muddy pb12-plus2

[DerekCV]

I just got my pb12-plus/2 and I placed it in the corner of where I have my HT set up in my basement. I have a sort of odd shaped basement because of where the stairs are and where the half bath is located. The problem is that my bass feels muddy to me and not nearly as solid as I expected. I did calibrate it, I might try to place the sub in front of my couch and then do the crawl on the floor thing…. I just know that, do to my setup, my placement of the sub is limited, I just assumed that in the corner near the right main would be the best bet. I do have a PEQ on the sub that I would like to play with, I’m just not sure where to begin on that. what is the best material to play when trying to set up a sub, any sign waves needed? How can I easily adjust my PEQ? Any advice? please walk this newbie through it!!

[mojomike]

Go to Radioshack and invest in SPL meter, approx. $45.00. Download test tones from the download section of http://realmofexcursion.com/ and burn them to CD. Test the frequency response for your sub as you have it setup in your room and note large peaks and nulls in the response. It is those peaks which will sound muddy and the nulls which will kill the impact. Experiment with sub positioning, crawl test, or adjust the seating position to see if you can get a smoother response.

The thing about the corner placement is that it will get you the most bass, but not necessarily the most accurate bass. Try moving the sub in small increments along one wall or the other, out of the corner.

Once you have decided on the best position, then adjust the PEQ as described in the manual to reduce the one largest peak which still might be present. After moving and adjusting, recalibrate the level.

There are also acoustic room treatments that can sometimes help.

Another thing whcih can make the bass seem less solid is a phase problem between the sub and your main speakers. Use a test tone that is close to the frequency of your crossover and adjust the phase control on the sub to what gives you the loudest tone.

If you have a problematic room, it can take a bit of work to get the best out of the sub, but that SVS should be very capable of excellent bass reproduction with tremendous impact.

[DerekCV]

That is exactly what i did last night. You can see my graph here: http://www.hometheatershack.com/foru...-response.html
I might try to bring the sub over to the left side of my room which is more in the middle of the basement wall and see it that helps. I'm trying to balance the function/cosmetic issues.

[mojomike]

That valley at 45 hz is not all that severe. The broad peak from about 22 to about 36 hz is most likely making things sound muddy. You may be able to set the PEQ to reduce that and flatten the curve overall.

Do you have the crossover set at the sub or at the receiver/pre-amp? If it's at the receiver/pre-amp, then turn the crossover setting on the sub all the up (or off). The sharp drop off from about 63 hz and higher may be causing the bass to sound less solid.

Once again, make sure the sub and your mains are phase aligned or you will be getting cancellation of the bass where they overlap.

[Sonnie]

I own a pair of those subs and when you get them smoothed out, you will be happy.

[DerekCV]

I tried to paly with the PEQ by ear but couldn't really tell anything, can you suggest some sort of starting point? I have the recieve crossover set at 80Hz and the one on the sub is off. I've played with the phase knob a few times, i having figured our which way is the best yet though.

Thanks for the input.

[mojomike]

If you are trying to to reduce the peak between approx 22 and 36, set the FREQ nob to about 30. Try the Q at about 3/4 and then adust the level to see waht sounds or measures the best.

[DerekCV]

I took your suggestion and i updated my graph in the other tread. Let me know what you think... Thanks

[mojomike]

Well, you have brought the peak down a bit. I'd try it again after raising the FREQ control about 5 hz. Any improvement in the sound yet?