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Acoustical Treatments Master Thread - Page 291

post #8701 of 9548
2/22/12 at 9:29am
Quote:
Originally Posted by kromkamp View Post

Continuing that thought, is it worth describing again with more detail the kinds of room problems that we do want to fix, and by how much?

As dragonfyr put it, what is the specific acoustical response goal we want to hit for a residential, small room home theater?

Absolutely! I don't know if it should be here, or in Bigus' thread, or wherever.

The first task is understanding that there ARE different models.
Next is understanding their differences and how that applies to home theater.
Then picking one, which as Dennis is suggesting, may be a more subjective choice.
Last, implementing it to some degree.
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post #8702 of 9548
2/22/12 at 9:38am
Quote:
Originally Posted by NicksHitachi View Post

Some simple starting points that would get most of us 90% of the way there. I'll bet most will agree on the best starting points.

Yeah, I see people here wanting to know, "What's the stuff that probably applies in 80% of the cases that probably won't do harm, that I don't need to spend 100 hours in planning to determine whether I should implement?"

Maybe porous corner bass traps fall in that category, but your chosen model would dictate what the front corners are doing with mid-to-high frequencies. You can broadband absorb, diffuse, only absorb the bass, etc.

And maybe "lastly after other bass treatment, EQ in modal region those peaks that are consistent for your important seats, where it's minimum phase."

The rest depends on the model, but if we're talking home theater, and not a large choral performance space, I suspect some of the models can be winnowed down due to the use of multi-channel source and speakers providing some of the ambiance, as well as real-world constraints like not being able to cover all the surfaces with diffusors.

The room model thread ended in January with two pages, last post by kromkamp. It should be continued, maybe with more concerted intent at coming to agreement, rather than disagreement.
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post #8703 of 9548
2/22/12 at 9:56am
Quote:
Originally Posted by Eyleron View Post

The room model thread ended in January with two pages, last post by kromkamp. It should be continued, maybe with more concerted intent at coming to agreement, rather than disagreement.

Well, four or five posts into that link, I encountered the same lack of respect that just erupted here over the last several days. It's not the thread topic that makes or breaks a thread, it's members not interacting properly with others.
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post #8704 of 9548
2/22/12 at 10:04am
Quote:
Originally Posted by NicksHitachi View Post

+1 and leave this one for theory banter.

IMO if you have to quote a scientific paper to support your view your probably deep in left field theory territory and of little use to the average DIY HT enthusiast.

I challenge one of the elite folks here to Erskine, Winer, etc. to start a thread focused on the low hanging fruit for DIY HT folks.

Some simple starting points that would get most of us 90% of the way there. I'll bet most will agree on the best starting points. Getting the last 10% is where all the theoretical discussions and differing of opinions convelude the simple things which would make the average HT better.

Here are two posts that get to some basics - I have these bookmarked

http://larchive.avsforum.com/www.avs...3#post17390783

http://www.avsforum.com/avs-vb/showt...8#post15406068

From Bob's post, this always struck me as very basic - "In an otherwise empty/reflective room, studiotips superchunks and first reflection point absorbers are a good thing. In other rooms, your mileage will vary."
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post #8705 of 9548
2/22/12 at 11:44am
Quote:
Originally Posted by NicksHitachi View Post

+1 and leave this one for theory banter.

IMO if you have to quote a scientific paper to support your view your probably deep in left field theory territory and of little use to the average DIY HT enthusiast.

I challenge one of the elite folks here to Erskine, Winer, etc. to start a thread focused on the low hanging fruit for DIY HT folks.

Some simple starting points that would get most of us 90% of the way there. I'll bet most will agree on the best starting points. Getting the last 10% is where all the theoretical discussions and differing of opinions convelude the simple things which would make the average HT better.

I think Mr Winer;s book may help many people:
http://www.ethanwiner.com/book.htm


Quote:
I've always wanted to write a book about audio, and a few years ago I started making notes about what I would include. As it happens, a major publisher of technical books approached me in early 2011 after seeing my hour-long AES Audio Myths video. So I submitted a proposal for my book, The Audio Expert, which they quickly approved. I worked on the book literally non-stop since then, and finally finished the first draft in late November. All 26 chapters were then sent to black belt technical editor Mike Rivers for his comments and suggestions, which I applied. (Thank you Mike!) I then did one final "polish" pass on the entire book, and sent it to the publisher January 8. The copy editor and layout department are now putting the book into its final form, then I'll review it one last time before it goes to the printer.



This is a very comprehensive "reference" type book covering all aspects of audio, with many practical as well as theoretical explanations. It's written for people who want to understand audio at the deepest, most technical level, but without needing an engineering degree. The Audio Expert explains how audio really works in much more depth than usual, using common sense plain-English explanations and mechanical analogies, with minimal math. It's presented in an easy to read conversational tone, and includes more than 400 figures and photos to augment the printed text. You can view the Table of Contents now, which includes a list of all the videos that total more than 3-1/2 hours running time.

However, this book goes beyond merely explaining how audio works. It brings together the concepts of audio, aural perception, musical instrument physics, acoustics, and basic electronics, showing how they're intimately related. It also describes in great detail many of the practices and techniques used by recording and mixing engineers, including video production and computers. This book is meant for intermediate to advanced recording engineers and audiophiles who want to become experts. It's definitely not a "Dummies" type book for beginners!

One unique feature is explaining how audio devices such as equalizers, compressors, and A/D converters work internally, and how they're spec'd and tested, rather than merely describing how to use them. This book is also unique because it includes much original research, such as methods to test the audibility of distortion and other artifacts using your own listening system, while explaining why many common home-made tests are not valid. It also addresses the perennial "measuring versus listening" and "subjectivist versus objectivist" debates head on, and resolves them using science, logic, and hard proof. There's plenty of myth-busting and consumerism too. Indeed, truly understanding how audio gear works leads to smarter buying. So while I won't tell readers what brand power amplifier to buy, I explain in great detail what defines a good amplifier, so people can choose a first-rate model wisely without over-paying.

Most explanations throughout the book are platform-agnostic, applying equally to Windows and Mac computers, and to most software and hardware. Many audio and video examples are included to better present complex topics such as vibration and resonance. Other videos demonstrate editing techniques and audio processing, and there are several video interviews with skilled musicians demonstrating their instruments and playing techniques. In the piano video, a professional piano technician disassembles a $100,000 Steinway grand to show how it works! Of course, there's also a comprehensive Acoustics section, bringing together much of my writings from past years into one coherent reference, along with a wealth of new information. There's literally nothing else like this book.

The Audio Expert is due out April 15, 2012, with an anticipated length of 656 pages and a list price of $54.95. The book can be pre-ordered now at the Amazon book store, and will also be available as an eBook at the Kindle store. Watch for a glowing review in an upcoming issue of Electronic Musician magazine.

Upon looking at the chapters it's clearly for those in the making music business, sound engineering, so I asked could a reduced pdf online version be avaialble....
http://forums.musicplayer.com/ubbthr...ok#Post2383341
Quote:
Originally Posted by mtbdudex View Post

Ethan;
I'm a Home Theatre enthuasist.
Looking over your book table of contents, http://www.ethanwiner.com/book_toc.htm clearly it is written for those who are in the "music business".
Making, creating, recording, editing, playback, etc.

For the Home Theatre related portions, is there any thinking to make say a smaller version, even download pdf only.
Ch 1, 2, 3, 4, 16, 17, 18, 19, 20, 22, 23, maybe some others.
Just a thought....
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post #8706 of 9548
2/22/12 at 12:51pm
btw, Low hanging fruit is very clear, it's been stated here and many-many other acoustic forums:

1) Pick RFZ zone as your small room acoustic model, it's the easiset for DIY (IMO); front sound stage specific ; I've not seen surrounds addressed specifically in the various small room acoustic model's ....
2) Broadband bass traps in corners, big ones if possible, 34" x 24" x 24" (use pink fluffy for that size). Soffit style on wall/ceiling is also.
Plan to cover them on room facing surface with thick kraft paper or 6mil plastic to reflect the mid-hi freq back into the room. Fabric cover over that.
3) Using mirror trick, plan where your side wall 1st reflection treatments could be
.....If you want to use measurement and verify exact placement, use ETC and the techniques discussed for ID/placement.
.....If not, using just mirror trick, you may over dampen slightly, or may not get all the reflection points, but definitley improvement will be heard (the 90/10 rule)
4) by the book for side wall treatments, 4" OC703 + 4" air gap is best to even absorption thru the freq spectrum 250hz and up, again 16" of space may not work for some, 2" + 2" air gap will leave some of the lower freq not addressed.
>>Trade off time for the customer to decide
5) Using mirror trick, plan where your ceiling 1st reflection treatments could be....same comments as 4) above.

Plan them
Build them
Hang them
Listen and enjoy them

Better is measurements, but many don't want to shell the $225 or so for measurement mic/gear and learn the software.
Not hard, but just one more thing in a busy life.

I see some are asking for a "Plan...do...check....act" cookbook approach.....



Looking at this link, everyone can see visually the various small room models, it's 7 pages from the book "Acoustics and Psychoacoustics Applied"
http://eetimes.com/design/audio-desi...n?pageNumber=0
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post #8707 of 9548
2/22/12 at 1:28pm
Quote:
Originally Posted by mtbdudex View Post

btw, Low hanging fruit is very clear, it's been stated here and many-many other acoustic forums...

Seems reasonable and that it'd do the most good with the least harm.
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post #8708 of 9548
2/22/12 at 1:38pm
Quote:
Originally Posted by mtbdudex View Post

btw, Low hanging fruit is very clear, it's been stated here and many-many other acoustic forums:

2) Broadband bass traps in corners, big ones if possible, 34" x 24" x 24" (use pink fluffy for that size). Soffit style on wall/ceiling is also. Plan to cover them on room facing surface with thick kraft paper or 6mil plastic to reflect the mid-hi freq back into the room.

Is there any cons if chunk bass traps are covered with 6mil plastic paper surrounding three sides of triangle? If it is not advised, how do you stop fibers coming from the back or sides?
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post #8709 of 9548
2/22/12 at 1:54pm
Quote:
Originally Posted by sukumar View Post


Is there any cons if chunk bass traps are covered with 6mil plastic paper surrounding three sides of triangle? If it is not advised, how do you stop fibers coming from the back or sides?

Sorry not stated, they need fabric covers over the reflective material for that reason.
Plus, they need to look nice, right?
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post #8710 of 9548
2/22/12 at 2:03pm
I think he's asking about totally encasing the SSC's in poly/kraft paper for environmental reasons.

Jeff
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post #8711 of 9548
2/22/12 at 2:23pm
Quote:
Originally Posted by pepar View Post

I think he's asking about totally encasing the SSC's in poly/kraft paper for environmental reasons.

Jeff

Yes. that is right. I wonder encasing triangle basstrap in 6 mil plastic instead of just front side is ok or causes any problems.

I intend to encase first with 6mil plastic then with fidelio velvet cloth.
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post #8712 of 9548
2/22/12 at 4:27pm
Quote:
Originally Posted by sukumar View Post


Yes. that is right. I wonder encasing triangle basstrap in 6 mil plastic instead of just front side is ok or causes any problems.

I intend to encase first with 6mil plastic then with fidelio velvet cloth.

As I type this on my iPhone, in my basement home theatre, watching pirates of the carribean with my 6 yr old son, I'm looking at 6 bundles of pink fluffy sitting wrapped in their plastic still.....there for some side experiments on low freq bass stuff....need I say more.

Many people buy and stack pink fluffy in the corners. Sure, it's compressed, but gives you directionally the improvement possible. Uncompress it for the install.
Fully wrapping in plastic is up to you.

I believe dragon or local posted some link to clear the issue of health of loose fibers, simply a non issue.

Have fun.
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post #8713 of 9548
2/22/12 at 4:47pm
Quote:
Originally Posted by sukumar View Post

Yes. that is right. I wonder encasing triangle basstrap in 6 mil plastic instead of just front side is ok or causes any problems.

I intend to encase first with 6mil plastic then with fidelio velvet cloth.

+1 on what Mike said, plus, if the traps are behind a false wall, it's just silly to spend the cash on Fidelio. Go to Joanns and buy some some cheap speaker cloth to cover. Save the Fidelio for the screen frame, although I personally think that's overkill as well compared to some less expensive options.
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post #8714 of 9548
2/22/12 at 6:44pm
Quote:
Originally Posted by fotto View Post

+1 on what Mike said, plus, if the traps are behind a false wall, it's just silly to spend the cash on Fidelio. Go to Joanns and buy some some cheap speaker cloth to cover. Save the Fidelio for the screen frame, although I personally think that's overkill as well compared to some less expensive options.

Thanks. I already bought 20 yards of Fidelio and it is sitting for a while. After buying, I got confused if it is accoustically transparent enough for sound absorption and did not do anything with it. At the time of purchase, my intention was to make screen wall and surroundings as dark as possible and never thought about filling space with bass traps or first reflection panels.
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post #8715 of 9548
2/27/12 at 9:55pm
Quote:
Originally Posted by nathan_h View Post

Quote:
Originally Posted by dragonfyr View Post

Nathan, we can help you. But help us by posting the REW .mdat file so that we can convolve the frequency response into the various views and window them accordingly.

And as local observed, we want to drive each source individually with the measurement mic remaining in the EXACT same (reproducible) position for all current and future tests.

And with treatment in place, its difficult to say what can be done, or what original actual issues exist that require treatment and thus to suggest what needs to be done, as we do not have the untreated baseline response to judge. Untreated measurements would be a wonderful addition if the concept does not scare you too badly... We can then determine the effectiveness of the treatments and suggest any additional measures...

And seeing as how REW can be used in any number of configured audio topologies it hardly seems work all the effort to attempt to configure it to a specific configuration when it is simply but one possible topology out of many when its easier and quicker to simply manually change the input relative to the device you want to test.

Okay, once I get the measuring of individual speakers working, I'll post the mdat file. I assume the one for the stereo pair isn't as useful, interesting?Okay, once I get the measuring of individual speakers working, I'll post the mdat file. I assume the one for the stereo pair isn't as useful, interesting?


Working on getting set up to test speakers individually. First step was just to remove bass mgmt, the sub, etc and do a fresh measurement of the room with all channels driven with the test sweep.

Calibrated mic from Dayton. I'll post the mdat file and this picture set of pictures.

EDIT: mdat file is 1.7mb and the upload limit is .5MB
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post #8716 of 9548
2/27/12 at 10:19pm
Single speaker measurements. Right front, run full range, no sub, no eq, etc.
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post #8717 of 9548
2/28/12 at 3:50am
nathan_h, it is best to post the files (upload to www.sendspace.com).

also, ETC needs to utilize loopback --- in preferences/analysis, DE-select 'T=0', Select 'use loopback for timing reference', and DE-select 'decimate IR'

re-run the test and post .mdat files (one speaker/source at a time).
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post #8718 of 9548
2/28/12 at 7:24am
I'll re-run ETC, but for now, here is the mdat for the single speaker test.

http://www.sendspace.com/file/n56o2r
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post #8719 of 9548
2/29/12 at 7:02pm
I am looking for some advice and may have some dumb questions, but would really appreciate the help.

I ran across a really good deal on (4) Thiel PowerPlane 1.2 speakers. I already have the speakers for a surround sound setup in a HT without using these speakers for that. I am in the process of building a garage building with a finished space above. In the garage area, I am planning to install a projector and am thinking about installing the four Thiel speakers in this room (the room is 30' x 40' with 12' ceiling). I will use this primarily to watch sports when people are over and listen to music. Upstairs, I plan to setup more of a theater with surround sound. I would like to hook everything up through one receiver and I am looking at the Yamaha Aventage RX-2000. Will I be able to send video to my theater room TV and the projector as well as power all of the speakers with this one unit? Do I need an amp for the Thiel speakers or will this receiver work without an amp?

Again, any advice is appreciated as I am trying to learn as I go and make sure I make the right decisions as I am in the build process on the new building right now.
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post #8720 of 9548
2/29/12 at 9:41pm
This is the acoustical treatments thread ...
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post #8721 of 9548
3/1/12 at 7:28am
yeah, i recommended he ask here, since i've seen a few discussions of the calculations regarding speaker sensitivity, spl, and amp output. there might be a better place to ask but i couldn't think of one...
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post #8722 of 9548
3/1/12 at 7:42am
Quote:
Originally Posted by nathan_h View Post

yeah, i recommended he ask here, since i've seen a few discussions of the calculations regarding speaker sensitivity, spl, and amp output. there might be a better place to ask but i couldn't think of one...

Probably be more likely to get good advice on a Thiel thread or one for the receiver. Members on a Thiel thread would be familiar with the speakers.

Jeff
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post #8723 of 9548
3/1/12 at 8:11am
reasonable suggestion.... ironic that *that* is where he posted at first.... crickets.
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post #8724 of 9548
3/1/12 at 8:19am
Maybe they are all off enjoying their speakers.
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post #8725 of 9548
3/1/12 at 3:26pm
bingo
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post #8726 of 9548
3/1/12 at 3:52pm
Quote:
Originally Posted by nathan_h View Post

reasonable suggestion.... ironic that *that* is where he posted at first.... crickets.

Maybe this was the wrong thread but the right forum, if it has to be one question.

Or it could be two questions: one in Thiel and one in receivers.
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post #8727 of 9548
3/3/12 at 11:45pm
Opinions on two different diffusers sought:

I have been using broad band absorption, the basic GIK panels, on my side wall first reflection points.

Recently, I got a good deal on some cheap Auralex Metrofuser panels. They are shallow and made of styrofoam, but I figured it would be an interesting experiment to place them over the side wall panels and see what I thought.

The result? Bigger soundstage and all spatial cues appear to be preserved.

So now I'm sold on the idea of diffusion at my side wall fist reflection points.

But these panels may not be ideal. I'm still trying to learn, but so far what I have picked up is:

The pattern should not repeat,though being mirrored is okay. In that case, since the panels are 24" square and I only have to cover 4' square, they should be okay.

The depth should be shallow, when seated lose to the panels. I'm about six to seven feet from the side wall reflection points, so I think that's considered close. These panels are only two inches deep, so the wells are even shallower, so I think that's good.

But they are made of styrofoam, which can't be spray painted and would probably still have low WAF even when painted. And I cannot tell what calculations were used for them.

So I am considering two upgrades:

http://www.decware.com/p1324.htm look good, and buying as a kit makes them affordable. The narrowness of the wells seems to mean their diffusion only happens at higher frequencies.

The other option is the QRD panels from GIK. They are bother wider (which I think is good in that it means a wider range of frequencies are impacted) but they are also deeper, which I suspect is not ideal in the close quarters I'll be using them in.

Thoughts?
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post #8728 of 9548
3/4/12 at 12:14am
How about a third option: BAD panels for way higher WAF?

They diffuse and absorb the LF.

EDIT: I didn't phrase that well above. For the record, it looks like they diffuse upper and mid frequencies and absorb lower than their diffusion threshold, such as 1000hz, depending on the particular model's design.
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post #8729 of 9548
3/4/12 at 12:29am
Quote:
Originally Posted by Eyleron View Post

How about a third option: BAD panels for way higher WAF?

They diffuse and absorb the LF.

Those look interesting, but I don't think I'd get 32 square feet of coverage for 600 bucks, like the other two solutions. She's okay with the look of these others. It's just the styrofoam panels that have to go :-)
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post #8730 of 9548
3/4/12 at 7:36am
Quote:
Originally Posted by dragonfyr View Post

Nathan...

Lots of issues using those panels.

First, their effective bandpass is FAR too high. To be effective over the broadband bandpass, you are going to need QRD style diffusors generally about a foot deep to get the lower extension required.

With the Auralex product you are effectively EQing the reflected energy seriously coloring the direct sound. The minority of he mid and low mid energy does not even see them and effectively see a flat wall surface.

If you'd like a more complete explanation and additional practical options, PM me and we can talk by YM, Skype or telephone...

Having been reading this thread for a few years, I think a conversation about diffusion here may be useful (I don't recall seeing lots of details). Thanks for the offer to take it off line. But if we can keep it online, I suspect others may find it interesting/useful.

My understanding so far is that to get impact over a broad frequency range, I need a panel with WIDE wells, and to get a panel that is impactful at short distances, I need a panel with SHALLOW wells.

So I agree the Auralex aren't the right ones. And the DIY kit I list doesn't have wide enough wells. I was actually thinking the GIK panels might be too deep.

But you are suggesting the GIK panels aren't deep enough, correct? (I've mentioned three different commercial solutions in my post, so when you say "those panels" I'm not sure if you mean all three, of just the Auralex ones.)
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