Acoustics in the Home Theater

[PHC1]

Ok, here is a question for the HT gurus. How acoustically dead does one need to make the HT room that is focused on multichannel movie watching only with no regard to the 2 channel music playback? Should one concentrate on keeping the reverb down to a minimum and have very little ambiance and diffusion of sound and instead lots of absorption? Or should it still be a blend of diffusion and absorption. Another words, is it beneficial to over-dampen the HT room to keep the movie sound effects, dialog, etc.. to be as reverb and echo free as possible for increase in intelligibility?

[Masterlu]

Use lots of absorption & traps, perhaps a road trip.

[JFR0317]

Originally Posted by Masterlu

Use lots of absorption & traps, perhaps a road trip.

Sage advice as usual!

[schaefer11]

IMO, the rules for good sound apply to music and home theater. Controlled directivity, with minimal room influence, will get you closest to what the artist intended.

Of course it is much easier for me to say that than for you to accomplish it!

[howiebrou]

Serge,

I am still in the same boat as you are in that I am still totally unsure how much to dampen my room. I definitely need some bass traps (clap echo behind speakers) and some wall mounted first reflection points. However with no ability to demo them and them not being cheap it makes commitment difficult.

Overdamping would probably be worse than not damping enough as I envisage everything would just sound lifeless.

You guys in the US have a great resource for companies who will do site visits. That's what I would do if I lived there

howie

[smmbear]

check this Acoustic Treatment and Design for Recording Studios and Listening Rooms
make your own . i found rigid fiberglass at a local oven manufacturer they use it to line the cabs of ovens etc . it was 703 (2inch thick) for 24.00 (us) for a 4x8 sheet . industry uses alot of rigid fiberglass for fire protection . i made wood frames and cut the glass to go inside than went to a sowing store and found decritive meterial to cover the frames . just hold the fabric up to the light and make sure you can see alot of light through it (like speaker grill) i chose multible styles and miss matched through my room .looks great . i hung the panels on the walls like a picture this way you can move them take them down what ever you need to do to make the room the way you want . good luck

[chessman]

One would not wish to dampen it anymore than what is good for two channel listening. The primary need is for bass traps so that the sub(s) do not sound boomy. Room modes are very strong for the long waves of low (<80H) notes. In that range one cannot really overdampen the room. Higher notes are a different story and one can kill the ambient effects with too much absorption.

Many of us go with absorption behind the mains, absorption at the first reflection points (and ceiling if you can get away with it), and bass traps in the corners. That is probably enough if you have carpeting and drywall walls. If you have bare block walls or bare concrete floors, you may have to do more.

If you are hardcore, you get something like True RTA and start running "waterfall" graphs of frequency response and delay times, but that is mostly not necessary.

[UFTE]

Question for all on dampening: My HT is located in middle of my open basement - block walls drop ceiling, etc. I never really gave much thought to dampening, etc in my HT when setup, just kind of used the open area I had. My question on dampening derives from my insulation, as I opted for a spray in foam approx 3" thick behind the drywall. What do you think this foam backing paired with the drywall does for sound dampening? Not saying my HT sounds off or anything, just looking trying to learn a bit more as I go along. Reading through post in the forum, there are quite a lot of things I never really thought about for adding to sound quality!

[chessman]

I am not an engineer, but I bet it is not doing much. You will get a lot of reflection from the drywall outer covering. What does penetrate is not likely to be absorbed by the insulation, so it rebounds off of the cement block behind the drywall.

If you clap your hands in the room does it echo?

Does it seem like the bass is boomy or non-existent?

In other words, what are you trying to fix?

[PHC1]

Originally Posted by UFTE

Question for all on dampening: My HT is located in middle of my open basement - block walls drop ceiling, etc. I never really gave much thought to dampening, etc in my HT when setup, just kind of used the open area I had. My question on dampening derives from my insulation, as I opted for a spray in foam approx 3" thick behind the drywall. What do you think this foam backing paired with the drywall does for sound dampening? Not saying my HT sounds off or anything, just looking trying to learn a bit more as I go along. Reading through post in the forum, there are quite a lot of things I never really thought about for adding to sound quality!

I assume you are not worried about the sound radiating out of the room as you are trying to improve the acoustics within the room? The insualtion will have very little to do with that. You can use various acoustical panels and bass traps from mild to wild to treat the room where your theater is. That is really the only way to improve the sound drastically. You can hear for yourself what an untreated vs treated room sounds like. RPG Diffusor Systems This track makes it really easy to hear the difference. http://www.rpginc.com/listen/sample02.htm