Axiom Home Page Forums General Discussion Home Theater Right Speaker "calibrated", quiet in crossover

My Issue: In the crossover test each speaker was consistent with a spl reading of around 65db except the right which was about 56db in the higher frequency (back up to 65db for when it crossed over to the sub).


FYI, prior to the cross over test, I calibrated speakers in 5.1 using "Sound & Vision calibration dvd" using radio shack spl (digital). All receiver adjustments are within 2db.
Verified Phase

I did this test last night (girlfriend wanted to watch Survivor) and was not able to troubleshoot.

Any advise?
Is this normal?

I am going to swap the front speakers (m22's) tonight and see what happens, if the offending m22 (now left speaker after switch) behaves the same way any suggestions for next steps.

Thanks in advance

Tom,

If your speaker swap didn't fix it (it probably didn't) I can take a pretty good guess what is causing it.

You are most likely gettting destructive interference between the sub and the right speaker.

Unless your room is perfectly symetrical, your listening position is exactly in the middle and the main speakers are the same distance from the front and side walls AND the sub is in the center this can/will happen in at least some frequencies.

A way to start understanding how bass interacts with the room and multiple speakers is to take the meter and play some tones while slowly moving/walking around. These dips and peaks you'll see are called "nulls" and "peaks" are areas where the sub freq have destructive and contructive interference with themselves.

If you have two subs, you can place one on each side symetrically and you would no longer see one speaker having a drop in the xover area. Also try moving you listening position or sub, left/right/forward/back to find an area that is at the midpoint of both interactions.

Hope this helps!

If you sub has a phase dial or switch, I'd start by adjusting that.

Thanks for the responses, ptaaty & pmbuko.

I switched the speakers and per ptaaty’s expectations, it did not make a difference.

I also switched the phase on the sub to 180 to rule out the sub being out of phase in general. The switch to 180 reduced the “db’s delivered” and did not help the right side.

So then I walked around with the spl meter to check out the “destructive” interference with the sub and right speaker, the only place where there was only little destructive interference was right in front of the speaker (within 2-3 feet).

Unfortunately I do not have options to move around my sub or speakers, so I will live with the “destruction”.

Does anyone have any idea how much I am “missing” in the way of fidelity? Since I am only having the problem with one speaker, are there any adjustments I should make to compensate? Like increase the db’s on the right speaker?