Setting subwoofer level with RDC-7

[wbk]

I'm having trouble getting my subwoofer level up to the level of the other speakers in my system. I have an Integra Research processor and, when I try to balance speaker levels through my processor, the subwoofer (Revel B15) level is way down even if I decrease the levels of the other speakers (Legacies) and increase the level of the subwoofer by as much as 10 db.
Also, during the set up procedure for the Revel when I compare the output of the Revel with the output of the other speakers playing together, the Revel is at least 10 db down, although the Revel set up procedure says that I should control the level of the Revel through the processor so that the levels are equal which is impossible.
There is a level control on the Revel and I can advance it beyond its recommended value so that the level of the Revel comes up to nearly that of the system. However, when this is done, when a DVD plays with Dolby digital, the Revel immediately starts bottoming out.
Any comments or advice would be appreciated.

[Burke Strickland]

When you say you are balancing your speaker levels "through the processor" does that mean you are you using the RDC-7's internal test tones via menu 1. Speaker Setup 1-3. Level Calibration, or are you using a setup disc such as AVIA?

With the RDC-7's internal test tone procedure, which sends a pink noise signal to each speaker in sequence, you should be able to get the levels to match pretty closely without bottoming out the Revel. Each channel can be adjusted across a pretty wide range, so as an experiement, instead of starting with the left front channel as recommended, try setting your sub level at a given SPL reading level with the RDC-7's setting at "0" and then cycle through the rest of the channels and set them to the same SPL reading level, whatever the RDC-7's adjustment numbers may end up being.

OTOH, if you are using AVIA, it is pretty well known to have output levels for the bass which read 5db to 10 db lower on the meter than the other channels. (Because the Radio Shack sound meter is not sensitive to very low frequencies it'll read several dBs lower than what's actually set. ) I found through trial and error that I couldn't stand to listen to the heavy bass that resulted when I tried to "match" the levels of the sub to the other speakers before I found out that the sub signal via AVIA would always read lower than the actual level with normal playback material. This is due to the known anomolies in the Radio Shack SPL meter, which is supposedly "way off" at the lower bass frequencies and for which compensation factors have been published various places.

If the "Revel set up procedure" depends on the AVIA disc subwoofer setup tones, then the same thing is occuring -- when the sub is in balance with the rest of the channels for normal playback, the test tones will show it 5db - 10 db lower than the rest of the channels. Since (using AVIA) the sub is already several db louder than it is reading, if you set it to "match" the reading of the other channels, it is actually way louder than the other speakers.

Since most of us don't bother with the "correction factors" and take the SPL readings pretty much at face value, I've always wondered why the test discs are purposely "compensated" to read lower on the sub channel, since that leads to confusion and skewed settings for many of us, but I guess the reason is to be technically accurate when all factors are considered. Meanwhile, it has pretty well persuaded me to use the internal test tones to set the overall level for my sub rather than a test disc. For whatever reason, they seem to work OK for me. And when I set the levels with the internal test tones and then run AVIA, sure enough the sub reads a lot lower than the other channels.

If there is more that we need to consider in addressing the issues you've encountered with your sub set up, (if I've "missed the boat" in interpreting your description of what is going on when you are setting up your sub), please let us know and we'll go from there.

Burke

[wbk]

Burke, thanks for your thorough reply. Let me address your first question. Yes, I play the pink noise through the RDC-7 to level calibrate all the speakers including the subwoofer using the 80 db setting on the RS meter. The regular speakers are within 0-2 db of reference level which I easily corrected. However the subwoofer level doesn't even raise the meter. I then recalibrated by balancing the regular speakers at approximately -10 to -12 db (using the same pink noise) and raising the subwoofer level. This brought the subwoofer level up to about -6 db of the regular speakers - still too low a value.

[wbk]

Burke, I finally discovered the cause of my trouble - it was my 5 year old Radio Shack Analog sound pressure level meter. It simply wouldn't register the bass frequencies! I got the new digital version on Sat. and was able to set up and equalize my B15. Sounds great now, and I am a happy camper!
I would therefore like to caution everybody to use the RS analog meter with caution for the above reasons.