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Acoustical Treatments Master Thread - Page 315

post #9421 of 10165
Quote:
Originally Posted by wse View Post

Which one was first?

Wisdom Audio. See my post above yours.

Jeff
post #9422 of 10165
Quote:
Originally Posted by sdurani View Post

The only one I can think of is the recently released Marantz 8801.

Thanks for that! Looks like a winner for my application!
Quote:
Originally Posted by erkq View Post

Very nice woofers, especially for their time. Their combination of sound, efficiency and deep bass response (in a properly large box) is unmatched. I'm a great fan, having purchased my first pair of 416-8A's from Electronics Plus (in San Rafael) in 1978 for $95 each! And, I still have them in my living room speakers system. They work like the day they were new. But I've never been a big fan of their horns. Instead I pair them up with Dynaudio D-76's and Esotar D-260's in a tri-amp'd configuration so efficiencies and phase match. It's all very sweet.

I, too, bought a batch from a closing theater (in Oregon) and used 8 of those for an IB sub. They did a very credible job, but I later swapped them out for a set of AE-IB15's, which do a very incredible job!

EDIT: BTW, my 416's -3dB point is 18Hz in their 6 cu. ft. box!

A theater in Oregon eh? Small world! Those A6a's have 3154's (IIRC). I've heard the 416's in A7 cabs a few times but never as a direct radiator. I was all set to go with a handful of IB15's in my last theater, but we moved before I got the chance. This time round I'll be using four horn loaded, high excursion 18". Won't go as low as your IB's, but with 11,000 cubic ft an IB would be out of the question.

What didn't you like about the Altec horns? I've heard and owned a bunch of them over the last few years (288 CD's) and to my ears, they have a mid range to die for. The A6a's are a little rolled off, but a worthy trade off for that mid-range. I've tried tri-amped with a Gauss 1502's and 515g's in DIY 80hz bass horns, but I wanted to have the same speakers all the way round and 7-11 active speaker are just too noisy with the high efficiency drivers. Unless you're prepared to spend BIG on active crossovers.

Sure sounds like you have a killer setup though, do you have any links to your speaker/theater build?

Quote:
Originally Posted by Peter M View Post

LOL ! It certainly is if you live in Rose Bay !!! biggrin.gif

Hehe. Lots of fond memories of Bondi.
post #9423 of 10165
Quote:
Originally Posted by steve71 View Post

...
A theater in Oregon eh? Small world! Those A6a's have 3154's (IIRC). I've heard the 416's in A7 cabs a few times but never as a direct radiator. I was all set to go with a handful of IB15's in my last theater, but we moved before I got the chance. This time round I'll be using four horn loaded, high excursion 18". Won't go as low as your IB's, but with 11,000 cubic ft an IB would be out of the question.

What didn't you like about the Altec horns? I've heard and owned a bunch of them over the last few years (288 CD's) and to my ears, they have a mid range to die for. The A6a's are a little rolled off, but a worthy trade off for that mid-range. I've tried tri-amped with a Gauss 1502's and 515g's in DIY 80hz bass horns, but I wanted to have the same speakers all the way round and 7-11 active speaker are just too noisy with the high efficiency drivers. Unless you're prepared to spend BIG on active crossovers.

Sure sounds like you have a killer setup though, do you have any links to your speaker/theater build?
Hehe. Lots of fond memories of Bondi.

It's been decades, but I thought they "rang". I just started using other drivers and never looked back. So perhaps a re-eval is in order. Also, when using the 416's as direct radiators the efficiency doesn't match well and other direct radiators (like my beloved Dynaudios) work well.

I built my theater's speakers using all Dynaudio drivers (except for those 8 AE's of course) so efficiency isn't a problem and they stay nice and quiet as tri-amp'd speakers.

Wow... horn loading bass for a 11,000 cu. ft. space? That sounds like a fun project. Here's a horn to look at. I'm sure you've seen this before: http://www.royaldevice.com/custom31.htm

I have no links. It doesn't photograph well. All the dark walls that stay hidden jump to the fore with a flash and there's not enough light to not use a flash. The problem is, when the sound and pic get to a certain point (and I'm there) work on the room stops! smile.gif
post #9424 of 10165
Quote:
Originally Posted by erkq View Post

It's been decades, but I thought they "rang". I just started using other drivers and never looked back.

They do have a lot more HF energy (due to their constant directivity design) than direct radiators, which beam. So in an untreated room they will ring more. But in a treated room it's not an issue, and really that's not the speakers fault. You can also band-aid it a bit with eq.

The other issue with them is they don't terminate into free air correctly, causing diffraction. There are better horns (modern) out their in that regard, but a little modification can work wonders. Especially with these MRII horns as they are pretty close to ideal anyway. The earlier multicells and manta-ray horns make correct termination into free air a bit harder, but still possible.

Finally, the other compromise is that the center to center spacing of big horns can never comply with the 1/4 wavelength rule. So there will be lobes at the crossover frequency.

Every design has it's compromise though and as I'm sure you know since you DIY! Danley's unity horns might be the exception. I'm dying to hear those babies!

Quote:
Originally Posted by erkq View Post

I built my theater's speakers using all Dynaudio drivers (except for those 8 AE's of course) so efficiency isn't a problem and they stay nice and quiet as tri-amp'd speakers.

What are you using for an active x-over? I could get the noise down to acceptable level's but it's really only an issue with the 115db/w/m horns.
Quote:
Originally Posted by erkq View Post

Wow... horn loading bass for a 11,000 cu. ft. space? That sounds like a fun project. Here's a horn to look at. I'm sure you've seen this before: http://www.royaldevice.com/custom31.htm

I'm crazy, but not that crazy biggrin.gif He must need some serious delays for his mains!

I'll be building these guys, just waiting on the back order drivers. "1 meter peak output numbers results in output levels of 130-140dB from a single cabinet over the entire 20-100Hz range and greater than 127dB at 16Hz".

http://www.data-bass.com/data?page=system&id=45




Anyway, getting back on topic I ordered two boxes (24 panels) of 2x4ft OC 703. Amazon had free shipping and a good price. I was very concerned that locating the stuff was going to be a pitta.

Now if only I could get my EMU 404 sound card to work with my laptop, I actually might be able to start taking some measurements when the stuff arrives.
Edited by steve71 - 3/28/13 at 9:22pm
post #9425 of 10165
Quote:
Originally Posted by steve71 View Post

...
What are you using for an active x-over? I could get the noise down to acceptable level's but it's really only an issue with the 115db/w/m horns.
...
I'll be building these guys, just waiting on the back order drivers. "1 meter peak output numbers results in output levels of 130-140dB from a single cabinet over the entire 20-100Hz range and greater than 127dB at 16Hz".

http://www.data-bass.com/data?page=system&id=45
...

It's taken me a while to answer because I don't want to hijack the thread and I'm embarrassed to admit I'm using Behringer x-overs. I tri-amp'd my whole 7.1 system and buying more expensive x-overs would have just killed the project. I still like the setup better than any passive x-over I've managed to design, though. Crossovers are the toughest part of DIY speakers for me. And... my Dynaudios are probably just under 90 db/w/m, so I don't hear any hissing.

Interesting stuff about the HF horns. So I knew what I was hearing, even back in my 20's. I definitely did not have a treated room.

Killer subs! I would love to build me some of those. I think it would destroy my house, though! smile.gif

OK... enough OT I guess... but it was fun for me.
post #9426 of 10165
Originally Posted by erkq Wow... horn loading bass for a 11,000 cu. ft. space? That sounds like a fun project. Here's a horn to look at. I'm sure you've seen this before: http://www.royaldevice.com/custom31.htm

This is unheard, you could cause a seismic trigger with those subs!
post #9427 of 10165
Quote:
Originally Posted by erkq View Post

I'm embarrassed to admit I'm using Behringer x-overs. I tri-amp'd my whole 7.1 system

Wow, that is harcore. biggrin.gif I was headed down that route but couldn't pass us the deal I got on the Altecs.

No need to be embarrassed about the ringer'. There isn't much choice in affordable x-overs. Electronics matter, but the smart place to spend your money is on room treatments and speakers (as I'm sure everyone here knows!).

I have a nice ATI 2007 amp arriving on Monday, but I'm honestly more excited about the OC 703 that's coming on Tuesday. biggrin.gif

And back on the topic of room treatments, I'm still SHOCKED at the bass I'm getting. It must be the room. I've been chasing this bass my whole life and figured that it just didn't exist in recorded music.
The kick drums & snares just kick you in the chest in every recording. There is that physical quality to drums that I've only heard with live drums.
post #9428 of 10165
Quote:
Originally Posted by pepar View Post

Wisdom Audio. See my post above yours.

Jeff

Totally agree with this btw. The Sage series blew my mind at RMAF. I've never had transients smack so hard, without sounding sharp. If I ever get a two-channel set up some day...they will be the Sage series line-source.
post #9429 of 10165
Hi guys, I have no real clue about sound treatments, and I'm wondering if it is even worth it in the room I am planning to turn into my HT.

The room has a large sliding door/window to the rear; a big window on one side wall; and a large open doorway on the other side wall. I was going to cover these areas with curtains and look at bass traps in the four corners. I was also going to put something on the walls for the first reflection and build a soffit with coffers as per the below pics.




With the limitations of the room (windows/doors etc.) is it even worth doing the bass traps? Any suggestions on limiting the bass going upstairs?

Thanks for your help.
post #9430 of 10165
Quote:
Originally Posted by Jonny5nz View Post

Hi guys, I have no real clue about sound treatments, and I'm wondering if it is even worth it in the room I am planning to turn into my HT.

The room has a large sliding door/window to the rear; a big window on one side wall; and a large open doorway on the other side wall. I was going to cover these areas with curtains and look at bass traps in the four corners. I was also going to put something on the walls for the first reflection and build a soffit with coffers as per the below pics.

With the limitations of the room (windows/doors etc.) is it even worth doing the bass traps? Any suggestions on limiting the bass going upstairs?

Thanks for your help.

I'm no expert (still learning lots), but the bass traps should be a no- brainier if you can sacrifice the room in the corners. OC 703 on the first reflections is also a good idea, but the windows might get in the way of that and you want the room to sound symmetrical. You can buy 6 or 12 sheets of 1"x2x4ft OC 703 online. Buy a box and start experimenting. You can just take the sheets out of the box and lean them up against the wall at the first reflection points. IIRC it's recommended to treat your entire screen wall.

If you really want to take it further, get some equipment to take measurements and pay attention to your rooms RT60.

Hope I got that right, but I sure someone will chime in and correct me if I didn't. smile.gif

I just started experimenting in my room with a few boxes of OC 703 and the results are really amazing. Imaging is a LOT better and more uniform across the frequency spectrum. Mono recordings image dead center now. No strange shifts in tonal balance/ringing when playing at high volume and I can hear deep into the recording's noise foor / reverberations.

Good luck with your man cave!
post #9431 of 10165
Hi Steve, thanks for your advice. I don't really know what good sound sounds like. I will be getting an Onkyo amp so I hope that it's self calibration thingy can do the job.
post #9432 of 10165
Quote:
Originally Posted by Jonny5nz View Post

Hi Steve, thanks for your advice. I don't really know what good sound sounds like. I will be getting an Onkyo amp so I hope that it's self calibration thingy can do the job.

Are there no other "nuts" in your area that you can visit? Building yourself an understanding of what good sound is and how far the boundaries can be pushed takes time and experience. Don't know how many times I've felt "it can't get much better than this" and I've pushed the envelope substantially since...
post #9433 of 10165
No, unfortunately I know of no nuts in my area. I'm guessing that appreciating quality sound is like appreciating fine wine or good coffee.
post #9434 of 10165
Is treating the entire screen wall still considered the way to go? In my room I have standing super chunk style bass traps in all the corners but one (Too close to a door to put there) and have treated at the first reflection points. I have been thinking of building a psuedo wall out of 1X2's that I can use to hold some 2" OC703 and treating as much of the front wall as is realistic, but wanted to check and see what the thoughts are on how much return you see before putting the work into doing this.

Thoughts?
post #9435 of 10165
Quote:
Originally Posted by Jonny5nz View Post

Hi Steve, thanks for your advice. I don't really know what good sound sounds like. I will be getting an Onkyo amp so I hope that it's self calibration thingy can do the job.

Positive improvements in sound should be obvious, but you could get a $100-$200 pair of headphone for reference. With that room you could do bass traps in the corners (floor to ceiling), treat the entire front wall (assuming you have an acoustically transparent screen) and try to get as many first reflection points as you can (search this thread for the mirror method). Make sure you get really heavy velvet drapes for those windows and you might even have to mirror the drapes on the other side of the room (without the window). Maybe some diffusion on the rear wall.

Look into what RT60 means. You want an RT60 value of 0.35-0.4 seconds. A measurement mic and software would be a good idea, but it all depends on how far you want to take it.

More on RT60 here: http://www.avsforum.com/t/332289/rt60-what-is-a-good-value

Buy a couple of boxes of 1" thick 2ftx4ft Owens Corning 703 rigid fiberglass insulation. You should be able to mock up the bass traps and first reflection points in an afternoon. If you like what you hear, go ahead and DIY some nice looking room treatments (using the 703 you just bought).
Edited by steve71 - 4/8/13 at 11:11am
post #9436 of 10165
Quote:
Originally Posted by kertofer View Post

Is treating the entire screen wall still considered the way to go? In my room I have standing super chunk style bass traps in all the corners but one (Too close to a door to put there) and have treated at the first reflection points. I have been thinking of building a psuedo wall out of 1X2's that I can use to hold some 2" OC703 and treating as much of the front wall as is realistic, but wanted to check and see what the thoughts are on how much return you see before putting the work into doing this.

Thoughts?

From what I've read so far in this thread - yes you want to treat the entire front wall. If you have an acoustically transparent screen, then use OC 703 as a first layer, but if your screen is acoustically reflective, then just treat the front wall for midbass/bass frequencies (where it's blocked by the screen).
post #9437 of 10165
Quote:
Originally Posted by steve71 View Post

From what I've read so far in this thread - yes you want to treat the entire front wall. If you have an acoustically transparent screen, then use OC 703 as a first layer, but if your screen is acoustically reflective, then just treat the front wall for midbass/bass frequencies (where it's blocked by the screen).

I've read that as well, and did treat the entire cavity behind my AT screen/screenwall. But now that I am turning my attention to lengthening the decay time ... in my over-deadened room, I am eying that wall for some conversion from absorption to diffusion.

Jeff
post #9438 of 10165
Quote:
Originally Posted by pepar View Post

But now that I am turning my attention to lengthening the decay time ... in my over-deadened room,

Interesting - at what frequency band/range?

Have you tried covering it up with plastic first?
post #9439 of 10165
Quote:
Originally Posted by Elill View Post

Interesting - at what frequency band/range?

Have you tried covering it up with plastic first?

'Tis covered with 2" Linacoustic RC ...
Product thickness density 125hz 250hz 500hz 1000hz 2000hz 4000hz NRC
Linacoustic RC 2" (51mm) 0.25 0.66 1.00 1.05 1.02 1.01 0.95

So removing some would help broadly ... above Schroeder. anyway, it's now covered floor to ceiling and I am considering removing that which is below the screen bottom. I'd speculate that would be all that I'd want to remove as there is still the reflections off the screen back that need attenuating. Make sense?

Jeff
post #9440 of 10165
If its the mid range you're talking about I'd just cover it in plastic at least this way you'll get some bass trapping and you wont have to go to the effort of taking it all down. If it works then you can tidy it up, if it doesn't you've just lost a few dollars in plastic sheet. Other option is cover in pegbaord.

I assume its mid-high you're worried about as I have been in very "lossy" rooms for bass and love it - in saying that it takes a little getting use to
post #9441 of 10165
Quote:
Originally Posted by pepar View Post

I've read that as well, and did treat the entire cavity behind my AT screen/screenwall. But now that I am turning my attention to lengthening the decay time ... in my over-deadened room, I am eying that wall for some conversion from absorption to diffusion.

Jeff

Hi Jeff,

If it was me I think I'd be looking to remove absorption from the side / rear walls and not the front wall. Just MHO.

Cheers,
post #9442 of 10165
Quote:
Originally Posted by Elill View Post

If its the mid range you're talking about I'd just cover it in plastic at least this way you'll get some bass trapping and you wont have to go to the effort of taking it all down. If it works then you can tidy it up, if it doesn't you've just lost a few dollars in plastic sheet. Other option is cover in pegbaord.

I assume its mid-high you're worried about as I have been in very "lossy" rooms for bass and love it - in saying that it takes a little getting use to

The plastic sheeting sounds like a good way to "audition" the change. For the bottom end, I am "well-trapped" with more to be installed in the rear to tame the remaining ringing.

Thanks,
Jeff
Edited by pepar - 4/9/13 at 9:12am
post #9443 of 10165
Quote:
Originally Posted by Peter M View Post

Hi Jeff,

If it was me I think I'd be looking to remove absorption from the side / rear walls and not the front wall. Just MHO.

Cheers,

Thanks, I do have some "skylines" to swap for the rear 1st reflection point absorbers. (2" OC 703) But past that, removing my wall "treatment" gets messy. Below seated ear level, I have cheap "acoustical" carpet GLUED to the walls that I am loathe to touching. So, the rear treatment change I just mentioned, and maybe a 1D diffusor for the front ceiling FRP absorber are where I am looking.

Jeff
post #9444 of 10165
I am looking for acoustic treatment that allow you to have your own pictures on it! I heard of several but though pricing was ridiculous
post #9445 of 10165
Quote:
Originally Posted by wse View Post

I am looking for acoustic treatment that allow you to have your own pictures on it! I heard of several but though pricing was ridiculous

http://www.avsforum.com/t/1316623/diy-custom-printed-movie-poster-acoustic-panels-cheap
post #9446 of 10165
Quote:
Originally Posted by pepar View Post

The plastic sheeting sounds like a good way to "audition" the change. For the bottom end, I am "well-trapped" with more to be installed in the rear to tame the remaining ringing.

Thanks,
Jeff

Yes, I would suggest trying it out at first as well. I don't typically suggest to completely cover any wall with insulation unless the room is really large and needs it. The main point of treating the entire front wall that I see is that your sides and surround don't interfere with the mains. Definitely a good goal IMO - lets get the front information purely from the mains, and get the "surround" to "surround" us and not contort the front image. But this can of course be taken care of with many other types of treatment, not just absorption.

If you use plastic to try it out, try to get at least 10mil plastic to reflect some highs. Maybe consider trying double thickness so that it reflects some of the lower highs, maybe around 2kHz or so (as a general guess). Note that if you do place a decent amount of diffusion on the front wall, you don't necessarily have to remove the 2" insulation. Covering it with diffusion will simply help remove the over-absorption of high frequencies, while still giving you some decent midbass absorption, which is all well on the front wall IMO.

Lightweight diffusors or perhaps simple sequences of slats in front of the current absorption could help to scatter sound, give some diffusion, but still absorb some of the lower frequencies.
post #9447 of 10165
Quote:
Originally Posted by steve71 View Post

Positive improvements in sound should be obvious, but you could get a $100-$200 pair of headphone for reference. With that room you could do bass traps in the corners (floor to ceiling), treat the entire front wall (assuming you have an acoustically transparent screen) and try to get as many first reflection points as you can (search this thread for the mirror method). Make sure you get really heavy velvet drapes for those windows and you might even have to mirror the drapes on the other side of the room (without the window). Maybe some diffusion on the rear wall.

Look into what RT60 means. You want an RT60 value of 0.35-0.4 seconds. A measurement mic and software would be a good idea, but it all depends on how far you want to take it.

More on RT60 here: http://www.avsforum.com/t/332289/rt60-what-is-a-good-value

Buy a couple of boxes of 1" thick 2ftx4ft Owens Corning 703 rigid fiberglass insulation. You should be able to mock up the bass traps and first reflection points in an afternoon. If you like what you hear, go ahead and DIY some nice looking room treatments (using the 703 you just bought).

Thanks for the advice Steve.
post #9448 of 10165
If your front speakers are either baffle mounted or less than 3.5' from the front/side walls, you'll need absorption or diffusion on that front wall.
post #9449 of 10165
We just bought a new house and I decided (being the unselfish husband and father that I am) to take the biggest room in the house for home theater. After much debate, my wife convinced me to turn it into a home theater/multi purpose room by adding a kitchenette in the back. The room is finished and is 22' x 32' with 8' ceiling. It has a wicked echo and there is a column that is 10' from the screen wall and 7' from the side wall and a beam that runs the length of the room. I would like to acoustically treat this room, but I'm struggling to come up with a plan and I definitely need some help. Here is what I have so far.
  • I want to put up a fake wall on the front wall with OC703 or Duct Board across the entire front. Install corner trap in the right front corner, but there is a door in the other corner.
  • Corner traps in the back corner
  • Some type of acoustic panels or bass traps on the walls
  • Not sure, but maybe corner traps on both sides of beams
  • Some type of treatment on the ceiling with either bass traps or drop ceiling

Here is what the room looks like now.


Here is my layout.


Any suggestions?
post #9450 of 10165
Quote:
Originally Posted by sojodave View Post

We just bought a new house and I decided (being the unselfish husband and father that I am) to take the biggest room in the house for home theater. After much debate, my wife convinced me to turn it into a home theater/multi purpose room by adding a kitchenette in the back. The room is finished and is 22' x 32' with 8' ceiling. It has a wicked echo and there is a column that is 10' from the screen wall and 7' from the side wall and a beam that runs the length of the room. I would like to acoustically treat this room, but I'm struggling to come up with a plan and I definitely need some help. Here is what I have so far.
  • I want to put up a fake wall on the front wall with OC703 or Duct Board across the entire front. Install corner trap in the right front corner, but there is a door in the other corner.
  • Corner traps in the back corner
  • Some type of acoustic panels or bass traps on the walls
  • Not sure, but maybe corner traps on both sides of beams
  • Some type of treatment on the ceiling with either bass traps or drop ceiling
Any suggestions?

Forget the Kitchen fridges make horrible noises and when they quick in suck up power. Great idea to take care of all accoustics for the room, might be worth getting some expert advice so you room is the best it can be. :)

 

You can put a wicked screen in there 

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