universal definition, so not sure how I’d be redefining the term for convenience or otherwise.

It’s a term generally not dismissed among those who evaluate speaker design / performance, as a characteristic of how we perceive a speaker’s playback.

Uh huh

 

[Sokel]

Maybe it's not about drivers alone.
Bigger drivers=bigger speaker=bigger room (usually).
So...

 

[Chrispy]

While better subwoofage can definitely provide a fuller response/experience, I don't see what it has to do with soundstage, particularly as most lower bass content is very limited in recordings.

 

[benanders]

Maybe it's not about drivers alone.
Bigger drivers=bigger speaker=bigger room (usually).
So...

You’re correct. This exposes an inadvertent omission of mine in how I phrased the original query:

If there is any relationship to be found, it would have to be exclusive of total driver surface area as a variable. That is, to assume equal total surface area (via replicates) of whatever driver sizes were being evaluated.
E.g. if comparing 4” drivers to 10” drivers, you’d require more 4” drivers for a valid comparison.

Absolutely, if folks weigh in with experience based on inconsistent room sizes, those comparisons are flawed by design.
I’d hope those in speaker design / testing would be experimenting with their different options in the same room dimension - is there reason for speaker designers to use a different room to design each model?
I’d also hope someone with experience limited to using one or a few subs in a home system wouldn’t feel compelled to type definitively-toned input, but hey, I suppose this is the Wild Wild Web.

 

[benanders]

Uh huh

Got it.
Where does this one put ya on the quota for most abused term in ASRphilia?

 

[benanders]

While better subwoofage can definitely provide a fuller response/experience, I don't see what it has to do with soundstage, particularly as most lower bass content is very limited in recordings.

Perhaps this could clarify, or maybe muddy, the waters:
Think in terms of different floor-standers with similar (or better: equal) surface area LF drivers: what role, if any, do those LF driver sizes play in rendering soundstage differently?

I’m not talking about lower bass content, btw.
Never specified that.
Subwoofers play up to or beyond 100 Hz for many setups. In such a case, if you wanted better optimal “subwooferage” (I do like that term @Chrispy , ha! ), would it be rendered better by more small drivers, fewer big drivers, or of no consequence. Again, assuming same total surface area between said driver options for the given frequencies.

 

[MaxwellsEq]

I'm not aware of any research supporting the thesis that driver size impacts image accuracy. I suspect it would be hard to prove it either way, but my instinct says there is no reliable correlation.

 

[benanders]

I'm not aware of any research supporting the thesis that driver size impacts image accuracy. I suspect it would be hard to prove it either way, but my instinct says there is no reliable correlation.

I suspect someone may have input, though, since driver size could indicate some relationship between speed and excursion, which in turn could affect dispersion in a way that influences our perception of soundstage.

I understand it’s problematic, given the seeming lack of analytical metrics, but since soundstage is a performance trait that many folks evaluate speakers based on (heck, it’s such a big part of what stereo imaging tricks are premised upon), shouldn’t it be of interest whether there’s any predictable difference among driver sizes in rendering capability?

 

[kemmler3D]

driver size could indicate some relationship between speed and excursion, which in turn could affect dispersion in a way that influences our perception of soundstage.

So, I think your inquiring about dispersion is the more on-track point you've made here, but the fact that you're specifically talking about low frequencies is pretty off-track to begin with.

If we take 'soundstage' to imply something about stereo image, i.e. being able to localize sounds, bass is pretty much disqualified from the discussion. The reason being, bass wavelengths are too long to have much directionality in normal listening setups, and people can barely localize bass in the first place.

Dispersion is largely determined by the difference between wavelength and driver size. Beaming starts when the wavelength approaches and then becomes smaller than the driver diameter. At bass frequencies, this essentially doesn't happen. 100hz is 3.4m, the difference between a 15" and 6" driver at this frequency has no implication for dispersion.

This might sound counterintuitive, but think of it like this. (somewhat oversimplified) A big wave in the ocean will splash on a 10-foot rock, but it goes right around a 1" pebble as if it's not there. It's similar for sound waves. To a 100hz wave, the entire loudspeaker is a 1" pebble. The sound 'can't see' the speaker and it goes in all directions as if it wasn't there. As such, directivity and imaging at those frequencies aren't really a consideration either way.

This is why cardioid speakers need fancy slot configurations or active drivers to cancel low frequencies, in order to get directionality from bass frequencies, you actually have to cancel the wave in certain directions, otherwise it just goes everywhere. Blocking the wave would require a 10-foot baffle, which tends to get low WAF ratings...

This is also (I guess) why people can't easily localize low frequencies - the waves are bigger than we are.

 

[benanders]

… the fact that you're specifically talking about low frequencies is pretty off-track to begin with.

Why? Maybe my second question (re: subwoofers) is out of place.
I’m not only referring to below ~80 Hz frequencies.

If we take 'soundstage' to imply something about stereo image, i.e. being able to localize sounds, bass is pretty much disqualified from the discussion. The reason being, bass wavelengths are too long to have much directionality in normal listening setups, and people can barely localize bass in the first place.

Bass in general? And if so, why is ~80 Hz the approximate number for being able to locate subwoofers instead of 110 - 120+ Hz? There’s evolutionary reason to assume the lower reach of the human voice is our threshold for localization, which dips into LF / subwoofer territory for many audio setups (a bit above 80 Hz).

Dispersion is largely determined by the difference between wavelength and driver size. Beaming starts when the wavelength approaches and then becomes smaller than the driver diameter. At bass frequencies, this essentially doesn't happen. 100hz is 3.4m, the difference between a 15" and 6" driver at this frequency has no implication for dispersion.

Can we be sure re: bass frequencies vs. driver size? The 15” and 6” drivers will not likely operate with the same speed or excursion. As an integral part of driver size, do those characteristics not influence dispersion, too?

...

This is also (I guess) why people can't easily localize low frequencies - the waves are bigger than we are.

I mean no offense, but that doesn’t make intuitive sense to me.
The human vocal range makes me think this shouldn’t be the case. It also wouldn’t explain why a localization cutoff of ~80 Hz is typical for subwoofers; or even if it were 100, 120+ Hz, etc. since those wavelengths all exceed average human body size and certainly average head width.

Consider bookshelf speaker models that benefit from subwoofer assistance above 100 Hz (esp. for some male voices) - they don’t all share LF dispersion behavior. Similarly, they don’t all seem to share soundstage characteristics in lowest frequencies on their own or paired with subwoofer(s).

I know it may seem like I’m arguing for sake of arguing - that’s not my intention or interest. This is an area of curiosity to me based on a speaker designer’s postulation (not my own supposition).

The constructive input so far, and any that might yet come, is definitely appreciated.

 

[Chrispy]

I know it may seem like I’m arguing for sake of arguing - that’s not my intention or interest. This is an area of curiosity to me based on a speaker designer’s postulation (not my own supposition).

What speaker designer particularly?

 

[benanders]

What speaker designer particularly?

Good question.
Since he didn’t state the idea publicly, that I know of, I’ll refrain from saying, lest I “hereticize” a professional’s reputation.

I mentioned mostly because it’s relevant for anyone considering the question to know it’s more than a hare-brained notion of an internet “rando” ( = me). Even if it’s ultimately not more than a hare-brained notion of an acoustical engineer!

 

[Chrispy]

Good question.
Since he didn’t state the idea publicly, that I know of, I’ll refrain from saying, lest I “hereticize” a professional’s reputation.

I mentioned mostly because it’s relevant for anyone considering the question to know it’s more than a hare-brained notion of an internet “rando” ( = me). Even if it’s ultimately not more than a hare-brained notion of an acoustical engineer!

Engineer as in he's actually schooled in the science or just a self proclaimed audio/acoustical engineer as many seem to be? After your dodging of specifics earlier, not sure just what the proposition is either.

 

[benanders]

Engineer as in he's actually schooled in the science or just a self proclaimed audio/acoustical engineer as many seem to be? After your dodging of specifics earlier, not sure just what the proposition is either.

I meant engineer. Have some trigger words, do we?