Room acoustics

[ni-cad]

You guys I know would appreciate these videos (not to mention this guys home cinema set up) he's one of the foremost figures in acoustics.

Ethan Winer:

http://www.youtube.com/watch?v=lbLVjHfHahg

http://www.youtube.com/watch?v=4nzmBhkR4JQ

http://www.youtube.com/watch?v=aHkAFSZmMk4

Regards ni-cad.

[krazeyeyez]

lol@ the mantle being the ONE concession he had to make for his wife, i need a woman with that mentality

gonna have to watch the other vids when i get more time but interesting stuff!

[Drew664]

Ha!

So if you are making a dedicated HT room, wouldn't you want your walls to all be bass traps essentially? Why not just carpet the walls out of a similar material?

[crazyBLUE]

Originally Posted by Drew664

Ha!

So if you are making a dedicated HT room, wouldn't you want your walls to all be bass traps essentially? Why not just carpet the walls out of a similar material?

I would think that if you completely covered the room it would make the room dead ! Killing the acoustics of the room .

[richteer]

Originally Posted by Drew664

Ha!

So if you are making a dedicated HT room, wouldn't you want your walls to all be bass traps essentially? Why not just carpet the walls out of a similar material?

Because carpet does a lousy job of absorbing bass frequencies.

Everyone with an interest in acoustics should check mout Ethan's other videos on his company's site, www.realtraps.com.

[Drew664]

Ah, I shouldn't have used the word carpet as it was misinterpreted. I meant the word as to cover every inch of the wall, like Crazy implied.

Killing off all of the acoustics seems plausible though. It's good to know about the diffusers in the back making the room sound larger than it is as well as having a section of the back wall extended back to help with bass frequencies.

Any idea as to what % of surface area should be covered then to make for optimal treatments?

[crazyBLUE]

Originally Posted by Drew664

Any idea as to what % of surface area should be covered then to make for optimal treatments?

This I think would be hard to judge for every room is different !
For me In all my viewing of video's & reading material , Help from Big Daddy & others I took A guess at how much I would need & probably to much but that's no big deal ! Placing is the fairly easy part of it !!

[rded]

I was told by a very knowledgeable guy from a different forum that: Rule of thumb is to not cover more than 30% of the wall's surface area with acoustic panels.

[Drew664]

So let's set up a scenario. Let's say I have an unfinished basement, and I wanted to make a HT. Going by those videos and standard set ups, I have come up with this.



The acoustic panels are missing except for the diffusers in the back which apparently make the room sound larger. I'm more interested in the significance of having that extended portion of the room which apparently will help with the bass.

I'd like to know what other forum members would do if they could build a HT out of an unfinished basement. Is there a 'best' design out there or are there certain architectural designs that enhance the listening experience?

[Beta Man]

You should try to put some panels at the first point of reflection from the speakers....... this is just a general rule of thumb that I've found to work in most cases.

If you're going completely from scratch with an unfinished basement, a "waved" style ceiling can do wonders to deal with standing waves.

good luck.

[crazyBLUE]

Originally Posted by Beta Man

You should try to put some panels at the first point of reflection from the speakers....... this is just a general rule of thumb that I've found to work in most cases.

If you're going completely from scratch with an unfinished basement, a "waved" style ceiling can do wonders to deal with standing waves.

good luck.

+1 ~ I agree !

[Drew664]

Interesting with the wave style ceiling - I haven't seen any HTs with it. Let's say that I have a 10' ceiling for this unfinished basement. What would be the measurements of the peaks and valleys of the waved ceiling? Would it cover all the area or should it be subject to the 30% rule as well?

I'd like to know more about it, but Google isn't giving me informative articles about waved ceilings. Any chance you remember where you heard/read about it?

[richteer]

Originally Posted by Drew664

So let's set up a scenario. Let's say I have an unfinished basement, and I wanted to make a HT. Going by those videos and standard set ups, I have come up with this.

In your diagram, there's no absorbtion at all! At the very least you'll need some bass traps and some absorbtion on the side walls to kill first reflections (and tame flutter echo).

[richteer]

Originally Posted by Drew664

I'd like to know what other forum members would do if they could build a HT out of an unfinished basement. Is there a 'best' design out there or are there certain architectural designs that enhance the listening experience?

Non-parallel walls are a great feature if you can swing it, and room dimensions that are close to the Golden Ratio can also help.

[Drew664]

OK. So non parallel as in the walls bottle neck towards your fronts or away from them?

[richteer]

Originally Posted by Drew664

OK. So non parallel as in the walls bottle neck towards your fronts or away from them?

Away from them. So, a bit like this: \_/ with the fronts in the narrower end.

[Drew664]

Alright, I've come up with this now.



This room seems very doable as long as the basement is unfinished and the utilities are huddled in the corner (they don't have to be but then the oblong triangle shape would be about worthless. Maybe just storage instead?)

Now that my room is shaped different, do I still need that extra addition for help with bass frequencies? This can be done like a hallway, so it wouldn't be that difficult to implement and look good.

For actual lengths (to maintain the Golden Ratio), you would have to take your projection wall * 1.618, which would equal the length of your back wall. No clue how you would find the side wall lengths though. Maybe someone can help chime in on the use of the Golden Rule as a whole.

Any other things that need to be tweaked/mentioned?

Hopefully this can be an informative thread for those that want to see room acoustics put down 'on paper' to visualize them. I know it's helping me at least.

[Big Daddy]

Don't forget the basic rules of room treatment.

Absorption.jpg


Diffusion.jpg


Echo.jpg


Reflections.jpg


Treatment.jpg

[crazyBLUE]

Those 5 pics Big Daddy put up were vary helpful in how I applied my treatments to my room ! I still need A few diffusers though

[ni-cad]

Just found a good example of the waved style ceiling that Beta man pointed out (using carpets) carpets are ok but they're a bit of a fire hazard though can be trated.

Listening rooms are often have treatment covering evry surface, these kinds of rooms are caled Anechoic chambers and employ the use of diffusers, they can actually look very cool, I've seen some lovely looking chambers reacently that would deffinitely lend themselves nicely to a home cinema.





btw, check out the underfloor porting in one of the rooms pictured bellow.