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Bass in my room isn't good? Help

Hi,
I just measured the bass in my room by using the Radio Shack'sound Level Meter (analog)and Stereophile Test 1 (track 20 to 31). All I got for the bass requencies aren't looking smooth, and here is the result
1Kz = 78.5db
200Hz= 78
160Hz= 71.5
125Hz= 78.5
100Hz= 76
80Hz = 76
63Hz = 71
50Hz = 71
40Hz = 79
31.5Hz= 75
By looking at the result, I can see the problem happens at 160,63, and 50Hz. However, when I bought the Buster bass trap, they told me that thier bass trap can control down to 40Hz. My JMlab mini monitor can goes down to 57Hz, so I have to use a JMlab sub which can goes down to 30Hz, and my Classe ssp25 has the cross over requency of 80Hz. Does anybody have any solutions for this problem? I have only 2 Echo bass trap (6'tall), do I need more?
Thank you very much
DT
Ps: I set the meter C weighting, Slow, Range 80. Vollum on my pre-amp was -20db, and the meter was on my seat as same height of my ear when I sit.
worldcup86
sean
6,231 posts
 
EXCELLENT suggestions !!! I too think that the crossover needs fine tuning as there is not enough "blend" taking place between the two woofers.

I would also like to add that the drop at 160 hz could be due to floor bounce from the monitor. I am not familiar with these speakers or their size, so i don't know how high up on stands they are mounted. Adding a "speaker beard" below them might help to cure this, as it adds baffle area below the drivers. One would have to play with the length of the "beard" to fine tune the response accordingly.

Other than that, i would take the bass trap out of the room and then measure the response. Then try several different placements for the trap and compare readings. I would start off by walking around the room and see where you hear the muddiest / most bloated response and place the bass trap there, as that is where the strongest node is occuring. Sucking up the excess energy at that spot will PROBABLY do wonders in terms of "bass detail" in the rest of the room.

Overall, it appears that your problems are not nearly as severe as others might be dealing with and mostly correctable with some fine tuning. Good luck and keep us posted.
worldcup86 OP
68 posts
 
Hi,
Thanks for your responds. Here are more of information.
My stereo system is on second floor and don't have any spikes yet. Room size L=14.8'X W=12'X H=8'. The Jmlab monitor Electra 905 goes down 57Hz with -/+3db. The Classe SSP25 has only one crossover frequency 80db, and I set the sub at 85db. The vollum on the sub is about 1/4 of the max.
I set the speakers 5'from the wall behind it, and 3'from the side wall for the last measurement. I changed the speakers 3' from the wall behind it, 2.5' from the side wall this morning.
1k=79; 200=76; 160=74; 125=78.5; 100=75; 80=78.5; 63=69.5
50=67.5; 40=78; 31.5=75
Look like everything are almost the same except for 160Hz improving a bit and 63, and 50Hz get worst.
One more question, if I measure from 30Hz to 20Khz, what should I expect the grap look like? How many db difference between the peak to valley is acceptable?
Thank you very much
DT
sean
6,231 posts
 
Just for kicks, turn the crossover on the sub as high in frequency as it goes and then check your readings again. If that doesn't do it, it's time to "bust out with a beard".

Quite honestly, your response is NOT bad. You are looking at a baseline of 75 db's +/- 4 db's and that is with NO work on your room. I have seen systems that were FAR worse than this with TONS of work put into them.

Since frequency response / tonal balance is but a small part of the picture, don't forget to deal with such things as soundstage, imaging, etc... Once you get the best in-room response that you can ALONG with good imaging and soundstage, I would THEN work on "tweaking" the small peaks and dips that you have. Sean
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