Simplified REW Setup and Use (USB Mic & HDMI Connection) Including Measurement Techniques and How To Interpret Graphs - Page 261 - AVS Forum
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post #7801 of 11702 Old 01-08-2014, 06:55 AM
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sdrucker,
This may be a somewhat uninformed (dangerous) comment, but to make sure I understand the above:

So;
Trinnov seems to be doing something to improve reflection issues?
And in this example Audyssey, almost nothing?

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post #7802 of 11702 Old 01-08-2014, 07:09 AM
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I want to repeat as a true single speaker measurement (i.e. Center only, same crossover, confirmed that the speaker is level matched to +/- 1 db on the 'Audyssey' and 'Trinnov' plots) to confirm it, but tentatively yes. And with suggestions (specific filtered IR bands?) before we draw any 'firm' conclusions. Note that I'm trying to be cautious about this. ESPECIALLY considering I don't have formal acoustic treatments. Not that they're still not important for other reasons regardless.

What's scarier is that this data is from my 'proof of concept' Trinnov calibration results I posted on the R-972 thread here:
http://www.avsforum.com/t/1179978/sherwood-r-972-user-thread/3000#post_24126807

That was before I tried (and am still trying) to tighten up the bass response with a MiniDSP managing my two ULS-15 subs and bass from LFE on my Mythos ST, and reran for other reasons.

I still want to know about FS vs. a % FS scaling for the Y axis as well.

FWIW you're in the area (suburbs and I'm downtown)...you could hear it for yourself smile.gif.

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Oppo 93 and 103

Panasonic VT50

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post #7803 of 11702 Old 01-08-2014, 08:23 AM
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Originally Posted by sdrucker View Post

I want to repeat as a true single speaker measurement (i.e. Center only, same crossover, confirmed that the speaker is level matched to +/- 1 db on the 'Audyssey' and 'Trinnov' plots) to confirm it, but tentatively yes. And with suggestions (specific filtered IR bands?) before we draw any 'firm' conclusions. Note that I'm trying to be cautious about this. ESPECIALLY considering I don't have formal acoustic treatments. Not that they're still not important for other reasons regardless.

What's scarier is that this data is from my 'proof of concept' Trinnov calibration results I posted on the R-972 thread here:
http://www.avsforum.com/t/1179978/sherwood-r-972-user-thread/3000#post_24126807

That was before I tried (and am still trying) to tighten up the bass response with a MiniDSP managing my two ULS-15 subs and bass from LFE on my Mythos ST, and reran for other reasons.

I still want to know about FS vs. a % FS scaling for the Y axis as well.

FWIW you're in the area (suburbs and I'm downtown)...you could hear it for yourself smile.gif.

Hey,
I might have to jump on the Metra to see that for myself. Better yet; perhaps after you have unraveled the finer points of implementing a MiniDSP (something I am also curious about). And if you ever wish to jump off the Metra in the NW burbs - perhaps I can find something HT worthy to share (SEOS DIY speaker builds, or ....)
smile.gif

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post #7804 of 11702 Old 01-08-2014, 09:26 AM
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Been working with my own "bass trap problems" so haven't kept up with the thread for a while. Those were IMO a failure as far as my objective is concerned, so moving on for now... smile.gif

Was wondering about a reflection shown in Audionut11's (I think) ETC graph @ 392µs a page back. What is the time frame during which we can ignore these reflections? Surely this one is so soon we couldn't hear it, even though it probably shouldn't be there at that magnitude (is that the true concern, not the hearing of it per se?). Somewhere (here?) a while ago I read that somebody had a significant reflection at ~15ms and he said it wasn't a real problem because we couldn't distinguish it so soon after the main signal. In the Acoustical Standards for Stereo Listening Rooms document they suggest a standard of reflections should be at least 10dB down within 40ms. What do you guys find practically good?

Also, how do you guys find the reflecting culprit when it's not an obvious first reflection point, say? Do you use the method in Jerry's guide? I tried that, and yes it does pretty accurately identify the first reflection points, since I already know where they are so easy to find with the string. smile.gif But for other reflectors that aren't those, I'm having difficulty.
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post #7805 of 11702 Old 01-08-2014, 09:48 AM
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Originally Posted by cfraser View Post

Been working with my own "bass trap problems" so haven't kept up with the thread for a while. Those were IMO a failure as far as my objective is concerned, so moving on for now... smile.gif

Was wondering about a reflection shown in Audionut11's (I think) ETC graph @ 392µs a page back. What is the time frame during which we can ignore these reflections? Surely this one is so soon we couldn't hear it, even though it probably shouldn't be there at that magnitude (is that the true concern, not the hearing of it per se?). Somewhere (here?) a while ago I read that somebody had a significant reflection at ~15ms and he said it wasn't a real problem because we couldn't distinguish it so soon after the main signal. In the Acoustical Standards for Stereo Listening Rooms document they suggest a standard of reflections should be at least 10dB down within 40ms. What do you guys find practically good?

Also, how do you guys find the reflecting culprit when it's not an obvious first reflection point, say? Do you use the method in Jerry's guide? I tried that, and yes it does pretty accurately identify the first reflection points, since I already know where they are so easy to find with the string. smile.gif But for other reflectors that aren't those, I'm having difficulty.

So I am fighting with Bass Trap issues as well, my bass trap testing isn't "fixing" what I think is a reflection problem.

 

 

 

I was reading somewhere (cant remember where) that perhaps 4 subs (2 front/2 year) adjusted/tuned (not sure what this means) the right way would "block" the oncoming bass waves and do a MUCH BETTER job than bass traps.  Although many can't do this, if you can any idea what this is all about ?



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post #7806 of 11702 Old 01-08-2014, 10:08 AM
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Originally Posted by cuzed2 View Post

sdrucker,
This may be a somewhat uninformed (dangerous) comment, but to make sure I understand the above:

So;
Trinnov seems to be doing something to improve reflection issues?
And in this example Audyssey, almost nothing?

 

Some people maintain that Audyssey does nothing in the time domain other than as a byproduct of what it does in the frequency domain. My own measurements also seem to confirm this.



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post #7807 of 11702 Old 01-08-2014, 10:12 AM
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Originally Posted by cfraser View Post


Also, how do you guys find the reflecting culprit when it's not an obvious first reflection point, say? Do you use the method in Jerry's guide? I tried that, and yes it does pretty accurately identify the first reflection points, since I already know where they are so easy to find with the string. smile.gif But for other reflectors that aren't those, I'm having difficulty.

 

You and me both. I have reflections which show up in the ETC for which there seems to be no possible cause. I have come to the conclusion that they might emanate from the speaker cabinet itself, and possibly from the mic stand. They are not all that serious and don't appear to cause me any audible issues so I have (for now at least) stopped chasing them. I also have a reflection off the PJ. There is nothing that can be done about that - the PJ cannot be moved for obvious reasons and nor can it be swathed in absorption materials for equally obvious reasons. I have become more philosophical as a result :)



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post #7808 of 11702 Old 01-08-2014, 10:15 AM
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Originally Posted by cfraser View Post

Been working with my own "bass trap problems" so haven't kept up with the thread for a while. Those were IMO a failure as far as my objective is concerned, so moving on for now... smile.gif

Was wondering about a reflection shown in Audionut11's (I think) ETC graph @ 392µs a page back. What is the time frame during which we can ignore these reflections? Surely this one is so soon we couldn't hear it, even though it probably shouldn't be there at that magnitude (is that the true concern, not the hearing of it per se?). Somewhere (here?) a while ago I read that somebody had a significant reflection at ~15ms and he said it wasn't a real problem because we couldn't distinguish it so soon after the main signal. In the Acoustical Standards for Stereo Listening Rooms document they suggest a standard of reflections should be at least 10dB down within 40ms. What do you guys find practically good?

Also, how do you guys find the reflecting culprit when it's not an obvious first reflection point, say? Do you use the method in Jerry's guide? I tried that, and yes it does pretty accurately identify the first reflection points, since I already know where they are so easy to find with the string. smile.gif But for other reflectors that aren't those, I'm having difficulty.

 

The general "best practice" we have been working with is to reduce all reflections to -20dB within the first 20ms.  Managing reflections is not a simple topic, and there are quite a few opinions expressed by valuable contributors to this thread, so perhaps we will hear some other inputs.

 

As far as finding the reflections, the "blocking method" seems to be the most reliable.  For this, you will need a reasonably large non-reflective "blocking tool".  For example, I use a leftover 2'x4' bass trap, but a large piece of pink fluffy may work equally well.  I start by placing the tool immediately to the right, left, top, or bottom of the speaker.  This narrows the general direction of the reflection (e.g. east, west, up or down).  Then I follow that general direction, placing the tool at various spots and taking measurements.  This approach will normally isolate a reflection that has a single path.  Of course, the ETC graph and the string method will also give you a general distance that the reflection is travelling, which is also useful in the hunt.

 

Reflections off multiple surfaces are more difficult to isolate.  For example, I had a significant reflection off the ceiling, then onto the back wall, and finally down to the MLP.  Treatments on both the ceiling and back wall were required. 

 

Early reflections are especially tricky to isolate.  They can be caused by the speaker cabinet, SBIR, the mic stand, the MLP chair, etc.  Again, persistent use of the blocking technique should isolate the cause.

 

And also remember to try filtered IR response measurements, as per Jim's recommendations.  IIUC, reflections at higher frequencies that are not present at lower frequencies are likely caused by smaller surfaces.  A very narrow reflective surface can be causing a reflection.  For example, the hard frame around a bass trap could be the source of a high-frequency reflection.

 

And then, of course, there are the ceiling fan reflections, mitigated only by installing a Big Ass Fan.  ;) 


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post #7809 of 11702 Old 01-08-2014, 10:16 AM
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Some people maintain that Audyssey does nothing in the time domain other than as a byproduct of what it does in the frequency domain. My own measurements also seem to confirm this.

 

+1.


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post #7810 of 11702 Old 01-08-2014, 10:20 AM
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Some people maintain that Audyssey does nothing in the time domain other than as a byproduct of what it does in the frequency domain. My own measurements also seem to confirm this.

FWIW, I don't think anything Trinnov does is superceding your exhaustive use of treatments in your dedicated room, or that you might do better head to head with your room, than I might by having no treatments and using a Trinnov unit in the same room. You probably would smile.gif.

My first take is that you get ETC improvement, but nothing that isn't happening already influencing bass decay. Meaning that reducing energy in the right place helps your results on a waterfall and spectrogram, but so far I don't see much if any difference otherwise from Audyssey unless it's specific to the hump being corrected. And as we know, you can still make a given area of the response worse by a boost rather than a cut WRT bass decay, if the area in question is already questionable. Life is a tradeoff.

And that leaves aside other things like RT60 or Group Delay. Thus treatments still are a good thing, and only cost time and effort to sculpt your way. Plus you have 100% control over them.

Note that this is for the "simple" version of Trinnov I have in the R-972. A full-featured unit is a different story.

Stuart

 

Denon 4311 with XT32 and Audyssey Pro

Oppo 93 and 103

Panasonic VT50

Sherwood R-972 with its version of the Trinnov Optimizer

MiniDSP 10x10 HD

PSB Imagine T2, Center, and Surrounds (as of 5/2014); HSU ULS-15 subs (2)

 

The Audyssey FAQ Guide can be found here:


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post #7811 of 11702 Old 01-08-2014, 10:31 AM
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toofast68: Well, as a few people again said here just recently, a second sub does a helluva lot for you in a "regular"-sized room. You are going to have a hard time with only one. I use two subs. My bass traps (very large DIY) were doing squat for me in the LFE range, in fact I finally admitted they were making things worse overall. Main problem is I don't have proper corners in the room, I guess you could call them stepped corners, would need massive custom traps, or multiple tube traps, to fill them properly. The traps definitely were cleaning up some of the lower midrange though, but that is not what I wanted from them and they just weren't earning their floor space = gone for now.

The final thing that made me remove the traps is Audyssey was really jacking up the THD for whatever reason (in sub-300Hz range) when the traps were there. Especially noticeable in certain ranges that Audyssey wasn't otherwise apparently doing much as it was in "flat" parts of the bass FR curve where no problems of any sort were showing up in any of my measurements (e.g. THD goes up ~10X). I spent a long time trying to figure that out, still haven't. I always use Audyssey with movies so it matters. Don't want up to 5% THD from Audyssey when the speakers are like 0.1% by themselves in the same range. Judgment call, everything Audyssey does is not roses, and since for me it's a take it all or leave it all thing (Denon XT32) , I have to make these decisions on an overall basis for my own taste/requirements.
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post #7812 of 11702 Old 01-08-2014, 10:49 AM
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toofast68: Well, as a few people again said here just recently, a second sub does a helluva lot for you in a "regular"-sized room. You are going to have a hard time with only one. I use two subs. My bass traps (very large DIY) were doing squat for me in the LFE range, in fact I finally admitted they were making things worse overall. Main problem is I don't have proper corners in the room, I guess you could call them stepped corners, would need massive custom traps, or multiple tube traps, to fill them properly. The traps definitely were cleaning up some of the lower midrange though, but that is not what I wanted from them and they just weren't earning their floor space = gone for now.

The final thing that made me remove the traps is Audyssey was really jacking up the THD for whatever reason (in sub-300Hz range) when the traps were there. Especially noticeable in certain ranges that Audyssey wasn't otherwise apparently doing much as it was in "flat" parts of the bass FR curve where no problems of any sort were showing up in any of my measurements (e.g. THD goes up ~10X). I spent a long time trying to figure that out, still haven't. I always use Audyssey with movies so it matters. Don't want up to 5% THD from Audyssey when the speakers are like 0.1% by themselves in the same range. Judgment call, everything Audyssey does is not roses, and since for me it's a take it all or leave it all thing (Denon XT32) , I have to make these decisions on an overall basis for my own taste/requirements.

While I don't disagree multiple subs often has its advantages, one sub (in my case) can work just fine.

If your room treatment was causing Audyssey to clip, then their maybe another more fundamental problem at work.


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post #7813 of 11702 Old 01-08-2014, 10:54 AM
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...And also remember to try filtered IR response measurements, as per Jim's recommendations.  IIUC, reflections at higher frequencies that are not present at lower frequencies are likely caused by smaller surfaces.  A very narrow reflective surface can be causing a reflection.  For example, the hard frame around a bass trap could be the source of a high-frequency reflection.

And then, of course, there are the ceiling fan reflections, mitigated only by installing a Big Ass Fan.  wink.gif  

Thanks Jerry. Actually just started using the Filtered IR graphs yesterday as per the ASfSLR document to help track the reflecting surfaces down. The more I learn, the more features of REW I use. It's pretty apparent now that any one type of REW graph isn't very informative on its own... I don't even have a single absorption panel to use as a "blocker". Maybe I can make something out of a multiply-folded towel for reflection sleuthing.

And as for their 10dB down in 40ms suggestion, I already have easily that in my untreated room from all 7 speakers. It sounds OK, but I didn't think that was really good enough, why I was asking about what you guys use as a goal/"standard". Sure don't have 20dB down in 20ms though, that sounds like a better realistic goal for me (I have 10dB down in 18ms for all speakers, some are much much better than that).

Edit: just to correct my last statement there, it is 20dB down in 18ms that I have for the 7 speakers in my untreated room. So that still isn't that high a standard.
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post #7814 of 11702 Old 01-08-2014, 11:01 AM
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Thanks Jerry. Actually just started using the Filtered IR graphs yesterday as per the ASfSLR document to help track the reflecting surfaces down. The more I learn, the more features of REW I use. It's pretty apparent now that any one type of REW graph isn't very informative on its own... I don't even have a single absorption panel to use as a "blocker". Maybe I can make something out of a multiply-folded towel for reflection sleuthing.

And as for their 10dB down in 40ms suggestion, I already have easily that in my untreated room from all 7 speakers. It sounds OK, but I didn't think that was really good enough, why I was asking about what you guys use as a goal/"standard". Sure don't have 20dB down in 20ms though, that sounds like a better realistic goal for me (I have 10dB down in 18ms for all speakers, some are much much better than that).

The bolded has always been a bit of a headscratcher for me. I have read that paper. And while I agree with the vast majority of it, this seems out of place. Most acoustic models call for 20db down by 1ms if possible, not 10db down at 40ms. And what does 40db down by 40ms seconds mean anyway? Does it mean -5db at 20ms? Or -2.5db at 10ms? Could it be talking about Decay rather than the ETC?


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post #7815 of 11702 Old 01-08-2014, 11:08 AM
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While I don't disagree multiple subs often has its advantages, one sub (in my case) can work just fine.

If your room treatment was causing Audyssey to clip, then their maybe another more fundamental problem at work.

True, I was happy with one sub too, for the seat *I* sat in. But to clean things up, with limited practical placement options and no treatments, two subs made things easy. Of course I already had the second sub here (unused with just MultEQ XT), otherwise I might have tried harder with just one...

Audyssey is not necessarily clipping. I have mentioned this LF distortion from Audyssey for years, even with XT. It is occurring in regions where Audyssey shouldn't even be doing anything, as far as I can tell. I have no control over what it does anyway. Things are just fine there with the front speakers and subs by themselves (no Aud.). I have no idea what Audyssey is doing in these specific areas. It is not high THD throughout the whole sub-300Hz range BTW, only in numerous ranges especially above 100Hz. I'm not even saying I can hear it, it bugs me on principle, and considering the other shortcomings of my bass trap experiment, was the final straw to make me turf them for now.
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post #7816 of 11702 Old 01-08-2014, 11:10 AM
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toofast68: Well, as a few people again said here just recently, a second sub does a helluva lot for you in a "regular"-sized room. You are going to have a hard time with only one. I use two subs. My bass traps (very large DIY) were doing squat for me in the LFE range, in fact I finally admitted they were making things worse overall. Main problem is I don't have proper corners in the room, I guess you could call them stepped corners, would need massive custom traps, or multiple tube traps, to fill them properly. The traps definitely were cleaning up some of the lower midrange though, but that is not what I wanted from them and they just weren't earning their floor space = gone for now.

The final thing that made me remove the traps is Audyssey was really jacking up the THD for whatever reason (in sub-300Hz range) when the traps were there. Especially noticeable in certain ranges that Audyssey wasn't otherwise apparently doing much as it was in "flat" parts of the bass FR curve where no problems of any sort were showing up in any of my measurements (e.g. THD goes up ~10X). I spent a long time trying to figure that out, still haven't. I always use Audyssey with movies so it matters. Don't want up to 5% THD from Audyssey when the speakers are like 0.1% by themselves in the same range. Judgment call, everything Audyssey does is not roses, and since for me it's a take it all or leave it all thing (Denon XT32) , I have to make these decisions on an overall basis for my own taste/requirements.

 

Mmmmm....ok, so I have MASSIVE custom traps in my two front corners...put in place via a home theater (well respected) consultant. I honestly don't know if they are helping or hurting.

 

What if I added a 4th sub....anyone know if my readings (or my dreams) have any validity ?  Meaning the opposing subs tuned to defeat the reflections, etc.



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post #7817 of 11702 Old 01-08-2014, 12:54 PM
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^ I'm not nearly experienced enough to answer specifics. Or generalities lol. Maybe provide a room drawing/photo of subs and trap placement, perhaps Sanjay Durani etc. will help.

I just went back and forth with and without traps (4), making measurements and rearranging subs/traps. Pretty time-consuming. Those more organized and experienced (and being paid...) would have a more sensible workflow. Besides, starting with a blank slate is better, you don't have any attachment to things because of $$ already spent. So measure with and without traps and look at all the different types of graphs. Try to be ruthless in your judgment (I wasn't at first, wastes a lot of time/effort).

Looks like a lot of crap below 35Hz, the hardest to treat. A lot of piling-up in the corners. Your level falls off a lot above 80Hz, I'm guessing that's your bass management XO frequency. You did have both your main speakers on when you took that bass measurement? You need both front L/R and any subs on for sub-300Hz waterfall measurement.

Above 35Hz, to 300Hz, I'd say your waterfall doesn't look too bad at all. Maybe some noise or a mode in the ~60Hz area. I just question the level >~80Hz.
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post #7819 of 11702 Old 01-08-2014, 01:06 PM
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^ I get the hint! smile.gif

I didn't even know what My Setup is.
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post #7821 of 11702 Old 01-08-2014, 02:09 PM
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Originally Posted by cfraser View Post

Also, how do you guys find the reflecting culprit when it's not an obvious first reflection point, say? Do you use the method in Jerry's guide?

I didn't have enough string handy to do it that way so I used a laser pointer and a mirror to illuminate the L tweeter from each of the LP, then the R tweeter. Definitely a two person job and I don't recommend that the second person be a ten y-o that likes to play with lasers. eek.gif

P.S. Is there a particular forum where the My Setup thread should be created?
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post #7822 of 11702 Old 01-08-2014, 02:14 PM
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It probably doesn't matter, but I set mine up here: http://www.avsforum.com/f/15/general-home-theater-media-game-rooms

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post #7823 of 11702 Old 01-08-2014, 02:36 PM
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I was reading somewhere (cant remember where) that perhaps 4 subs (2 front/2 year) adjusted/tuned (not sure what this means) the right way would "block" the oncoming bass waves and do a MUCH BETTER job than bass traps.  Although many can't do this, if you can any idea what this is all about ?
[/quote]

I cannot comment on how adding 2 add'l subs might affect this waterfall. I have a suspicion that someone more experienced will suggest that the issue at 60Hz is related to a room mode or room dimension?
BTW - that waterfall is very respectable (even with the 60Hz concern)

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Quote:
I was reading somewhere (cant remember where) that perhaps 4 subs (2 front/2 year) adjusted/tuned (not sure what this means) the right way would "block" the oncoming bass waves and do a MUCH BETTER job than bass traps.  Although many can't do this, if you can any idea what this is all about ?

I cannot comment on how adding 2 add'l subs might affect this waterfall. I have a suspicion that someone more experienced will suggest that the issue at 60Hz is related to a room mode or room dimension?
BTW - that waterfall is very respectable (even with the 60Hz concern)

This Powerpoint by Geddes may help.
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This Powerpoint by Geddes may help.

Artur,

Thanks for that link!
Can't believe this is the first time I had seen this.

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post #7826 of 11702 Old 01-08-2014, 08:11 PM
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This Powerpoint by Geddes may help.

The accompanying video is also well worth watching. The beginning of the PowerPoint presentation covers the missing beginning of the video.
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post #7827 of 11702 Old 01-09-2014, 03:36 AM
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Here's the FS plot (L speaker+subs no Trinnov vs. Trinnov Flat, no remapping, measured from the R-972):


And here's the % FS plot of the same comparison:

Have you tried to measure at different locations around the sweet "spot"? Also your before/after graphs for Trinnov does not look like it is the same measurement point as there are quite hard reflections found on it when there is nothing at the same distance in the "before" graph... I hardly believe it is something Trinnov has caused and more probably there were some differences in acoustical environment between measurements. The improvements of the impulse response at first millisecond looks promising, but such big improvements at 5-10 ms make me worry... Either they are caused by the differences in environment or if Trinnov is actually correcting them then how it will measure 1 feet around (esp. forward-backward if it is a back wall reflection, or right-left if it is a side reflection)...
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post #7828 of 11702 Old 01-09-2014, 03:43 AM
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The final thing that made me remove the traps is Audyssey was really jacking up the THD for whatever reason (in sub-300Hz range) when the traps were there.

Have you pre-out measurements confirming this?
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Don't want up to 5% THD from Audyssey when the speakers are like 0.1% by themselves in the same range.

0.1% THD speakers? Where have you found those? According to published measurements I've found the best speaker drivers are usually showing 0.3% and rarely go down to 0.1% and only in some very limited frequency range. And a lot more THD for the bass range...
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post #7829 of 11702 Old 01-09-2014, 04:58 AM
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Rattling panels can create a tremendous amount of noise. Should be easy to fix though.

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post #7830 of 11702 Old 01-09-2014, 06:23 AM
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Have you tried to measure at different locations around the sweet "spot"? Also your before/after graphs for Trinnov does not look like it is the same measurement point as there are quite hard reflections found on it when there is nothing at the same distance in the "before" graph... I hardly believe it is something Trinnov has caused and more probably there were some differences in acoustical environment between measurements. The improvements of the impulse response at first millisecond looks promising, but such big improvements at 5-10 ms make me worry... Either they are caused by the differences in environment or if Trinnov is actually correcting them then how it will measure 1 feet around (esp. forward-backward if it is a back wall reflection, or right-left if it is a side reflection)...

No, I've measured my results at the sweet spot, since that's where MLP is and I'm the only one that cares. Also, while I try to measure at exactly the same spot (44" inches from either end of the sofa, 36" high sitting down, about 33" from the back of the sofa, and about six inches above the top of the sofa to have clearance) there may be variation of an inch or so on height. Is that "close enough" for measurements in your book?

Igor, I certainly understand your skepticism, since I wasn't sure I believed the results myself until I repeated it, despite the claim that Trinnov makes for their technology. In fact, I've been very reluctant to do ANY posts from the R-972 I picked up because I was concerned they'd be controversial. My original REW question was actually about FS vs. %FS plots, but I felt obligated to post some results - even fragmentary - because I've been chattering about trying out Trinnov long enough here smile.gif.

Without dragging the thread off-topic too far, as a recap, I picked up a Sherwood R-972 with a basic (DSP) version of the Trinnov Optimizer, which as per Curt Hoyt of Trinnov, represents a hard-wired version of their 2.0 technology when the AVR was developed in 2008/2009 (their pro units are have progressed since then). Trinnov supposedly first addresses room modes and first reflections as part of the correction process, and then applies a mix of IIR (below < 250 Hz) and FIR (above 250 Hz) filters. I can't vouch for whether this is a 100% description of what the Optimizer does in their high-end units, but the basic technology is described below:
http://www.sonotechnique.ca/trinnov-optimizer

The mic that comes with the R-972 for calibration is a bit unusual. It has a so-called "3D microphone" with four mic elements arranged in a pyramid-like pattern. See this example from Kal Rubinson's review of the unit I have:
http://www.stereophile.com/content/music-round-42-page-2

A broader description of the more advanced version of the mic in their full featured kits is below (from http://www.trinnov.com/products/pro-audio/st2-pro/features-st2-pro/?lang=en_us). I have the consumer version, which is batch-calibrated rather than individually calibrated, loosely akin to "Audyssey" vs. "Audyssey Pro". But the mic I have has the four element configuration as well.

At any rate, their mic allegedly measures in 3D space, so if you believe what the Optimizer is doing, it's conceivable that you can get improvements at this level. I think Hoyt on the dedicated R-972 thread claimed that they correct up to 150 ms, but I've only measured to 40 ms.

Again, repetition under more controlled conditions is the only way to see if this is really happening, hence I'm repeating with a single speaker, nobody home, and a time stamped/photographed mic position as soon as I get some free time. And also to make sure that obscure elements like whether a baby bouncy seat against the side of a wall isn't creating variations. smile.gif

I can also give you pre/post separate plots as well as the combined one with Overlay, if that helps with readability. And I don't believe the complete "clean of reflections" part either, but I believe that it's possible that given what Trinnov does, some of the correction process may reduce certain first reflections.

FWIW, here's another user illustrating what the unit's allegedly doing. Again, this is from the "consumer" R-972, not the high-end ADA/Trinnov units that have far more parameter flexibility. And his graph ranges are for an % FS plot and not an ETC (and from the thread, is apparently actually unfiltered), so I'm not clear if it meets our standards:
http://www.avsforum.com/t/1397757/r972-trinnov-user-notes/450#post_22736260

Note: with the AVR I'm testing as a processor, the pro reviews and user comments didn't doubt the ability of Trinnov to correct and do 2D/3D remapping with the Optimizer so much as basic AVR functionality issues.

Stuart

 

Denon 4311 with XT32 and Audyssey Pro

Oppo 93 and 103

Panasonic VT50

Sherwood R-972 with its version of the Trinnov Optimizer

MiniDSP 10x10 HD

PSB Imagine T2, Center, and Surrounds (as of 5/2014); HSU ULS-15 subs (2)

 

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