Acoustical Treatments Master Thread - Page 234

OK, but they are no where near flat off axis ... or isn't that important?

Jeff

You should use your ears first to optimize the toe-in for soundstage. Different speakers will interact differently in every different room and layout. Once you have determined optimum soundstage, use your laser to shoot beyond your listening position, which will give more accurate readings for fine-tuning. Be sure to bubble level the speakers first for accuracy and/or symmetry.

hey mtbdudex, thanks so much for sharing.

i noticed that you only wrapped the OC703 only, instead of the whole frame.

how did you keep the OC in the frame, so it doesn't fall out? i see 2 back panels support, but how about the front?

Some how the point is being missed:

1. No speaker will be flat off axis.
2. The off axis plot should have the same shape and character as the angle increases. Note the good response ... the shape, is the same at all angles ... is just rolls off on the high end. Basically, the frequency response is exactly the same...just the SPL rolls off.
3. Look at the bad response ... the off axis picks up a notch. That is bad, bad, bad. When your off axis doesn't match your on axis, you want to absorb. When it does you want diffusion. In the case of the B&W plots, the FR of the on axis and off axis are very different. Not good.

Does this mean making the front of the room dead and back live is not needed?

Having an AT screen (and screenwall), I guess I am confused about this as well. The THX folks recommended the cavity be deadened, and Ken Kreisel (M&K) does as well.

FWIW, I deadened the area around and between my LCR speakers, flush with their baffles behind an AT screen and intelligibility is really excellent. I don't know how it could be better. As the reporter retreats into Hugo's chicken shack in Season 3 of Lost, you can hear her mutter "I hate these assignments, everyone's got a story." plain as day at comfortable volume levels for the rest of the audio. It's a throw-away line, but my Lost addicted neighbors burst out laughing. "We never heard THAT!"

Dennis,

I sent my pics and room dimensions to Mike Orlowski at AlpineVista.com, he is busy with another client at the moment. Being that I don't have a laptop computer and am unable to take measurements myself, specifically the response of my speakers. I got this from Paradigm's site on the Studio 60s, now mine are the V4s but the specs are the same.
Frequency Response:
On-Axis
30° Off-Axis
±2 dB from 45 Hz - 22 kHz
±2 dB from 45 Hz - 20 kHz
Does this information help without taking any actual measurements?

Thanks

Jay ... no. Measurements are required since the room has the bigger impact. Positioning counts, seating locations count, etc.

...of course cavities have to be deadened which is different from the LEDE adopted in early two channel, free standing arrangements.

THX is talking about baffle walls and the cavity behind the baffle is deadened to avoid resonance. There's also the SBIR notch issue to be cautious about.

Alright, I understand the front cavity needs to be dead, but what about the opposite end. Does it need to be live? Or is this not standard and needs to be determined on a case by case basis?

Hi Guys,

Couldn't see this mentioned in the thread, but I was wondering has anyone used these kits for treating their theatre room, are these appropriate or are they setup only to work for a recording studio?

http://vintagemicrophone.com/JShop/p...d2fb22c7b3c64d

Cheers,

Matt

My read is that flat is not possible. The goal: Consistent response as the off axis angle increases. That is, gradual change. No way to be flat but one wants to avoid radical changes over the space of a few degrees.

Kinda related, while doing tile work in my basement I saw these in the store and they reminded me of the diffusers I was reading about while doing some of my acoustic research 1+ year ago.
Yea, they look like them somewhat but depth is too shallow and I'm sure their pattern does not follow some 7th order function...
Wonder how heavy they'd be if built "properly".....100's lbs?


Since I'm in a log home I was looking for some more natural/organic material for diffusors than the metal/plastic ones I've come across.
Some of those commercial wood ones are really neat looking, and with science behind them.


The DIY wood ones seem like lots of work....(this is from a 3 year old thread with Ethan also in it, http://recording.org/studio-construc...mparisons.html)

I've been thinking to make a separate thread on the DIY construction methods of hanging acoustic panels, currently none exist, I've searched AVS forum.
Just these for Fabric frames, which are integrated as part of the wall itself, not hanging and locatable to where only needed.
(these are great threads btw for those whole wall coverage methods)
Fabric Frames - GPowers Thread
Another Fabric Frame Thread - Canvas Stretcher Bars

I'll start it later, and others can then add their methods there.
IMO, this "Master treatments" thread is more for the theory, science, and practical application for acoustics of your particular room situation/issue, not the DIY construction methods, that will clutter it too much.

Having separate DIY construction technique thread will keep that ready for others to grasp as well, this 100's pages thread can be overwhelming at times.

You certainly do not want the back wall "dead" if you have surround speakers back there. The extent to which that wall is treated, and exactly with what, is dependent upon many factors ... distance from speakers, distance from nearest row, available height for rear speaker installation, overall decay rate by frequency in the room, where are the side surrounds (and type), etc.

great idea.

i agreed this is probably not the right thread for diy panels, and frankly the size of this thread and its content is overwhelming for people looking for diy materials.

please post link when you get a chance to getting around on creating this new thread.

thanks

Okay, well I guess I'll wait to hear from Mike about what to do with my room. I still think I'm safe to put corner bass traps in though.

Thanks

I don't see enough detail there to know what's included, but it's better to work with a treatment manufacturer directly who will guide you and make sure you get what's most appropriate for your specific room. In my experience, few resellers understand acoustic treatment well enough to advise specific products and placement etc.

--Ethan

Heck, for that price spend a few hundred bucks for a pro to come measure your room and tell you what to get and where to place it. Overall you'll likely spend less, and get a better (ie, perfect fit) solution.

EDIT: At the very least, Ethan's suggestion to have one of the expert vendors advise you is worthwhile. No cost for those remote consults, though it's of course polite to purchase at least some of what they sell.

Hello everyone. I am a newbie to the site and was told to come to this thread for a good response. First, I am turning a large frog into a dedicated theater room (except for a few pieces of excercise equiptment that the wife has to keep in there). I would love to see some pics and get advice from some theater room owners that did a great job at "faking luxury" using some sort of curtains on all the walls for the "theater look", and of course for the benefit of sound dampening (doesn't have to be red velvet, can be any color and any material...I'm really looking for a cheap way to get the best theater look). I am thinking of running painted black dowels down the ceiling of the entire room, and using simple clearance curtains from Lowes that will reach the floor. There are so many responses on where to put curtains as well. here's my set up: rectangular room, entrance to room has large built ins where 50 Panasonic will be mounted, subs in bottom niches (large niches). do i put curtains over this stuff as well?? do I put it along all walls and in back?? There is a double window in the back of the room. This will be a 7.2 system (maybe 7.1 depending on the response I get from the sub-heads).
I have a 2 sub question as well , but will be posting it in the sub forums unless I have any subbies on this forum.
Basically here's my equiptment: Harmon kardon reciever, 50 panasonic plasma, 1 jbl powered 8sub, 1 veladyne powered 8, sony and jbl satalite speakers for front, mid, rear, and sony center channel.

Here is the thread I just started in this same forum, called DIY construction methods of hang-able acoustic panels (not fixed frames)

I'd like others who make DIY hang-able acoustic panels, whether absorption, diffusion, reflection, etc. to also feel free to add your construction techniques/methods there.
>>We need to learn from you!

Looking for a reccomendation for a company to install a LCD TV and run the wires behind the wall.

Had you considered posting this in a thread more closely related to installing an LCD and running wires inside the wall? Include a location, too. "Bills Fan" might say it, but you could be a translpant as well.

I currently through a threads on construction projects to say how peoples did it. Doing this I came up with questions related to soundproofing.

1) I want to use tubing to be used a cables channels between the rack and near each speakers. I saw that almost all setup pass their tubing through the ceiling. I was planning to pass my tubing under the floor to try to get shorter cable runs. Soundproofing wise is their a benefit of method was to other?

2) Does the soffit add anything acoustic wise or are they strictly there for cosmetic reasons? Do they need to be symmetrical?

3) One of my walls is made of 2x6 on which I am using sound clips and hat channels. What should I do soundproofing wise with that extra 2" compare with 2x4 structure? Increase the 1" air space between the R13 pink insulation and gypsum? Increase the pink insulation thickness to 5"1/2?

Hey Guys,

My wife and I built a fairly large dedicated HT a couple of years ago. At the time we hired an acoustics "consultant" to help with the design and construction. He provided a set of plans and after it was too late, we discovered that many of the "acoustical" tricks he had recommended had been mis-communicated to our builder in the beginning and it was too late to implement most of them. Things such as built in corner bass traps and soffit diffusers and so on and so on. In addition, they would have made the aesthetics of the theater horrible. When challenged by myself and the builder, it became obvious that the guy had sub contracted the whole design and drawing set to someone else and he really didn't know what he was talking about. There were actually two aspects to the construction, the sound proofing / isolation of the room from the rest of the house and the interior acoustical treatment. We got the isolation stuff right from the start. But the interior treatment stuff didn't get implemented.

At first pass, the room seems to sound pretty good but I would really like to take some analytical measurements and begin experimenting with acoustical treatments. So my question is what instrumentation do I acquire? Computer? Software? Mics? Etc? This may have been covered already and if so I apologize for repeating. Just point me to the right thread. I have a EE degree so I'm not scared of the in depth technical stuff. I've also been a lifelong "audiophile" for what that's worth - if anything :-)

Thanks
Dale Troutt
Frisco TX

Here's my standard list of room measuring links:

Room EQ Wizard, Windows and Linux and Mac OSX 10.4+, Freeware
ETF, Windows, $150
FuzzMeasure, Mac, $150
Room Measuring Primer
Comparison of Ten Measuring Microphones

--Ethan

Laptop, USB sound "card" or preamp, Room EQ Wizard and a calibrated mic. But it will be the time needed to get around the learning curve .. or "curb" depending on how well you assimilate. But even then with measurements in your hand you may not know what they mean. I don't mean to dissuede you, but you have a bit of a daunting task ahead.

You might consider a design service like the one offered here by AVS or Dennis Erskine.

Also, acoustical treatment vendors such as Ethan Winer and GIK Acoustics offer design recommendations as part of their customer service.

I have a "flutter" echo in the back of my theater. Fortunately it doesn't seem to get activated by the speakers. I just unscientifically covered the walls with 1" black-faced fiberboards and it went away with great audio clarity. But talk of "over damping" got me to experiment with positioning absorption using the "mirror test". The results are again very clear and satisfactory, but if I go to the back of the theater and even utter a "sss" I hear the flutter echo.

The room is a little complicated back there. The 6' wide projection booth juts out a foot creating a 1' deep 6' wide alcove on one side (I'd like to eventually use for a huge bass trap) and a 4.5' entryway on the other. Not only that, but the ceiling starts at 12' and pitches up to 17' about midway to the screen.

So there could be lots of places the flutter echo is occurring. I'd like to measure the flutter's period because that would give me the dimension to look for. How can I do that? A 'scope might be good but I don't have one. Can REW do this? I have that, a laptop and a calibrated mic. Is it worth setting those up and playing with available measurements and graphs?

A while back I asked if it was a good/bad idea to use OC 703 and fabric on all vertical surfaces in my theater and was told not to do so. So my next simple question without asking for a too complex answer. Is it ok to use OC 703 and fabric on both side walls to chair rail height or basicially 4ft? Also what about the rear wall? Chair rail or floor to ceiling?

Ethan,

Thanks so much for the recommendations. I am a MAC computer guy primarily. I have a MAC Book Air and a MAC Desktop (both a couple of years old) and I've been thinking about buying a Mini to hook up to the Theater. My question is will REW do all the same stuff as FuzzMeasure or do I need to get both. Will I be giving up anything significant by not going Windows? Also, where do I buy one of the recommended mics and will I need an external mic preamp with a MAC? If so, which one and where to buy?

Thanks Again
Dale