Fed up with room accoustics!! Please read (1 Viewer)

[Chris:-/OV]

Hi Guys
I've managed to build up a fairly good theater even though i'm on a tight budget. It consists of a Denon AVR 3803, B&W DM 603 S3 (fronts), DM602 S3 (rears), LCR 600, Polk Audio PSW450 Sub all wired up with Monster bi-wire cable. Interconnects are Van den Hul The First Ultimate. I've spent every last penny on all of my equipment, upgraded, upgraded and upgraded!! But I'm still not happy. It's the room I'm in which is 6m(l) by 3m(w) by 2.3m(h) which is causing problems for me. The room is tiled and I have a large window situated behind my speakers (front). The walls are almost bare and there's only a couch in the room and carpets covering the tile and curtains for the window.

The problem is that when playing music especially rock, the frequencies are all mixed and muddled up and I can't differentiate between the different instruments. The same thing happens when watching movies. Also, the bass is very uneven in the room, in some places loud and in other places soft. I've tried everything, carpets on the window, foam on the wall, repositioning of speakers but now I'm fed up as nothing has improved the sound. This holiday though I am giving treatments to the room one more time before resigning my home theatre hobby. (thats how bad it is)

I've thought of building bass traps(one for each corner) and putting some sound absorbing panels on the walls. Do you guys have any other ideas which could remedy my problem?
Please, I'm counting on you guys to help me out.
Chris

 

[Frank Zimkas]

The walls are almost bare and there's only a couch in the room and carpets covering the tile and curtains for the window.

Sounds like you are getting a lot of reflected sound hitting you from multiple places. Have you tried using mirror and laser pointer to figure out where the best place would be for sound absorption panels? Have an assistant place a small mirror against the wall next to your primary listening position. While pointing the laser pointer at the mirror have your assistant move the mirror along the wall toward the speaker. Once the reflected laser dot hits the speaker, you've found the best place for your panel. Then do the other side of the room.

Bare walls can cause all kinds of grief, so don't be afraid to start adding "stuff" to your room.

You might want to try this as well, lots of good info.

http://www.polkaudio.com/home/librar...hthandbook.pdf

 

[Cees Alons]

Chris,

Wait with the bass traps. First your room has to be in better shape. It's quite normal for bass to be louder at some places in a room than at some other places. you'll have to try to optimize it for the "hot spot", which is the more easy for you, because you have only one couch. And don't make it too loud, especially at the start of your calibrating phase, because it may "muddy up" the sound.

Now, you said you tried different measurements. It's difficult to give you exact advice here, because we still don't know exactly how your HT looks, but here are some guidelines:

First of all, don't forget the ceiling. Reflections off the ceiling are often the most important source of garbled sound. Here's a simple test: stand in your HT and speak loud. Compare with other places, especially outside the house (no ceiling). Do you hear the reflection-effect? If yes, simple treatment of the ceiling might be indicated.

Tiles are "bad". You said you added carpet. Does it indeed cover most of the exposed area? Same for the walls. Are they mainly bare? Do not spend excessive money on wall treatments. First try to cover them with, say, pseudo-cloth like wall paper. But even before that, make tests with inexpensive loose "solutions" (bed linen, foam boards, etc.). Make sure it does make a difference.

Smaller rooms are always a challenge, but yours isn't too small, compared to many other rooms (in Europe, rooms are generally smaller even than in US houses! I don't know about South Africa, of course, but if you're in the Dutch tradition...).

Last point: start your testing at low sound levels. Does it sound better (although too soft, of course)? If so, it must be possible to achieve the same quality at louder levels. Don't give up your hobby for this, but first and all: don't start spending too much money already, especially if you're not sure the result will be anywhere near the intended effect!

Good luck.

Cees

 

[Greg Kolinski]

In my opinion the almost empty room is a lot of the problem.I have read,believe it or not. that bookshelves,good size plants,and "puffy" furniture help out a lot to break up reflections.I have multiple plants in my room that help break things up.Also have a large bookcase right behind me,and it has helped a lot with rear reflections.

Greg

 

[Chad Anson]

Sounds like your room is too reflective or said another way, has too much reverberance. The measure of reverberance is RT60, the time it takes sound to decay 60 dB, or to inaudibility. You can use RT60 calculations for several things, but for a small home theater room, RT60 is useful in determining a rough amount of absorption materials needed to treat the room.

There is a simple calculator at http://www.trinitysoundcompany.com/rt60.html

and a more complex calculator at
http://www.csgnetwork.com/acousticreverbdelaycalc.html

I don't recall what the preferred RT60 levels are for home theater, but I'm sure a Google search will provide that data.

Good luck!

 

[Chris:-/OV]

Hi
Thanks for the replies guys.
The tiled floor is not completely covered in carpet.
I will be trying a few of the methods above to treat the room. I'll try adding a few plants, bookshelves and experiment with thick foam on the walls.
Chris

 

[Wayne A. Pflughaupt]

Chris,

I feel your pain, brother! I lived for a while in a cinderblock house with concrete walls and floor, and the sound was positively dreadful. :frowning:

You don’t really need “thick” foam on the walls – just something absorptive. Something like a short-pile carpet would do wonders. I would also do wall-to-wall carpet for the floor –it will do wonders for the sound.

The windows shouldn’t be a big problem since they are behind the speakers. However, if there is nothing on the back wall to diffuse the sound, then it bounces right back to the front, and that’s when the windows become a problem. If something like bookcases aren’t an option, then try some kind of fold-up paneling that will spread across the back in a zig-zag pattern.

Bass traps don’t do anything for the problem you’re having. They are for taming bass response. However, you can do that much better and cheaper by getting a dedicated parametric equalizer for your sub.

Regards,
Wayne A. Pflughaupt

 

[Chris:-/OV]

Hi
How would you use and couple up an equilizer like that and how much will one pay for such an equilizer?

 

[Terry Montlick]

Chris,

I'm afraid an equalizer won't help your situation for anything above subwoofer frequencies. You need to reduce reverberation from the hard surfaces, as others have said. When you tried foam on the walls, how much of the room surface did you cover? How thick was the foam?

For quality movie sound, you typically need an inch of porous sound absorber, such as fiberglass, mineral fiber, or acoustical foam. Thickness is necessary to absorb medium and moderately low frequencies, as well as just high frequencies. Covering at least 1/4 of the surface area is common for home theaters. Music listening is more forgiving, and you should be able to get by with less just for this.

Acoustical treatment is a necessary part of a home theater - as necessary as amps and speakers. Your room is simply an extension of your speakers, and no less acoustically important. Stores and HT magazine ads don't tell you this because they don't have any acoustical treatments to sell you, and anything they can't sell they are not interested in.

If you can't afford this, here is a cost-free solution which may help, at least to some degree. Simply place your speakers a lot closer to your listening position. This increases the amount of direct sound compared to reverberant sound. Since the reverberant sound is what is causing your problems, you will hear far less of it.

Regards,
Terry

 

[Wayne A. Pflughaupt]

Chris,

Hi
How would you use and couple up an equilizer like that and how much will one pay for such an equilizer?

Do a search on the DIY and Advanced Projects Forum, and the Speakers and Subwoofers Forum for “Behringer, BFD and “Parametric” and you’ll get enough material to keep you busy for days. As many here have noted, EQing your sub is a separate issue from the acoustics problem, but a very important one nevertheless.

Regards,
Wayne A. Pflughaupt

 

[Mike*Williams]

I don't recall what the preferred RT60 levels are for home theater, but I'm sure a Google search will provide that data.

I found some things on the web saying .4-.5 sec is good for RT60. The only problem I've found with these calculators is they assume that there are 4 full walls (with windows, or whatever, which is cool). I'm soon to be setup in a room with 3 walls and the "right" wall (relative to sitting in the sweet spot) isn't mostly gone and opened up to other parts of the house. No way to calculate that with those calculators (so I just put in Acoustic tile suspended assuming it would absorb the most and act like a non-wall). I got between .34 to .51 over the range of frequencies, so the my room should be ok once I get setup (not perfect but that's ok..... for now )

Mike W.

 

[Chad Anson]

Mike, once you move from horrible to "ok" you can start the real tweaking. Trying to tweak an acoustically awful room would be an exercise in futility.

 

[Chris:-/OV]

Hi
Thanks for all the help and ideas guys. I figured that for now I'll put a few absorbing panels on the walls in all the first reflection points and throw a few bean bags into the room for now to see if it sounds any better.
Is absorbtion really more critical for home theater than music?
Chris

 

[Chad Anson]

You may also want to try making a simple broadband bass absorber for one or more of the corners for your room. Do a search for "quick and dirty bass trap recipe" on Google. Good acoustics are equally important with respect to home theater and music, and absorption plays a big role in both.

 

[Cees Alons]

Is absorbtion really more critical for home theater than music?

Nnnno... but you have more different channels and tend to have them louder as well.

Cees