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The Audyssey Pro Installer Kit Thread (FAQ in post #1) - Page 105

post #3121 of 5257
Quote:
Originally Posted by jevansoh View Post

Frequency response is just one of many factors and quite honestly, not nearly the most important for the lower frequencies.

If magnitude response is not the most important factor, what is the most important factor at low frequencies? What specific frequency range are you talking about?
post #3122 of 5257
Quote:
Originally Posted by markus767 View Post

Quote:
Originally Posted by jevansoh View Post

Frequency response is just one of many factors and quite honestly, not nearly the most important for the lower frequencies.

If magnitude response is not the most important factor, what is the most important factor at low frequencies? What specific frequency range are you talking about?

Looks like I need to learn to re-read and properly edit my posts when shortening them from novel status to simply long-winded, eh. smile.gif As I have said many times, words mean things! I'll do better in the future.

Here's what I "meant" to say (and originally did say before editing to shorten the post).

When looking at frequency response, it is most imperative to look at the lower frequencies, below around 300hz or so.

Above that approximate range (Schroeder/transition) the ETC shows much more detail and can tell you exactly what to do/where to do it to help get rid of comb filtering and if reflections are properly taken care of (not necessarily by absorption) the frequency response will be affected positively in the higher frequencies.

The frequency response "alone" simply doesn't give us enough information or detail, for either the lower frequencies or the higher frequencies but if it is the only tool one will use, of course it is much more useful for the lower frequencies.

Dips in lower frequencies aren't as harmful as long resonances that aren't necessarily associated with peaks/modes but the FR will only show us, well....Just the peaks/dips. Plus, at 1/12th smoothing, while more than fine for higher frequencies, above transition, is simply not enough detail to get the whole picture in the lower frequencies we're talking about now, especially if it is the only tool used.

When making comparisons and trying to show differences, using one tool, at this resolution, simply doesn't paint an accurate picture. That's the only point I was (inaccurately after editing down) trying to make. smile.gif

To answer your question regarding range, a Waterfall, IMHO, should show us a range of 0-300hz or so, with a 60db scale (into the noise floor, but not including), and a time range set long enough to show the longest peak but not so long that detail is lost, and will show a lot more than just a simple frequency response.

If "I" had to pick only ONE tool, it'd be this one and not a FR as I'd see a pseudo FR using this tool anyway. It's great people are willing to share their efforts to achieve audio nirvana with us and looking at other peoples results then comparing with my own is quite frankly the most fun I have here. If folks are going to go to that trouble though, it sure would be more meaningful IMHO to see the Spectral Decay Plot/Waterfall if we only get to see "one" graph. smile.gif The more detail the merrier!

Getting back to the original topic and my post (which I'll edit to correct) I was simply asking for more data and was simply trying to state that a frequency response, while good for low frequencies, and not so much for revealing detail or the whole story at transition and higher frequencies, is really incomplete. Especially if smoothed to 1/12th Octave.

Thanks,

--J
post #3123 of 5257
While I'm contributing and since this is my first time communicating directly with you, Markus, I'd like to further our discussion by getting your thoughts and opinions on the following.

Taking this beyond the original post/point, as I planned to do after Jerry responded with the Waterfall charts and without going into detail, Audyssey makes a lot of claims, one of which that it works in the Time Domain and doesn't simply invert the impulse response, fixing frequency response errors only. Specifically, that it can help with early reflections.

I've been doing countless measurements and tweaks using a combination of XT and the AS-EQ1 a little at a time, with both measuring and listening in between, for months now. While a lot of times I can get better frequency response in certain areas (sometimes problems are simply moved around) almost every single time I compare the Waterfalls with
Audyssey/AS-EQ1 on/off the resonances are both moved and worse with the EQ on.

To help control the modal region, I have a DSP1124 coming soon to plug in both in addition to and instead of the AS-EQ1. Since my room is pretty darn good to begin with, without any EQ [+/- 5db 20-20k unsmoothed] I'm hoping a bit of simple parametric EQ will do the trick to tame the few peaks I have below 80hz plus actually help the resonances instead of moving them or making them worse, in addition to giving me control of what I correct vs. an automated routine that gives me less control.

As for the spectral region, has anyone looked at any ETC's to see if there are changes, for better or worse. I haven't yet asked Jerry for his ETC's as his post focused on the low end and ETC's are for specular reflections, of which there can be none below the transition frequency which we're currently discussing.

However, since Jerry is currently doing comparisons and since he's about to make a change by replacing his 4311 with a 4520, even though both have XT32, they may have undocumented fixes/tweaks and I'd be very curious to see his ETC's too, in a range of 0ms to 40ms to begin with unless he has a huge room.

Markus, have you done any of these comparisons, looking at the ETC both w/ Audyssey on and off? Do you have any data to share while waiting to see if Jerry is willing to share his?

I'll go into more detail on the why's if asked and/or if Jerry is interested/willing to post these results as part of his
comparison. If you have data to add, that would be great!

I have a room approaching LEDE standards (not simply a live at one end and dead at the other; there are "standards" in place here of which most aren't familiar) in which I can control which reflections (first, early, late) are absorbed, diffused,
and/or reflected as I intimately know which acoustical treatment (and at which locations) performs it's dedicated and surgically placed function and the locations at which they do so. When I receive my 4520, I will be performing all the
comparisons already talked about above between the 5805CI and 4520, along with trying my best to get a "different" response in the ETC with Audyssey both on and off using every conceivable (within reason) change in acoustical behavior I can control in my room to try my best to back up Audyssey's claims.

Just to be clear, I am a HUGE Audyssey fan and believe it has its place in literally everyone's system and have the utmost respect for Chris K and of course Tom Holman. I am happy with both of my Audyssey products and use them on a regular basis. I mean no disrespect to either person mentioned above or Audyssey as a company.

I am an eternal tweaker and obsessed with acoustics, which is why I'm up at 5:00 A.M. typing all this. I'm a fan, not a detractor, just so we're clear.

Looking forward to continuing discussion and education,

--J
post #3124 of 5257
jevansoh,

Thanks for the detailed answer. I think we're on the same page. You raise a lot of points which are complex and each of them would probably deserve a separate thread. So I'd like to stick to Pro vs. consumer.

There shouldn't be any difference when running MultEQ Pro or consumer with the same setup and settings. Measuring the frequency response of the MultEQ filters will reveal any differences. They should be minuscule between Pro and consumer.

If there are differences then all we can do is to accept the fact and continue speculating what Audyssey is doing. This is a highly unsatisfactory situation because in digital signal processing there are things that can be done (because they are technically feasible) and then there are things that should be done (because they are perceptually desirable). I'd like a DRC system to do the latter.

Here's a very good paper by Dirac discussing that topic: http://www.dirac.se/media/12044/on_room_correction.pdf
post #3125 of 5257
I'm up early as well, and am fascinated with this discussion. Jevansoh, I will post the graphs you requested later today--I have a few things that must take priority first this morning. And, of course, I'll also measure the pre outs for Markus. BTW, I am not as knowledgeable with REW as you both might be, so if I need any guidance regarding how to generate these additional graphs, I may be sending a PM. No need to clutter up this thread with tips on how to measure. If you provide the guidance, I am willing to do the work.

Regarding the build quality of the 4520, I can't comment yet--it is scheduled for delivery Wednesday. I'll likely be posting my general impressions of the AVR in the 4520 thread, which I am sure you are following as well.
post #3126 of 5257
Quote:
Originally Posted by markus767 View Post

Jerry,
Did you measure the preamp outputs too?

 

Attached below now.

Quote:
Originally Posted by jevansoh View Post

Jerry,

I would like to see your before/after and standard/pro results "Unsmoothed" at least for the 0hz-300hz range and Waterfall graphs for the same range.
 

 

Pro calibration vs. standard calibration, 8-position average, 10-300 Hz, no smoothing:

 

 

Pre-out measurements, Audyssey on, DEQ and DVol off. 

 

Right speaker:

 

 

Left speaker:

 

 

Center speaker (input mode set to PLII Cinema):

 

 

Comments?  Above 40 Hz, I don't see any huge differences that could not be explained by the fact that two different mic's are used.

post #3127 of 5257
Thanks Jerry.

That's what I expected, the results are virtually the same. The differences at higer frequencies are probably caused by mic variations and mic location variations. The larger deviations at lower frequencies might be caused by the "tapering bug". There obviously has been a change in how XT32 behaves. I could observe it when comparing a Onkyo 3008 and a 818: http://www.avsforum.com/t/1412714/onkyo-tx-nr818-official-owners-thread-discussion/2430#post_22436970
post #3128 of 5257
Markus - does that mean that Audyssey appears to have "fixed" the potential issue with the normalization process causing subs to overdriven below the point at which the Audyssey filters taper off?
post #3129 of 5257
Quote:
Originally Posted by batpig View Post

Markus - does that mean that Audyssey appears to have "fixed" the potential issue with the normalization process causing subs to overdriven below the point at which the Audyssey filters taper off?

I would need to test it more thoroughly to be 100% certain but the data I've linked is pretty conclusive. In my test I've left the mic in the very same location for the 3 mandatory MultEQ measurements. Then the sub preamp out was measured (Dynamic EQ off). All that was changed was the AVR.
post #3130 of 5257
Quote:
Originally Posted by jevansoh View Post

I would like to see your before/after and standard/pro results "Unsmoothed" at least for the 0hz-300hz range and Waterfall graphs for the same range.
Here is the waterfall graph.  I don't know how to interpret it, so feedback would be appreciated.

 

 

 


 

post #3131 of 5257
Quote:
Originally Posted by AustinJerry View Post

Quote:






 

Jerry,

Overall this looks pretty good.

I see resonances at 30hz, 40hz, 50hz, and around 70hz. These aren't exact/specific frequencies, but as close as I can tell.

From our PM's and in looking at your room dimensions/layout, it appears these are your first order length, width, and height modes. The 70hz resonance would be easiest to deal with as it's most likely a height mode and is high enough in frequency that velocity based absorption (pink fluffy cheap insulation) would probably be able to get rid of this.

The very lowest resonance at and below 20hz will always be there. There's really nothing you can do about it, but most people don't complain about explosions sounding too boomy. wink.gif Music (other than some classical music) doesn't really have much info down that low, so that first resonance and even the 30hz resonance probably isn't too bad.

The only thing that really concerns me is the 40hz resonance. I have the same thing in my 20'x26.5'x8.8' room and have a Behringer DSP1124p coming soon to hopefully help with this last remaining pesky peak/resonance in my room.

The 40hz mode is important because it is a fundamental bass guitar mode, is high enough in frequency to be present on most recordings and actually heard, not mainly felt.

It is very difficult to suppress the effects of this mode but Audyssey has at least flattened it out nicely. That's the good news. The bad news is that unless you have a foot or more to spare, just for insulation (the back wall would be the best candidate for this) you won't be able to get rid of it cheaply.

This is a great opportunity to use pressure based tuned absorption but it's not really a DIY project unless you have a lot more skill than I do. smile.gif GIK Acoustics makes a Scopus tuned trap, tuned right at 40hz (so you don't over absorb other frequencies which is very easy to do when trying to trap such troublesome low frequencies like 40hz) at a pretty reasonable price. I'd check them out. (I have no relationship with them whatsoever other than I am a happy customer and they've treated me great)

If you play some bass heavy tracks, something with Victor Wooten, Stanley Clarke, etc and you don't hear the resonances and/or they don't bother you, then honestly, I wouldn't worry too much about it.

If it were my room, I'd concentrate first on the highest frequency where there is a problem, which is around 70hz. Corner mounted SSC (super chunks, which work best when using cheap pink fluffy insulation and not high gass flow resistivity expensive stuff like OC 703/705) very thick, using the 34" wide corner chunk as a minimum (I do square soffit style corner absorbers using 4 pieces of R30 insulation for $15 at Lowe's, hung vertically, to make an 18" x 30" trap and haven't found anything that works better yet!) should take care of your problem at 70hz and put a dent in the 40hz to get it at least in line with the other resonances.

Once you get to that point, I'd say you are good to go.

Remember, there is always room for improvement, but in looking at this graph, it really isn't all that bad. You should be proud of your efforts.

Would you mind now showing us the same graph, with the same settings, with Audyssey OFF?

Then we can compare and see if Audyssey made everything better or made some things worse while making other things better. smile.gif

Also, it appears your crossover is set around 80hz. Is this correct? If so, no problem, but if it's much lower or higher, I'd work with the distance tweaks a bit more and see if you can smooth out the FR around that area, which the top line of the waterfall (closely but not totally accurately) represents.

It would also be of assistance in comparing, especially if you decide to add more treatment to make sure the room isn't too dead (and hopefully it isn't too dead already) to show us an RT60 (just use the TOPS/green line and uncheck all the others in REW) and in controls set it to 1/3'd octave and to show as bars. There shouldn't be a difference in this with Audyssey on/off, but shouldn't and does/doesn't is not always the case. wink.gif

There are more things we can check and I'll be happy to continue to work with you via PM or in another thread, but they're not necessarily appropriate for an Audyssey thread, so to stay on topic, I'd like to see the aforementioned/requested charts/graphs both with and without Audyssey at this point.

If you were to leave everything alone as far as treatment goes, I'm sure you will continue to enjoy your system for years to come, but if like me, you strive for perfection, I'd seriously consider investing in more treatment for the low frequencies, being careful not to over deaden the room, and before adding more, it's also wise to maybe try some different locations for your existing treatment, which is FREE!

Last but not least, using the ETC, you'll be able to see EXACTLY where you need treatment and where you don't so you can surgically insert the amount (and in the proper location) you need treatment. However, I believe that is straying a bit too far off topic for this thread, so might we continue (if you're interested, of course) that in another thread?

Thanks for sharing!

Lookin' good,

--J
post #3132 of 5257
Quote:
Originally Posted by jevansoh View Post

Jerry,
Overall this looks pretty good.
I see resonances at 30hz, 40hz, 50hz, and around 70hz. These aren't exact/specific frequencies, but as close as I can tell.
From our PM's and in looking at your room dimensions/layout, it appears these are your first order length, width, and height modes. The 70hz resonance would be easiest to deal with as it's most likely a height mode and is high enough in frequency that velocity based absorption (pink fluffy cheap insulation) would probably be able to get rid of this.
The very lowest resonance at and below 20hz will always be there. There's really nothing you can do about it, but most people don't complain about explosions sounding too boomy. wink.gif Music (other than some classical music) doesn't really have much info down that low, so that first resonance and even the 30hz resonance probably isn't too bad.
The only thing that really concerns me is the 40hz resonance. I have the same thing in my 20'x26.5'x8.8' room and have a Behringer DSP1124p coming soon to hopefully help with this last remaining pesky peak/resonance in my room.
The 40hz mode is important because it is a fundamental bass guitar mode, is high enough in frequency to be present on most recordings and actually heard, not mainly felt.
It is very difficult to suppress the effects of this mode but Audyssey has at least flattened it out nicely. That's the good news. The bad news is that unless you have a foot or more to spare, just for insulation (the back wall would be the best candidate for this) you won't be able to get rid of it cheaply.
This is a great opportunity to use pressure based tuned absorption but it's not really a DIY project unless you have a lot more skill than I do. smile.gif GIK Acoustics makes a Scopus tuned trap, tuned right at 40hz (so you don't over absorb other frequencies which is very easy to do when trying to trap such troublesome low frequencies like 40hz) at a pretty reasonable price. I'd check them out. (I have no relationship with them whatsoever other than I am a happy customer and they've treated me great)
If you play some bass heavy tracks, something with Victor Wooten, Stanley Clarke, etc and you don't hear the resonances and/or they don't bother you, then honestly, I wouldn't worry too much about it.
If it were my room, I'd concentrate first on the highest frequency where there is a problem, which is around 70hz. Corner mounted SSC (super chunks, which work best when using cheap pink fluffy insulation and not high gass flow resistivity expensive stuff like OC 703/705) very thick, using the 34" wide corner chunk as a minimum (I do square soffit style corner absorbers using 4 pieces of R30 insulation for $15 at Lowe's, hung vertically, to make an 18" x 30" trap and haven't found anything that works better yet!) should take care of your problem at 70hz and put a dent in the 40hz to get it at least in line with the other resonances.--J

I'd like to spin this a bit differently. Even though there is not, short of E Power Biggs, content down low in music where Jerry's room "blooms" any excitation of that region, including explosions, will muddy all frequencies from bottom to top. And along with very long organ pipes, some kick drums and floor toms will touch below 30Hz. So I would work on cleaning that up. I've been in one room that bloomed below 20Hz from some sympathetic resonance in the space above the theater. We had been listening to the Queen BD concert and the boominess/overhang was very noticeable.

My other slightly different take is on what material to use for SSC traps. If you only have the space for SSC corner traps, then I think the 703 is the right material. If there is a lot more space, then pink and fluffy would get my nod.

Jeff
Edited by pepar - 10/2/12 at 6:28am
post #3133 of 5257
Quote:
Originally Posted by jevansoh View Post

pink fluffy cheap insulation

Sorry but in my opinion porous absorption below 100Hz is pointless. One would need to apply monstrous amounts to achieve a significant effect. More effective are structural arrangements that make the walls work as absorbers. This approach is also not very practical if the house has already been built and it is expensive.

There's only one real alternative in order to reduce modal decay at low frequencies: active absorption. A "source to sink" principle is applied. The sub(s) at a wall is the source whereas the other sub(s) is placed at an exact mirror position where it acts as the sink. Please see http://www.avsforum.com/t/837744/double-bass-array-dba-the-modern-bass-concept

Another approach is to bring the sources closer to the listener. This reduces modal effects significantly. It also lowers power requirements considerably. A single sub is probably sufficient in most cases. The drawback is a large level drop when one moves away from the main listening position. This can be counterbalanced by a second sub.

Both approaches (near field sub and active absorption) can be combined which I'm currently testing. Hope to have something to show soon.
post #3134 of 5257
Quote:
Originally Posted by jevansoh View Post


Here's what I "meant" to say (and originally did say before editing to shorten the post).
When looking at frequency response, it is most imperative to look at the lower frequencies, below around 300hz or so.

Above that approximate range (Schroeder/transition) the ETC shows much more detail and can tell you exactly what to do/where to do it to help get rid of comb filtering and if reflections are properly taken care of (not necessarily by absorption) the frequency response will be affected positively in the higher frequencies.

...

Getting back to the original topic and my post (which I'll edit to correct) I was simply asking for more data and was simply trying to state that a frequency response, while good for low frequencies, and not so much for revealing detail or the whole story at transition and higher frequencies, is really incomplete. Especially if smoothed to 1/12th Octave.
Thanks,
--J

I am pretty well convinced by Amir's excellent article in Widescreen Review I previously cited that comb filtering above the transition frequency is pretty much inevitable. That is, unless you make your room near anechoic, which is not a good thing to do sonically. I do not think DSP EQ can be of much help with it, and it need not be. The good news is that human ears display decreasing sensitivity to comb filtering as frequency increases because they do their own frequency smoothing. So, trying to eliminate or control comb filtering above the transition frequency, to me, is somewhat like like tilting at windmills. The fact that we can measure such comb filtering with greater precision than we can actually hear at frequencies above transition does not mean that we should take action on every little squiggle in the frequency curve. That is not to say that we cannot benefit from broader control of the smoothed frequency response.

In fact, Amir concludes that more reflections, at least from vertical surfaces like walls, are a good thing, creating more, not less comb filtering. He recommends against absorption at the sides. However, he goes on to state that reflections from horizontal surfaces, like floors and ceilings, are not good due to the nature of our binaural hearing. I do not think any measurement by any means can tell you which are vertical or horizontal comb filtering effects.

It is a complex subject, and I agree that not all the answers are embodied in Audyssey or in the Pro frequency graphs. They may not be embodied in any graphs, no matter how precise.

But, I recommend getting hold of Amir's article in the current Widescreen Review.
post #3135 of 5257

Thank you for the detailed and informational response, Jevansoh.  And thanks also to Jeff and Markus for their comments.  Jevansoh, you asked a very important question in a PM, "Have you heard good tight bass in an accurate room before, for comparison, and how does your room compare?"  The answer is no, I don't have any frame of reference, which is a problem.  However, as I have worked on equipment placement, technology upgrades, and room treatments over the last two years, and based on my own perception, my sound has improved considerably.  I don't hear any resonance problems with the source material that I use for my testing, so perhaps I don't have a problem, or perhaps my ears are not well trained. 

 

This doesn't mean that I don't value your comments, and that I won't continue experimenting for even better sound.  I am especially interested in the GIK Scopus product, and have emailed them for more information.  I am not familiar with super chunks, so I will read up on that approach in the room acoustics forums. 

 

Since this started out as a discussion comparing standard and Pro calibrations in anticipation of the delivery tomorrow of my new Denon 4520 AVR, I probably will focus for now in getting the 4520 installed and calibrated, and reporting my experiences.  Jevansoh, I am definitely interested in leveraging your expertise further, but it's probably best we do this in PM's, rather than this forum.  As I am calibrating the 4520 and measuring results, I'll capture a number of measurements, including Audyssey off in my room, measurements of the pre output, and RT60, ETC, etc. (with your guidance). 

post #3136 of 5257
Quote:
Originally Posted by markus767 View Post

Sorry but in my opinion porous absorption below 100Hz is pointless. One would need to apply monstrous amounts to achieve a significant effect. More effective are structural arrangements that make the walls work as absorbers. This approach is also not very practical if the house has already been built and it is expensive.
There's only one real alternative in order to reduce modal decay at low frequencies: active absorption. A "source to sink" principle is applied. The sub(s) at a wall is the source whereas the other sub(s) is placed at an exact mirror position where it acts as the sink. Please see http://www.avsforum.com/t/837744/double-bass-array-dba-the-modern-bass-concept
Another approach is to bring the sources closer to the listener. This reduces modal effects significantly. It also lowers power requirements considerably. A single sub is probably sufficient in most cases. The drawback is a large level drop when one moves away from the main listening position. This can be counterbalanced by a second sub.
Both approaches (near field sub and active absorption) can be combined which I'm currently testing. Hope to have something to show soon.

Good point. "Sub position" includes multiple subs, and it is just above "acoustical treatments," and both are above "electronic correction." in fact, the latter is last on the list.
post #3137 of 5257
Quote:
Originally Posted by AustinJerry View Post

"Have you heard good tight bass in an accurate room before, for comparison, and how does your room compare?" The answer is no, I don't have any frame of reference, which is a problem.

Try the near field approach I've proposed. Use only one of your subs, place it directly behind your seat so the driver is approximately at shoulder heigt, pointing upwards. Run MultEQ with just the 3 minimum runs (position 1 at the center where your head would be, position 2 and 3 about 1ft in front and to the left and the right of 1). You will be amazed at how this sounds.
post #3138 of 5257
Quote:
Originally Posted by AustinJerry View Post

Thank you for the detailed and informational response, Jevansoh.  And thanks also to Jeff and Markus for their comments.  Jevansoh, you asked a very important question in a PM, "Have you heard good tight bass in an accurate room before, for comparison, and how does your room compare?"  The answer is no, I don't have any frame of reference, which is a problem.  However, as I have worked on equipment placement, technology upgrades, and room treatments over the last two years, and based on my own perception, my sound has improved considerably.  I don't hear any resonance problems with the source material that I use for my testing, so perhaps I don't have a problem, or perhaps my ears are not well trained. 

This doesn't mean that I don't value your comments, and that I won't continue experimenting for even better sound.  I am especially interested in the GIK Scopus product, and have emailed them for more information.  I am not familiar with super chunks, so I will read up on that approach in the room acoustics forums. 

Since this started out as a discussion comparing standard and Pro calibrations in anticipation of the delivery tomorrow of my new Denon 4520 AVR, I probably will focus for now in getting the 4520 installed and calibrated, and reporting my experiences.  Jevansoh, I am definitely interested in leveraging your expertise further, but it's probably best we do this in PM's, rather than this forum.  As I am calibrating the 4520 and measuring results, I'll capture a number of measurements, including Audyssey off in my room, measurements of the pre output, and RT60, ETC, etc. (with your guidance). 

If your room is rectangular, then dual subs placed midwall on opposing walls as Markus suggests will do wonders for taming room modes. His nearfield technique is new to me, so I'm interested in hearing your comments if you try it.

Re Studiotips SuperChunks ... here's the straight poop and here's a dummy's guide to building them ... the "dummy" being me ... smile.gif

Jeff
Edited by pepar - 10/2/12 at 8:53am
post #3139 of 5257
Quote:
Originally Posted by pepar View Post

If your room is rectangular, then dual subs placed midwall on opposing walls as Markus suggests will do wonders for taming room modes. His nearfield technique is new to me, so I'm interested in hearing your comments if you try it.
Re Studiotips SuperChunks ... here's the straight poop and here's a dummy's guide to building them ... the "dummy" being me ... smile.gif
Jeff

Interesting read, Jeff, thanks.
post #3140 of 5257
Glad to hear that as I find most of your posts interesting to read!

Jeff
post #3141 of 5257
Can someone tell me the correct folder in which to place the microphone file?

I haven't done this since 2010 and I have all new computers and placing the Integra (80.1) in a completely different HT. Talk about rusty.......I'm having to learn this all over again.
post #3142 of 5257
Cant check my installation now but if you install initially from the installation CD it will place the mic file correctly. Subsequent upgrades will use the same folder structure.

Jeff
post #3143 of 5257
Quote:
Originally Posted by Stevetd View Post

Can someone tell me the correct folder in which to place the microphone file?
I haven't done this since 2010 and I have all new computers and placing the Integra (80.1) in a completely different HT. Talk about rusty.......I'm having to learn this all over again.

 

Here 'tis:

 

post #3144 of 5257
Quote:
Originally Posted by pepar View Post

Cant check my installation now but if you install initially from the installation CD it will place the mic file correctly. Subsequent upgrades will use the same folder structure.
Jeff

Jeff, thanks but I had already installed 3.6 from the website.
Quote:
Originally Posted by AustinJerry View Post


Here 'tis:


Thanks much!!
post #3145 of 5257
Quote:
Originally Posted by pepar View Post


I'd like to spin this a bit differently. Even though there is not, short of E Power Biggs, content down low in music where Jerry's room "blooms" any excitation of that region, including explosions, will muddy all frequencies from bottom to top. And along with very long organ pipes, some kick drums and floor toms will touch below 30Hz. So I would work on cleaning that up. I've been in one room that bloomed below 20Hz from some sympathetic resonance in the space above the theater. We had been listening to the Queen BD concert and the boominess/overhang was very noticeable.

My other slightly different take is on what material to use for SSC traps. If you only have the space for SSC corner traps, then I think the 703 is the right material. If there is a lot more space, then pink and fluffy would get my nod.

Jeff

Jeff, to be perfectly honest, I totally agree and have personally been working on my resonance issues below 40hz.

My advice to Jerry was geared more towards helping him set a goal to get started tweaking things a bit better and my personal preferences as to where I thought he should start. There is always room for improvement and as I'm sure you know, no matter how much time and money you spend, it will never be perfect. If we strive for perfection though, we can at least expect excellent results.

We have almost identical taste in music as we've discussed before. I listened to the Queen BD concert recently (specifically Roger's drum solo) after adjusting some phase settings post-Audyssey calibration which tamed a 22hz peak/resonance a bit, and for the first time, I realized how powerful, tight, and quick parts of that solo were. I previously had the same experience (that it got better after further EQ tweaks) on the Chick Corea/RTF BD concert (the song that begins with Chick playing drums on keyboards) but after these last tweaks both tracks are just that much better. Every time I feel like I'm finally hearing what was intended and the maximum quality my system/room can produce, I am yet again astonished at what can be accomplished, all with no "gear" upgrades. biggrin.gif

I will state that I don't believe ANY velocity based/porous material will help "cure" Jerry's issues below 70hz although he can help tame his 40hz problem but would absolutely not advise attempting to cure or even tame much below that.

Honestly, even with pressure based traps, it's very improbable that he'll be able to totally (or even make a huge dent) get rid of the problems around 20-30hz with absorption of any kind.

For that one needs to use either active products (want to get my hands on and test one of those "black hole" devices) or EQ and phase tweaks along with placement, not only of his subs but also his MLP. These ultra low frequencies are exactly what EQ is best at handling.

As for the material to use for SSC's, I don't agree or disagree with you. My comments were specific to Jerry's room and his circumstances. He shared with me pictures of his room, room dimensions, material/construction type, and even his marital status/living arrangements with me via PM (and gave me permission to discuss the contents of our PM's) and in reviewing his options I believe he has the room to throw some R30 cheap insulation up to see if it helps. If he then wants something smaller, something that looks nicer, and has the budget, he can look into alternatives. My recommendation was simply a cheap and quick/dirty way to see what benefits may arise.

When it comes to any type of velocity based/porous absorption/insulation, one cannot simply look at the thickness. I know the common knowledge and information on these threads tells people to go for OC 703/705 and very high densities of mineral wool, etc, however, one must consider the overall absorber and its form and function.

The lower the frequency you're trying to absorb (using velocity based traps) it has been proven that the thicker and lower GFR (around 5000 rayl/s) material such as cheap R30 insulation in thicker (more than 12") form outperforms OC703/705.

In fact, if you were to use 9.5" of OC705 vs 9.5" (the nominal thickness of R30) of pink/fluffy in the lowest frequencies, the the much cheaper and more readily available R30 wins hands down. It's not as effective in the mid band, but that's actually also a plus as at these sizes these are obviously supposed to act as bass traps and not broadband anyway. (I would still cover any/all corner traps and other large exposed areas not in reflection points with thin plastic or
post #3146 of 5257
Quote:
Originally Posted by markus767 View Post

Quote:
Originally Posted by jevansoh View Post

pink fluffy cheap insulation

Sorry but in my opinion porous absorption below 100Hz is pointless. One would need to apply monstrous amounts to achieve a significant effect. More effective are structural arrangements that make the walls work as absorbers. This approach is also not very practical if the house has already been built and it is expensive.

There's only one real alternative in order to reduce modal decay at low frequencies: active absorption. A "source to sink" principle is applied. The sub(s) at a wall is the source whereas the other sub(s) is placed at an exact mirror position where it acts as the sink. Please see http://www.avsforum.com/t/837744/double-bass-array-dba-the-modern-bass-concept

Another approach is to bring the sources closer to the listener. This reduces modal effects significantly. It also lowers power requirements considerably. A single sub is probably sufficient in most cases. The drawback is a large level drop when one moves away from the main listening position. This can be counterbalanced by a second sub.

Both approaches (near field sub and active absorption) can be combined which I'm currently testing. Hope to have something to show soon.

I've actually had very good results down to 80hz using a simple device made of 4 pieces of R30 insulation (9.5" x 15"), hung vertically so there is no messy cutting involved and to get the added benefit of no compression for a finished size of approximately 18" x 30". Now, I have a 20x26.5' room and totally understand this may not be possible in all rooms, but there are other ways to utilize "monstrous amounts" of absorption, such as in the second row riser, which I've also done, and had great success with. (Truthfully, more success than the corner absorbers!) Again, this is a 10' x 12' isle riser though and may not be appropriate for all rooms.

The funny thing is, one might not realize that the smaller the room the need arises for MORE, not less absorption.

Pink/fluffy insulation is only a quick and cheap way of figuring out what works and to get a good idea of what is possible for a room, in my opinion, unless you do have massive amounts of space.

I find porous based absorption is used way too often and seldom in the proper amounts or proper locations.

I agree with you 100% that other methods of taming modes/resonances are vastly superior to porous/velocity based absorption but unfortunately there is not as much easily and readily available information on the common forums/threads that discuss these things leading to not a lot of DIYers trying these methods and leading to very high prices from the companies that make such devices.

More education is needed on this topic, but again, I'm afraid we're way out of line in discussing this in this particular thread.

I absolutely would love to continue this discussion though but someone needs to point me to the proper thread or we need to create a new one. wink.gif

Markus, thanks for the link and for the Dirac link you sent yesterday! I plan to read them as soon as I finish replying to these posts. I'll get back with you after reviewing them. It seems we actually agree on pretty much everything and I'd love to share some knowledge and information with you as I am always interested in learning more. I absolutely do not profess to be a know-it-all and try to learn something new in the field of acoustics every day. It's getting harder and harder as the topics are getting more and more advanced as I further my research and application though! wink.gif

Thanks,

--J
post #3147 of 5257
Quote:
Originally Posted by fitzcaraldo215 View Post


I am pretty well convinced by Amir's excellent article in Widescreen Review I previously cited that comb filtering above the transition frequency is pretty much inevitable. That is, unless you make your room near anechoic, which is not a good thing to do sonically. I do not think DSP EQ can be of much help with it, and it need not be. The good news is that human ears display decreasing sensitivity to comb filtering as frequency increases because they do their own frequency smoothing. So, trying to eliminate or control comb filtering above the transition frequency, to me, is somewhat like like tilting at windmills. The fact that we can measure such comb filtering with greater precision than we can actually hear at frequencies above transition does not mean that we should take action on every little squiggle in the frequency curve. That is not to say that we cannot benefit from broader control of the smoothed frequency response.

In fact, Amir concludes that more reflections, at least from vertical surfaces like walls, are a good thing, creating more, not less comb filtering. He recommends against absorption at the sides. However, he goes on to state that reflections from horizontal surfaces, like floors and ceilings, are not good due to the nature of our binaural hearing. I do not think any measurement by any means can tell you which are vertical or horizontal comb filtering effects.

It is a complex subject, and I agree that not all the answers are embodied in Audyssey or in the Pro frequency graphs. They may not be embodied in any graphs, no matter how precise.

But, I recommend getting hold of Amir's article in the current Widescreen Review.

I read Amir's article a few weeks back and while I don't really disagree with anything either you or he stated, I do have some thoughts.

First, comb filtering, as seen on an FR graph is absolutely inevitable. You are not going to totally get rid of it nor should that be the goal.

There must be a fine balance between making the room too dead/anechoic and trying to totally get rid of one problem which almost always inevitably makes other things worse.

However, one must also learn to choose his poison. There are so many different types of rooms and room responses to strive for.

I do not believe in simply placing some panels up and putting some bass traps in corners and calling that a treated room.

There must be goals. Those goals (LEDE, Ambechoic, Anechoic, etc) correlate with the type and size of the room, the purpose of it (HT, 2-Channel, recording, control room, etc) and the types of speakers to be used paying closest attention to their off axis dispersion and response.

Once you've "picked" there are clear goals to be met from defined rules/characteristics of each type of room.

I won't agree that anechoic is "bad" however I will agree that I wouldn't choose it.

However, I've found that by having a room that approaches LEDE (which does NOT mean live end dead end by the way) and having just the first 20ms or so effectively anechoic then having controlled diffuse reflections back into the room after that, the effects of comb filtering are severely diminished and are no longer of concern. They also look much better on the FR graph, too! wink.gif

You're correct that DSP EQ cannot help much. In fact, it can't help at all. It can move things around and appear to help, and maybe even do so in one area, while making another worse, but you cannot correct non-minimum phase areas.

Unfortunately, this will probably get me yelled at and I really don't want to argue. I'm a nice guy and am sensitive, lol. wink.gif

But... Facts are facts. There are some systems that claim to be able to "correct" non-minimum phase issues up to around 25ms from 0, but I cannot personally attest to the truthfulness in that statement as I don't have multiple thousands of dollars to get the gear in here for my own testing.

Audyssey really does do a great job and I have to admit I haven't quite figured out exactly everything it is doing and how it does it. It does, overall, make my room better on paper (the graphs) and "most" of the time sound better. I'm a true believer and use it. I'm a fan. wink.gif

There are certain things I believe it should be used for and certain things it should not and also believe it's better at certain things than other, despite having the same filter resolution over the entire bandwidth.

Audyssey, in my opinion, is absolutely best at and should be used for the lower frequencies and any minimum phase issues you may have, however, if you have a minimum phase response, you're less likely to have many issues, so that's a bit of a catch 22.

Unfortunately, we continue to see FR's posted all over the forums and are just starting to see spectral decay's/waterfalls and NEVER see ETC's and Group Delay's.

I would LOVE to see some of the regular forum members/posters here that have rooms they simply couldn't listen to without Audyssey post these graphs, which are so simple to do using an SPL meter and free software (REW).

Not so I can point out faults, but so hopefully I can better understand how Audyssey is working, what it is improving, and any issues it may be causing while doing so.

Without this data, and a lot of it, from many different people, it's very difficult to learn more about the EQ process and exactly how Audyssey works.

That's why I'm here though. I wish to learn. I hope to one day apply my knowledge in the field to help benefit others that are obsessed as I am about audio and who also wish to achieve audio nirvana.

Maybe this discussion will lead people to post more before and after graphs not only of simple FR's, but also Waterfall, ETC, and even group delay so we can really "See" what's going on, since we can't all go to each others homes and personally "Listen." wink.gif

If I've missed anything or didn't cover anything, let me know, but it's late and I have created a bit more for folks to have to read/wade through that intended, so I'm going to bed now. tongue.gif

Thanks,

--J
post #3148 of 5257
Quote:
Originally Posted by markus767 View Post

Quote:
Originally Posted by AustinJerry View Post

"Have you heard good tight bass in an accurate room before, for comparison, and how does your room compare?" The answer is no, I don't have any frame of reference, which is a problem.

Try the near field approach I've proposed. Use only one of your subs, place it directly behind your seat so the driver is approximately at shoulder heigt, pointing upwards. Run MultEQ with just the 3 minimum runs (position 1 at the center where your head would be, position 2 and 3 about 1ft in front and to the left and the right of 1). You will be amazed at how this sounds.

I'm going to try this myself. I have a Behringer DSP1124p coming that should allow me to do some specific/easy tweaks for projects like this and am interested.

I enjoy my theater alone. Although I do not live alone, nobody else is interested one bit! So this gives me flexibility to do what's best for ME.

However, Jerry hasn't stated whether he watches in larger groups and whether he cares about the sound in other seats or not. If he does, might I suggest that this may not offer the best results?

What are your ultimate feelings and conclusion on this method, Markus?

I have to admit, I've not heard of this method before but am eager to both read more about it and try it in my own room.

Thanks,

--Jason
post #3149 of 5257
Quote:
Originally Posted by pepar View Post

Quote:
Originally Posted by AustinJerry View Post

Thank you for the detailed and informational response, Jevansoh.  And thanks also to Jeff and Markus for their comments.  Jevansoh, you asked a very important question in a PM, "Have you heard good tight bass in an accurate room before, for comparison, and how does your room compare?"  The answer is no, I don't have any frame of reference, which is a problem.  However, as I have worked on equipment placement, technology upgrades, and room treatments over the last two years, and based on my own perception, my sound has improved considerably.  I don't hear any resonance problems with the source material that I use for my testing, so perhaps I don't have a problem, or perhaps my ears are not well trained. 

This doesn't mean that I don't value your comments, and that I won't continue experimenting for even better sound.  I am especially interested in the GIK Scopus product, and have emailed them for more information.  I am not familiar with super chunks, so I will read up on that approach in the room acoustics forums. 

Since this started out as a discussion comparing standard and Pro calibrations in anticipation of the delivery tomorrow of my new Denon 4520 AVR, I probably will focus for now in getting the 4520 installed and calibrated, and reporting my experiences.  Jevansoh, I am definitely interested in leveraging your expertise further, but it's probably best we do this in PM's, rather than this forum.  As I am calibrating the 4520 and measuring results, I'll capture a number of measurements, including Audyssey off in my room, measurements of the pre output, and RT60, ETC, etc. (with your guidance). 

If your room is rectangular, then dual subs placed midwall on opposing walls as Markus suggests will do wonders for taming room modes. His nearfield technique is new to me, so I'm interested in hearing your comments if you try it.

Re Studiotips SuperChunks ... here's the straight poop and here's a dummy's guide to building them ... the "dummy" being me ... smile.gif

Jeff

Just to be clear, if using two subs, I also agree opposite mid-wall placement is the best place to "Start." Remember though, this is like placing ONE Sub directly in the middle of the two subs.

I'll be curious to see the differences in this approach vs. Markus' approach both on paper and in subjective listening.

I'm currently running four subs, but found in my room, I get the best pre-EQ response (+/- 5db unsmoothed) having my two DefTech Supercube References on the front wall at approximately 20% from each side wall and the two Epik Empire's stacked vertically and centered on the back wall.

What is normally the best, or at least a great starting point, doesn't always end up being the best spot or where the subs "should" end up.

I really think, going back to the original intent of my first reply, in Jerry's case, he may be able to get better pre and post Audyssey results by experimenting with placement a bit more.

--Jason
post #3150 of 5257
Quote:
Originally Posted by jevansoh View Post

What are your ultimate feelings and conclusion on this method, Markus?

I'm still testing different techniques but I believe that near field sub has a lot of potential. It can reduce the influence of modal decay by an amount that is normally only available in more complex and therefore more expensive solutions. That's probably the reason why neither the acoustic treatments industry nor the speaker industry have any interest in such a solution smile.gif

There's one configuration I need to test, then I'll post the results. Hope this won't be too long but first I have to build two new subs for testing purposes.
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