Room problems

[kyle]

Hey everyone. I just received my 340's today. I have a problem although its not the speakers. My room setup is causing a sever lack in midbass from the speakers and am wondering if anyone has any suggestions for room treatments that may help my situation. My room is 12x18x8, but I'm only 2/3rds of the way back (10 feet away from the speakers). I have my bed and furniture behind me, so I can't really do a whole lot about the location. Strangely, if I stand up from the chair I hear the bass a little more.

anyway my setup kind of looks like


-------------------
[L] [TV] [R] |
|
|
[SUB]|
[Chair] |
---------- |
Bed | |
---------- |
-------------------

EDIT: I can't get it to work the same way I did it when I entered the text, how can I fix that?

Thanks for any advice!

Kyle

[curtis]

what are you comparing the lack of midbass to?

[kyle]

My DB meter. At 120hz, it was down about -6db and then slowly rose from there. I didnt measure past 1000hz. Plus it just sounds a bit too hollow compared to when you stand in other parts of the room, the music comes alive (although it won't image so its pointless).

[davef]

Hi Kyle,

Room treatments to try to solve a problem at a specific frequency can be problematic.

Best results might be obtained by rearranging locations.

Can you take some pictures of the room and forward them to me? Or even link to them from this thread?

Also, are you using the speakers with a subwoofer? If you are, the speakers and sub might be out of phase thus causing cancellation, try flipping the phase switch on the subwoofer.

Thanks in advance.

[kyle]

Hi Dave. The problem is not caused by the subwoofer. I've been reading http://www.ethanwiner.com/acoustics.html and it seems to be a great resource. If the problems can't be solved by minor rearranging I will try adding bass traps and if that helps great, if not its not that big of a deal. I didn't really do much of a formal test but maybe sometime tomorrow I will and then graph it.

I'm in the basement with a cement floor (carpeted). It is 3:30am and I have no idea where my camera is, so I won't have any pictures tonight but I'll post them up ASAP.

Here were the results from my really quick test. Definitely take this with a grain of salt as the test tones came off of my MP3 as my Cd burner is broken and I can't burn a test tone CD.


(0 = 70db)
80hz -2db
100hz +1db
120hz -10db (or more)
150hz -6db
200hz -2db
250hz +5db (odd)
300hz -1db
350hz -1db
400hz -4db
500hz -5db
750hz +5db
1000hz -10db

Tomorrow if I have time I'll create a much more detailed and accurate graph as well as post pics of the room.


Aside from the erratic FR caused by my room the speakers sound great. They are very clear and detailed.

Also, the rest of my equipment is a Panasonic XR-55 and a Bic H100 sub. I'm sure it would probably help a lot to upgrade both of those but I'm in no hurry. I'll be transferring to a different school (out of state, so I won't be living at home anymore...I don't think I want to attempt this in a dorm room!) in the fall so i don't want to invest too much right now.

Thanks for your help,

Kyle

[kyle]

Ok I made some frequency response graphs. The numbers are the opposite of the value I had to turn the stereo up to in order for it to reach 70db. Also, i did have my subwoofer turned up a bit to high but I don't feel that is important. I tried the test with the subwoofer off also, and all the values between 80-150hz were only +/- 3 decibels so the subwoofer is not causing anything too erratic.

http://members.cox.net/kylescha/image001.gif
http://members.cox.net/kylescha/image002.gif

Not pretty.

Here are pics of my room:

http://members.cox.net/kylescha/room.jpg
http://members.cox.net/kylescha/room2.jpg

[BradJudy]

What's your crossover set to? Does the BIC have a phase adjustment switch/knob? If so, try adjusting that too. You can do a lot with room position and phase for sub response/integration.

[kyle]

It isnt the sub. I tried it with and without the sub on and got the same results. My problem isnt the sub its the 100-150hz range which is 13-18dbs lower than everything else and at 110hz it is almost cancelled out completely.

Crossover is at 80hz

The sub is at an interesting spot, but near the speakers it is almost inaudible at the listening position. I think I'm going go to ahead and treat the room. I've been looking at before and afters and seems to make a huge difference at times.

Once I get the speakers right I'll worry about the sub 80hz frequencies.

[Mike^S]

How close are the speakers to the wall behind them? Try pulling them out into the room more.

[kyle]

About 16 inches.

[davef]

Hi Kyle,

Are you using our stands with the speakers? If not, what is the vertical height from the bottom of the speaker to the floor?

I suspect you are smack dab in the middle of an axial room mode.

[kyle]

No I'm not using the stands that came with the 340's, but the ones I have are 24 inches, the same height. What is an axial room mode?

[audibleconnoisseur]

No I'm not using the stands that came with the 340's, but the ones I have are 24 inches, the same height. What is an axial room mode?


Oh yea, pull up a chair boys, schools about to be in session!