Sound pros - need advice on absorber/diffusor wall panel for first reflection?

Question

I have a two-channel listening room with speakers near the side walls. I need something to deal with first reflections. I am currently using egg-carton shaped foam, but this seems to create a deadness at the edges of the soundstage. Do I need a diffusor, or something that will absorb and diffuse? What products are recommended for this type of application?

Answer 1

First, if you're using free-standing loudspeakers, and if you haven't already, you should angle the loudspeakers toward the listening position; this should form an angle that is roughly 30° as measured from an imaginary centerline bisecting the listening position between each of the stereo loudspeakers. The loudspeakers should be positioned at least 30-to-36 inches from the rear and side walls (if you have the space.)

If the floor around the loudspeakers is bare use heavy area rugs or carpeting to help diminish the more deleterious first reflection that typically occurs with bare floors beneath loudspeakers.

For near-field walls the less expensive solution is to use a couple of heavily upholstered chairs and/or indoor plants. You will need to experiment with positioning these items along the side walls in an attempt to minimize near-field reflected energy. The ‘professional’ alternative entails using diffusive/absorptive sound control products for near-field surface treatment such as RPG's CineMusic Products, specifically their Abffusor and/or Absorbor panels, or their Binary Amplitude Diffsorbor (BAD™) panels. Keep in mind that it is not necessary to cover the entire surface of the wall with sound control products to achieve effective room treatment unless you prefer to do so for aesthetic reasons.
 

Answer 2

You are probably getting too much absorption. Try some cloth hangings instead, something you can vary the wall coverage with so you can get the right amount of deadening. Foam can be very absorbent and deadening, acoustic wall panels may work better. You don't need to but expensive sound-absorbing panels; experiment with different materials and amount of coverage.

For side walls, you don't want a diffuser, you really want to subdue the reflection. Diffusers are beneficial on rear walls, especially if they have windows or are wood-paneled.

Answer 3

Are your speakers floor standing or book shelf size? If they are small are they on stands? If not they should be on stands so that when you are seated the tweeter should be at ear level.Carpet on the entire floor is recommended. If not use plenty of scatter rugs around the speakers .Make sure you are on the"stereo axis"by angling the speakers inwards .You should be equidistant to both loudspeakers.Your speakers should be well away from the wall behind them if that is possible.To deal with your first side reflection you can use open full book cases or record shelves, heavy fabric hangings or draperies made of heavy material.The sound -deadening panel should be placed 2 to 3 feet from the leading edge of the speaker cabinet.It only has to be about 4x4 feet with 2 feet above and below the mid-range and high frequency units of your speaker.Make sure both speakers are treated exactly the same.Hope this helps.

Answer 4

You ideally want to absorb the first reflection. Typically diffusers in the rear of the room and absorbers along the side and front (depending on the speakers)

try www.pmiltd.com/cinepanel.html

have fun

Answer 5

Whoa. This can be a very complicated issue. Room acoustics is a very involved subject. Carpet & wall coverings are an issue too. You can consider "quiet-rock" sheet rock, or building a false, de-coupled wall, but it would be easier and cheaper to try adding different furniture & carpets to get an moderated effect.

Answer 6

Duct board that is commonly used for air vents can be very beneficial and you can cover it with a porous cloth for looks it is cost effective and easy to work with. Put the soft side out.