HORRIBLE room acoustics?

[asauer]

I cannot figure out my room acoustics for the life of me. The bass response in my bedroom is so splotchy and odd.
I live in a 100+ year old house, so it's built alot different than nowadays, so could this have anything to do with room acoustics? The room is rectangular with the exception of one corner having a chimney running up from the 1st floor (no fireplace in my room). ALSO has 10 foot ceilings...this a problem?
I have moved my sub around everywhere and rearranged/taken things out of my bedroom...
It's IMPOSSIBLE to get bass response in the center of my room at all, it's so cancelled out you can't tell there is bass except for the door rattling as well as the floorboards.
The best bass response is with the sub in the corner with the chimney, and there is alot of bass around the sub 5' or so, then completely dead in the center, and HUGE bass gain in the opposite corner where my bed is. The gain is so large I can feel the bass in my chest and see my bedsheets vibrating...all with a 100W amp and single 12" sub.
I have tried ALL different equipment from enclosure, amp, sub, cd player, everything.
Driving me nuts.
Also, I just bought a Dayton DVC 12" (the $38 one) and although it sounds great for rock, it falls very short in the low end for rap and whatnot...4ft^3 tuned to 28Hz...which according to WinISD is the flattest response possible.

[454Casull]

The height in itself doesn't really matter, but what does matter are the ratio of the dimensions of the room. Is the room very much like a cube? Are the width and length of the room multiples of the height?

[Da5id4Vz]

How is the room furnished?

When I moved into my last house I set up the stereo in the living room. Hard wood floors, no drapes and a small couch. I thought I had blown something up when I started listening because I couldn’t find the low end. Then it dawned on me, I had always listened to this stereo in rooms with wall to wall. After recovering from the financial shock of the closing, I put down a thick Persian carpet that covered better than 75% of the floor. Its the best EQ I’ve ever heard.

[Bill Fitzpatrick]

Try this trick.

Put the woofer in your desired listening position. Play some music and wander around the room, making notes of where you are standing when the bass seems satisfactory. Those noted positions are good candidate positions for the woofer.

[asauer]

Oh, sorry i forgot. I have carpet completely covering the floor. It's not a short berber, but not a shag, it's in between, forget what it's called. The walls themselves are plaster, with 2" slats behind the plaster.
Also...Bill I have done what you have just reccommended, and it doesn't help. About the only two good bass spots are where the sub currently is, and the opposite corner. Putting the sub in the opposite corner is just about the same, and any other position is even worse.
Would two subs solve the problem, or introduce more cancellations?
If a put the sub in one spot, bass is good in certain areas and bad in others. If the sub is in another spot, the bass is good where it was lacking in the other position, and lacking where the other was good. Hope I didn't lose you.
So would putting one sub in each "good spot" solve the problem, or introduce even more cancelling waves, hurting and not helping?

[sreten]

A lower tuning frequency (~22Hz) will give an alignment
more suited to room gain.

Corners as a placement or listening position are a nightmare.

Place the subwoofer 1/3 along the shortest wall, and
adopt a reasonable listening position for smooth bass.

The distance of the listening postion from the rear wall will
control the level of the lowest room mode, and its integration
with other frequencies.

2 (or more) subs do give smoother bass but I'd suggest
your maximally flat alignment is the main problem.

sreten.

[Bill Fitzpatrick]

asauer:

If your listening position is in the center of the room you will be sitting in some standing wave nulls regardless of where you place your woofer.

If you post your room dimensions, acceptable range of sitting positions, acceptable range of woofer positions and tell me the width of the wall you look at when listening, I might be able to find something workable for you.

[asauer]

Oh, my listening position isn't in a corner, it's about 2/5 of the way from the back wall when looking at the tv.
I will have to post some room dimensions later, I am too tired tonight.
Thanks for all your help so far.

[brsanko]

have you checked to see if your sub is out of phase with your main speakers?

[batdorf9]

you might want to play with the room response calculator available on the FRD Consortium website.

This will save you the hassle of moving (heavy) stuff around a lot and trying to compare the sound to something you heard 2 hours ago and forgot. I used it for my room, and found the peaks and dips to be spot on. Then I tried a variety of locations in the simulations and found something better.

- Robert