Gentlemen,

I've owned the 990/7125 combination for awhile now. They're paired with an Axiom 5.1 home theater speaker system (M60 fronts, VP150 center, QS8 surrounds and the EP500 500w powered subwoofer). I originally calibrated the speakers (including the subwoofer) using the 990 supplied microphone. I did not calibrate with an SPL meter as I didn't have one nor could I find one to purchase. I've run with this calibration for some time and always thought the subwoofer ran hot - much to the detriment of my wife who cringed everytime the sub (literally) shook the room/house. Not having owned a home theater system prior to this purchase, I assumed the subwoofer was (somewhatt) properly calibrated and everything was normal.

Well, I solicited the help of a fellow Axiom owner and he came by with his RadioShack SPL meter. Testing my original setup revealed a couple of results - my center channel was 8dB too high and was drowning out the front soundstage and the surrounds, and my subwoofer was running at enormous SPL levels. After calibrating the other speakers at 75dB reference level, we noticed that the subwoofer was running almost 95-100 dB and was completely overpowering everything.

Now the problem - we attempted to calibrate the subwoofer level to 75dB and we weren't able to do it. We had to turn the EP500's volume level to the absolute minimum setting and we had to set the 990's subwoofer trim to -15dB. Even at these settings the subwoofer is running approx. 5dB higher (~80dB) than the other speakers. We cannot reduce the level anymore.

I'm connected via the balanced XLR connector. We tried using the RCA connector and (oddly) this produced an even hotter signal.

Any ideas on how to reduce the subwoofer level? Is this normal? I wouldn't expect that I would have to trim the 990 setting to -15dB and set the sub's amplifier gain to its absolute minimum. Even this doesn't get it down to reference level. Could their be something wrong with the 990's subwoofer output? Something wrong with the EP500's amplifier? Has anyone else experienced something similar?

Although my system sounds much better now (after lowering the sub level significantly and lowering the center channel level), I'm concerned that I cannot get the sub down to 75dB reference level. Also, I'm concerned that running at -15dB with no sub amplifier gain will cause the signal to be so low at lower volume levels that the sub will simply shut off.

Any thoughts/advice?

Thanks in advance.

Bryan

What crossover setting do you have your speakers set at?
The M60's are a full range speaker so I would guess you have them set at either 40Hz or 60Hz.
One thing you might try, because the M60's are a full range speaker, is to balance the sub to the center channel and see what it sounds like.
I had the same problem when I was running Polk RTi10's as my front speakers.
The bass that the RTi10's produced, combined with the sub, made the SPL meter go nuts.

My crossover settings are at 60hz for the fronts and 80hz for the center/surrounds.

I calibrated the speakers to balance with the left front speaker. This resulted in a -2 to -5db trim for the center and minor (+/- 1db) trim for the right front and surrounds to balance them with the left front.

The sub is the issue. According to the SPL meter, the best that can be accomplished is getting the sub to run at +5db (compared to the refence level of the left front) when both the receiver and sub amplifier are completely minimized (i.e. -15db trim on the 990 and the absolute minimum gain setting on the sub amp).

I suspect (although not confirmed) that the 990 is outputting a hot subwoofer signal. Has anyone experienced this with their 990?

To compensate, I might calibrate the fronts/center/surrounds to a higher trim setting to give me more headroom to minimize the sub's level compared to the other speakers.

Is there any concern with setting the sub's amplifier gain to the absolute minimum? Does this run the risk of "shutting it off" when I run at lower volume levels?

Thanks in advance!

Bryan

What is the gain setting on your sub set at? You may have to dial it back to match your other speakers.

That's the problem - the gain setting on the sub is at it's ABSOLUTE minimum - can't go any lower. And the 990 sub channel is at -15 dB. I simply have no more room to go down. My only option seems to be to increase the levels of the other speakers.

But this seems quite odd to me. I shouldn't have to set the sub's gain to it's minimum and the 990's sub level to it's minimum (-15 dB). Or am I wrong?

Did you try the high level inputs in your sub?
You might want to try that as an experiment to rule out a problem with your sub out connection out of the 990. You will need to temporarily change your settings to no subwoofer on the 990. You could leave your main speakers disconnected while you try this experiment. Also, gonk has a test disc that you can download and burn that can help you with this.

You might also be surprised how much difference placement makes. My Outlaw LFM1-EX was actually exhibiting the opposite behavior (initially) - it felt weak. I moved it 6 inches closer to a side wall and everything in the room started shaking and I have had to turn down the gain quite a bit.

I agree with garcianc2003. I would try a different placement if possible. What is the sub's placement in relation to the system, your seating, and the room's walls?

I seem to remember that AVS forums has a forum, or at least lots of postings re the SPL meters.

THEY ARE NOT LINEAR !!! I think the adjs might be up to 10 db depending on frequency.

Try a google search to find the calibration adjustment settings for SPL meters - correction tables (or other equiv term.)

Here are a couple places to start, there are tons of threads, if you find a concise and easy one to use, pls post it:

http://archive2.avsforum.com/avs-vb/archive/index.php/t-636795.html

http://www.avsforum.com/avs-vb/showthread.php?t=505236

Have fun-but in the end, trust your ears. Remember, everyone's hearing is different-ask an audiologist.