Simplified REW Setup and Use (USB Mic & HDMI Connection) Including Measurement Techniques and How To Interpret Graphs - Page 97 - AVS Forum
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post #2881 of 11685 Old 05-18-2013, 03:09 PM
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Quote:
Originally Posted by markus767 View Post

Is that what people say when they visit you?

The specific things people have said in this regard (their words, not mine)

"Its definitely not dead"

"Immersed in sound"

"Surrounded by sound"

Let me make a distinction. I say its a bit live, but not as spacious as id like. Subtle difference I admit, but I dont regard what I have as the finished product just yet. If I can figure out how to get it more live/spacious sounding WITHOUT compromising my ISD gap, then I want to proceed in that direction. Your ideas are welcome.


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post #2882 of 11685 Old 05-18-2013, 04:49 PM
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Thanks Jerry. (actually your only 2 hours away from me if you care to hear it)

 

 

Invitation is open to you as well, if you are down Austin way, Jim. 


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post #2883 of 11685 Old 05-19-2013, 12:42 AM
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Quote:
Originally Posted by jim19611961 View Post

If I can figure out how to get it more live/spacious sounding WITHOUT compromising my ISD gap, then I want to proceed in that direction. Your ideas are welcome.

Additional reflections from ±55° can bring back spaciousness. A simple experiment is to place additional speakers and run a delayed and attenuated version of L and R through them.

What I do is toe-in my speakers by more than 45° which generates loud contralateral reflections. Results in a very spacious presentation.


Markus

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post #2884 of 11685 Old 05-19-2013, 07:29 AM
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Re:  Weird distorted tone during a measurement sweep

 

I, as well as several others, have reported hearing an occasional distorted tone when running an REW measurement sweep.  I have attached an audio file which will give everyone an example of the "weird tone".  I am also going to post it over on Home Theater Shack to see if anyone has an explanation, and hopefully a fix.

 

Here is the link to the discussion over on HTS.

 

 

 

Wierd Tone.zip 118k .zip file
Attached Files
File Type: zip Wierd Tone.zip (118.5 KB, 21 views)

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post #2885 of 11685 Old 05-19-2013, 08:00 AM
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Quote:
Originally Posted by AustinJerry View Post

Re:  Weird distorted tone during a measurement sweep

 

I, as well as several others, have reported hearing an occasional distorted tone when running an REW measurement sweep.  I have attached an audio file which will give everyone an example of the "weird tone".  I am also going to post it over on Home Theater Shack to see if anyone has an explanation, and hopefully a fix.

 

Here is the link to the discussion over on HTS.

 

 

 

Wierd Tone.zip 118k .zip file

 

Yes, I get a similar sounding noise from time to time. I just close and restart REW and that usually fixes it. Sometimes it doesn't and I have to reboot the laptop. It is annoying but not too hard to deal with so I haven't reported it before. 



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post #2886 of 11685 Old 05-19-2013, 10:07 AM
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Quote:
Originally Posted by markus767 View Post

Additional reflections from ±55° can bring back spaciousness. A simple experiment is to place additional speakers and run a delayed and attenuated version of L and R through them.

What I do is toe-in my speakers by more than 45° which generates loud contra lateral reflections. Results in a very spacious presentation.


And mine:



Not saying whose philosophy is better or worse, but I prefer ipsilateral reflections and after 20ms. My design is harder to achieve the gain and bandwidth that you are getting though.


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post #2887 of 11685 Old 05-19-2013, 11:56 AM
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Originally Posted by kbarnes701 View Post

Yes, I get a similar sounding noise from time to time. I just close and restart REW and that usually fixes it. Sometimes it doesn't and I have to reboot the laptop. It is annoying but not too hard to deal with so I haven't reported it before. 

Yep - Jerry's video clip accurately captures the sounds of the interference - does anyone know if this poses a threat to your speakers, and are measurements made during the "interference" valid - or should they be discarded and rerun?

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post #2888 of 11685 Old 05-19-2013, 12:15 PM
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Quote:
Originally Posted by ggsantafe View Post

Quote:
Originally Posted by kbarnes701 View Post

Yes, I get a similar sounding noise from time to time. I just close and restart REW and that usually fixes it. Sometimes it doesn't and I have to reboot the laptop. It is annoying but not too hard to deal with so I haven't reported it before. 

Yep - Jerry's video clip accurately captures the sounds of the interference - does anyone know if this poses a threat to your speakers, and are measurements made during the "interference" valid - or should they be discarded and rerun?

 

I doubt if the noise poses a threat to speakers. I discard the measurements (made when the noise appears)  and re-run that sweep if the noise occurs.



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post #2889 of 11685 Old 05-19-2013, 01:34 PM
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Quote:
Originally Posted by AustinJerry View Post

Re:  Weird distorted tone during a measurement sweep

I, as well as several others, have reported hearing an occasional distorted tone when running an REW measurement sweep.  I have attached an audio file which will give everyone an example of the "weird tone".  I am also going to post it over on Home Theater Shack to see if anyone has an explanation, and hopefully a fix.

Here is the link to the discussion over on HTS.



Wierd Tone.zip 118k .zip file

That's a great idea, Jerry. It's a real issue that needs attention. The distortion can be heard in the sub the moment the test tone begins, so you can catch it before it spreads to the mains. It's actually quite inconvenient and can put you on pins and needles.
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post #2890 of 11685 Old 05-19-2013, 04:01 PM
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Quote:
Originally Posted by ggsantafe View Post


Yep - Jerry's video clip accurately captures the sounds of the interference - does anyone know if this poses a threat to your speakers, and are measurements made during the "interference" valid - or should they be discarded and rerun?

 

Certainly discard the measurement.  Damage to the speakers?  I hope not.  Don't take any of those 100dB measurements, though.


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post #2891 of 11685 Old 05-19-2013, 04:45 PM
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I get same distortions. I have to unplug the HDMI cable and restart REW.

I just fished my 17 new acoustic panels. Five are corner mounted as bass traps. So total of 7 bass traps if I include two gik monster traps. I will be doing measurements tomorrow. Off work tomorrow. Little burned out from making and mounting the panels. Corner mounting was not fun.

Will report soon. I hope all that effort was worth it.
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post #2892 of 11685 Old 05-19-2013, 04:47 PM
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Actually , all the panels should have good bass absorption. They are open back made from 4 inch mineral wool.
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post #2893 of 11685 Old 05-19-2013, 05:40 PM
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Originally Posted by mp5475 View Post

I get same distortions. I have to unplug the HDMI cable and restart REW.

I just fished my 17 new acoustic panels. Five are corner mounted as bass traps. So total of 7 bass traps if I include two gik monster traps. I will be doing measurements tomorrow. Off work tomorrow. Little burned out from making and mounting the panels. Corner mounting was not fun.

Will report soon. I hope all that effort was worth it.

Do you mind to share some pics?

I'm about to start building my first set of acoustic treatments for my room. So, if you can share more information/tips on how to do, it I'll be highly appreciated.


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post #2894 of 11685 Old 05-19-2013, 05:55 PM - Thread Starter
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I get the weird noises using ASIO4ALL as well.

I've never gotten them when using Java.

All I do is cancel the measurement and open the ASIO4ALL control panel within REW then close it.

That fixes it.

For me, just taking another measurement after cancelling the one that has the distortions doesn't fix it.

I used to close/reopen REW, then found I only had to change the channel I was measuring and change it back, but recently all I've been doing is opening/closing the control panel and it seems to work just as well.

How often do you guys get the distortion? It seems as though if I take a bunch of measurements in a row (like all 7 channels, one after another) I don't get the distortion, but if some time goes by between each measurement (when doing distance tweaks for example) I'm more likely to get the distortion.

For me, I get it about one out of 10 measurements or so.

Again, this is with ASIO4ALL only.

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post #2895 of 11685 Old 05-19-2013, 06:17 PM
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I have not been able to figure out the sequence of actions that results in the distortion. It seems quite random, but there may be some specific logic going on. Now that I understand that it is par for the course, and know how to clear it, it doesn't bother me too much.

I'm hoping John responds to my HTS post--he may have some connections with the ASIO4ALL author to get a bug fix.

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post #2896 of 11685 Old 05-19-2013, 06:21 PM
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Originally Posted by cr136124 View Post

Do you mind to share some pics?

I'm about to start building my first set of acoustic treatments for my room. So, if you can share more information/tips on how to do, it I'll be highly appreciated.

Sure. I got 4x2 fill it yourself panels from ATS.

http://www.atsacoustics.com/item--Fill-it-Yourself-Frame-24x48x4--1031.html?d=GPGEN01&kw=1031-FiY-D

Got mineral wool from local insulation company.

What do you want to do? I wanted broadband absorption so I went with open back and mineral wool. Check this site, it tells you absorption coefficient .
http://www.bobgolds.com/AbsorptionCoefficients.htm

If you put them in corner, it increases the bass absorption.
I will post pics.

If you search, there are many posts about DIY panels. Mine was not completely DIY. I did make two panels myself for total of ten bucks(not including mineral wool)It was really simple to do. I wish I did it from the start. Would have cost about half of what I spent.

Since I don't want to hijack this thread into about making panels, you can pm me if you wish. Good luck. I will post before and after RC for everyone.
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post #2897 of 11685 Old 05-19-2013, 07:18 PM
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Sure. I got 4x2 fill it yourself panels from ATS.

http://www.atsacoustics.com/item--Fill-it-Yourself-Frame-24x48x4--1031.html?d=GPGEN01&kw=1031-FiY-D

Got mineral wool from local insulation company.

What do you want to do? I wanted broadband absorption so I went with open back and mineral wool. Check this site, it tells you absorption coefficient .
http://www.bobgolds.com/AbsorptionCoefficients.htm

If you put them in corner, it increases the bass absorption.
I will post pics.

If you search, there are many posts about DIY panels. Mine was not completely DIY. I did make two panels myself for total of ten bucks(not including mineral wool)It was really simple to do. I wish I did it from the start. Would have cost about half of what I spent.

Since I don't want to hijack this thread into about making panels, you can pm me if you wish. Good luck. I will post before and after RC for everyone.

Thanks man!

I'll send you a PM in few..........wink.gif


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post #2898 of 11685 Old 05-21-2013, 05:55 AM
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I doubt it is REW specific. I haven't made REW measurements yet but I use ASIO all the time for processing my audio with VST plugins and I get this breakup from time to time. Troubleshooting this kind of problem is very troublesome indeed if you want your ASIO audio to be glitch free 100% of the time, I wouldn't suggest going to the lengths required if all you want to do is make minute long sweep measurements.

What I WOULD suggest though, is to make damn sure that the audio isn't being corrupted in other ways. While the sweep is playing, listen with your ears to make sure a pure sine tone sweep is playing and there are no modulation distortions in the bass and the high frequencies above 10kHz aren't polluted by aliasing artifacts (you'd hear it as a warbling tone going up and down when the high frequencies should be fading smoothly out of your hearing range). It may help to compare the ASIO output with the Java output as it can be hard to know what you should be listening for if you haven't heard both the right and wrong versions before.
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post #2899 of 11685 Old 05-21-2013, 01:13 PM
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Every time I restart the latest beta REW, it asks for spl calibration. Anyone else get this? Also if I click the asio box, to fix the distortion, it asks for mic calibration files again.
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post #2900 of 11685 Old 05-21-2013, 01:22 PM
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I ran REW today on a different laptop. I set it up as before but this time it did not see the Calibration file or something as it asked me to run the sensitivity test. On the other laptop, both Toshibas though, it will not let me run calibration as is sees the calibration file or something. I entered the cal file on both. I ran calibration and got the reading below. Now the high end is rolled off! I check for any settings that would affect eq and made sure everything I could find is turned off. The low to 3000 Hz range looks OK and is similar to the OmniMic run. The other laptop is OK from 40Hz up to 20000Hz and looks ok. Ideas anyone?


Hi all,
After waiting for a while to get the miniDSP, I have it and am ready to try it. I still need to get some XLR cabled to get hooked u though. I have run the FIR upload with no issues and ran a test on the Biquads from REW and OmniMic and all went well just pasting them in to the advanced filter setting. I can't wait to hear the results and have some fun. I did have to load a new ASIO driver in both computers and it appears to have fixed the problem of different responses. It also fixed the problem of AcourateDRC not recognizing the OmniMic USB mic.

I put pics below of the un-equalized runs from REW, AcourateDRC and OmniMic below and the correction FIR from AcourateDRC and Biquads from REW.

This is the REW run R=Red, L=Blue, 1/12 smoothing


This is the AcourateDRC run, correction FIR target is the lower trace, Green=Right (?) Red=Left


OmniMike run, 1/12 smoothing, Right=Red, Left=Blue


miniDSP FIR file added from AcourateDRC


miniDSP biquads added by pasting in to advanced filter PEq from REW (these are just for test. I will run this again after measuring the FIR filter.
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post #2901 of 11685 Old 05-21-2013, 06:32 PM
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Good discussion about the mnidsp. and REW and the transfer of data

So my circumstance is
I have a DSP 1124p version 1.
Does anyone have any experience with this usb-midi interface? :Roland UM-ONE MK2 USB MIDI Interface and the transfer of REW settings to the 1124p.
Or something else to recommend perhaps, a t least for now. with regard to (dual) subwoofer application..

When I finish the BFM THTLP build, some of this may be a moot or new jumo off point.

Thank you.

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post #2902 of 11685 Old 05-21-2013, 08:03 PM
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Quote:
Originally Posted by Dwightlf View Post

Hi all,
After waiting for a while to get the miniDSP, I have it and am ready to try it. I still need to get some XLR cabled to get hooked u though. I have run the FIR upload with no issues and ran a test on the Biquads from REW and OmniMic and all went well just pasting them in to the advanced filter setting. I can't wait to hear the results and have some fun. I did have to load a new ASIO driver in both computers and it appears to have fixed the problem of different responses. It also fixed the problem of AcourateDRC not recognizing the OmniMic USB mic.

I put pics below of the un-equalized runs from REW, AcourateDRC and OmniMic below and the correction FIR from AcourateDRC and Biquads from REW.

This is the REW run R=Red, L=Blue, 1/12 smoothing


This is the AcourateDRC run, correction FIR target is the lower trace, Green=Right (?) Red=Left


OmniMike run, 1/12 smoothing, Right=Red, Left=Blue


miniDSP FIR file added from AcourateDRC


miniDSP biquads added by pasting in to advanced filter PEq from REW (these are just for test. I will run this again after measuring the FIR filter.

I also plan get mini dsp. I can't wait to see your results.

questions. Why the XLR cable, did you not get the unbalanced version? And how hard or easy is it to use? I have been playing around with REW eq for while, it seems pretty straight forward.
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post #2903 of 11685 Old 05-22-2013, 01:13 AM
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Qcan wrote:
Originally Posted by asarose247 View Post

Good discussion about the mnidsp. and REW and the transfer of data

So my circumstance is
I have a DSP 1124p version 1.
Does anyone have any experience with this usb-midi interface? :Roland UM-ONE MK2 USB MIDI Interface and the transfer of REW settings to the 1124p.
Or something else to recommend perhaps, a t least for now. with regard to (dual) subwoofer application..

When I finish the BFM THTLP build, some of this may be a moot or new jumo off point.

Thank you.

I can give you all the info you asked for but am away ftom home at tbe moment. Check back Friday. 



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post #2904 of 11685 Old 05-22-2013, 03:49 PM
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I have known for some time that my ETC measurements reveal a significant reflection attributable to the first reflection points on my ceiling.  For a number of reasons, esthetics and difficulty of installation in particular, I have been holding off doing anything about it.  But, like with many unpleasant tasks, one must eventually get down to business.

 

After consulting with Bryan Pape at GIK Acoustics, I received a recommendation to install two 244 panels at the first reflection point.  After struggling for several hours and finally perfecting the installation process, the panels were in place.  I ran a fresh Audyssey Pro calibration, and measured the results of my efforts.  The reduction of the reflection was significant, as demonstrated in the two graphs below:

 

 

 

 

 

Note that the reflection at ~8ft went from -10dB to -23Db, well below the -20dB target.  This is a good example of picking an issue, analyzing it, and installing a targeted solution.  As you can see, I have several other reflections at -15dB that could stand some work as well.

 

Does the room sound different?  Yes, but I'm still trying to determine exactly what the difference is.  It sounds counter-intuitive, but the room almost sounds more lively.  It's too early to come to a conclusion.

 

Here is a picture of the ceiling treatments.  Thanks to Keith for suggesting the use of cable-ties to secure the panels to the hooks in the ceiling.

 


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post #2905 of 11685 Old 05-23-2013, 12:50 AM - Thread Starter
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Congratulations Jerry,

This is the perfect example to prove that reducing "EARLY" reflections and increasing your ISD Gap will increase liveliness and spaciousness, not decrease it.

What you have done by getting rid of that high gain early reflection is to increase the amount of time of "effectively" anechoic space before then introducing reflections.

If you want it even more lively, you'll set your room up with more reflection panels (hardwood/plywood panels) to reflect all the early energy to the back/back sides of the room and then have those reflections bounce back from the back/back side walls after about 20ms or so and that will be a true LEDE/RFZ room. Then you'll see just how lively/spacious your room sounds and you will be getting much closer to how the engineers heard it in the control room/final mix down/what was "intended."

In Keith's case, he's stated he doesn't listen to music in his room and doesn't want to add any livliness/spaciousness and only wants whatever ambiance is recorded on the track, IE: From surround speakers, since he listens to movies only.

Keith would want to suppress all reflections with a gain higher than -20db and not terminate his ITD to achieve this. This method is based on the NE design (Non-Environment).

You should be proud/happy of what you've accomplished, but be forewarned, if you continue down this path of simply absorbing, instead of reflecting/redirecting your high gain early reflections (reflections above -20db in gain and before around 20ms) you'll end up with what Keith wants and that increased liveliness/spaciousness you're hearing right now will go away.

So you can't just keep adding more absorption, seeing those reflections disappear, and expect to continue getting more and more of the same benefits you have now. The only reason you got those benefits this time is because you got rid of a reflection that was much earlier than several other reflections you still have remaining, and it's because of those reflections you still have that you got this effect. If you do away with all of them, your room will sound very dry/dead.

I wish more people would start doing this because I have been waiting to become more active in this thread... People need to pick an acoustical model and we need to start talking about how to implement them and show our work, just as you have done!

If I can be of any assistance on your project, let me know!

Congrats,

--Jason

Thanks to EVERYONE that Helps Make These Threads so Awesome!

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post #2906 of 11685 Old 05-23-2013, 01:37 AM
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Jerry,

Would you be so kind to post those measurements? I'm always curious how other rooms "look" like.

Markus

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post #2907 of 11685 Old 05-23-2013, 07:21 AM
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Originally Posted by jevansoh View Post

Congratulations Jerry,

This is the perfect example to prove that reducing "EARLY" reflections and increasing your ISD Gap will increase liveliness and spaciousness, not decrease it.

What you have done by getting rid of that high gain early reflection is to increase the amount of time of "effectively" anechoic space before then introducing reflections.

If you want it even more lively, you'll set your room up with more reflection panels (hardwood/plywood panels) to reflect all the early energy to the back/back sides of the room and then have those reflections bounce back from the back/back side walls after about 20ms or so and that will be a true LEDE/RFZ room. Then you'll see just how lively/spacious your room sounds and you will be getting much closer to how the engineers heard it in the control room/final mix down/what was "intended."


You should be proud/happy of what you've accomplished, but be forewarned, if you continue down this path of simply absorbing, instead of reflecting/redirecting your high gain early reflections (reflections above -20db in gain and before around 20ms) you'll end up with what Keith wants and that increased liveliness/spaciousness you're hearing right now will go away.

So you can't just keep adding more absorption, seeing those reflections disappear, and expect to continue getting more and more of the same benefits you have now. The only reason you got those benefits this time is because you got rid of a reflection that was much earlier than several other reflections you still have remaining, and it's because of those reflections you still have that you got this effect. If you do away with all of them, your room will sound very dry/dead.

I wish more people would start doing this because I have been waiting to become more active in this thread... People need to pick an acoustical model and we need to start talking about how to implement them and show our work, just as you have done!

If I can be of any assistance on your project, let me know!

Congrats,

--Jason

 

Thanks for the feedback, Jason.  I understand now why the feeling of spaciousness has increased.

 

As far as your recommendation for picking a small room acoustic model, I have done some reading of white papers, and browsed some of the discussion threads, but I'm not sure I am any closer to making a decision.  I'm familiar with the terms now, and the high level objectives.  However, since I don't have a dedicated room, and since the back of the room is open to the rest of the ground floor, I'm not sure any of the models will fit.  Reading the "Small room acoustic models" here on AVS was a bit of a chore.  Too bad there isn't an "ignore the bickering" button. 

 

I actually think I have too much absorption of the mid to high frequencies, and will be removing some rather ineffective ATS Acoustics panels from my side walls.  They will be replaced with a single GIK panel at the primary reflection point.  I ordered the GIK panels with a "scatter plate", which is a new enhancement they have recently added, just to get an idea of what the plate does.  On the side with the fireplace, I will be placing a panel on a stand in front of the fireplace mantle so that I have matching treatments on each side of the room at the FRP.  My understanding is that reflection symmetry is also important.  I'll report back my findings.


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post #2908 of 11685 Old 05-23-2013, 07:22 AM
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Jerry,

Would you be so kind to post those measurements? I'm always curious how other rooms "look" like.

 

Markus, do you mean the actual REW measurement file uploaded to DropBox?


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post #2909 of 11685 Old 05-23-2013, 07:56 AM
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Jerry, those ceiling panels really helped. Lookin' good!

Once you deal with that 5ms reflection, you may be able to call it a day.


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post #2910 of 11685 Old 05-23-2013, 08:01 AM
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Quote:
Originally Posted by jevansoh View Post

Congratulations Jerry,

This is the perfect example to prove that reducing "EARLY" reflections and increasing your ISD Gap will increase liveliness and spaciousness, not decrease it.

--Jason

to clarify: in such a 2ch response, the ISD-gap dictates the perceived size of the acoustical space. eg, the distance (time) of the first significant reflection with respect to the direct signal. in small rooms, the ISD is naturally shorter than in larger rooms, as the speed of sound is a constant within that medium. attenuating the natural first-order reflections artificially increases the perceived size of the acoustical space without modifying the actual boundaries - as you are artificially delaying in time when the first indirect energy impedes the listening position. attenuating these high-gain signals within the haas interval also increases accuracy of localization, imaging, and intelligibility with respect to the direct signal. attenuating the high-gain first-order reflections also removes (minimizes) the 3d spatial polar lobing which results in the comb-filter interference pattern manifested within the 2d frequency plot. "comb-filtering" is not all inconsequential and "1/4 inch wide" ... the polar lobes and nulls can be many feet wide!.

the gain of the first significant reflection will dictate the liveliness. if you are reintroducing energy to the listening position (terminating the effectively anechoic ISD gap), the gain of this termination (sharply delineating the ISD) will dictate the liveliness of the space. a higher gain (with respect to the direct signal) of this first significant energy will be perceived as more lively than that of an indirect signal lower in gain.

the characteristics of the later-arriving sound-field dictate spaciousness. the energy is allowed to become more "well-mixed" in large rooms than small (where the energy is quite sparse/specular) - and this is why diffusers (reflection phase gratings of QRD or PRD variety) are used to artificially mix (spatially and temporally disperse) the energy as would naturally happen in larger, more "spacious" rooms. the diffusion breaks up the high-gain sparse reflection into MANY reflections scattered across the given hemisphere that are also delayed in time which thus induce MANY polar lobes which result in comb-filtering that is DENSER and MORE CLOSELY SPACED together in the 2d frequency response (eg, minimizing the "sparse" comb-filtering gaps).

in this particular 2ch response, accuracy (with respect to the direct signal) is maintained while still providing a sense of the room via the energy management and subsequent reintroduction of indirect energy to the listening position WITHOUT being destructive (in time and frequency domains). the ISD-gap dictates the perceived size of the acoustical space, the high-gain termination dictates liveliness (while removing the directional cues of the later arriving energy a la haas trigger), and the laterally arriving , exponentially decaying dense diffused soundfield provides the sense of envelopment and spaciousness (a la Dr. Manfred Schroeder's EU concert hall research).
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