Axiom Home Page Forums General Discussion Home Theater Subwoofer calibration issues

Gentlemen,

I posted this over at Outlaw Audio and I thought I would solicit your advice as well.

I've owned the Outlaw Audio 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 (sirquack)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

Bryan, what you've described is certainly far from normal. Although rooms vary and can result in somewhat different settings for bass level, they shouldn't be as far off the typical settings as yours are. My EP500 settings are probably fairly typical, with the sub level control around 7 o'clock and the receiver sub trim at -2.

The first oddity is that the original 990 calibration set the sub about 20dB too hot. Typically, the auto-calibration systems don't vary(as reported in S&V, etc. tests)by more than a dB or two from a manual calibration with a meter, and may be the more nearly correct of the two. Pretty clearly that was a 990 rather than EP500 problem.

Then, not being able to calibrate to 75dB even with both the receiver and sub level controls set at minimum would indicate either that the 990 sub output was far too high even when cut to the minimum, or the EP500 gain was far too high(either input)even with the input level cut by both the 990 and the EP500.

Of course, the idea isn't necessarily to calibrate at 75dB(or any other fixed number)but rather to have the speakers and sub at the same level, whatever the number is. Since you can't reduce the sub 5dB more, the idea would be to increase the speakers by 5dB with the sub setting staying the same(in effect calibrating at 80dB)so that they're equal. This doesn't explain why the 990 calibration was so far off or why two minimum sub settings are necessary for this result.

Bryan, I'm glad I could help, however, I think you had an imposter posing as me. Unless I was really drunk and don't remember, I've never helped anybody in the way you describe.

Do you live in Iowa?

I had similar problems with EP600 and EP500's. I've never been able to figure out if it is the subs design, or the output level of the AVR I was using. I ended up calibrating at a higher level than 75dB, try 78 or even 80. As long as the speakers are all the same, that is the key.

I did send my EP600 amp in for a replacement, and now I am able to have my Denon AVR on 0dB, the EP600 is around 6-7o'clock, and my EP350's are about 1 o'clock.

I'm still curious as to who is using my name.

Bryan, wasn't it Jakewash (Jay) that stopped by. I can't remember the thread that Jay had mentioned stopping by. Maybe Jay can validate this

Oops - I meant Jakewash (Jay) - not sirquack. Not sure why I did this - must have just read a thread where sirquack posted and his name was stuck in my mind.

To clarify, it was Jakewash who helped me - and it was/is greatly appreciated.

Thanks for mentioning this to me.

Bryan

Yes, it was me and my nephew that dropped by and we used REW on his sytem and tried the sub in a few different positions to see if we could adjust the level a little through positioning as well. We were able to find a position that evened out the bass a touch more.

The Outlaw preamp appeard to be working correctly, as we were able to drop the sub output by dropping the gain in the receiver, the sub output is almost where it should be, but EVERYTHING is at the absolute minimum, I suspect the EP500 amp is not working correctly and is stuck on near max output, I don't remember but I think turning the gain down on the sub's amp did nothing.