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Simplified REW Setup and Use (USB Mic & HDMI Connection) Including Measurement Techniques and How... - Page 140

post #4171 of 9577
Quote:
Originally Posted by cuzed2 View Post

WooHoo!
Just revisited my REW efforts. This time with a solid Win7 laptop , and no USB extender cable on the UMIK, seems to be working very well! I'll post some educational (for me ) graphs tomorrow. I now have one foot in the rabbit hole, and am ready to dive-in "head first". :-)

Nice progress, Cuz!

Gear mentioned in this thread:

post #4172 of 9577
Ok guys I now have the final readings....


First I have, four lots of readings all with L+R+SUBS. Three rows taken in each, front, centre and back row.


1. Front, mid and back rows without Audyssey.

Front Row
https://dl.dropboxusercontent.com/u/8646227/19%20july%20REW%20reading/without%20xt32/front%20row%20before%20xt32.mdat
Mid Row
https://dl.dropboxusercontent.com/u/8646227/19%20july%20REW%20reading/without%20xt32/mid%20row%20before%20xt32.mdat
Back Row
https://dl.dropboxusercontent.com/u/8646227/19%20july%20REW%20reading/without%20xt32/back%20row%20before%20xt32.mdat


2. Front, mid and back rows with XT32.

Front Row
https://dl.dropboxusercontent.com/u/8646227/19%20july%20REW%20reading/with%20xt32/front%20row%20after%20xt32.mdat
Mid Row
https://dl.dropboxusercontent.com/u/8646227/19%20july%20REW%20reading/with%20xt32/mid%20row%20after%20xt32.mdat
Back Row
https://dl.dropboxusercontent.com/u/8646227/19%20july%20REW%20reading/with%20xt32/back%20row%20after%20xt32.mdat

As I discovered adding some temporary towels to the first reflection definitely changed the results on REW. At this stage I haven't had time to demo this change but will report back later.....





3. 1st reflection with temp towels without Audyssey.

Front Row
https://dl.dropboxusercontent.com/u/8646227/19%20july%20REW%20reading/with%20towels/without%20xt32/front%20towel.mdat
Mid Row
https://dl.dropboxusercontent.com/u/8646227/19%20july%20REW%20reading/with%20towels/without%20xt32/mid%20towel.mdat
Back Row
https://dl.dropboxusercontent.com/u/8646227/19%20july%20REW%20reading/with%20towels/without%20xt32/back%20towel.mdat


4. 1st reflection with temp towels with Audyssey.

Front Row
https://dl.dropboxusercontent.com/u/8646227/19%20july%20REW%20reading/with%20towels/with%20xt32/front%20xt32%20towel.mdat
Mid Row
https://dl.dropboxusercontent.com/u/8646227/19%20july%20REW%20reading/with%20towels/with%20xt32/mid%20xt32%20towel.mdat
Back Row
https://dl.dropboxusercontent.com/u/8646227/19%20july%20REW%20reading/with%20towels/with%20xt32/back%20xt32%20towel.mdat

Let me know your thoughts...

Im sure everything has been labelled and done correctly.
post #4173 of 9577
Holy Moses, Murray, you must be exhausted! I'm on it...
post #4174 of 9577

A tip to make things easier, should you ever need to do this in the future:  all measurements can be kept in the same single file.

 

 

 

By selecting "All SPL", you can view all the measurements at once, or select which to view by checking and unchecking the measurements in the Legend.

 

 

 

This way, you only need to upload one file, rather than six.  Just trying to make it easier for you.

post #4175 of 9577

Murray, kindly describe your mic positions.  Did you follow the recommendation I made earlier?

post #4176 of 9577

OK, Murray, here is what I see.  First, the frequency response (Blue=before Audyssey, Red=with Audyssey):

 

 

 

 

Mid row looks the best, then back row, and finally, the front row.  All three show significant adjustment in the high end.  There continues to be some lumpiness below 100Hz, especially on the front row, but likely the best you can achieve, given the complexities of a 3-tier theater.  I don't see any reason for concern.

 

Bass decay (waterfalls), Audyssey on:

 

 

 

 

Mid row looks great, front and back rows look very good.  Considering that your objective was to improve the bass response, I would say you have accomplished the objective.  Good job!

 

And the reflections (ETC) before and after the towel (green is with the towel, both are with Audyssey on).  BTW, in the future, when analyzing reflections, it doesn't make a lot of difference if Audyssey is off or on.  Save yourself an extra set of measurements.  And all of the ETC graphs are suspect, because we cautioned you to measure only one speaker at a time, and it looks like you measured left+right.

 

 

 

 

The front row shows a big improvement (-10dB) at 5ms.  A bad reflection persists at 3ms, and a not-so-bad one at 8ms.

 

The mid row shows a slight improvement at 4-5ms, but nothing else.

 

The back row shows the best improvement, -9dB at 1.5ms, -10dB at 3ms, -10dB at 5ms, and -10dB at 8ms.

 

I wouldn't conclude too much from the ETC analysis, other than there is improvement to be had, if you want to work on it.

 

So, time to take a break, Murray.  I bet you are pleased with the progress!

post #4177 of 9577
Quote:
Originally Posted by AustinJerry View Post

Murray, kindly describe your mic positions.  Did you follow the recommendation I made earlier?

Yes Jerry the mic positions were all done in the mid row.
post #4178 of 9577
Quote:
Originally Posted by AustinJerry View Post


Mid row looks the best, then back row, and finally, the front row.  All three show significant adjustment in the high end.  There continues to be some lumpiness below 100Hz, especially on the front row, but likely the best you can achieve, given the complexities of a 3-tier theater.  I don't see any reason for concern.

Bass decay (waterfalls), Audyssey on:


Mid row looks great, front and back rows look very good.  Considering that your objective was to improve the bass response, I would say you have accomplished the objective.  Good job!

And the reflections (ETC) before and after the towel (green is with the towel, both are with Audyssey on).  BTW, in the future, when analyzing reflections, it doesn't make a lot of difference if Audyssey is off or on.  Save yourself an extra set of measurements.  And all of the ETC graphs are suspect, because we cautioned you to measure only one speaker at a time, and it looks like you measured left+right.


The front row shows a big improvement (-10dB) at 5ms.  A bad reflection persists at 3ms, and a not-so-bad one at 8ms.

The mid row shows a slight improvement at 4-5ms, but nothing else.

The back row shows the best improvement, -9dB at 1.5ms, -10dB at 3ms, -10dB at 5ms, and -10dB at 8ms.

I wouldn't conclude too much from the ETC analysis, other than there is improvement to be had, if you want to work on it.

So, time to take a break, Murray.  I bet you are pleased with the progress!

Im exhausted, its taken a whole day to sort all this out and I'm really disappointed I measured L+R+subs with the towels, sorry about that. Is it hard to read the way I did it?

Im happy the front row is the worst, the mid and back row are the most important.

I would like to work more on the reflections now that Im satisfied with the bass, want to lead me in the best direction Jerry?
post #4179 of 9577
Quote:
Originally Posted by AustinJerry View Post

Holy Moses, Murray, you must be exhausted! I'm on it...

I am, well and truly I assure you!!!!tongue.gif
post #4180 of 9577
Quote:
Originally Posted by RapalloAV View Post

Yes Jerry the mic positions were all done in the mid row.

The mic positions were all done in the mid row for XT32, seven.
post #4181 of 9577
Quote:
Originally Posted by AustinJerry View Post

???  If the mic locations were all in the mid row, then what does the measurement file "front row before XT32" mean?   confused.gif

All the mic positions for REW were taken from the middle of each row. One measure for each row from the middle of the four seats.

One was taken without Audyssey on and another with XT32 turned on. That was to show you every row with and without. All mic placements were done with and without Audyssey.

I hope this is clear now. rolleyes.gif
post #4182 of 9577
Quote:
Originally Posted by RapalloAV View Post


Im exhausted, its taken a whole day to sort all this out and I'm really disappointed I measured L+R+subs with the towels, sorry about that. Is it hard to read the way I did it?

Im happy the front row is the worst, the mid and back row are the most important.

I would like to work more on the reflections now that Im satisfied with the bass, want to lead me in the best direction Jerry?

 

OK, testing for understanding:

 

- For the Audyssey calibration, you took eight measurements with the mic in the center row, as per my earlier recommendations?

- For the REW measurements, you placed the mic in three locations:  mid-point of the front row at ear height, mid-point of the mid row, and finally mid-point of the back row?

- For all REW measurements you measured Left+right+subs?  (This would be correct for everything but the ETC, as I mentioned earlier).

 

Don't worry about the ETC measurements.  Using a towel wasn't the most scientific approach anyway.  We can focus on reflections after we have all had a bit of a break to enjoy our systems.  Besides, I am installing more treatments tomorrow.

post #4183 of 9577
Quote:
Originally Posted by RapalloAV View Post


All the mic positions for REW were taken from the middle of each row. One measure for each row from the middle of the four seats.

One was taken without Audyssey on and another with XT32 turned on. That was to show you every row with and without. All mic placements were done with and without Audyssey.

I hope this is clear now. rolleyes.gif

 

Clear now, and done correctly.  Sorry, I'm punchy as well.  Tomorrow is another day.

post #4184 of 9577
Quote:
Originally Posted by AustinJerry View Post

OK, testing for understanding:

- For the Audyssey calibration, you took eight measurements with the mic in the center row, as per my earlier recommendations?
- For the REW measurements, you placed the mic in three locations:  mid-point of the front row at ear height, mid-point of the mid row, and finally mid-point of the back row?
- For all REW measurements you measured Left+right+subs?  (This would be correct for everything but the ETC, as I mentioned earlier).

Don't worry about the ETC measurements.  Using a towel wasn't the most scientific approach anyway.  We can focus on reflections after we have all had a bit of a break to enjoy our systems.  Besides, I am installing more treatments tomorrow.

Yes to everything here on mic positions, that's all correct. And REW L+R+Subs
post #4185 of 9577
Guys Ive listened to lots of movies with the towels on the side walls catching the 1st reflection, it certainly is a vast improvement. I sat and listened to War Horse for some time, that film is great for listening to distinct sounds.... horse moving, hooves scraping ground, snorting, walking from left to right of screen, the sounds were very distinct, precise, it added so much more realism to the scene. Voices too are different, clean and distinct, my acoustic screen seems so different now and all this with some old towels on both side walls. Its obvious now to me no matter what some of the other experts say about the 1st reflection, that my tests prove its better and much more distinct after reducing the 1st reflection.

Imagine with some proper acoustic panels!

It can all only get better from here on!

Gee thanks guys for helping me on this thread, I really appreciate all your guidance and patience and encouraging me to go on..... I've learnt so much and finally its all coming together with results!smile.gif

I have ideas for dealing with the 1st reflections but maybe that's another thread is it?
post #4186 of 9577
Quote:
Originally Posted by RapalloAV View Post

Ok guys I now have the final readings....


First I have, four lots of readings all with L+R+SUBS. Three rows taken in each, front, centre and back row.

Those measurements don't look right. Did you also measure L, R and Sub separately?
Where and how did you place the Audyssey mic when running MultEQ?
Where did MultEQ set the crossover between sub and fronts?
Is there any other processing active in your AVR (e.g. DynamicEQ, "Listening Modes", etc.)?
post #4187 of 9577
Quote:
Originally Posted by markus767 View Post

Those measurements don't look right. Did you also measure L, R and Sub separately?
Where and how did you place the Audyssey mic when running MultEQ?
Where did MultEQ set the crossover between sub and fronts?
Is there any other processing active in your AVR (e.g. DynamicEQ, "Listening Modes", etc.)?

Sorry why do you say the measurements don't look right?

All the measurements are with L+R+Subs

The mic was placed in 7 points only in the middle row for XT32

XT32 set the crossovers to 60 and 40Hz, I moved them all to 80Hz

DEQ set to off for all readings, listening mode was only on PLII Movie
post #4188 of 9577
Quote:
Originally Posted by Saturn94 View Post

I greatly appreciate the example and the pics. smile.gif

I thought when I was poking around in there I did as your described, but no filters were created. I must have done something incorrectly. I'll give it another shot using your example as a guide.

 

You're very welcome. Let me know how you get on. Remember to click 'match response to Target curve' - you’d expect it to be a button or  something but its just a line of text on the right.

post #4189 of 9577
Quote:
Originally Posted by RapalloAV View Post

Sorry why do you say the measurements don't look right?

All the measurements are with L+R+Subs

The mic was placed in 7 points only in the middle row for XT32

XT32 set the crossovers to 60 and 40Hz, I moved them all to 80Hz

DEQ set to off for all readings, listening mode was only on PLII Movie

In all cases I've seen so far MultEQ performed a more aggressive equalization. Here's an example, measured at the locations where the Audyssey mic was placed during MultEQ calibration. Blue is the first, center location; mic locations approximatedly 1 ft apart:

L+sub before:



L+sub after:



Where and how exactly did you place the mic (Height? On a stand? Spacing?)? Why the middle row? Is this the row you want to optimize? I'd recommend to optimize the center seat of the first row because it isn't affected by diffraction effects from objects (seats) in front of it.
Did you also measure with the crossover point suggested by Audyssey?
Edited by markus767 - 7/19/13 at 3:17am
post #4190 of 9577
Quote:
Originally Posted by markus767 View Post

In all cases I've seen so far MultEQ performed a more aggressive equalization. Here's an example, measured at the locations where the Audyssey mic was placed during MultEQ calibration. Blue is the first, center location; mic locations approximatedly 1" apart:

L+sub before:



L+sub after:



Where and how exactly did you place the mic (Height? On a stand? Spacing?)? Why the middle row? Is this the row you want to optimize?
Did you also measure with the crossover point suggested by Audyssey? Raising it to 80Hz probably has thrown off results considerably (note the huge dip between 35Hz and 55Hz and the peak at 86Hz in your middle seat data).

I never placed the mic at 1" locations, I placed the mic for XT32 where Jerry told me earlier on here, just the middle row. I am trying to get the middle row the best and the back and front follows. Height at ears etc etc... everything to the book!
post #4191 of 9577
Quote:
Originally Posted by RapalloAV View Post

I never placed the mic at 1" locations, I placed the mic for XT32 where Jerry told me earlier on here, just the middle row. I am trying to get the middle row the best and the back and front follows. Height at ears etc etc... everything to the book!

You left the mic at a single location or how much did you move the Audyssey mic between runs?
Is there a floor plan available for your setup?

P.S. There's an error in my last post, it's "1 ft" not "1 inch".
Edited by markus767 - 7/19/13 at 3:18am
post #4192 of 9577
Quote:
Originally Posted by markus767 View Post

You left the mic at a single location or how much did you move the Audyssey mic between runs?
Is there a floor plan available for your setup?

P.S. There's an error in my last post, it's "1 ft" not "1 inch".

The measurements for XT32 were exactly as Jerry suggested yesterday. (see below)


When you run the XT32 calibration, try this for a change.

1. Optimize for the middle row.
2. Select the first (and most important) mic position in the exact center between the left and right walls, regardless of whether this is in the center of a seat or not. Make sure the mic is at ear height, and at least 12" in front of any seat backs.
3. Select the next four measuring positions, two to the left, and two to the right, along the center row spaced 18-24" apart, again keeping the mic at ear height.
4. Select the sixth, seventh and eight positions 12" in front of the first, second and third mic positions, again at ear height.

If you do this as recommended, the middle row will be optimized as far as the calibration goes. Then let's look at how the front and back rows fall out by taking the appropriate measurements: For each row, take four measurements, one for each seat, with the mic at ear height (for that row), and 12" in front of the seat backs. This will result in an REW measurement file with twelve measurements (all in one file). Make sure you label each measurement, e.g. Front row seat 1, front row seat 2, etc. Measure left+right+ subs, of course.

Send me the measurement file. We will examine average responses across all seats in a row and see if optimizing for the center row yielded a reasonable result for all rows. Who knows, by this time tomorrow, you may be on a REW vacation, watching movies with your friends!
post #4193 of 9577
So you used a much larger mic pattern only in the middle row. To save you some time, you don't need to measure the front or back row as they are not included in the optimization process anyway.

Do you have a floor plan of your room that shows speaker and seat locations? Are the tweeters at ear height when you sit in the middle row?
post #4194 of 9577
Quote:
Originally Posted by markus767 View Post

So you used a much larger mic pattern only in the middle row. To save you some time, you don't need to measure the front or back row as they are not included in the optimization process anyway.

Do you have a floor plan of your room that shows speaker and seat locations? Are the tweeters at ear height when you sit in the middle row?

No I didn't do anything to save time, Ive been working on this for 1.5 years......... I spent a whole day making all the calculations and I followed what Jerry asked me to do. We are optimizing the middle row, its impossible to have three rows good when the back row is up against the back wall and the three rows are on different heights due to the risers.......

I don't have a floor plan with the speakers and seats, I just have the room and seats on the plan. The tweeters are not at ear height as that would be impossible as the three rows are all at different heights. The tweeters are higher than ear height in the middle row.
post #4195 of 9577
I do see 3 major problems with your setup:
- No center seat
- Speaker at wrong height
- Diffraction from seats in front
This really should be fixed first.

Other than that the "mid row after xt32.mdat" looks good below 50Hz but above not so much. Maybe raising the crossover causes problems.
I'd first re-measure the locations where you plan to put the Audyssey mic. This will give you an idea how uniform the response across those seats really is. From there it's easier to decide how to proceed.
post #4196 of 9577
Quote:
Originally Posted by RapalloAV View Post


Sorry why do you say the measurements don't look right?

All the measurements are with L+R+Subs

The mic was placed in 7 points only in the middle row for XT32

XT32 set the crossovers to 60 and 40Hz, I moved them all to 80Hz

DEQ set to off for all readings, listening mode was only on PLII Movie

 

Murray and Markus, I see something else that that influences the measurements.  If the AVR is set to PLII Movie, only Center+Subs is being measured, not Left+Right+Subs.  There is nothing wrong with measuring Center+Subs, I am only pointing this out to make sure Murray is aware of how REW directs test tones to the speakers.  When I measure, I measure the following:

 

- Left+subs (Stereo mode, both with Audyssey off and Audyssey on)

- Right+subs (Stereo mode, both with Audyssey off and Audyssey on)

- Left+Right+Subs (Stereo mode, both with Audyssey off and Audyssey on)

- Left+Right+Subs (PLII Cinema mode, both with Audyssey off and Audyssey on)

 

It is pretty quick to take these measurements because the mic is in the MLP for all measurements.  For a three-row theater, the measurements will be a bit more tedious.

post #4197 of 9577
Quote:
Originally Posted by AustinJerry View Post

Murray and Markus, I see something else that that influences the measurements.  If the AVR is set to PLII Movie, only Center+Subs is being measured, not Left+Right+Subs.  There is nothing wrong with measuring Center+Subs, I am only pointing this out to make sure Murray is aware of how REW directs test tones to the speakers.  When I measure, I measure the following:

- Left+subs (Stereo mode, both with Audyssey off and Audyssey on)
- Right+subs (Stereo mode, both with Audyssey off and Audyssey on)
- Left+Right+Subs (Stereo mode, both with Audyssey off and Audyssey on)
- Left+Right+Subs (PLII Cinema mode, both with Audyssey off and Audyssey on)

It is pretty quick to take these measurements because the mic is in the MLP for all measurements.  For a three-row theater, the measurements will be a bit more tedious.

Jerry - please explain why you measure L+R+Subs in both Stereo & PLII Cinema mode - thanks
post #4198 of 9577
Quote:
Originally Posted by markus767 View Post

I do see 3 major problems with your setup:
- No center seat
- Speaker at wrong height
- Diffraction from seats in front
This really should be fixed first.

Other than that the "mid row after xt32.mdat" looks good below 50Hz but above not so much. Maybe raising the crossover causes problems.
I'd first re-measure the locations where you plan to put the Audyssey mic. This will give you an idea how uniform the response across those seats really is. From there it's easier to decide how to proceed.

 

However, on the positive side, Murray's bass response has improved considerably.  Given that this was his initial objective, and that the waterfalls show a nice improvement in controlling the bass ringing, I think he needs to be congratulated on a good job so far.  Unfortunately, some of the things you mention would require a major theater re-design.  Whether this would be warranted or not depends on how pleased Murray is with his sound.

post #4199 of 9577
Quote:
Originally Posted by markus767 View Post

I do see 3 major problems with your setup:
- No center seat
- Speaker at wrong height
- Diffraction from seats in front
This really should be fixed first.

Other than that the "mid row after xt32.mdat" looks good below 50Hz but above not so much. Maybe raising the crossover causes problems.
I'd first re-measure the locations where you plan to put the Audyssey mic. This will give you an idea how uniform the response across those seats really is. From there it's easier to decide how to proceed.

 

What is the rule of thumb when relocating speakers is not an option?  Do you still put the Audyssey mic at ear height or do you put it at tweeter level?

post #4200 of 9577
Quote:
Originally Posted by ggsantafe View Post

Jerry - please explain why you measure L+R+Subs in both Stereo & PLII Cinema mode - thanks

Because if the signal of L and R channel is the same, it is sent to the center speaker only. This behaviour can be affected by PLII-settings though.
Edited by markus767 - 7/19/13 at 6:46am
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