Imaging and SoundStage

Art Noxon

WBF Technical Expert (Room Acoustics)
Mar 29, 2011
38
1
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Eugene, OR
www.acousticsciences.com
Imaging and Sound Stage

I think we are not only interested in musicality but we are interested in imaging and the soundstage. Some listeners are very serious about musicality and consider imaging and sound staging something of a novelty. Other listeners, possibly more frivolous (I fit into this category) really love imaging and sound staging almost more than the musicality.

When I get to work with clients on their room I always have to sort out their preference focus in listening; music or imaging. I think the path to setting up a room is different depending on musicality v imaging preference. In the end, great rooms have it all, they sound great and their imaging/soundstage is out of this world.

A great introductory read in this area is Chapter 3 of Robert Harley’s The Complete Guide to High End Audio second, third and fourth editions. I was asked to write an article for the 4th edition about setting up acoustics for hifi room. Check it out.

First project. Get used to seeing the image. Put MATT into player and settle down into your chair. Play MATT and instead of worrying about garbled passages, worry about the image, where is it?

The MATT test is mono, a perfect mono. If the image is where it is supposed to be, it will be centered, dead ahead, a tiny bright dot right between the two speakers. Each time there is a tone burst there will also be a bright dot of light, center stage.

But in the real world, the bright center stage dot does not stay in one place. It moves around, gets larger and foggier or smaller and sharper. It can be a bright dot that does not stand still but one that moves around. .

So let’s get some rooms warmed up again and playing MATT mono and write up your observations about what happened to the image.

Art Noxon
June 2011
Acoustic Sciences Corp
 

RogerD

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Where is this MATT Cd available?

I'm in the camp,if you don't have great imaging,you have nothing.:p
 

microstrip

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Chapter 8 of Floyd Toole "Sound Reproduction" is also an excellent read on this subject: "Imaging and Spatial Effects in Sound Reproduction". The discussion on apparent source width and the contradictory aspects of image precision and spaciousness are very interesting. As he does systematically in his book, Toole exposes his own perspectives and also presents others opinions about this subject .
 

Phelonious Ponk

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This is stereo, and we're trying to reproduce a recording, so imaging is critical. I love it. Even when it crosses the line into pinpoint parlor tricks that you never hear live. I repeat: We're reproducing a recording. Musicality? I still don't know what that means unless we're ready to admit that it is system-wide tone.

Tim
 
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fas42

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Musicality? I still don't know what that means unless we're ready to admit that it is system-wide tone.
Probably a trite answer for some, but at least a good starting point to reference from: J. Gordon Holt, July, 1993 -- "musical, musicality A personal judgment as to the degree to which reproduced sound resembles live music. Real musical sound is both accurate and euphonic, consonant and dissonant."

Frank
 

amirm

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Guys: this is Art's expert forum. Please follow his lead and do not engage in side arguments. Create a thread if you want to do that in the debate area. We want these to be highly informational. Art can address that point if he likes and you can interact with him but not starting things on your own and running with it :).
 

Phelonious Ponk

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Then back to Art's original post: Let me repeat Ron's question, "Art, what is musicality?" and Terryj's question, "And how do you optimise for that at the express detriment of imaging?"

Tim
 

mep

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I don't think Amir wants that question repeated on Art's thread because it was inviting a food fight and Ron knew that when he asked it. Asking what is musicality is like throwing a steak into a pack of wild dogs and not expecting some bad results.
 

Ron Party

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Save the amateur psychology for a more appropriate forum. I agree with Amir's post. My question and that of Terry's were not invitations to (re)examine anyone else's definition of "musical". My question was specific, as was Terry's. We are solely concerned with Art's definition of "musicality" so we may have a clearer understanding of HIS original post.
 

Phelonious Ponk

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And I apologize for reacting to Frank's report on Holt's definition of "musicality" and await Art's clarification, so we can continue this discussion with clarity.

Tim
 

Art Noxon

WBF Technical Expert (Room Acoustics)
Mar 29, 2011
38
1
0
Eugene, OR
www.acousticsciences.com
OK, Musicality, from my perspective, is if a musical instrument sounds like the musical instrument. When I'm working on a room for an audiophile, they are very quick to point out that they are interested in musical accuracy, they want instruments and ensembles to sound great, real, somehow be lifelike. However, when someone is an image freak, they are mostly interested in the image of the sound, not the actual quality or accuracy of the sound.

I hope this simple effort clarifies my differentiation.

As for Floyd Toole, I knew him when he was working off govt grants in Canada as the Canadian govt was investing heavily into bolstering Canadian audio manufacturing. Yes, they even wanted a TubeTrap factory up there. But….we already had one in Kaslo BC. Those guys didn’t want to move. Floyd got bigger and bigger in stature when he left Canada for a stint in the US with Harmon/JBL. I ran into him one day, fairly early in his career...and what happened left me feeling pretty cold towards him. I wanted to bring him up to speed on advancements in TubeTrap room acoustics, as best I knew….when he told me that he already knew all he needed to know about TubeTraps, they were bass traps, and he didn’t want to spend anymore time on the subject. Well, there is a huge difference between a product and what you do with it. But, he was on his own roll and was busy with his own ideas…. Since then I kinda tuned him out. Sorry about the divergence, I’ll get his book, and see what he says. Back to my world…

Acoustically, a musical room is typically a relatively bright room. Not reverberant but full of early reflections. Early reflections are those that arrive at the listener’s ears within say 35ms following the direct signal. Early reflections fuse with the direct signal. They make the direct more clear, easier to understand. This is the Hass Effect which is related to the precedence effect. It is called sound fusion. Our ear-brain listening system remains open for the first 35ms following any particular sound, open to reflections of that sound. These early reflections increase perceived loudness of signals without turning the volume up. The early reflections are off axis versions of the direct signal and may not have the same frequency content. Accordingly, high musicality speakers tend to be full range omni or semi omni speakers.

We don’t allow late reflections in musical spaces, which mean strong reflections say 40ms and beyond. Pre echo reflections, between 40 and 60 ms cause smearing of the top end of the frequency range, the upper partials. And for later arriving reflections we have of course echoes. Distinct echoes or flutter echoes are verboten because they mess up tempo and the ability to actually focus on quickly changing music dynamics. we don't mind some reverberation, but really we want to hear the reverberation in the recording.

However nice early reflections may be for musicality, early reflections simply wreck imaging. High imaging systems are fairly reflection free. They do not have strong early reflections. What they might have is a healthy backflash of late reflections. Echoes are either absorbed or diffused, either way, echoes are not to be heard. And reverberation? The less the better.

Most rooms are some blend of these two extremes and it’s a dialed in personal preference. And it doesn’t stop with the room. Hi imaging speaker tend to be directional. High musicality speakers tend to be more omni. The speaker choice and the room acoustics combine to provide the right balance of musicality and imaging for each person.

Well, that’s my version of the opening salvo about how rooms and speakers interact differently depending on musicality and/or imaging listening preferences. And also, it shows how these two aspects of listening tend to be mutually exclusive. …..Art Noxon
 
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Phelonious Ponk

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OK, Musicality, from my perspective, is if a musical instrument sounds like the musical instrument.

OK. Then musicality must = accuracy if the recording is good and unobtainable if it is not.

However, when someone is an image freak, they are mostly interested in the image of the sound, not the actual quality or accuracy of the sound.

How can the possibly be mutually exclusive?

Tim
 

RogerD

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OK, Musicality, from my perspective, is if a musical instrument sounds like the musical instrument. When I'm working on a room for an audiophile, they are very quick to point out that they are interested in musical accuracy, they want instruments and ensembles to sound great, real, somehow be lifelike. However, when someone is an image freak, they are mostly interested in the image of the sound, not the actual quality or accuracy of the sound.

I hope this simple effort clarifies my differentiation.

As for Floyd Toole, I knew him when he was working off govt grants in Canada as the Canadian govt was investing heavily into bolstering Canadian audio manufacturing. Yes, they even wanted a TubeTrap factory up there. But….we already had one in Kaslo BC. Those guys didn’t want to move. Floyd got bigger and bigger in stature when he left Canada for a stint in the US with Harmon/JBL. I ran into him one day, fairly early in his career...and what happened left me feeling pretty cold towards him. I wanted to bring him up to speed on advancements in TubeTrap room acoustics, as best I knew….when he told me that he already knew all he needed to know about TubeTraps, they were bass traps, and he didn’t want to spend anymore time on the subject. Well, there is a huge difference between a product and what you do with it. But, he was on his own roll and was busy with his own ideas…. Since then I kinda tuned him out. Sorry about the divergence, I’ll get his book, and see what he says. Back to my world…

Acoustically, a musical room is typically a relatively bright room. Not reverberant but full of early reflections. Early reflections are those that arrive at the listener’s ears within say 35ms following the direct signal. Early reflections fuse with the direct signal. They make the direct more clear, easier to understand. This is the Hass Effect which is related to the precedence effect. It is called sound fusion. Our ear-brain listening system remains open for the first 35ms following any particular sound, open to reflections of that sound. These early reflections increase perceived loudness of signals without turning the volume up. The early reflections are off axis versions of the direct signal and may not have the same frequency content. Accordingly, high musicality speakers tend to be full range omni or semi omni speakers.

We don’t allow late reflections in musical spaces, which mean strong reflections say 40ms and beyond. Pre echo reflections, between 40 and 60 ms cause smearing of the top end of the frequency range, the upper partials. And for later arriving reflections we have of course echoes. Distinct echoes or flutter echoes are verboten because they mess up tempo and the ability to actually focus on quickly changing music dynamics. we don't mind some reverberation, but really we want to hear the reverberation in the recording.

However nice early reflections may be for musicality, early reflections simply wreck imaging. High imaging systems are fairly reflection free. They do not have strong early reflections. What they might have is a healthy backflash of late reflections. Echoes are either absorbed or diffused, either way, echoes are not to be heard. And reverberation? The less the better.

Most rooms are some blend of these two extremes and it’s a dialed in personal preference. And it doesn’t stop with the room. Hi imaging speaker tend to be directional. High musicality speakers tend to be more omni. The speaker choice and the room acoustics combine to provide the right balance of musicality and imaging for each person.

Well, that’s my version of the opening salvo about how rooms and speakers interact differently depending on musicality and/or imaging listening preferences. And also, it shows how these two aspects of listening tend to be mutually exclusive. …..Art Noxon

For me only, your conclusions that I bolded are dead wrong. Maybe I'm the exception,but accuracy along with imaging leaves me excited and is the primary reason for the lifelong love of this hobby.

My speakers are anything but directional,if fact most of the time they disappear completely and the image is top to bottom and well outside the speakers,many times with a description I use as 3D holographic. These speakers have exhibited this in 3 different rooms in the last 30 years and with no room treatments. The room treatment comment is just fyi ,maybe it would sound better with room treatments, I just have never thought I needed them.

Accuracy is the one thing that makes me laugh or cry. Accuracy is realism and provokes emotions,it is another reason I am hooked on this hobby.

Like I said,maybe I'm the exception.
 

Phelonious Ponk

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Jun 30, 2010
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For me only, your conclusions that I bolded are dead wrong. Maybe I'm the exception,but accuracy along with imaging leaves me excited and is the primary reason for the lifelong love of this hobby.

My speakers are anything but directional,if fact most of the time they disappear completely and the image is top to bottom and well outside the speakers,many times with a description I use as 3D holographic. These speakers have exhibited this in 3 different rooms in the last 30 years and with no room treatments. The room treatment comment is just fyi ,maybe it would sound better with room treatments, I just have never thought I needed them.

Accuracy is the one thing that makes me laugh or cry. Accuracy is realism and provokes emotions,it is another reason I am hooked on this hobby.

Like I said,maybe I'm the exception.

Well, at least you're not the only exception, Roger. I agree whole-heartedly.

Tim
 

Art Noxon

WBF Technical Expert (Room Acoustics)
Mar 29, 2011
38
1
0
Eugene, OR
www.acousticsciences.com
“dead wrong” sounds so awful and final. Let’s hope we are having a miscommunication instead of a funeral.

Directional speakers does not mean to me that they won’t diappear, it just means they play less mids and highs sideways, above and behind them, than does a pure omni speaker which plays all frequencies equally in all directions.

Here’s an outdoor test for speakers. Omni speakers can be rotated in position on a turntable and you’ll never hear any difference as they rotate. With directional speakers you will hear a difference in the sound they make as they rotate. That is what I mean by directional. Most speakers are directional, except for those few omni speakers (Ohm Walsh, Wolcott, Shahinian) which is a very specific type of speaker that has a small but loyal following.

I agree 100% with you that you know you are getting close when you don’t even know the speakers are in the room. They are to me like two silent field generators, machines that by weaving, they together create the sound field. I just love that. Your description about how good sounding systems disappear was something I was going to mention and then I forgot. Probably would have picked it up soon enough and here you moved us right along.

What are your speakers?

You said your speaker are anything but directional. And that they disappear. And that the image is huge vertically and horizontally. Your description is so vivid and it reminds me of something that took years for me to figure out. But I want to make sure we are using the same words to decribe the same experience. So, I ask you to do me a favor.

How about you get stereophile test cd #2 track 19 and play it. Listen carefully and focus only on the image. What color is it? Where is it? Does it stay in one place? How bright is it? How clear, well defined is it? And how small or large is it?.

Where the image is on the sound stage depends on the recording. How it appears pretty much depend on the room.

The sound stage is all the places where an image can be located. A sound stage is best seen with a Blumlein crossed pair recording of a symphony. On the sound stage will be many images, each instrument is an image. Many instruments located in many different places, filling the sound stage. There will also be an ambience, the hall reverb in a side to side space, across the ears.

I used to see the old timer audiophiles sketching out maps of their sound stage. Has anyone out there tracked image vs frequency, anyone out there ever sketched your sound stage. Anyone read about how to map sound stage? Where is an article or place in a book? I really want us to map our sound stages. It does take time and it’s fun. Just another way to get to know your system and talk about it.

I googled “what is hifi sound stage” and came up with

http://www.pinkfishmedia.net/forum/archive/index.php/t-55831.html

Now, for me, this thread pretty much demonstrates the lack of vocabulary in this area. People are throwing punches left and right. To me they are confusing imaging and sound stage.

The sound stage is all the places where the image can exit. The image can have many variations in shape and position. If there are many early reflections you will have a huge image and sound stage. The image will occupy most of the sound stage. It will be 6 to 8’ tall and 10 to 12’ wide and float between the speakers. And something else, it stays there. Get up move around the room and that image is locked down. This is how omni or fairly omni speakers work in reflective rooms.

In most acoustically treated audiophile rooms, when you get up and move to the left or right, the imaging, the sound stage seems to shift smoothly to the left or right. In crummy rooms, the image disappears when you move to the left or right and all you hear is the loudspeaker that is closest to you.

And now you have a clue as to in the beginning why your description of your huge image was so interesting to me. I’ve seen them and marveled at them. They are very unique, like a rainbow is unique. But let’s not jump to conclusions, just find and run the MATT test and listen to its image. Answer my questions, and let’s see what we dig up.

If you don’t have MATT, and want to download one or learn more about it, go to

http://www.acousticsciences.com/matt.htm

Art Noxon
ASC TubeTrap
 

microstrip

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May 30, 2010
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(...) Acoustically, a musical room is typically a relatively bright room. Not reverberant but full of early reflections. Early reflections are those that arrive at the listener’s ears within say 35ms following the direct signal. Early reflections fuse with the direct signal. They make the direct more clear, easier to understand. This is the Hass Effect which is related to the precedence effect. It is called sound fusion. Our ear-brain listening system remains open for the first 35ms following any particular sound, open to reflections of that sound. These early reflections increase perceived loudness of signals without turning the volume up. The early reflections are off axis versions of the direct signal and may not have the same frequency content. Accordingly, high musicality speakers tend to be full range omni or semi omni speakers.

We don’t allow late reflections in musical spaces, which mean strong reflections say 40ms and beyond. Pre echo reflections, between 40 and 60 ms cause smearing of the top end of the frequency range, the upper partials. And for later arriving reflections we have of course echoes. Distinct echoes or flutter echoes are verboten because they mess up tempo and the ability to actually focus on quickly changing music dynamics. we don't mind some reverberation, but really we want to hear the reverberation in the recording.

However nice early reflections may be for musicality, early reflections simply wreck imaging. High imaging systems are fairly reflection free. They do not have strong early reflections. What they might have is a healthy backflash of late reflections. Echoes are either absorbed or diffused, either way, echoes are not to be heard. And reverberation? The less the better.

Most rooms are some blend of these two extremes and it’s a dialed in personal preference. And it doesn’t stop with the room. Hi imaging speaker tend to be directional. High musicality speakers tend to be more omni. The speaker choice and the room acoustics combine to provide the right balance of musicality and imaging for each person.

Well, that’s my version of the opening salvo about how rooms and speakers interact differently depending on musicality and/or imaging listening preferences. And also, it shows how these two aspects of listening tend to be mutually exclusive. …..Art Noxon

Thanks for such a concise summary on the interaction of speakers and rooms, and how they relate to our preferences. I would like to ask you a question about the SoundLab A1s, a large speaker with some strange radiation properties as it is a full range 90 degree cylindrical radiator with dipole radiation. Should it be considered as an omni or just as a directional dipole?
 

RogerD

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May 23, 2010
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“dead wrong” sounds so awful and final. Let’s hope we are having a miscommunication instead of a funeral.

Directional speakers does not mean to me that they won’t diappear, it just means they play less mids and highs sideways, above and behind them, than does a pure omni speaker which plays all frequencies equally in all directions.

Here’s an outdoor test for speakers. Omni speakers can be rotated in position on a turntable and you’ll never hear any difference as they rotate. With directional speakers you will hear a difference in the sound they make as they rotate. That is what I mean by directional. Most speakers are directional, except for those few omni speakers (Ohm Walsh, Wolcott, Shahinian) which is a very specific type of speaker that has a small but loyal following.

I agree 100% with you that you know you are getting close when you don’t even know the speakers are in the room. They are to me like two silent field generators, machines that by weaving, they together create the sound field. I just love that. Your description about how good sounding systems disappear was something I was going to mention and then I forgot. Probably would have picked it up soon enough and here you moved us right along.

What are your speakers?

You said your speaker are anything but directional. And that they disappear. And that the image is huge vertically and horizontally. Your description is so vivid and it reminds me of something that took years for me to figure out. But I want to make sure we are using the same words to decribe the same experience. So, I ask you to do me a favor.

How about you get stereophile test cd #2 track 19 and play it. Listen carefully and focus only on the image. What color is it? Where is it? Does it stay in one place? How bright is it? How clear, well defined is it? And how small or large is it?.

Where the image is on the sound stage depends on the recording. How it appears pretty much depend on the room.

The sound stage is all the places where an image can be located. A sound stage is best seen with a Blumlein crossed pair recording of a symphony. On the sound stage will be many images, each instrument is an image. Many instruments located in many different places, filling the sound stage. There will also be an ambience, the hall reverb in a side to side space, across the ears.

I used to see the old timer audiophiles sketching out maps of their sound stage. Has anyone out there tracked image vs frequency, anyone out there ever sketched your sound stage. Anyone read about how to map sound stage? Where is an article or place in a book? I really want us to map our sound stages. It does take time and it’s fun. Just another way to get to know your system and talk about it.

I googled “what is hifi sound stage” and came up with

http://www.pinkfishmedia.net/forum/archive/index.php/t-55831.html

Now, for me, this thread pretty much demonstrates the lack of vocabulary in this area. People are throwing punches left and right. To me they are confusing imaging and sound stage.

The sound stage is all the places where the image can exit. The image can have many variations in shape and position. If there are many early reflections you will have a huge image and sound stage. The image will occupy most of the sound stage. It will be 6 to 8’ tall and 10 to 12’ wide and float between the speakers. And something else, it stays there. Get up move around the room and that image is locked down. This is how omni or fairly omni speakers work in reflective rooms.

In most acoustically treated audiophile rooms, when you get up and move to the left or right, the imaging, the sound stage seems to shift smoothly to the left or right. In crummy rooms, the image disappears when you move to the left or right and all you hear is the loudspeaker that is closest to you.

And now you have a clue as to in the beginning why your description of your huge image was so interesting to me. I’ve seen them and marveled at them. They are very unique, like a rainbow is unique. But let’s not jump to conclusions, just find and run the MATT test and listen to its image. Answer my questions, and let’s see what we dig up.

If you don’t have MATT, and want to download one or learn more about it, go to

http://www.acousticsciences.com/matt.htm

Art Noxon
ASC TubeTrap

Thank you Art. The "dead wrong" was a mis-communication,but as you and I can see reading a partial bit from the thread that you posted a link to,would be explainable because that is a real food fight.

My speakers are custom and use dynAudio drivers. I have some things to do but if my schedule permits will address your excellant post later. I think I have that Stereophile CD. So when I can spend some good time with my system I will address your questions to me.
 

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