There seems to be a bass vacuum at the mix position, i.e., where I sit. My Event PS6s are on Auralex Mopads on an Omnirax desk and everything's arranged as an equilateral triangle. If I move back the bass increases. In fact, it seems that EVERYWHERE in the room has 'better' bass than the position I'm sitting in!

The room is 8' deep by 11' long and a pair of doors open behind me. I tried doors open/closed with not much difference.

I believe I have decent corner bass trapping -- I have the top item on this page: http://www.foambymail.com/CornerSolutions.html -- with large, dense foam corner traps for the ceiling/wall and floor/wall, with 3 traps in each of the front corners and just one each on the back corners. There's an HVAC duct running the depth of the room to my right, above a window with venetian blinds. The ceiling bass trap on that wall starts under the duct, rather than next to it.

I've experimented with more traps in the rear corners, no traps, all sorts of combinations.

This has been driving me crazy, since it seems nothing I've tried, short of rearranging the room, will help. Are my monitors too much for such a small room? I don't remember this problem in other rooms but I did much more headphone mixing.

Thanks!

Unfortunately those foam products are not that good. They are a rip off of the much nicer Auralex LENRD. You shoudl seek to replace the Foam By Mail stuff with fabric wrapped 4" thick semi-rigid glass fiber insulation panels. A room as small as your will need from 9-12 of these panels to correct the low end. Once you get some proper treatment in there this low end location based problem will be less of an issue.

I'd like to venture a guess that you're sitting in the center of the room's lenght dimension. If so, moving your whole setup forward will help you out. If you can provide a drawing of your room with dimensions I could help you figure out where best to put everything.

hi, thanks... here's a pic of my room's layout -

http://markwinkler.com/residential/floorplans/brookdale2.html

it's the den on the righthand side. my desk is up against the wall on the right, i.e., the long wall opposite the two doors. there's no room to move it any further in that direction. yes, my position is about where the word 'Den' appears.
i know the FBM traps are a rip off of the LENRDs but the specs are nearly the same. How can they not work as well, then?
http://www.truesoundcontrol.com/products/LENRD8.html

> There seems to be a bass vacuum at the mix position <

This is very common, and the main cause is reflections from the wall behind you. As David explained, the center of a room front to back always has a deep bass null. But you can have deep nulls pretty much anywhere in a room.

The null frequency is determined in large part by the distance between you and the wall behind you. For a given frequency there are nulls at a distance of 1/4 wavelength, and also 3/4, 5/4 and so forth. Likewise, there are peaks at 2/4 and 4/4 and 6/4 wavelengths away.

> I believe I have decent corner bass trapping <

Nope, and again David had the right answer. The reason it appears that the Foam by Mail stuff is as good as Auralex is because Foam by Mail STOLE the data from Auralex. What FBM sells is in fact cheap packing foam. D'oh!

I can say this with confidence because I paid to measure both brands in an acoustics lab. If you want to see how big the disparity really is, you'll find that data on my company's web site, linked under my name below.

So the answer is to get four or more bass traps that are truly effective rather than small foam corners. Four good traps is a bare minimum, and even 12 won't be too many. The more traps you add, the flatter and tighter the low end will be. It's really that simple.

--Ethan

hi, thanks again.
i mix mainly with the doors open so it can't be the wall behind me since it's 24 feet back.

wow, they stole that data? it's not exactly the same, but i guess they manipulated it? i'll look at your data, though man... isn't there a law against false advertising?!

wow, i feel totally ripped off... when did you do this study? i bought my FBM crap about 2.5 years ago

I contacted FBM and brought this to their attention, including your results, and asked why they advertise inaccurate/false specifications. Here's the response:

Hello,
They are estimates of the foam, we are able to offer the prices we have because we accept ranges in the density from our manufacturer. Because of
how old your order is I cannot offer a refund.

Sincerely,
Carlo
Foam Factory

OK - so they admit they are a rip off.

Well - your problem is two fold - one is your lack of bass trapping - the other is your set up -
with your desk placed where it is - you must have your ears almost dead center of the room, which places you right in the center of a number of nulls in your space -

You would be much better off if you turned your room so that your speakers were shooting down the room the long way - and your ears were sitting around 38% of the rooms length (you can fine tune from there to get the optimum signal).

Then add more bass trapping.

Rod

thanks!

regarding the desk location -- the doors are almost always open behind me (99% of the time), and the actual wall space that remains is about 2-3 feet on the left, with the left door diagonally across that corner, and 2 feet on the right, with that door diagonally across that corner. so, the speakers are almost always firing down the length of 'room' which, when the doors are open, includes the living room and dining room. makes no difference? or does it?

Cebec, that is too funny! Thanks!

They have a page where you can see their "sound-proofing foam" products. Wow, poor unsuspecting consumers...

Yeah, that was one of the first comments that made a bunch of people leary.

Sorry for your situation Cebec. Sounds to me like you're getting all the right answers. Rod, Ethan, and David have all nailed it pretty well. Deal with the seating position and get some decent bass control in the room.

Bryan

cebec,

> wow, they stole that data? it's not exactly the same, but i guess they manipulated it? <

Yes, if you look closely you'll see the numbers for their corner foam differ by very little from Auralex LENRDs:

Auralex: 1.24 1.28 1.45 1.39 1.27 1.37
FBM: 1.25 1.26 1.47 1.42 1.24 1.29

It is unlikely that two different tests in different labs on different days would be so close, even if the exact same materials were tested.

> when did you do this study? <

April 19, 2004 at IBM's acoustics lab.

--Ethan

Hey Rod! Nice to see you here Buddy!

I don't believe that I have ever gotten such a nice gift like this statement by FBM.. I think a thank you card is in order!!!!

Glenn