Beyond Linearity: Why Speaker Dispersion Matters Far More Than People Expect

[thewas]

If interested, I can provide measurements of both speakers on and off axis in my living room on my listening position.

MMM measurements around the LP for each L and R separately (so in total 4 measurements, each around one minute) would really interest me, also to see if the dry character of the KEF is partially a result of its tuning and can be remedied with EQ.

 

[Keith_W]

It would be interesting to know, which characteristic in particular drives the impression. Is it the diffuse field, the steady state of reverberation, or is it mostly the first reflections.

The main difference between these is that first reflections interfere with the direct sound, leading to deep dips and relatively mild peaks, even comb filter effects. The steady state interferes in more chaotic fashion plus minus something.

If you have a copy of Toole, may I direct you to the whole of Chapter 7 where he discusses this. In particular, 7.6 "Perceptual Effects of Room Reflections".

Since you mention comb filtering, Toole says it is not as audible as it appears to be when we take measurements. I agree with him from personal experience. Now, comb filtering occurs when a signal is mixed with a delayed copy of itself. What I can't get my head around is why comb filtering that "mixes in the air" (i.e. acoustic comb filtering) is dramatically less audible than comb filtering that is created in the recording. If you have the ability to use VST's, try downloading a flanger VST that deliberately creates comb filtering. The audible effect is dramatic. Maybe someone has an explanation.

 

[MattHooper]

“You are there”/“they are here”

Generally speaking, I prefer “ you are there.”

But ideally, you can have both… And that will be dictated by the recording. A very dry recording for instance will be “ they are here” and one with greater ambiance or reverb will tend to be “ you are there.”

 

[levimax]

I find when listening to speakers in a room that there are 2 issues that complicate objective analysis of even what my preferences are: "sighted bias" (very hard to avoid in most circumstances and takes in a lot of variables) and "hearing through the room" (your brain is amazing at adapting to wonky rooms). I wonder how much these factors make finding consistent preferences difficult.

 

[bmc0]

What I can't get my head around is why comb filtering that "mixes in the air" (i.e. acoustic comb filtering) is dramatically less audible than comb filtering that is created in the recording. If you have the ability to use VST's, try downloading a flanger VST that deliberately creates comb filtering. The audible effect is dramatic. Maybe someone has an explanation.

As far as I know, the difference is due to spatial separation of the direct and reflected sounds. If the reflection comes from a different direction (especially in the horizontal plane), the auditory system is much better able to separate the two. This is also why reflected sound contained in a monophonic recording is so much more audible than in a (properly done) two or more channel recording when the direct to reflected ratio is the same. More than one channel enables spatial separation.

 

[JohnnyNG]

Of course, I have several 3-way loudspeakers in my collection with wide radiation 2" mid and 0.75" tweeters, commercial and one even designed by myself:

View attachment 438369

Those bevels are perfection.

 

[MattHooper]

I find when listening to speakers in a room that there are 2 issues that complicate objective analysis of even what my preferences are: "sighted bias" (very hard to avoid in most circumstances and takes in a lot of variables)

Yes, always an issue!

We tend to use the term “ sighted bias” around here as a sort of catchphrase for
“ knowing which gear you are listening to” (in other words without controls for bias effects).

But for the moment I’m going to interpret your comment in terms of how actual visual cues can affect our perception. For instance, the type of expectations we might have for the sound depending on how loudspeaker looks to us.

I’ve been fascinated with perceptual bias effects for a long time, especially applied to my interest in Home Theatre. I spent a lot of time reading about perceptual biases, and also experimenting with different ways of presenting images that affected the perceptual result. Lots of fun.

That carries over somewhat to the audiophile realm. I like to take advantage of some perceptual biases. For instance, the type of mood lighting I set up for my listening session, and the coloured lights displayed on my projection screen behind my loudspeakers, have an influence on how I perceive the sound. If I close my eyes and listen, I can notice the difference.

But then a little more to your point, I think, is the visuals a loudspeaker presents us and how it can influence our perception of the sound. We might expect a Really skinny smallish floor stand speaker to “ disappear” more as a source of the sound. And of course visually they kind of do, since they take up less visual space. And maybe we might expect a big squat loudspeaker with big drivers to sound more “beefy” and substantial or whatever.

This is one reason why I have always done the “ close my eyes test” when auditioning allows speakers, or listening at audio shows or wherever. It’s not scientific, but since it does have an effect, I think it’s telling me something. For instance, I can be in front of a very large floor standing loudspeaker, might be playing your typical audio file content of a vocal with light instrument accompaniment.
But if I close my eyes and I ask myself “ just concentrating on the sound only, what type of loudspeaker does this sound like? What would my mind predict simply from the sound?”

And often enough, it’s a different experience. I may realize that a large floorstanding speaker is sounding a little different than a much smaller stand, mounted speaker. Somehow for instance with the lack of bass in the sound becomes more obvious once I’m not staring at large speakers and large drivers.

I’ve had all sorts of characteristics From listening with my eyes open somewhat collapse or become less impressive with my eyes closed and only concentrating on the sound.

It’s similar to how watching A live performance video can make the sound sort of more convincing and authentic sounding, because of how my brain is mapping the sound to each instrument, even to each element of a drum kit that the drummer is hitting. But without those visual cues, the sound becomes less authentic or realistic, and even less clear and delineated.

So in the end, I tend to purchase speakers that hold up best in the “ close my eyes test.”
The smaller, the difference between listening while seeing speakers versus my eyes closed, the better.

That’s also because I often enough will listen with my eyes closed at home.

I wonder if your experience is similar or not?

and "hearing through the room" (your brain is amazing at adapting to wonky rooms). I wonder how much these factors make finding consistent preferences difficult.

Are you talking about your own personal preferences? In that it’s hard to find consistency in your own personal preferences?

If so, that’s not my experience.

I have found that my evaluations of loudspeakers in different rooms - whether they are at a store, a friend’s house, or my own room - stays quite consistent.

The essential characteristics of the loudspeaker are always there. The overall performance can be distracted from or enhanced by the room and set up. But to me, just as I still recognize the voice of somebody I know in different rooms, I still find I recognize the voice of loudspeaker in different rooms.

Which I think makes sense given Toole’s reminder of how our auditory system hears through rooms.

 

[levimax]

Yes, always an issue!

We tend to use the term “ sighted bias” around here as a sort of catchphrase for
“ knowing which gear you are listening to” (in other words without controls for bias effects).

But for the moment I’m going to interpret your comment in terms of how actual visual cues can affect our perception. For instance, the type of expectations we might have for the sound depending on how loudspeaker looks to us.

I’ve been fascinated with perceptual bias effects for a long time, especially applied to my interest in Home Theatre. I spent a lot of time reading about perceptual biases, and also experimenting with different ways of presenting images that affected the perceptual result. Lots of fun.

That carries over somewhat to the audiophile realm. I like to take advantage of some perceptual biases. For instance, the type of mood lighting I set up for my listening session, and the coloured lights displayed on my projection screen behind my loudspeakers, have an influence on how I perceive the sound. If I close my eyes and listen, I can notice the difference.

But then a little more to your point, I think, is the visuals a loudspeaker presents us and how it can influence our perception of the sound. We might expect a Really skinny smallish floor stand speaker to “ disappear” more as a source of the sound. And of course visually they kind of do, since they take up less visual space. And maybe we might expect a big squat loudspeaker with big drivers to sound more “beefy” and substantial or whatever.

This is one reason why I have always done the “ close my eyes test” when auditioning allows speakers, or listening at audio shows or wherever. It’s not scientific, but since it does have an effect, I think it’s telling me something. For instance, I can be in front of a very large floor standing loudspeaker, might be playing your typical audio file content of a vocal with light instrument accompaniment.
But if I close my eyes and I ask myself “ just concentrating on the sound only, what type of loudspeaker does this sound like? What would my mind predict simply from the sound?”

And often enough, it’s a different experience. I may realize that a large floorstanding speaker is sounding a little different than a much smaller stand, mounted speaker. Somehow for instance with the lack of bass in the sound becomes more obvious once I’m not staring at large speakers and large drivers.

I’ve had all sorts of characteristics From listening with my eyes open somewhat collapse or become less impressive with my eyes closed and only concentrating on the sound.

It’s similar to how watching A live performance video can make the sound sort of more convincing and authentic sounding, because of how my brain is mapping the sound to each instrument, even to each element of a drum kit that the drummer is hitting. But without those visual cues, the sound becomes less authentic or realistic, and even less clear and delineated.

So in the end, I tend to purchase speakers that hold up best in the “ close my eyes test.”
The smaller, the difference between listening while seeing speakers versus my eyes closed, the better.

That’s also because I often enough will listen with my eyes closed at home.

I wonder if your experience is similar or not?



Are you talking about your own personal preferences? In that it’s hard to find consistency in your own personal preferences?

If so, that’s not my experience.

I have found that my evaluations of loudspeakers in different rooms - whether they are at a store, a friend’s house, or my own room - stays quite consistent.

The essential characteristics of the loudspeaker are always there. The overall performance can be distracted from or enhanced by the room and set up. But to me, just as I still recognize the voice of somebody I know in different rooms, I still find I recognize the voice of loudspeaker in different rooms.

Which I think makes sense given Toole’s reminder of how our auditory system hears through rooms.

While not exactly the same thing I do believe that how speakers looks, especially their size, can change how we hear them, like the McGurk Effect

Regarding "hearing through the room", I notice that when I move from my main system to the TV system or some other system, at first I notice differences but after some listening time my brain adjusts and I don't really hear the system much any more, just the music playing.

 

[MattHooper]

While not exactly the same thing I do believe that how speakers looks, especially their size, can change how we hear them, like the McGurk Effect

That’s a very interesting comment! Relating visual stimulus of loudspeakers to the McGurk effect!

As you say, this might not be exactly the same thing. But right now I am remembering an experience I had listening to my old Thiel 02 two-way monitors, which I used in my system for quite a while. Those Thiels came with tiny stands. The stands were just some thin wire braces, that held the speakers several inches off the floor, and angled up at the listener.

When I would listen with eyes open, the sound stage and imaging tended to seem to hover generally around the speakers, in other words closer to the floor.

But then I did an experiment where I lay back in my sofa and closed my eyes, and I started imagining that the sound was actually coming from a tall floor standing speaker. And when I did that, I remember the perception of the sound literally slowly rising upwards, until it seems to be coming from a taller speaker in front of me. All achieved with a little help from my imagination!

 

[Weeb Labs]

There is a school of thought on ASR that asserts that "the soundstage is in the recording" and therefore we want narrower directivity speakers with more room treatment to attenuate reflections so that we can hear the recording directly .... when this school of thought is taken too far - the sound is headphone-like

This is very much my preference. My room serves as both an office and a home theater. It is as close to anechoic as I can reasonably achieve and in my experience, eliminating reflective characteristics results in what might best be described as a very low "perceptual noise floor". This does result in narrower stereo imaging relative to a reflective room but I regard it as a very worthwhile exchange.

Smooth directivity is always a primary criterion for me when choosing speakers but in a practical sense, directivity characteristics become less critical for me when the vast majority of the off-axis response is being absorbed regardless.

 

[Esprit]

I use my Adams a lot for watching movies and TV shows and the fact that the audio is exactly between the two speakers gives me the feeling of having the monitors behind the screen (120") and that every sound or effect is exactly where the projector makes me see it.

 

[Heinrich]

If you have a copy of Toole, may I direct you to the whole of Chapter 7 where he discusses this. In particular, 7.6 "Perceptual Effects of Room Reflections".

Since you mention comb filtering, Toole says it is not as audible as it appears to be when we take measurements. I agree with him from personal experience. Now, comb filtering occurs when a signal is mixed with a delayed copy of itself. What I can't get my head around is why comb filtering that "mixes in the air" (i.e. acoustic comb filtering) is dramatically less audible than comb filtering that is created in the recording. If you have the ability to use VST's, try downloading a flanger VST that deliberately creates comb filtering. The audible effect is dramatic. Maybe someone has an explanation.

I have, and the book is good in that it gives room and stimulation for speculation. It mixes (as far as possible) established results and deductions, the latter of which, however, require further investigation.
A critical reader will take advantage of this and formulate hypotheses in the spirit of science, and thus design a test.
Unfortunately, the means to do this are not available to everyone. Anecdotes are quickly exhausted, so they are of no help here.

Most recently, I built a couple of wide-beam boxes, which unfortunately now interfere with the asymmetries of my living room. So far, I don't have much to share. After all, the action is moving further back, and it seems to me that the synthetic reverberation in vocal recordings is amplified - with the same frequency response/sound pressure on axis.

The aim of the experiment, however, was miniaturization in bass reproduction down to 30Hz, intermodulation and, last but not least, cost optimization with regard to 'normal' requirements. Without critical listening as an objective in itself, hardly anything will come out in connection to “early reflections”, apart from the perception of the stupid room. If that's an anecdote, sorry.

 

[chervokas]

If you have a copy of Toole, may I direct you to the whole of Chapter 7 where he discusses this. In particular, 7.6 "Perceptual Effects of Room Reflections".

Since you mention comb filtering, Toole says it is not as audible as it appears to be when we take measurements. I agree with him from personal experience. Now, comb filtering occurs when a signal is mixed with a delayed copy of itself. What I can't get my head around is why comb filtering that "mixes in the air" (i.e. acoustic comb filtering) is dramatically less audible than comb filtering that is created in the recording. If you have the ability to use VST's, try downloading a flanger VST that deliberately creates comb filtering. The audible effect is dramatic. Maybe someone has an explanation.

I've always wondered if there's a wider range of experience and preferences out there than Toole's testing ever took into effect, or if I'm just an individual outlier, but I have to say, for me, one of the most distracting things about listening to recorded music and one of the most disruptive things to the illusion or realism, is hearing the local room. That means everything from hearing wall and floor rattle, to hearing reflections (I had to take down my ceiling treatments for some home reno work and haven't had a chance to put them up and I can't hear the ceiling adding brightness and image blur and it's annoying -- just like when I go to Carnegie Hall I have subscription seats in a box with next level of boxes above me and only the front seats in the box are cantilevered out into open space. I sit in the middle set and the ceiling above me totally closes in blurs and darkens the sounds and make me a little nuts. Every year I put in for the front seat tickets, where the sound is open, bright and full).

As to the comparison of room comb filtering effects to a flanger effect, the room experience is obviously different in being both less pronounced and having a kind of 3D IRL character that the electronic effect doesn't have but I certainly I can hear an effect when I place reflective objects in the sound path near my listening place, even if it sounds less like a flanger effect and more like the subjective experience of blurred and variable imaging and maybe tonal change, and definitely changed that are more like a flanger effect when I move my head while listening -- I'm not talking about a doppler effect from moving my head, I'm talking about hearing a difference in boundary interference response and interchannel and direct and reflected sound phase relationships as you move a couple of inches this way and back.

I've never been in an anechoic chamber, but I have been in lots of recording and broadcast studio control rooms in my professional life. I'd get my home listening room as dead as some of those spaces if it were financially and aesthetically practical for me -- though certainly I don't might some diffusion if the space is big enough not to be able to hear the lobing. A very damped, and evenly damped, listening spaces has never sounded at all to me anything like headphones, which is a kind of listening I really dislike because I find it totally unnatural (and I find having something on me head or in my ears cognitively dissonant with the expected illusionary experience of real instrument sounding in a room in which I'm sitting). It just lets me hear what's on the recording -- including and spatial ambient cues on the recording -- in a way that I get drawn away from when I start hearing the sound of the room around me. Totally different of course from the sound that I might prefer for hearing a actual instrument being played (my kitchen/great room kind of space, which is a big, open room with lots of wood, angled wall areas, and 14' cathedral ceilings is a great live room for acoustic instruments -- I'd sometimes do home demo recording tracking in it,, but not so much a great room for stereo playback).

 

[tmuikku]

Totally, thats the hifi sound for me as well. I get rid of early reflections effect to perceived sound with my stereo by reducing listening distance. I get both sounds on my system, good involving sound that totally captivates me, and the typical home stereo sound with heavy effect of the local room. I can switch between the two, at will, by changing listening distance.

Like you I find it very easy to hear, but on the other hand it's not annoying to me to have some early reflections because if sound is not the one I want I can change it at will. Sometines either is better depending whether it's for background or if I want to really listen deep. Also, some recordings are to wild listened close without effects of local room. So, I just adjust at will and listen whichever I feel like, super power

 

[JaMmy]

Yes, always an issue!

We tend to use the term “ sighted bias” around here as a sort of catchphrase for
“ knowing which gear you are listening to” (in other words without controls for bias effects).

But for the moment I’m going to interpret your comment in terms of how actual visual cues can affect our perception. For instance, the type of expectations we might have for the sound depending on how loudspeaker looks to us.

I’ve been fascinated with perceptual bias effects for a long time, especially applied to my interest in Home Theatre. I spent a lot of time reading about perceptual biases, and also experimenting with different ways of presenting images that affected the perceptual result. Lots of fun.

That carries over somewhat to the audiophile realm. I like to take advantage of some perceptual biases. For instance, the type of mood lighting I set up for my listening session, and the coloured lights displayed on my projection screen behind my loudspeakers, have an influence on how I perceive the sound. If I close my eyes and listen, I can notice the difference.

But then a little more to your point, I think, is the visuals a loudspeaker presents us and how it can influence our perception of the sound. We might expect a Really skinny smallish floor stand speaker to “ disappear” more as a source of the sound. And of course visually they kind of do, since they take up less visual space. And maybe we might expect a big squat loudspeaker with big drivers to sound more “beefy” and substantial or whatever.

This is one reason why I have always done the “ close my eyes test” when auditioning allows speakers, or listening at audio shows or wherever. It’s not scientific, but since it does have an effect, I think it’s telling me something. For instance, I can be in front of a very large floor standing loudspeaker, might be playing your typical audio file content of a vocal with light instrument accompaniment.
But if I close my eyes and I ask myself “ just concentrating on the sound only, what type of loudspeaker does this sound like? What would my mind predict simply from the sound?”

And often enough, it’s a different experience. I may realize that a large floorstanding speaker is sounding a little different than a much smaller stand, mounted speaker. Somehow for instance with the lack of bass in the sound becomes more obvious once I’m not staring at large speakers and large drivers.

I’ve had all sorts of characteristics From listening with my eyes open somewhat collapse or become less impressive with my eyes closed and only concentrating on the sound.

It’s similar to how watching A live performance video can make the sound sort of more convincing and authentic sounding, because of how my brain is mapping the sound to each instrument, even to each element of a drum kit that the drummer is hitting. But without those visual cues, the sound becomes less authentic or realistic, and even less clear and delineated.

So in the end, I tend to purchase speakers that hold up best in the “ close my eyes test.”
The smaller, the difference between listening while seeing speakers versus my eyes closed, the better.

That’s also because I often enough will listen with my eyes closed at home.

I wonder if your experience is similar or not?



Are you talking about your own personal preferences? In that it’s hard to find consistency in your own personal preferences?

If so, that’s not my experience.

I have found that my evaluations of loudspeakers in different rooms - whether they are at a store, a friend’s house, or my own room - stays quite consistent.

The essential characteristics of the loudspeaker are always there. The overall performance can be distracted from or enhanced by the room and set up. But to me, just as I still recognize the voice of somebody I know in different rooms, I still find I recognize the voice of loudspeaker in different rooms.

Which I think makes sense given Toole’s reminder of how our auditory system hears through rooms.

I’m really enjoying this discussion.
In addition to sight and other perceptual biases what I notice a lot is the switch between listening to the music and listening to how my system is reproducing the music. I enjoy and spend a significant amount of time (I’m retired) building amps or crossovers or refurbishing bits of vintage gear picked up at auctions. I therefore spend a fair bit of time exploring how this or that bit of gear ‘sounds’. But switching this attention off and just listening to the content of the music becomes a challenge - I get distracted into wondering if the soundstage is as defined as it should be or if the violins are sounding slightly harsh etc etc.
Is this just me? If this is something others notice, how do you deal with it?

 

[Kr2d2]

I’m really enjoying this discussion.
In addition to sight and other perceptual biases what I notice a lot is the switch between listening to the music and listening to how my system is reproducing the music. I enjoy and spend a significant amount of time (I’m retired) building amps or crossovers or refurbishing bits of vintage gear picked up at auctions. I therefore spend a fair bit of time exploring how this or that bit of gear ‘sounds’. But switching this attention off and just listening to the content of the music becomes a challenge - I get distracted into wondering if the soundstage is as defined as it should be or if the violins are sounding slightly harsh etc etc.
Is this just me? If this is something others notice, how do you deal with it?

I know the problem too, sometimes it's kind of hard not to notice the devices, but the music that's playing through them.

But sometimes, when things are going well, even a simple little DAB radio can be enough to make you forget which devices you're listening to.

Maybe it helps to ‘ground’ yourself with the help of a real musical event, a concert with natural instruments and voices? That can help you remember the true magic of music... although the devices can have their (albeit different) magic too.

And, as has already been mentioned here, it can help to close your eyes - at least then you won't SEE the equipment that distracts you from the music.

A very interesting discussion here!

 

[rdenney]

We should recognize that it's not only the quantity of directionality, but also its quality. One of the key features of a "good" spinorama is that the spectral response off axis is naturally related to the response on axis. There is an expectation of a downward slope that increases as the measurement moves away from the axis, but that is realistic. High frequencies tend to be absorbed in reflective materials more readily than low frequencies, especially in the presence of acoustic treatments.

Speakers with wide directivity at higher frequencies might localize the reflective surface too much, giving an unpleasant echo effect. Or, it might have very different directivity above and below crossover points such that the reflected sound has a different timbre than the direct sound. This will also localize the reflective surface unpleasantly, it seems to me. Narrow directivity with widely spaced speakers might resolve those issues to some extent, but at the expense of a tiny sweet spot. Wide, but spectrally smooth directivity increases the apparent width without the reflective surfaces calling attention to themselves.

This seems to me to be the conclusion of Toole's research concerning directivity.

My listening room is wider than it is deep, and I want a big sound everywhere in the room when I crank it up. So, wide, smooth directivity works best for me. When I was using Advents that are simply not as good about that (through not actually terrible)

The apparent preference for a somewhat downward-sloping frequency response is where the statistically popular preference may not be preferred by any one individual. Toole often says in interviews "everyone likes bass" but his research should really state "most people like bass, particularly naïve listeners." I personally seem to prefer a more horizontal frequency response than the models suggests for the tested population. I've said this before: Preferential models are great for manufacturers trying to hit the middle of the market, but they don't tell individuals what they do or don't prefer. That's j_j's point with "you prefer what you prefer," which is not a statement of right and wrong.

But likewise I expect reflected sound to be less bright than direct sound, because that's how sound works in nature. Early reflections that call attention to themselves with a noticeable peak well above the bass region sound unnatural to me.

My Revel F12's have the intentional wide, smooth directivity that was Revel's design objective from the beginning. I can sit in the sweet spot and point to the instruments with my eyes closed, but I can also do that if I move over a couple of feet. That wide directivity did nothing to undermine staging clarity, it seems to me, but it does seem to enlarge the sweet spot usefully in my experience.

Rick "learned about staging after buying those Revels" Denney

 

[anphex]

Someone requested it, here are the moving mic measurements.

Tweeter Axis

On listening position

 

[Sokel]

Someone requested it, here are the moving mic measurements.

Tweeter Axis
View attachment 439902
View attachment 439904

On listening position
View attachment 439903
View attachment 439905

You may want to use RTA mode (1/48) if you want to get results comparable with the main REW's method.

 

[thewas]

Someone requested it, here are the moving mic measurements.

Thank you, please L and R separately for each.

You may want to use RTA mode (1/48) if you want to get results comparable with the main REW's method.

Also averaging enabled: