What makes big speakers sound "big"and smaller ones sound "small"?

[Zapper]

Question: Do very narrow large-ish speakers like the KEF LS60 (1042 x 130 x 321 mm) (41.0 x 5.1 x 12.6 in.) sound small or big, when played at a non-taxing level that does not expose their limited output? Based on their impressive low frequency response, they should sound huge. But I'm guessing they don't.

The design goal of the LS60 appears to be to emulate a point source. The small coaxial driver covers much of the frequency range, albeit with a fairly narrow radiation pattern. The 4 side-firing woofers arranged symmetrically to the coax driver emulate a unipolar bass driver. The cabinet width is only 130mm / 5.1".

But is a point source really a desirable goal for a speaker design? Or will it actually sound like a tiny point? Is this an instance of engineers pursuing a mathematical ideal at the expense of sonic appeal?

 

[Zapper]

Apart from tonality and spl, what will phase impact?

The time alignment of various frequencies, which some claim is audible. Also, the relative strengths of direct and reflected waves for a given SPL at the listening position. There are an infinite number of ways to produce a given SPL at a given frequency in a non-anechoic sound field.

 

[Duke]

No, but it tells you what effect it has at your listening position.

If there cannot be an audible difference between different direct-to-reflected sound ratios, then the radiation pattern doesn't matter, and only the SPL and frequency response matter.

If there can be an audible difference between different direct-to-reflected sound ratios, then the radiation pattern can make an audible difference.

But let’s step back - you are suggesting, at least, that radiation pattern is a key part of what makes speakers “sound big”.

Yes, but I see now that we need to make sure we're using our terms the same way, so that we're at least talking about the same things. And I haven't been precise about what it means for a speaker to "sound big" because that's not a term that I normally use, and maybe I'm mistaken about what other people mean when they use that term.

I AM suggesting that radiation pattern is a key part of both sound quality and and spatial quality.

If you can tell me what you mean by "big" in the context of sound quality and spatial quality, I'll try to relate that to radiation patterns.

 

[RobL]

The time alignment of various frequencies, which some claim is audible. Also, the relative strengths of direct and reflected waves for a given SPL at the listening position. There are an infinite number of ways to produce a given SPL at a given frequency in a non-anechoic sound field.

Yes, but we are all referring to what the listener experiences, so back to tonality and spl. Anyway, as far as I’m aware most studies show human listeners to be agnostic to phase, especially with music.

 

[ahofer]

If there cannot be an audible difference between different direct-to-reflected sound ratios, then the radiation pattern doesn't matter, and only the SPL and frequency response matter.

If there can be an audible difference between different direct-to-reflected sound ratios, then the radiation pattern can make an audible difference.



Yes, but I see now that we need to make sure we're using our terms the same way, so that we're at least talking about the same things. And I haven't been precise about what it means for a speaker to "sound big" because that's not a term that I normally use, and maybe I'm mistaken about what other people mean when they use that term.

I AM suggesting that radiation pattern is a key part of both sound quality and and spatial quality.

If you can tell me what you mean by "big" in the context of sound quality and spatial quality, I'll try to relate that to radiation patterns.

Ok, you are taking about phase/delay, which is still part of the measured response.

As for defining “sounds big” I don’t know. That seems to be the mystery idea that this thread is plumbing. My primary point is that whatever it is, it is some characteristic of things that can be measured, as opposed to some ineffable quality. And, IMO, a wide radiation pattern probably helps, but the primary characteristic is likely to be the undistorted peak and range of low frequency SPL available from (usually) a larger driver in a large space.

 

[Pearljam5000]

Ok, you are taking about phase/delay, which is still part of the measured response.

As for defining “sounds big” I don’t know. That seems to be the mystery idea that this thread is plumbing. My primary point is that whatever it is, it is some characteristic of things that can be measured, as opposed to some ineffable quality. And, IMO, a wide radiation pattern probably helps, but the primary characteristic is likely to be the undistorted peak and range of low frequency SPL available from (usually) a larger driver in a large space.

I can't find a better term than big and small as my English is not so good .
But when it happens you can definitely hear it , and often from the first second .
It happened to me numerous times with big and small speakers.

 

[ahofer]

I can't find a better term than big and small as my English is not so good .
But when it happens you can definitely hear it , and often from the first second .
It happened to me numerous times with big and small speakers.

But you are not saying it isn’t measurable. Are you?

 

[Pearljam5000]

But you are not saying it isn’t measurable. Are you?

I don't know what is and what isn't measurable
I'm just asking for an explanation for the phenomenon

 

[RobL]

Thinking about this more and we are able to perceive vertical information from sound…we all look up when an airplane flies over. The sound field in a room is obviously very complex but perhaps the brain can sort out the various driver locations from the soup and impress that information as “size”?
I don’t overtly get that impression when I listen to a speaker though, the sound seems to sum from the drivers and emanate from what I assume is the acoustic axis of the system. I don’t perceive individual drivers (unless I’m too close). Even my PA speaker's 8 driver array doesn’t sound like a three foot tall source, the sound seems to only emanate from just above the bottom of the array.
Still, maybe what we perceive as “size” isn’t really measurable but is simply the brain doing some amazing localization in the background. Pure speculation of course.

 

[Duke]

Ok, you are taking about phase/delay, which is still part of the measured response.

I'm not talking about phase/delay.

As for defining “sounds big” I don’t know. That seems to be the mystery idea that this thread is plumbing. My primary point is that whatever it is, it is some characteristic of things that can be measured, as opposed to some ineffable quality.

I am definitely NOT saying whatever goes into "sounds big" cannot be measured. However it is unclear to me what measurements would be the most revealing and/or predictive of "sounds big". Imo frequency response and SPL are inadequate predictors of "sounds big".

I might use the word "big" to describe a speaker that conveys the impression of impact, particularly in the lower midrange down through the bass region. Ime this is something large woofers with powerful motors do better than small woofers with small motors. Ime this is also something that speakers with less compression of the peaks do better than speakers that have more compression of the peaks. Ime this is also something that speakers with wide baffles tend to do better than speakers with narrow baffles. I think the narrower radiation pattern width of the large woofer (and/or wide baffle) has something to do with it, and I think the more powerful motor has something to do with it. I also think that lack of compression on the peaks has something to do with it.

It is not obvious to me that any of these characteristics are disclosed or delineated in a frequency response or SPL measurement.

Some might use the word "big" to describe the soundstage width and/or depth, or the sense of "envelopment" conveyed, and if so, that's a "bigger" topic than I want to go into without being sure it's what we're both talking about.

 

[egellings]

I experimented with an op-amp based first order all-pass filter that altered the phase angle between its input & output and nothing else. If both channels of the stereo got the same treatment, I was hard-pressed to tell a difference with or without the filter implemented. If I added the filter to just one channel, then the effect was audible-odd imaging and a phasey sort of sound.

 

[Ze Frog]

Apart from tonality and spl, what will phase impact?

Time arrival, cohesion, cancellation effects, nulls and peaks etc etc. Phase is massively important if you want a truly clear and correct sound.

 

[DonH56]

This is still going?

IME/IMO the "bigger" sound comes from a few features:

1. They are visually larger and thus our eyes/brain goes "they must sound bigger";
2. More extended (deeper) bass leads to a presumption of "bigness";
3. Larger speakers usually play louder before distorting heavily (leading folk to crank them up because they are bigger); and,
4. Larger speakers with multiple drivers, or just large drivers (e.g. panels), provide a larger wave front to the listener, less of a point source over a wider frequency range, so can indeed sound "bigger" (I tend to think this is due to their more extended vertical dispersion).

I have almost always preferred larger speakers because of the extended bass. A smaller box is less efficient, leading to less speaker sensitivity, but that does not account for "bigger" sound. Smaller speakers often extend the bass through padding the tweeter and tweaking the response, but that leads to lower sensitivity and hitting physical limits of the (smaller) bass driver(s) so they won't play as loud.

FWIWFM - Don

 

[Ze Frog]

I experimented with an op-amp based first order all-pass filter that altered the phase angle between its input & output and nothing else. If both channels of the stereo got the same treatment, I was hard-pressed to tell a difference with or without the filter implemented. If I added the filter to just one channel, then the effect was audible-odd imaging and a phasey sort of sound.

On an all pass it will be less noticeable because the effect will change all drivers to be just as out of phase as eachother. It's variations between driver's in crossover that can be problematic or two different speakers with different phase characteristics, although that's rare unless mixing and matching. In theory though, two speakers despite being different should provide good sound still given a well designed integration of the driver's in each speaker. And then there's placement as well, I used to run 4 speakers at one point, 2 in front and 2 behind, and to make that work correctly regarding phase you needed to wire the speakers behind with polarity reversed.

Speaking of which, that's something that's always baffled me about home theatre set-ups. Does the receiver change the polarity internally so the consumer matches the correct + and -? I'm guessing so, unless it tells people to reverse polarity for speakers behind them. I don't know mutch about home theatre.

 

[Duke]

Time arrival, cohesion, cancellation effects, nulls and peaks etc etc. Phase is massively important if you want a truly clear and correct sound.

Agreed.

Writing about concert hall acoustics and psychoacoustics, researcher David Griesinger reports that clarity is degraded if the phase of the harmonics north of 1 kHz are scrambled. My recollection is that he's primarily talking about excess early reflections being detrimental.

I think the same psychoacoustics are in play in home audio, but the perceptual effects of loudspeaker phase response may be somewhat masked by the typical abundance of relatively early in-room reflections.

My understanding of Griesinger is this: If the fundamental and the harmonics all arrive at the same TIME, they combine to create an instantaneous energy PEAK that is perceptually analogous to a higher signal-to-noise ratio. Spreading out the arrivals of the harmonics over time has the effect of reducing the effective signal-to-noise ratio. This matters because what grabs our attention has to do with the direct sound perceptually standing out as distinct from the in-room reflection field.

 

[ahofer]

I'm not talking about phase/delay.



I am definitely NOT saying whatever goes into "sounds big" cannot be measured. However it is unclear to me what measurements would be the most revealing and/or predictive of "sounds big". Imo frequency response and SPL are inadequate predictors of "sounds big".

I might use the word "big" to describe a speaker that conveys the impression of impact, particularly in the lower midrange down through the bass region. Ime this is something large woofers with powerful motors do better than small woofers with small motors. Ime this is also something that speakers with less compression of the peaks do better than speakers that have more compression of the peaks. Ime this is also something that speakers with wide baffles to better than speakers with narrow baffles. I think the narrower radiation pattern width of the large woofer (and/or wide baffle) has something to do with it, and I think the more powerful motor has something to do with it. I also think that lack of compression on the peaks has something to do with it.

It is not obvious to me that any of these characteristics are disclosed or delineated in a frequency response or SPL measurement.

Some might use the word "big" to describe the soundstage width and/or depth, or the sense of "envelopment" conveyed, and if so, that's a "bigger" topic than I want to go into without being sure it's what we're both talking about.

I’m with you on the definitional problems, but a lot of what you are describing is still sound pressure. Compression is a lack of sound pressure, powerful motors sound different because they create greater sound pressure. The different dynamics can easily be measured and compared to test this thesis.

It’s quite possible that a lot of indirect sound (which has a *delay* and *phase change* am I missing something?) creates a larger impression. But I think by far the biggest reason bigger speakers sound “bigger” is simply the greater sound pressure in the room. The rest is probably sighted bias.

And apparently, in your last post, it turns out you ARE taking about phase. I’m confused by your contradiction.

 

[Duke]

I’m with you on the definitional problems, but a lot of what you are describing is still sound pressure. Compression is a lack of sound pressure, powerful motors sound different because they create greater sound pressure. The different dynamics can easily be measured and compared to test this thesis.

Yes is it possible to measure compression by running multiple frequency response curves at different power input levels.

It’s quite possible that a lot of indirect sound (which has a *delay* and *phase change* am I missing something?) creates a larger impression.

Agreed. The indirect sound has effects on both sound quality and spatial quality.

But I think by far the biggest reason bigger speakers sound “bigger” is simply the greater sound pressure in the room.

Greater sound pressure = greater sound pressure level = higher SPL. So it sounds to me like you're simply equating "bigger" with "louder". Am I missing something?

And apparently, in your last post, it turns out you ARE taking about phase. I’m confused by your contradiction.

I agree with @Ze Frog that phase matters for sound quality, and I also think it probably matters for spatial quality. But I have not been talking about phase in any of my replies to you.

 

[JeremyFife]

Little question, expanding answers. Nice. I'm not sure it's helping me much yet but it's interesting.

There's no clear definition of 'big' sound. That's instructive. I don't understand the phase arguments, or why that is related to speaker size. I'll keep reading.

If I close my eyes ( I just mean no sighted bias) and a sound reaches me - a frequency at an SPL - it doesn't matter what size of speaker produced the sound.

I could be wrong, but isn't the volume of air hitting me ( the pressure) just a description of SPL. The volume of air a speaker can move becomes irrelevant.

If I'm further away from the speaker, then a small speaker is (assumption) less likely to be able to generate high SPL, but that's not what we're talking about re. 'bignness '.

Room acoustics: the sense and difference between big rooms and small ones, make a difference. Again, that's not the point.

Does it come down to directivity, and is that related to speaker (driver) size?

Speakers that can produce higher SPL will sound bigger than speakers that can't, but that's not surprising.
Seems as if sighted bias is the most likely answer?

 

[ahofer]

Greater sound pressure = greater sound pressure level = higher SPL. So it sounds to me like you're simply equating "bigger" with "louder". Am I missing something?

No. I think most of the “bigger” claim is about volume/sound pressure. But clearly I am missing something. I don’t even know where we may disagree at this point, other than perhaps I think that the reflected sound produces a signal at the listening position that is delayed and therefore of uncertain phase mismatch and…I dunno.

I guess I’ll just return to my original point, which is that whatever it is that makes the ‘bigger’ sound can be measured in frequency response and dynamic measurements (as you say) of SPL at the listening position. I agree that the directivity properties of the speaker make a difference, but only in the sense that they change these measurable properties. Therefore, we could devise an experiment where we got a bunch of listeners to agree on what sounded “bigger”, then take measurements and develop a more specific thesis. I don’t know if anyone has taken measurements of mini-monitors at distance vs close up, but I’m sure that would be revealing. I know my 8010s sound radically different at distance, despite the subwoofer.

 

[Duke]

... whatever it is that makes the ‘bigger’ sound can be measured in frequency response and dynamic measurements (as you say) of SPL at the listening position.

If you're going to include "dynamic measurements", then you and I are much closer to agreement.

I agree that the directivity properties of the speaker make a difference, but only in the sense that they change these measurable properties.

Well, imo it's not that simple.

Directivity has a significant impact on the degree to which the direct sound is perceptually differentiated from the reflection field, and this differentiation is desirable because (among other things) it is a component of perceived dynamic contrast. Ime there are perceptual thresholds which are not conveyed by frequency response curves, especially if those response curves are in-room curves which do not differentiate between direct and reflected sound.