Folks,

My living room is killing me. It's sucking up all the midbass energy! What can I do to minimize this?
Areas from 60hz to 120hz are hit and miss with HUGE dips in the frequency response. My Rocket RS550 tower speakers (dual 6.5's) sound like 4" speakers. My subwoofers rumble but don't have midbass slam. And it's all because of my room!

Here is an experiment where I moved my subwoofer to my listening position and then tested with an SPL meter from various locations around my room. Notice how bad the midbass valleys are?
The chart shows the following frequencies; 15hz/20/30/40/50/60/70/80/90/100/200hz
http://i14.photobucket.com/albums/a340/czeddie/audio-video/Tempest-X/REW%20of%2012%20cu%20ft%20box%20ported%20vs%20sealed/comparison_.jpg


Here is the room floorplan. It's a two story house. The living room is ~3500 sq. ft. Plus the hallway and kitchen areas, which make it all much larger.
http://i14.photobucket.com/albums/a340/czeddie/audio-video/Tempest-X/REW%20of%2012%20cu%20ft%20box%20ported%20vs%20sealed/spots.jpg


Does anyone have any suggestions on what I can do about this problem? I've tried three different subwoofers and various different types of enclosures.
My RS550 tower speakers sounded great in my last couple of houses. But in this house they are just weak, no matter if placed against the wall or moved out two feet (like they currently are).
Same for the first sub I had in this house. In my last house, it was a midbass monster. In this house, I and all other subs that have followed, are weak in the midbass region. :(

You could use some absorption on your front wall, and back right tri-corner.

That will reduce my midbass valleys? I thought absorption was for treating peaks?

That will reduce my midbass valleys? I thought absorption was for treating peaks?

It could help the midbass areas. I don't know if it would make a dramatic difference to you, but I assume that changing the rooms walls was not an option. Treating areas with absorptions smooths out the overall decay and improves both dips and peaks. I focussed on the dips for the testing. I used my living room which may be similar to yours. I used postion 3. A decibal or two difference is usually a good indication to me that it is helping, and that I would hear a difference. These traps are desinnged for treating lower, but I saw some midbass improvement. You would find your own results by placing such things as piles of blankets etc to check if you want. This is just my observations, and perhaps someone else will have something better to contribute.

http://farm4.static.flickr.com/3223/3092917590_753eb813d7_o.jpg

No trap

http://farm4.static.flickr.com/3177/3092898348_dd67389791_o.jpg

Trap in my kitchen back right corner

http://farm4.static.flickr.com/3137/3092899572_a5d95ae1d0_o.jpg

Trap on the front wall

http://farm4.static.flickr.com/3264/3092900680_e62a06ddd0_o.jpg

WOW! Those are some nasty valleys!

Double check the polarity of your Rockets just to be sure.

What does the response of the Rockets look like at the listening position?

Bass traps, as many as you can fit/stand.

When you were moving your sub around:
1. Was only the subwoofer on?
2. Was bass management on and what was the xover set to?
3. If all the speakers were on, was bass management on and were the LCR's set to small or large?

That will reduce my midbass valleys? I thought absorption was for treating peaks?(1) Acoustic treatment absorbs energy and nulls, as well as peaks, are caused by the interaction of reflected energy. (2) In order to be effective at mid-bass, the panels need to be thick and large and placed in the corners where bass (and midbass) can be affected most efficiently.

I've got the same questions as Dennis. If this is the sub-only response, some positions don't look bad at all. For a crossover at 80 Hz, positions 3-6 look quite workable. Parametric EQ could make 'em nearly as smooth as a baby's butt. :)

Regards,
Terry

I've got the same questions as Dennis. If this is the sub-only response, some positions don't look bad at all. For a crossover at 80 Hz, positions 3-6 look quite workable. Parametric EQ could make 'em nearly as smooth as a baby's butt. :)

Regards,
Terry

I had dips worse than that in my original theater, I had close to 60dB nulls. When you stood in the middle of the theater, if was as if I had noise cancellation headphones on.

I ended up doing three things to solve the problem.
1. On one of my Def tech mains ,I reversed the polarity of one of the subs to fire out of phase of the other sub. This move the location of the peaks / nulls from the center of the room out to the walls where no one was sitting. It also really reduced the intensity of the peaks / nulls.

2. Added full lengths super-chunk bass traps in all 4 corners. Cheap to build if you use Roxul and burlap. Of course, you have asthetic issues with it being in the living room, but hide the traps where you can. Tri-corners would be best.

3. Added a Behringer Feedback destroyer (they are around $99) into my SVS input, and I used a hometheater shack program to tune it (can't remember the name) and crossed the mains over at 80. When I was done, the bass in the primary location was, as Terry put it above, smooth as a babies butt up to 80hz. I think it was within 2db all the way. As I moved around the room, i still had some peaks / nulls, but no more than 10 dB. it was a drastic improvement.