Room Treatments added, with negative effects..


Hi Folks:
I purchased a set of foam acoustic room treatments and set them up in my listening room. It now seems that the soundstage has collapsed somewhat, and the sound is less ambient, filling the room less. I'm wondering have I overdone the treatments, or placed them incorrectly or maybe I really just didn't need them to begin with. Can anyone offer any advice or thoughts?

I purchased 12 24inch by 24inch panels of ProFoam treatments from Audioadvisor.com which were pretty reasonable at about $150 for the set. I set up four panels behind the speaker position going from left to right at about 20 inches above the floor, and seven panels behind the listening position (three from left to right about 10 inches above the floor and the other four above those from left to right). Side positioning wasn't really possible because I have glass doors on one side and a corridor on the other.

My system is Audio Physic Virgo, Supratek Syrah pre, Blue Circle BC2 monos, Teres 135/OL Silver/Shelter 501mk2 vinyl rig.

I'm keen to hear any comments or advice on how I can improve my use of the room treatments, or whether I just need to scrap them. Thanks!
Outlier.
128x128outlier
Well, folks I think I solved the complex room treatment challenges...... by removing the *$(%&#@ treatments altogether. From the effects I was getting, it's hard for me to see how these absorbtion treatments can have any benefit. I'd still be open to experimenting with tube traps and defraction type treatments (although those two seem like pricey experiments compared to the cheap foam), and I'm still of the opinion that room set (especially speaker placement) up can have a huge impact on sound quality. That said, I think I'm done with this foam stuff. Thanks to all for the suggestions though. Cheers,
Outlier.
No, no, how could I be a contrarian? I never yes, I never say no, quite the contrary.
Outlier,

I'm not surprised to read that you have had a miserable time w/ these foam acoustical treatments! When I was in the market for acoustical treatments, the $150 package was mighty tempting in lieu of buying ASC tube traps. In hindsight I'm happy that I didn't buy these foam treatments & bought the ASC tube traps instead. These traps are awesome & have done wonders for my room & as you rightly said, they are phenomenonally expensive! I had mid-bass & upper-bass boom that needed treatment.

1st, you never told us what was wrong w/ your room! What are you trying to correct for or are you just jumping on the acoustical treatment bandwagon? Different issues require materials & some of the room issues just cannot be solved with passive materials (& require a TacT or Rives-like unit). It would be nice if you could (anyways) let us all know what you were trying to achieve.

Foam panels are acoustic velocity absorbers ie. they absorb higher freq. & high freq, usually above 400Hz. It is no surpise here that they "deadened" the sound! These panels absorbed the high freq & left you with the mid-bass & lower thereby giving you a dead-like sound. BTW, for acoustic velocity absorbers to work, they must be placed atleast 4" from the wall where there still an acoustic velocity of the sound wave! Once the acoustic wave hits the wall, the velocity goes to zero & the foam panels do not act on a zero velocity wave. In contrast, ASC tube traps are acoustic pressure absorbs (bass is acoustic pressure). One hemisphere is reflective & is used to reflect 400Hz & higher. The cool thing about ASC tube traps is that when one uses it to reflect 400Hz & higher that reflective surface is away from the wall by the diameter of the cylinder. This occurs naturally as the reflective side faces the room (rather facing the wall surface)!! So, one doesn't need to make stands or any such thing to get the reflective side to work correctly.

My suggestion to you (as some others have also pointed out earlier) is that you keep some panels to treat the 1st reflection off the side wall next to the speakers. Here, make a 4-ft tall frame from 2X4 from Home Depot. Make a stand for this 4-ft tall frame so that you can free stand it anywhere in the room. Attach 2 2'X 2' panels (to create a 4' tall X 2' wide) using Velro to this frame. Place these panels in front & to the wall side of the speaker so that it can "treat" the 1st side wall reflection. You will have to play with exact position. Now, I have assumed that your tweeter is not higher than 4' off the floor. If your tweeter is higher then you will have to make taller panels or simply raise the 4' tall panels off the floor.

Like the others, I do not recommend using more panels behind the rack/back wall or behind your listening seat - it'll deaden your sound as you have already found out. Use them only if your room is very lively.

For bass traps, you can roll your own. Try Jon Risch's receipe. In yahoo! search for the name "jon risch" it should bring up his website. There is tons of very, very good info there. I have found his info to be accurate (he is trained as an acoustics engineer) & my friends have used his panels receipe with great success.

IMHO. FWIW. YMMV.
The Tube Traps are very helpful in taming room acoustic problems. I know; I've had 30 of them since 1988, when Stereophile first reviewed them.
HOWEVER, you can NOT simply place them and forget them. You must tune them carefully, by moving them along the side wall (if that's where you are using them). Try moving them 1/8 inch at a time, with the reflective side facing into the side wall, and them rotating the seam TOWARDS the speaker.
For a more detailed setup of them, go to Peter Moncrieff's classic article on Tube Traps. Here's the website: http://home.wanadoo.nl/thingman/trapart4_u.htm

This is an EXCELLENT article on how to optimize the Tube Traps. I used it to great effect when I had WATTS (the first 3 generations of them).
You can also buy some RealTraps, which I recently purchased. They are as effective (in the bass especially) as Tube Traps. Their website is: www.realtraps.com. They are MUCH less expensive than tube traps and work quite well at ceiling/floor junctures, as well as placed in corners. I was quite surprised at how much they cleared up the bass range; I put the Tube Traps in the same positions, and they're about equal in their effectiveness. HOWEVER, the tube traps have the advantage of absorbing AND reflecting, while the RealTraps, which work as well, don't allow for tweaking. The good thing about the RealTraps is that they come with a 30-day money back guarantee, so if they don't work well (unlikely), you can request a refund. I can tell you that a few people at TAS are using them, and I'm loaning a couple of mine to the Sea Cliff gang (although, they could clearly ask for their own!).
Finally, the Tube Traps, once you place them along a wall, MUST be rotated in tiny, tiny, TINY increments. Forge about 1/2 inch rotation: I'm talking about a 1/100" rotation. Trust me, it changes the sound in quite tiny increments. I think, as HP said in a past issue, that people don't use them right at all. They turn them 2" at a time: WAY too much. You'll have to experiment with them. It's the difference between good and excellent when you rotate the columns.