Room acoustics needs help.


Since I moved into a new house, my new living room sounds terrible. The hardwood floor is all throughout the house. I believe it is the reason for the bad sound quality. I made some wall panels and hung them on the wall behind the speakers, and on the side walls it help a lot. However, the sound of the music and the voice of the singer seems to be way behind the speakers and not extended. Looks like there are reflection or deflection somewhere in the room. I wonder if an area rug, 100% wool will help extend the music. My room size is 14'x22'speakers are placed on the short wall 4' away from the back wall, 2-1/2' from side wall, and 9' from speakers to listening chair. On one side wall have a hallway in the mildle of the room, and another one at the end leads to another room. Other side wall has 2 windows, and wall behind the listening chair has a 8' wide bay window. Any professional help will be appreciated. Thanks.
ht802
Jadem6 is stealing my recommendations! I got into this Thread preparing to say exactly what he said about Everest. (Could I dare to hope that he got the idea from me? All I can be sure of is that I didn't get it from him.) If you want to hear about DIY RPG-style diffusors or DIY Argent Room Lens clones, please get in touch--I send out 10 pages single-spaced on these topics on request. But read Everest first, by all means, to get an idea of all you need.
I was so excited to have found an acoustics thread before you Tom. I must say Tom here has helped me out even more than the book, so if you need further advise after reading the basics, Tom is a Saint!
J.D.
In addition to the above, you might try the $100 computer software "Room Optimizer" from www.rpginc.com. It evaluates your speaker and listener positions in your room and searches for better setups. It also suggests positions for acoustic room treatments, including both absorption and diffusion. Its analysis evaluates both the short term comb filtering effects due to the room's first reflections along with the longer term room resonance modes. I have found it to be a help in improving my room. For more information, you can read RPG's white paper on the software www.rpginc.com/cgi-bin/byteserver.pl/news/library/ropt_wp.pdf
While room acoustics are, for the most part, a matter of physics - Sound acts predictably in a given environment - listening to music is a very personal and extremely subjective thing. Room acoustics in the home environment are a good example of this.

In recording studios and other sound-sensitive environments, we take great care to dimension, shape and otherwise design the rooms so as to work with, eliminate and/or control acoustically harmful manifestations, such as adverse reflections, low-frequency build-ups and inadequecies due to room nodes, standing waves et cetera. Conversely, in the home we are stuck, more often than not, with bland rectangular spaces, not unlike boxes, in which to create 'our' perfect soundstages.

One of the first considerations should always be: How will sound react in this room? In short, how will the room be involved in the reproduction of the sound coming from the speakers? Will the hard, reflective surfaces of the walls, ceiling and, perhaps, the floor adversely color the mids and highs, causing acoustic 'smearing' - a lack of definition due to multiple and overlapping, uncontrolled reflections - and the inability to locate sound sources correctly? Will the physical dimensions of the room cause an unwelcome reinforcement of the lower musical registers, affecting low-frequency definition and uniform bass extension? What can be done to improve and correct any anomilies?

In acoustical design in the home, as in recording studios et cetera, there are two major, and different, areas of concern. Environmental Acoustics addresses how sound will react in a given space/environment. The second area, sometimes referred to as Boundary Acoustics, deals with how sound will transmit to other areas of the home or building, be it through the air, through the HVAC ducting or through the structure of the building itself in the form of leakage through walls or floors and/or vibration. Boundary Acoustics are, I think, a discussion for another time.

There are many books available which will give a lot of helpful information and suggestions for people who want to do it themselves. Alton Everest's "Master Handbook of Acoustics" is one of them. For others there are companies and individuals who specialize in design and acoustics.

Ht802, it sounds like you are having the most trouble with reflective surfaces? Experiment by temporarily hanging heavy blankets (or some such devices) on the various walls and auditioning the effects that they have on the music that you are hearing from the speakers. If possible, try and minimize the 'liveness' at either side of you listening area. This will tend to dampen and eliminate the secondary, and definition occluding reflections arriving at your listening position.

The idea is not to have a 'dead' room where there is a lack of excitement, no (kinetic) energy. In rooms such as this the music tends to sound thin and brittle and, to me, lifeless and uninviting. Rather the ideal is to have an environment where the room is involved in the reproduction of the sound in a complimentary and pleasing manner.

This is were room acoustics come in. Even the distance that you place your speakers from the wall can have a, sometimes, significant effect on how accurate and smooth your bass response might be. For instance, you say that you have placed your speakers 48" off the back wall? If this measurement is from the wall to the front of the speaker then you can expect a dip near 70.5Hz (more accurately 70.625Hz). This is because if a speaker is placed 282.5Hz (4'- 0") from the front wall there will be a predicted frequency dip at near 70.5Hz. By way of explanation: Sound travels 1/4 wavelength to the wall, bounces off and travels 1/4 wavelength back and is subsequently 180 degrees out of phase (1/2 wavelength) with the direct signal at the front of the speaker.

Of course, if it all sounds good, who cares? Let me know if I can be of any further help?