Simplified REW Setup and Use (USB Mic & HDMI Connection) Including Measurement Techniques and How To Interpret Graphs - Page 265 - AVS Forum
Forum Jump: 
 219Likes
Reply
 
Thread Tools
post #7921 of 12191 Old 01-12-2014, 09:59 AM
AVS Special Member
 
Selden Ball's Avatar
 
Join Date: Jan 2001
Location: upstate NY
Posts: 7,414
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 614 Post(s)
Liked: 464
My impression is that there are some things which are measurable but which are not actually being measured. For example, many of the articles in Stereophile which show speaker measurements include the phase shift that they introduce in the audio across the full audible bandwidth. (They're usually in the same plot with the impedance variations.) I haven't seen any similar measurements here.

Such changes in phase might be responsible for the differing quality of soundstages which some people report when room EQ is applied to a stereo signal.

Selden

Marantz SR7009/7.1.4/FH+TM/DefTech PM1000/LCR+TM amped
Selden Ball is online now  
Sponsored Links
Advertisement
 
post #7922 of 12191 Old 01-12-2014, 10:05 AM
AVS Special Member
 
AustinJerry's Avatar
 
Join Date: Jan 2003
Location: Austin, Texas
Posts: 7,778
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 933 Post(s)
Liked: 864
Quote:
Originally Posted by pepar View Post

Shouldn't the delay be a good indication of which of the six room boundaries is causing any given spike?

Is there an app where one can enter our room geometry and speaker/listener positions and have it output the expected spikes sorted by delay and attributable to a boundary or combination of boundaries? Does a 3-boundary bounce still have significance or is two as deep as we should care about?

Jeff

 

Jeff, I am unaware of any app that would assist in predicting reflection patterns in a listening room.  Sound behaves in a predictable fashion based on physics--any hard surface will reflect sound.  The direction of the reflection is governed by the law of angle of incidence equals the angle of reflection.  The size of the reflecting surface will affect which frequencies are reflected (the smaller the surface, the higher the frequency).  And the arrival time of the reflection gives clues to how far away from the measurement mic the reflective surface is located.

 

So, assuming we are interested in reflections that arrive at the MLP (for those of us who are primarily interested in improving one listening spot), we measure the reflections using the Impulse response measurement at the MLP.  We establish certain objectives WRT which reflections we want to control (e.g. any reflection that has not been reduced by 20dB in the first 20ms is an objective many of us are using).  From that point forward, we have established techniques to identify where the reflections are coming from, i.e. what is causing them, regardless of whether they are caused by one reflection, or multiple reflections.  Once we isolate the source of the reflection, we chose a treatment that is designed for the type of reflection (i.e. its frequency), and what we want to do with it (i.e. absorb it, or re-direct it), or in some cases we simply remove the cause of the reflection (e.g. a picture on a wall).

 

I don't think this is rocket science, it's just tedious and sometimes frustrating work.  The frustration comes when we have difficulty isolating the reflection, when efforts to tame it are unsuccessful, or when eliminating the reflection would require a change to our listening room that we would find difficult to live with.  Where it might be considered rocket science is when reflections are used to tailor a room's audio characteristics to accomplish a specific goal, e.g. Jim's wonderful creation of a stunning LEDE environment.

AustinJerry is online now  
post #7923 of 12191 Old 01-12-2014, 10:08 AM
AVS Special Member
 
markus767's Avatar
 
Join Date: Apr 2009
Posts: 5,376
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 845 Post(s)
Liked: 335
Quote:
Originally Posted by Selden Ball View Post

My impression is that there are some things which are measurable but which are not actually being measured. For example, many of the articles in Stereophile which show speaker measurements include the phase shift that they introduce in the audio across the full audible bandwidth. (They're usually in the same plot with the impedance variations.) I haven't seen any similar measurements here.

Such changes in phase might be responsible for the differing quality of soundstages which some people report when room EQ is applied to a stereo signal.

If this leads to interaural differences then yes, it will be audible. But in my opinion similarity of the interaural magnitude response is more important.

Markus

"In science, contrary evidence causes one to question a theory. In religion, contrary evidence causes one to question the evidence." - Floyd Toole
markus767 is online now  
post #7924 of 12191 Old 01-12-2014, 10:15 AM
AVS Special Member
 
AustinJerry's Avatar
 
Join Date: Jan 2003
Location: Austin, Texas
Posts: 7,778
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 933 Post(s)
Liked: 864
Quote:
Originally Posted by pepar View Post


That is the missing piece for me; are there things that I can hear but can't measure? Beyond this is are there things that I can hear and can measure, but can't see on a little graph?

Beyond waterfalls/decay and obvious problem spikes on an ETC, I DONT KNOW. You and I have "discussed" this already, but as certain as you are is how uncertain I am.

Among the myriad of variables in the sound of reproduced music, soundtracks, etc, I will mention timbre matching of surrounds and LCR. Can the improvement heard from no "room correction" to using room correction be measured/seen on a graph? Can the very subtle difference I hear from XT32 to XT32/Pro be measured/seen on a graph?

Jeff

 

Philosophically, I agree with Keith--if something sounds different, we should be able to measure the difference.  The problem arises because we may not be able to interpret the measurements in such a way as to explain the differences in what we hear.

 

Take your example of timbre.  To me, if two speakers are timbre-matched it means that if they are fed the same audio signal, they will reproduce the signal in exactly the same way.  All speakers have some level of coloration, so two timbre-matched speakers would have similar, if not identical, coloration.  I firmly believe that coloration is measurable, as long as the measurement system is accurate enough, so comparing two sets of before/after measurements should be able to isolate whether the speakers are timbre-matched.

 

The same logic would apply to other subjective assessments of sound, like "spaciousness", "depth of soundstage" and "imaging".  If it subjectively sounds different, there is a method of measurement that will be able to objectively show the difference.

AustinJerry is online now  
post #7925 of 12191 Old 01-12-2014, 10:24 AM
AVS Special Member
 
jim19611961's Avatar
 
Join Date: Mar 2011
Location: Texas
Posts: 1,406
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 134 Post(s)
Liked: 88
Quote:
Originally Posted by AustinJerry View Post

Philosophically, I agree with Keith--if something sounds different, we should be able to measure the difference.  The problem arises because we may not be able to interpret the measurements in such a way as to explain the differences in what we hear.

Take your example of timbre.  To me, if two speakers are timbre-matched it means that if they are fed the same audio signal, they will reproduce the signal in exactly the same way.  All speakers have some level of coloration, so two timbre-matched speakers would have similar, if not identical, coloration.  I firmly believe that coloration is measurable, as long as the measurement system is accurate enough, so comparing two sets of before/after measurements should be able to isolate whether the speakers are timbre-matched.

The same logic would apply to other subjective assessments of sound, like "spaciousness", "depth of soundstage" and "imaging".  If it subjectively sounds different, there is a method of measurement that will be able to objectively show the difference.

While I agree with you in theory, I have not found any direct correlation via measurement to "spaciousness", "depth of soundstage" and "imaging". Like I said in another post to Keith, these things depend on psychoacoustic factors such as the frequency domain of reflections (which most do not measure), the direction from which those reflections arrive (which do not show in measurement at all), and the diffuse vs specular nature of those reflections (which also has no measurement data).

My Room
My Music
Rega - Apollo, Rega - DAC, Goldpoint Passive, (2) Classe CA-100 bridged power amps (350w)
Jenzen Next
jim19611961 is online now  
post #7926 of 12191 Old 01-12-2014, 10:30 AM
AVS Addicted Member
 
kbarnes701's Avatar
 
Join Date: Jan 2008
Location: Main Listening Positon
Posts: 19,074
Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 2126 Post(s)
Liked: 2076
Quote:
Originally Posted by AustinJerry View Post
 
Quote:
Originally Posted by pepar View Post


That is the missing piece for me; are there things that I can hear but can't measure? Beyond this is are there things that I can hear and can measure, but can't see on a little graph?

Beyond waterfalls/decay and obvious problem spikes on an ETC, I DONT KNOW. You and I have "discussed" this already, but as certain as you are is how uncertain I am.

Among the myriad of variables in the sound of reproduced music, soundtracks, etc, I will mention timbre matching of surrounds and LCR. Can the improvement heard from no "room correction" to using room correction be measured/seen on a graph? Can the very subtle difference I hear from XT32 to XT32/Pro be measured/seen on a graph?

Jeff

 

Philosophically, I agree with Keith--if something sounds different, we should be able to measure the difference.  The problem arises because we may not be able to interpret the measurements in such a way as to explain the differences in what we hear.

 

Take your example of timbre.  To me, if two speakers are timbre-matched it means that if they are fed the same audio signal, they will reproduce the signal in exactly the same way.  All speakers have some level of coloration, so two timbre-matched speakers would have similar, if not identical, coloration.  I firmly believe that coloration is measurable, as long as the measurement system is accurate enough, so comparing two sets of before/after measurements should be able to isolate whether the speakers are timbre-matched.

 

The same logic would apply to other subjective assessments of sound, like "spaciousness", "depth of soundstage" and "imaging".  If it subjectively sounds different, there is a method of measurement that will be able to objectively show the difference.

 

Yup. We are on the same page, Jerry. If it sounds different to the ears, then the cause of the difference in the sound can be measured. So if a system has poor 'imaging' and sounds cannot be readily pinpointed in space, this will show up in measurements. The difficult bit, I guess, is knowing what causes poor spatial localisation of individual sounds and therefore knowing where to look in our measurement armoury. 

 

Once we know that the sound is 'muddied' (ie there is a lack of ability to precisely pinpoint individual sounds in between and around the speakers) by unwanted reflections and room mode issues, we can then measure appropriately and look to our ETCs and spectrograms which will reveal problems caused by these unwanted reflections in graph form. We are then able to take countermeasures, with treatments, speaker placement optimization and/or even different speakers (with different dispersion characteristics) - or all three of course  -  and then measure again and see the improvements. In fact I did this myself and each time I introduced countermeasures, I heard a significant improvement in imaging: it could be heard and it showed up in measurements. 

 

The converse of the above is that if we look at ETCs and spectrograms which show significant problems with uncontrolled early reflections and poor decay in the modal region, then we will be able to make valid assumptions about how the system will sound in the room.

 

So some sort of understanding of acoustics and room-induced issues is needed. IOW one needs to know the likely cause of the problem which is being heard, so one can track it down using measurements. To this end, I today, at last, ordered Floyd Toole's book, "Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Rooms" and am looking forward immensely to reading it. 

kbarnes701 is offline  
post #7927 of 12191 Old 01-12-2014, 10:33 AM
AVS Addicted Member
 
kbarnes701's Avatar
 
Join Date: Jan 2008
Location: Main Listening Positon
Posts: 19,074
Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 2126 Post(s)
Liked: 2076
Quote:
Originally Posted by Selden Ball View Post

My impression is that there are some things which are measurable but which are not actually being measured. For example, many of the articles in Stereophile which show speaker measurements include the phase shift that they introduce in the audio across the full audible bandwidth. (They're usually in the same plot with the impedance variations.) I haven't seen any similar measurements here.

Such changes in phase might be responsible for the differing quality of soundstages which some people report when room EQ is applied to a stereo signal.

 

Agreed, Selden. But you are also agreeing that if it can be heard, it can be measured, I think. It's just that we need to know what to measure. That is of course, the hard part :)

kbarnes701 is offline  
post #7928 of 12191 Old 01-12-2014, 10:43 AM
AVS Addicted Member
 
kbarnes701's Avatar
 
Join Date: Jan 2008
Location: Main Listening Positon
Posts: 19,074
Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 2126 Post(s)
Liked: 2076
Quote:
Originally Posted by jim19611961 View Post
 
Quote:
Originally Posted by AustinJerry View Post

Philosophically, I agree with Keith--if something sounds different, we should be able to measure the difference.  The problem arises because we may not be able to interpret the measurements in such a way as to explain the differences in what we hear.

Take your example of timbre.  To me, if two speakers are timbre-matched it means that if they are fed the same audio signal, they will reproduce the signal in exactly the same way.  All speakers have some level of coloration, so two timbre-matched speakers would have similar, if not identical, coloration.  I firmly believe that coloration is measurable, as long as the measurement system is accurate enough, so comparing two sets of before/after measurements should be able to isolate whether the speakers are timbre-matched.

The same logic would apply to other subjective assessments of sound, like "spaciousness", "depth of soundstage" and "imaging".  If it subjectively sounds different, there is a method of measurement that will be able to objectively show the difference.

While I agree with you in theory, I have not found any direct correlation via measurement to "spaciousness", "depth of soundstage" and "imaging". Like I said in another post to Keith, these things depend on psychoacoustic factors such as the frequency domain of reflections (which most do not measure), the direction from which those reflections arrive (which do not show in measurement at all), and the diffuse vs specular nature of those reflections (which also has no measurement data).

 

I never replied to your post, Jim, for which I apologise. I just didn't get a round tuit - no excuse. The problem with terms such as 'spaciousness' is that they are essentially subjective and what you mean by it is perhaps different to what I mean by it. I think in the post you refer to, we both seemed to have different understandings of what 'soundstage' might mean (IIRC).

 

WRT to spaciousness, you gave an example of a recording in a large space and the time the sound took to reverberate around etc and how this gave the impression of a large space, even if we were taken onto that space blindfolded. I agree, in those circumstances we would know we were in a large space. My point there was that all the 'spaciousness' I need from a recording has already been 'baked in' by the recording engineer, so all I need is a system which can faithfully reproduce its input at its output (all caveats apply).

 

IOW, I need a system that plays pretty flat, has controlled (or even removed) room reflections, has suitable decay characteristics etc. If I have that, then I will hear, especially in a m/ch system, all that 'spaciousness'. In fact I do hear it all the time in movies where it is a factor on screen and in the audio mix, because it is baked in and because my system is reasonably competent. So, IOW, all the measuring I have done, to get the system pretty flat, to control reflections and decay etc etc has now enabled me to hear the environment that the mixer intended me to hear, whether it is a cathedral or the inside of an elevator. 

kbarnes701 is offline  
post #7929 of 12191 Old 01-12-2014, 11:01 AM
AVS Special Member
 
jim19611961's Avatar
 
Join Date: Mar 2011
Location: Texas
Posts: 1,406
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 134 Post(s)
Liked: 88
Quote:
Originally Posted by kbarnes701 View Post

I never replied to your post, Jim, for which I apologise. I just didn't get a round tuit - no excuse. The problem with terms such as 'spaciousness' is that they are essentially subjective and what you mean by it is perhaps different to what I mean by it. I think in the post you refer to, we both seemed to have different understandings of what 'soundstage' might mean (IIRC).

WRT to spaciousness, you gave an example of a recording in a large space and the time the sound took to reverberate around etc and how this gave the impression of a large space, even if we were taken onto that space blindfolded. I agree, in those circumstances we would know we were in a large space. My point there was that all the 'spaciousness' I need from a recording has already been 'baked in' by the recording engineer, so all I need is a system which can faithfully reproduce its input at its output (all caveats apply).

IOW, I need a system that plays pretty flat, has controlled (or even removed) room reflections, has suitable decay characteristics etc. If I have that, then I will hear, especially in a m/ch system, all that 'spaciousness'. In fact I do hear it all the time in movies where it is a factor on screen and in the audio mix, because it is baked in and because my system is reasonably competent. So, IOW, all the measuring I have done, to get the system pretty flat, to control reflections and decay etc etc has now enabled me to hear the environment that the mixer intended me to hear, whether it is a cathedral or the inside of an elevator. 



Here is Toole's definition of spaciousness.



Here he illustrates what frequencies prevail for different areas or impressions.

My Room
My Music
Rega - Apollo, Rega - DAC, Goldpoint Passive, (2) Classe CA-100 bridged power amps (350w)
Jenzen Next
jim19611961 is online now  
post #7930 of 12191 Old 01-12-2014, 11:07 AM
AVS Special Member
 
jim19611961's Avatar
 
Join Date: Mar 2011
Location: Texas
Posts: 1,406
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 134 Post(s)
Liked: 88


More food for thought.

My Room
My Music
Rega - Apollo, Rega - DAC, Goldpoint Passive, (2) Classe CA-100 bridged power amps (350w)
Jenzen Next
jim19611961 is online now  
post #7931 of 12191 Old 01-12-2014, 12:05 PM
AVS Special Member
 
jim19611961's Avatar
 
Join Date: Mar 2011
Location: Texas
Posts: 1,406
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 134 Post(s)
Liked: 88
Quote:
Originally Posted by kbarnes701 View Post

I never replied to your post, Jim, for which I apologise. I just didn't get a round tuit - no excuse. The problem with terms such as 'spaciousness' is that they are essentially subjective and what you mean by it is perhaps different to what I mean by it. I think in the post you refer to, we both seemed to have different understandings of what 'soundstage' might mean (IIRC).

WRT to spaciousness, you gave an example of a recording in a large space and the time the sound took to reverberate around etc and how this gave the impression of a large space, even if we were taken onto that space blindfolded. I agree, in those circumstances we would know we were in a large space. My point there was that all the 'spaciousness' I need from a recording has already been 'baked in' by the recording engineer, so all I need is a system which can faithfully reproduce its input at its output (all caveats apply).

IOW, I need a system that plays pretty flat, has controlled (or even removed) room reflections, has suitable decay characteristics etc. If I have that, then I will hear, especially in a m/ch system, all that 'spaciousness'. In fact I do hear it all the time in movies where it is a factor on screen and in the audio mix, because it is baked in and because my system is reasonably competent. So, IOW, all the measuring I have done, to get the system pretty flat, to control reflections and decay etc etc has now enabled me to hear the environment that the mixer intended me to hear, whether it is a cathedral or the inside of an elevator. 

No apology necessary.

As has been pointed out before, your take is relevant for AV and mine for 2ch audio. I think we are both right in our separate worlds.

My Room
My Music
Rega - Apollo, Rega - DAC, Goldpoint Passive, (2) Classe CA-100 bridged power amps (350w)
Jenzen Next
jim19611961 is online now  
post #7932 of 12191 Old 01-12-2014, 12:50 PM
AVS Addicted Member
 
kbarnes701's Avatar
 
Join Date: Jan 2008
Location: Main Listening Positon
Posts: 19,074
Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 2126 Post(s)
Liked: 2076
Quote:
Originally Posted by jim19611961 View Post
 
Quote:
Originally Posted by kbarnes701 View Post

I never replied to your post, Jim, for which I apologise. I just didn't get a round tuit - no excuse. The problem with terms such as 'spaciousness' is that they are essentially subjective and what you mean by it is perhaps different to what I mean by it. I think in the post you refer to, we both seemed to have different understandings of what 'soundstage' might mean (IIRC).

WRT to spaciousness, you gave an example of a recording in a large space and the time the sound took to reverberate around etc and how this gave the impression of a large space, even if we were taken onto that space blindfolded. I agree, in those circumstances we would know we were in a large space. My point there was that all the 'spaciousness' I need from a recording has already been 'baked in' by the recording engineer, so all I need is a system which can faithfully reproduce its input at its output (all caveats apply).

IOW, I need a system that plays pretty flat, has controlled (or even removed) room reflections, has suitable decay characteristics etc. If I have that, then I will hear, especially in a m/ch system, all that 'spaciousness'. In fact I do hear it all the time in movies where it is a factor on screen and in the audio mix, because it is baked in and because my system is reasonably competent. So, IOW, all the measuring I have done, to get the system pretty flat, to control reflections and decay etc etc has now enabled me to hear the environment that the mixer intended me to hear, whether it is a cathedral or the inside of an elevator. 



Here is Toole's definition of spaciousness.



Here he illustrates what frequencies prevail for different areas or impressions.

 

And it can all be measured, right?

kbarnes701 is offline  
post #7933 of 12191 Old 01-12-2014, 12:54 PM
AVS Addicted Member
 
kbarnes701's Avatar
 
Join Date: Jan 2008
Location: Main Listening Positon
Posts: 19,074
Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 2126 Post(s)
Liked: 2076
Quote:
Originally Posted by jim19611961 View Post



More food for thought.

 

This seems to support the view I was putting forward. He is saying, AIUI, that measurements of various parameters contribute to our understanding of spaciousness. I can't cut and paste from the images, but there are several references which support that view. He also makes the point which I was making before - in a m/ch system, we get what we need from the recording the 'greatest improvement' to the 'sense of space' as he calls it.

kbarnes701 is offline  
post #7934 of 12191 Old 01-12-2014, 12:55 PM
AVS Addicted Member
 
kbarnes701's Avatar
 
Join Date: Jan 2008
Location: Main Listening Positon
Posts: 19,074
Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 2126 Post(s)
Liked: 2076
Quote:
Originally Posted by jim19611961 View Post
 
Quote:
Originally Posted by kbarnes701 View Post

I never replied to your post, Jim, for which I apologise. I just didn't get a round tuit - no excuse. The problem with terms such as 'spaciousness' is that they are essentially subjective and what you mean by it is perhaps different to what I mean by it. I think in the post you refer to, we both seemed to have different understandings of what 'soundstage' might mean (IIRC).

WRT to spaciousness, you gave an example of a recording in a large space and the time the sound took to reverberate around etc and how this gave the impression of a large space, even if we were taken onto that space blindfolded. I agree, in those circumstances we would know we were in a large space. My point there was that all the 'spaciousness' I need from a recording has already been 'baked in' by the recording engineer, so all I need is a system which can faithfully reproduce its input at its output (all caveats apply).

IOW, I need a system that plays pretty flat, has controlled (or even removed) room reflections, has suitable decay characteristics etc. If I have that, then I will hear, especially in a m/ch system, all that 'spaciousness'. In fact I do hear it all the time in movies where it is a factor on screen and in the audio mix, because it is baked in and because my system is reasonably competent. So, IOW, all the measuring I have done, to get the system pretty flat, to control reflections and decay etc etc has now enabled me to hear the environment that the mixer intended me to hear, whether it is a cathedral or the inside of an elevator. 

No apology necessary.

As has been pointed out before, your take is relevant for AV and mine for 2ch audio. I think we are both right in our separate worlds.

 

Yes, it must always be remembered that I speak only as someone who uses the HT for movies, and not music. I ought to put that on a macro and add it to the beginning of every relevant post I make :)

kbarnes701 is offline  
post #7935 of 12191 Old 01-12-2014, 01:00 PM
AVS Special Member
 
jim19611961's Avatar
 
Join Date: Mar 2011
Location: Texas
Posts: 1,406
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 134 Post(s)
Liked: 88
Quote:
Originally Posted by kbarnes701 View Post

Yes, it must always be remembered that I speak only as someone who uses the HT for movies, and not music. I ought to put that on a macro and add it to the beginning of every relevant post I make smile.gif

Since most of the posters on this thread are AV guys, I am probably the one that needs to qualify my comments, not you.

My Room
My Music
Rega - Apollo, Rega - DAC, Goldpoint Passive, (2) Classe CA-100 bridged power amps (350w)
Jenzen Next
jim19611961 is online now  
post #7936 of 12191 Old 01-12-2014, 01:04 PM
AVS Addicted Member
 
kbarnes701's Avatar
 
Join Date: Jan 2008
Location: Main Listening Positon
Posts: 19,074
Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 2126 Post(s)
Liked: 2076
Quote:
Originally Posted by jim19611961 View Post
 
Quote:
Originally Posted by kbarnes701 View Post

Yes, it must always be remembered that I speak only as someone who uses the HT for movies, and not music. I ought to put that on a macro and add it to the beginning of every relevant post I make smile.gif

Since most of the posters on this thread are AV guys, I am probably the one that needs to qualify my comments, not you.

 

Maybe :) There are a fair number of multi-purpose guys though I think. I often forget that the perspective of a m/p user or a music-predominately user will be different from mine. I am totally sure that having a single use in mind has made my job way, way easier.

 

BTW, if those passages above are from the Toole book I just ordered, I shall look forward even more to reading it. FT really has a way of explaining things that pretty much anyone could understand doesn’t he?  The mark, IMO, of someone who is a true master of his subject.

kbarnes701 is offline  
post #7937 of 12191 Old 01-12-2014, 01:12 PM
AVS Special Member
 
jim19611961's Avatar
 
Join Date: Mar 2011
Location: Texas
Posts: 1,406
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 134 Post(s)
Liked: 88
Quote:
Originally Posted by kbarnes701 View Post

And it can all be measured, right?

I think we have reached the crux of what you and I keep going back and forth about.

For AV, you are not relying on the room for the presentation and its associated illusions. For the most part, you are only trying to keep the room out of the way from what the main & surround speakers are attempting to provide. I dont think most of you in AV are trying to make the room itself provide or be responsible for ambiance or spaciousness.

In 2ch audio, the room plays a more critical role. While you still want it to stay out of the way of the recording, some need/want it to also play a role in spacial and ambient perceptions. In a sense, your trying to acoustically provide what multi channel does inherently but derived strictly from 2 channels.

So what needs measuring and taken into account for AV is different than 2ch. 2ch Lede/RFZ concepts are much more complicated and required things that dont show up in measurement. For AV, your not trying to tailor reflections to behave in a certain manner in terms of direction. I would argue that the reflections you have you want to be broadband attenuated which can only be addressed (as far as I know) through the use of ETC slicing (which most people don't measure).

To say something can be measured isn't the same as saying people do measure it or that we have the proper tools to measure it.
pepar likes this.

My Room
My Music
Rega - Apollo, Rega - DAC, Goldpoint Passive, (2) Classe CA-100 bridged power amps (350w)
Jenzen Next
jim19611961 is online now  
post #7938 of 12191 Old 01-12-2014, 01:27 PM
Advanced Member
 
artur9's Avatar
 
Join Date: Mar 2013
Location: near philly
Posts: 785
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 74 Post(s)
Liked: 44
Quote:
Originally Posted by jim19611961 View Post

Since most of the posters on this thread are AV guys, I am probably the one that needs to qualify my comments, not you.

Although my space is multipurpose any trade off I make will be in favor of 2ch.
artur9 is offline  
post #7939 of 12191 Old 01-12-2014, 01:36 PM
AVS Special Member
 
jim19611961's Avatar
 
Join Date: Mar 2011
Location: Texas
Posts: 1,406
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 134 Post(s)
Liked: 88
Quote:
Originally Posted by kbarnes701 View Post

Maybe smile.gif There are a fair number of multi-purpose guys though I think. I often forget that the perspective of a m/p user or a music-predominately user will be different from mine. I am totally sure that having a single use in mind has made my job way, way easier.

BTW, if those passages above are from the Toole book I just ordered, I shall look forward even more to reading it. FT really has a way of explaining things that pretty much anyone could understand doesn’t he?  The mark, IMO, of someone who is a true master of his subject.

Yes they are. (I have the book in pdf form on my computer)

My Room
My Music
Rega - Apollo, Rega - DAC, Goldpoint Passive, (2) Classe CA-100 bridged power amps (350w)
Jenzen Next
jim19611961 is online now  
post #7940 of 12191 Old 01-12-2014, 01:48 PM
Advanced Member
 
artur9's Avatar
 
Join Date: Mar 2013
Location: near philly
Posts: 785
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 74 Post(s)
Liked: 44
Quote:
Originally Posted by jim19611961 View Post


Are you sure 1" OC703 is what you want to use?

I believe you are suggesting that the absorption will not be broadband enough?

I may need to put up more absorption (3.5" SafeNSound is what I have easy access to).

My plan is to use the black tiles to start. The vendor suggests placing them under the existing drop tiles.

I'll measure and see what the effect is. I then intend to fill the joist area above the tiles with SafeNSound to improve LF absorption and waterfall.

Once that's in place I plan to remove some (all?) of the existing tiles behind/above the black tiles. This should allow the sound to travel through the tile to be absorbed by the SafeNSound in the joists.

Measurements along the way, of course.

Unfortunately, I have two goals for this. Making it quieter upstairs while improving imaging/soundstaging for me 2ch.
artur9 is offline  
post #7941 of 12191 Old 01-12-2014, 01:53 PM
AVS Special Member
 
jim19611961's Avatar
 
Join Date: Mar 2011
Location: Texas
Posts: 1,406
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 134 Post(s)
Liked: 88
Quote:
Originally Posted by artur9 View Post

I believe you are suggesting that the absorption will not be broadband enough?

Yes.

Quote:
Originally Posted by artur9 View Post

Unfortunately, I have two goals for this. Making it quieter upstairs while improving imaging/soundstaging for me 2ch.

What you hear upstairs is low bass (mostly) which 1" nor 3.5" is going to affect. The second goal is obtainable though smile.gif

My Room
My Music
Rega - Apollo, Rega - DAC, Goldpoint Passive, (2) Classe CA-100 bridged power amps (350w)
Jenzen Next
jim19611961 is online now  
post #7942 of 12191 Old 01-12-2014, 01:58 PM
AVS Addicted Member
 
kbarnes701's Avatar
 
Join Date: Jan 2008
Location: Main Listening Positon
Posts: 19,074
Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 2126 Post(s)
Liked: 2076
Quote:
Originally Posted by jim19611961 View Post
 
Quote:
Originally Posted by kbarnes701 View Post

And it can all be measured, right?

I think we have reached the crux of what you and I keep going back and forth about.

For AV, you are not relying on the room for the presentation and its associated illusions. For the most part, you are only trying to keep the room out of the way from what the main & surround speakers are attempting to provide. I dont think most of you in AV are trying to make the room itself provide or be responsible for ambiance or spaciousness.

In 2ch audio, the room plays a more critical role. While you still want it to stay out of the way of the recording, some need/want it to also play a role in spacial and ambient perceptions. In a sense, your trying to acoustically provide what multi channel does inherently but derived strictly from 2 channels.

So what needs measuring and taken into account for AV is different than 2ch. 2ch Lede/RFZ concepts are much more complicated and required things that dont show up in measurement. For AV, your not trying to tailor reflections to behave in a certain manner in terms of direction. I would argue that the reflections you have you want to be broadband attenuated which can only be addressed (as far as I know) through the use of ETC slicing (which most people don't measure).

To say something can be measured isn't the same as saying people do measure it or that we have the proper tools to measure it.

 

We have reached concurrence!  :)

kbarnes701 is offline  
post #7943 of 12191 Old 01-12-2014, 02:39 PM
Wireless member
 
pepar's Avatar
 
Join Date: Jul 2002
Location: Quintana Roo ... in my mind
Posts: 25,144
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 185 Post(s)
Liked: 163
Quote:
Originally Posted by kbarnes701 View Post

What do you mean by 'timbre matching'?  I would have thought this would mean that a speaker has a given set of characteristics which result in its final sound. If that is the definition then I also think that those characteristics are readily measurable. 

Fair enough. A few years ago I and another AVS member attended CEDIA and heard a lot of manufacturers' demos. Most were good, but ho hum. One stood out, and a second was positively magical. Standing out was the Procella demo. Magical was Wisdom Audio. Both were in el cheapo traveling trade show "rooms" made out of, basically, carpet covered cardboard. There were no treatments. Wisdom did calibrate with Audyssey Pro (over MultEQ XT), but I would not attribute the difference to Audyssey.

I would also not attribute the difference to frequency response as both systems were spec'd to the max. The sound of the Wisdom Audio was far more immediate and transparent. It was the closest I have ever heard to "being there."

I assure you that everyone here would come away with the same comments. What characteristics would you measure to document the difference?

Jeff
pepar is online now  
post #7944 of 12191 Old 01-12-2014, 02:51 PM
Wireless member
 
pepar's Avatar
 
Join Date: Jul 2002
Location: Quintana Roo ... in my mind
Posts: 25,144
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 185 Post(s)
Liked: 163
Quote:
Originally Posted by AustinJerry View Post

Jeff, I am unaware of any app that would assist in predicting reflection patterns in a listening room.  Sound behaves in a predictable fashion based on physics--any hard surface will reflect sound.  The direction of the reflection is governed by the law of angle of incidence equals the angle of reflection.  The size of the reflecting surface will affect which frequencies are reflected (the smaller the surface, the higher the frequency).  And the arrival time of the reflection gives clues to how far away from the measurement mic the reflective surface is located.

So, assuming we are interested in reflections that arrive at the MLP (for those of us who are primarily interested in improving one listening spot), we measure the reflections using the Impulse response measurement at the MLP.  We establish certain objectives WRT which reflections we want to control (e.g. any reflection that has not been reduced by 20dB in the first 20ms is an objective many of us are using).  From that point forward, we have established techniques to identify where the reflections are coming from, i.e. what is causing them, regardless of whether they are caused by one reflection, or multiple reflections.  Once we isolate the source of the reflection, we chose a treatment that is designed for the type of reflection (i.e. its frequency), and what we want to do with it (i.e. absorb it, or re-direct it), or in some cases we simply remove the cause of the reflection (e.g. a picture on a wall).

I don't think this is rocket science, it's just tedious and sometimes frustrating work.  The frustration comes when we have difficulty isolating the reflection, when efforts to tame it are unsuccessful, or when eliminating the reflection would require a change to our listening room that we would find difficult to live with.  Where it might be considered rocket science is when reflections are used to tailor a room's audio characteristics to accomplish a specific goal, e.g. Jim's wonderful creation of a stunning LEDE environment.

My initial calculations were to "cover" the FRP for ALL speakers for ALL listeners. I only used a tape measure and visualization (I have been known to play pool). When I get home I plan on selling my balanced, phantom powered Dayton and Teac USB preamp and going the route in the thread subject. At that point, I suppose, I will find out how good my cocktail napkin calculations were.

Jeff
pepar is online now  
post #7945 of 12191 Old 01-12-2014, 02:58 PM
Wireless member
 
pepar's Avatar
 
Join Date: Jul 2002
Location: Quintana Roo ... in my mind
Posts: 25,144
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 185 Post(s)
Liked: 163
Quote:
Originally Posted by kbarnes701 View Post

I never replied to your post, Jim, for which I apologise. I just didn't get a round tuit - no excuse. The problem with terms such as 'spaciousness' is that they are essentially subjective and what you mean by it is perhaps different to what I mean by it. I think in the post you refer to, we both seemed to have different understandings of what 'soundstage' might mean (IIRC).

WRT to spaciousness, you gave an example of a recording in a large space and the time the sound took to reverberate around etc and how this gave the impression of a large space, even if we were taken onto that space blindfolded. I agree, in those circumstances we would know we were in a large space. My point there was that all the 'spaciousness' I need from a recording has already been 'baked in' by the recording engineer, so all I need is a system which can faithfully reproduce its input at its output (all caveats apply).

IOW, I need a system that plays pretty flat, has controlled (or even removed) room reflections, has suitable decay characteristics etc. If I have that, then I will hear, especially in a m/ch system, all that 'spaciousness'. In fact I do hear it all the time in movies where it is a factor on screen and in the audio mix, because it is baked in and because my system is reasonably competent. So, IOW, all the measuring I have done, to get the system pretty flat, to control reflections and decay etc etc has now enabled me to hear the environment that the mixer intended me to hear, whether it is a cathedral or the inside of an elevator. 

How do we measure the amount of direct to reflected ratio? Nearfield listening is quite different than being outside the critical distance. How would that be measured?

Jeff
pepar is online now  
post #7946 of 12191 Old 01-12-2014, 03:06 PM
Advanced Member
 
artur9's Avatar
 
Join Date: Mar 2013
Location: near philly
Posts: 785
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 74 Post(s)
Liked: 44
Quote:
Originally Posted by jim19611961 View Post

.
What you hear upstairs is low bass (mostly) which 1" nor 3.5" is going to affect. The second goal is obtainable though smile.gif

Well, at the moment it's a lot more than the low bass that is making its way upstairs. mad.gif Sometimes it seems that I have an 8.1 system with the 8th speaker in the kitchen eek.gif At the moment, there's no insulation of any kind between the floors.

Although it's nice to hear that one of my goals is obtainable. That may be a first for me smile.gif
artur9 is offline  
post #7947 of 12191 Old 01-12-2014, 03:29 PM
AVS Special Member
 
jamin's Avatar
 
Join Date: May 2001
Location: moot point
Posts: 1,056
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 7 Post(s)
Liked: 12
Quote:
Originally Posted by pepar View Post

Quote:
Originally Posted by kbarnes701 View Post

I never replied to your post, Jim, for which I apologise. I just didn't get a round tuit - no excuse. The problem with terms such as 'spaciousness' is that they are essentially subjective and what you mean by it is perhaps different to what I mean by it. I think in the post you refer to, we both seemed to have different understandings of what 'soundstage' might mean (IIRC).

WRT to spaciousness, you gave an example of a recording in a large space and the time the sound took to reverberate around etc and how this gave the impression of a large space, even if we were taken onto that space blindfolded. I agree, in those circumstances we would know we were in a large space. My point there was that all the 'spaciousness' I need from a recording has already been 'baked in' by the recording engineer, so all I need is a system which can faithfully reproduce its input at its output (all caveats apply).

IOW, I need a system that plays pretty flat, has controlled (or even removed) room reflections, has suitable decay characteristics etc. If I have that, then I will hear, especially in a m/ch system, all that 'spaciousness'. In fact I do hear it all the time in movies where it is a factor on screen and in the audio mix, because it is baked in and because my system is reasonably competent. So, IOW, all the measuring I have done, to get the system pretty flat, to control reflections and decay etc etc has now enabled me to hear the environment that the mixer intended me to hear, whether it is a cathedral or the inside of an elevator. 

How do we measure the amount of direct to reflected ratio? Nearfield listening is quite different than being outside the critical distance. How would that be measured?

Jeff
Try this link -- p 117 & p 125
http://www.artalabs.hr/download/ARTA-user-manual.pdf

That will get you a feel for some of the measures used. Then Google direct to reverberant ratio and have fun. Somewhere in the google you will find the equations typically use as it is part of some measure software systems, notably EASE. What you may find is the start and stop times for the integrals seem to be geared for larger spaces. I can't remember if EASE will let you change those parameters.

plug in to play
Acoustic Mafia - Hear No Evil
jamin is offline  
post #7948 of 12191 Old 01-12-2014, 03:52 PM
Wireless member
 
pepar's Avatar
 
Join Date: Jul 2002
Location: Quintana Roo ... in my mind
Posts: 25,144
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 185 Post(s)
Liked: 163
pepar is online now  
post #7949 of 12191 Old 01-12-2014, 06:42 PM
AVS Special Member
 
djbluemax1's Avatar
 
Join Date: Oct 2004
Location: MI
Posts: 2,278
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 28 Post(s)
Liked: 287
Quote:
Originally Posted by artur9 View Post

Quote:
Originally Posted by jim19611961 View Post

.
What you hear upstairs is low bass (mostly) which 1" nor 3.5" is going to affect. The second goal is obtainable though smile.gif

Well, at the moment it's a lot more than the low bass that is making its way upstairs. mad.gif Sometimes it seems that I have an 8.1 system with the 8th speaker in the kitchen eek.gif At the moment, there's no insulation of any kind between the floors.

Although it's nice to hear that one of my goals is obtainable. That may be a first for me smile.gif
Maybe try tacking this to the ceiling? Don't stretch it taut and be aware that it's heavy.

http://m.homedepot.com/p/Unbranded-dB-3-4-ft-x-8-ft-Acoustical-Barrier-DB348X96BX/100663624


Max
djbluemax1 is offline  
post #7950 of 12191 Old 01-12-2014, 07:32 PM
Member
 
FLViking2011's Avatar
 
Join Date: Apr 2011
Posts: 35
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 10
Hi,

Below are subwoofer graphs:

I currently have a single sub in the front corner of the room responses from three different seats on the couch:



Another option is to place the sub in the rear corner of the room:



Based on the two graphs, which position has the best response across the three seats?

Also, would getting an additional sub and having both corners covered improve the overall response? Is it necessary or are either of the locations ok on their own. My room is 14' x 13'. 8' ceiling.

I measured using a 90db subwoofer level.

Thanks.
FLViking2011 is offline  
Reply Audio Theory, Setup, and Chat

Tags
Dayton , Dayton Audio , Room Equilizer Wizard Rew

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off