Perceptual Effects of Room Reflections

[Scott Borduin]

That is my impression too. On orchestral music reflections can be heavenly. But on some rock/pop music it can get excessive if the room is too live. So a balance is needed.

This is interesting - my personal impressions are almost exactly the opposite. Most of my listening is classical, and most of that orchestral, and I'm always trying to listen through the system to some subjective notion of real instruments in a real hall. And I find that most systems tend to create, as an exaggeration, a loud, confusing, miniaturized orchestra in my room. Whereas sitting relatively close to directive speakers tends to create more of a sense of listening through a window into the hall - at least with decent recordings, which are much more prevalent in classical than in the dire wasteland of modern pop engineering.

But I may be a weird case. Before I had the Revels I owned MBLs. These were superficially the most impressive speakers I ever had. At the occasional party we would throw, I'd put music on in the media room and invariably I'd come around to find a few people sitting in the room absolutely mesmerized. They'd never heard audio like that and loved it. I loved it too - for a while. And for some kind of material - oh, say, some unchallenging Joe Sample jazz fusion - I'd still take it.

But after a while I got more and more disillusioned with a system that made every recording sound like MBL + Scott's room. That's when I went to a full Revel system - which was better, but still not fully satisfying for me. In some ways I still yearned for the sound that I got from my first real "high end" system in college, used Acoustat 3s driven by a Hafler DH250 kit I built (it was jointly financed by multiple roommates, I wasn't born with a silver spoon And so when I saw Robert E Greene's review of the Sanders 10E in TAS, I decided to go for it, knowing there's a 30 day money back. Done. These work for me, in spades, for 1 year+ now. The only thing I can imagine changing my direction is the advent of really good synthetic surround (QLS, you might have saved us had you only been born

But at the recent New Years day party my wife likes to throw, I didn't even bother to put on music in the media room - just had Roon send it to the living room Sonos. I knew nobody would be impressed with the way the Sanders sound on first impression. Or maybe the 100th impression, for a lot of folks. So I know my preferences are not those of most people. But having surveyed all of the literature, and tried a number the various options for myself, I'm at least confident that I prefer what I prefer.

Digression on Robert E Greene: he's a complete outlier on the TAS staff, an opinionated reviewer with an almost purely objective bent. He will allow that DACs or amps might sound very subtly different, but focuses on speakers, room, DSP or EQ, and especially recordings as the overwhelming factors. He's a math professor, and thus quite analytical about the differences in speakers, components, mic techniques, etc. He has a Yahoo Groups forum (yeah, I know!) called "regsaudioforum" that is worth joining if you want an interesting and opinionated perspective on audio recording and reproduction.

Scott

 

[Blumlein 88]

This is interesting - my personal impressions are almost exactly the opposite. Most of my listening is classical, and most of that orchestral, and I'm always trying to listen through the system to some subjective notion of real instruments in a real hall. And I find that most systems tend to create, as an exaggeration, a loud, confusing, miniaturized orchestra in my room. Whereas sitting relatively close to directive speakers tends to create more of a sense of listening through a window into the hall - at least with decent recordings, which are much more prevalent in classical than in the dire wasteland of modern pop engineering.

But I may be a weird case. Before I had the Revels I owned MBLs. These were superficially the most impressive speakers I ever had. At the occasional party we would throw, I'd put music on in the media room and invariably I'd come around to find a few people sitting in the room absolutely mesmerized. They'd never heard audio like that and loved it. I loved it too - for a while. And for some kind of material - oh, say, some unchallenging Joe Sample jazz fusion - I'd still take it.

But after a while I got more and more disillusioned with a system that made every recording sound like MBL + Scott's room. That's when I went to a full Revel system - which was better, but still not fully satisfying for me. In some ways I still yearned for the sound that I got from my first real "high end" system in college, used Acoustat 3s driven by a Hafler DH250 kit I built (it was jointly financed by multiple roommates, I wasn't born with a silver spoon And so when I saw Robert E Greene's review of the Sanders 10E in TAS, I decided to go for it, knowing there's a 30 day money back. Done. These work for me, in spades, for 1 year+ now. The only thing I can imagine changing my direction is the advent of really good synthetic surround (QLS, you might have saved us had you only been born

But at the recent New Years day party my wife likes to throw, I didn't even bother to put on music in the media room - just had Roon send it to the living room Sonos. I knew nobody would be impressed with the way the Sanders sound on first impression. Or maybe the 100th impression, for a lot of folks. So I know my preferences are not those of most people. But having surveyed all of the literature, and tried a number the various options for myself, I'm at least confident that I prefer what I prefer.

Digression on Robert E Greene: he's a complete outlier on the TAS staff, an opinionated reviewer with an almost purely objective bent. He will allow that DACs or amps might sound very subtly different, but focuses on speakers, room, DSP or EQ, and especially recordings as the overwhelming factors. He's a math professor, and thus quite analytical about the differences in speakers, components, mic techniques, etc. He has a Yahoo Groups forum (yeah, I know!) called "regsaudioforum" that is worth joining if you want an interesting and opinionated perspective on audio recording and reproduction.

Scott

Familiar with REG, but didn't know he had a yahoo group. Will have to check it out.

Interesting description of the MBL's. Impressive, but sound like MBLs (and your room). I've not had the pleasure of listening to any MBLs. As a former Acoustat Two owner to another Acoustat owner thanks for your post.

 

[amirm]

But after a while I got more and more disillusioned with a system that made every recording sound like MBL + Scott's room.

Exact problem I have with MBLs. And don't hit me but similar issue with all panel speakers. They make everything grand, bit and airy. For a while, I found them to be more true to the source as you say but the constant impression they have homogenizes music too much for me.

 

[oivavoi]

Interesting to read, Scott! I actually don't think your experiences contradict mine (or Amir's perhaps), or the research of Toole, Olive and others on the perceptual effect of reflections. It's about the old debate in hifi about "you being there" (in a different room where music is happening) or "they being here" (with music happening in your very own room).

The research indicates that reflections - mainly lateral, but also from behind and above - have two main psychoacoustic effect. One is increasing the "apparent source width" (ASW), how large and extended the images on the virtual acoustic scene seem to be. The other main effect is about "listener envelopment" (LE), how much one feels surrounded by music. The research shows that most listeners seem to prefer a larger ASW, and more LE. But not everybody. One of the main effects of increasing the ASW and the LE is that one gets closer to the "they are here" thing. After all, when moving closer to something, it will appear larger, and when moving farther away it will appear smaller. Increased LE will also give the sensation that music is happening in one's own room. The price to pay for this is that one's own room becomes the dominant room, on the expense of the recording venue - "they are here"!

Reducing lateral reflections, either through acoustic sidewall treatment or highly directional speakers such as horns or panels, will change our perception. The images on the virtual acoustic scene will appear smaller. There will be less feeling of being surrounded by the music. What this will do is make the musicians appear farther away. The acoustic analogy that is often being used is looking down on the concert scene from a distant balcony, or looking into another room where musicians are playing. "You are there" - almost.

I don't think there is a right answer here, it's a question of preference. As indicated, I perceive the "you are there" thing as slightly artificial for my ears and my brain. In my case that might be because 80 percent of my exposure to acoustic music is as a performer, either by singing/performing with a classical choir or by jamming and improvising on my piano for myself or with others. If my main exposure to classical music was sitting in a concert hall far away from the stage, I might have had other reactions. But for me, I find a "miniaturized orchestra in my room" to be more convincing. It's like my brain accepts that illusion easier than the illusion of looking through a window into another room.

 

[Blumlein 88]

Panel speakers do seem to me as if they give you the listening thru a window into the hall perspective.

Seems only mch does a really good job of a you are there enveloping perspective.

Small monitors (or the rare superb large box speaker) seem better at a they are here perspective.

 

[oivavoi]

As to the MBLs: I have listened to them quite extensively, because I like the omni idea in principle. My perception is similar: They are impressive, but they feel slightly artificial to me. I tried to understand what the rational reasons could be for this feeling of artificiality. I figured out that the reason could be that they are not point source speakers. The effect of this is that 1) one has to listen farther away from the speakers, so that the different frequencies mix together. 2) this changes the ratio of direct/indirect sound, with more indirect sound, which makes the stereo image more diffuse. 3) because the different frequencies illuminate the room from slightly different places, the indirect sound doesn't become a perfect replica of the direct sound.

These considerations led me to take a leap into the unknown and buy a pair of omnis from Morrison Audio, without having heard them. They are the only commercially available point source omnis in existence, I think. Can be listened to in the near-field, which allows for more direct sound vs. indirect sound. Expecting them in a couple of months from now. Rests to see if they are what I hope them to be!

 

[Blumlein 88]

As to the MBLs: I have listened to them quite extensively, because I like the omni idea in principle. My perception is similar: They are impressive, but they feel slightly artificial to me. I tried to understand what the rational reasons could be for this feeling of artificiality. I figured out that the reason could be that they are not point source speakers. The effect of this is that 1) one has to listen further away from the speakers, so that the different frequencies mix together. 2) this changes the ratio of direct/indirect sound, with more indirect sound, which makes the stereo image more diffuse. 3) because the different frequencies illuminate the room from slightly different places, the indirect sound doesn't become a perfect replica of the direct sound.

These considerations led me to take a leap into the unknown and buy a pair of omnis from Morrison Audio, without having heard them. They are the only commercially available point source omnis in existence, I think. Expecting them in a couple of months from now. Rests to see if they are what I hope them to be!

The model 29 like this? Will be interested in hearing what you think of it.

 

[oivavoi]

Yap. Those. They tick most of my "rational boxes" when it comes to speaker design, so we'll see if my ears agree or not!

 

[amirm]

Wow, that is one unusual speaker!

 

[svart-hvitt]

Another true omni, by AES Fellow John Watkinson:

http://www.legendloudspeakers.com/

 

[Cosmik]

I do wonder if everyone is on the same page when it comes to the degree and type of 'liveness' of listening rooms. If I do a google image search for 'listening room', the majority of rooms feature hard or wooden floors with a token rug in the middle, often covering less than half the floor area. This is not untypical:

Some don't even bother with the token rug.

Two audiophiles could easily have a conversation, swapping their experiences of room acoustics without realising they are based on vastly different levels of 'liveness' derived from their preferences for interior design or the climate of where they live. One might prefer the cosy 1970s carpeted cocoon with thick curtains, while the other prefers Miami Vice or industrial warehouse. Some houses will be old, made of solid materials with directly plastered walls, and some will be made of plasterboard. Some floors will be concrete and some will be wood.

 

[Blumlein 88]

CCRMA multi-channel listening room at Stanford university. Dig the floor treatment there.

Is there room for a thread about ceiling vs floor reflections?

 

[oivavoi]

Another true omni, by AES Fellow John Watkinson:

http://www.legendloudspeakers.com/

Yes, I checked thouse out as well! Seems like well-executed speakers, and John Watkinson isn't your average garage speaker builder. What ultimately made me choose the Morrisons over the Legends, since I could listen to neither, was these points:

a) The Legend speaker are only omni horizontally, not vertically. I believe their dispersion is 360 degrees horizontally, and approx 100 degrees vertically, plus minus. If I remember correctly. My rational hunch is that if you go omni, you should go all the way, so that the indirect sound really becomes a perfect replica of the direct sound. This means even dispersion both horizontally and vertically (the Morrisons have 360 degrees horizontal dispersion and 180 degrees vertical, essentially spreading sound like a mushroom)
b) The Legends have only 105 db maximal sound output, which limits dynamics.
c) The Legends were more expensive.

But I'm sure they sound good!

 

[oivavoi]

CCRMA multi-channel listening room at Stanford university. Dig the floor treatment there.

Very cool. I guess the idea is to have no floor bounce at all?

 

[Wombat]

It looks like " Don't get too fussed in your pokey domestic space".

 

[March Audio]

I do wonder if everyone is on the same page when it comes to the degree and type of 'liveness' of listening rooms. If I do a google image search for 'listening room', the majority of rooms feature hard or wooden floors with a token rug in the middle, often covering less than half the floor area. This is not untypical:

Some don't even bother with the token rug.

Two audiophiles could easily have a conversation, swapping their experiences of room acoustics without realising they are based on vastly different levels of 'liveness' derived from their preferences for interior design or the climate of where they live. One might prefer the cosy 1970s carpeted cocoon with thick curtains, while the other prefers Miami Vice or industrial warehouse. Some houses will be old, made of solid materials with directly plastered walls, and some will be made of plasterboard. Some floors will be concrete and some will be wood.

I am one of those that dislikes highly reverberant listening rooms. I find that my preference tends to tie in with ebu3276, about 0.3 seconds mid range in my room.

 

[Blumlein 88]

Very cool. I guess the idea is to have no floor bounce at all?

Well I do see speakers in the pit. They can do full Ambisonics in this listening space. So perhaps the area under the mesh is too allow proper full Ambisonics with height information.

 

[Kal Rubinson]

Exact problem I have with MBLs. And don't hit me but similar issue with all panel speakers. They make everything grand, bit and airy. For a while, I found them to be more true to the source as you say but the constant impression they have homogenizes music too much for me.

Yes. I went through a Stax/Apogee era in the past and came to the same conclusion.

 

[DonH56]

I like panels (ESL, planar dynamic, ribbon) but have always dampened the back wave. It is very rare that I have had a large enough room to feel they worked without that treatment behind them. Interestingly, the image at the MLP thrown by the conventional speakers I am using now (Revel Salon 2's) is very similar to that of my Maggies (with all the same -- extensive -- room treatment in place, natch). Changes more when I stand, of course, but that is not a concern of mine. It's my media room, not a stadium or concert hall that needs to sound the same everywhere ('ish).

OTOH I never liked Bose 901's and other full-on omni systems. Impressive at first, but I quickly tired of 10' wide violins and wall-to-wall piano sounds with no clear image, and of course the position of instruments wandered all over due to the reflections and interaction with the room. Not like you can damp the back wave of a 901 and have anything left... I did have a pair of C800's as midrange drivers for sound reinforcement use. Got them cheap and they worked OK.

 

[Scott Borduin]

Exact problem I have with MBLs. And don't hit me but similar issue with all panel speakers. They make everything grand, bit and airy. For a while, I found them to be more true to the source as you say but the constant impression they have homogenizes music too much for me.

It depends a lot on where you sit, and what you do with the back wave. In my room, the back wave is largely damped, and I'm less that 8 feet from the speakers. Given the highly directive radiation pattern of the near full range flat panel, I'm very much sitting in the near field. I'm not saying my system doesn't have a characteristic sound, but it is quite different from a typical maggie system, for instance, and closer to what I imagine one would hear in near-field monitoring. Which raises the legitimate question of why I didn't just go for a full near-field setup in the first place - I've no answer for that

Edit: I see @DonH56 has just beaten me to the point on part of this