Technically Correct Subwoofer Settings.....

Here's a huge debate that's been lingering around that frankly I'm determined to get to the bottom of...

What is the correct method of setting a Subwoofer's output to blend with a home theater AND music system....?????

Here's the issue: I use a sound level meter w/ the Avia disk for audio calibration of my home theater. IF one uses the standard pink noice from the disk or a preamp, we can get one sub setting. If one uses the "Subwoofer" setup section, it makes the person setting up the system ADD about 10 dB to the sub output.

Here's my understanding, it is technically correct to use the standara pink noise to set ALL speakers to the same level, including the sub. When one uses the Avia subwoofer setup section to calibrate the sub for home theater, one adds about +10dB to achieve the same decibel output. Now music sounds too boomy.

I spoke w/ those tech gurus from the "Ranch" and they agreed that one should technically use the pink noise from the processor to calibrate and NOT the Sub pink noise to calibrate your system, from a demo disk such as Avia. Has anyone else run across this Sub for music vs. Home theater calibration issue???

Just guessing here.... Maybe the HT standard has a deliberate bass boost in it? Wouldn't surprise me, given the wildly overblown bass in many theaters. If this is the case, the only solution I know of is the most recent REL subs which can be hooked up simultaneously for HT (5.1 LFE channel) and music (full range) with separate inputs.

The only other guess is that the "subwoofer" track has low-pass filtered noise, i.e., it simulates the LFE spectrum rather than a full-range signal. This might account for the level difference. If this is the case, though, one would think the disc would have high-pass filtered noise as well, to be used for setting the main/rear/center. Then you would be back to a level response again.

If all else fails, I'd set it where it sounds right on music and live with it for HT; this is a lot better than the alternative!

Use your ears!

Get a cut with a good full drum set. I like Phil Collins "Hello! I must be going." Work on it--then leave it and come back the day after with some more music. It's very subtle changes ( as little as 0.1 dB ) that make the magic happen...

I am assuming your system's main speakers are already tuned...

Try reading Vans Evers website notes on tuning bass. Also the Audiophysik website is excellent.


I've used both the technical (1/3 octave analyzer with pink noise) and empirical (listening to music) methods. Over time I've shifted almost entirely to the latter. Integration requires both level and phase. Pink noise is of no help with the critical phase setting which causes the music to 'lock in.' I use cut 11 on Albert Collin's Deluxe Edition from Alligator Records. It's a 20 bit recording that starts with a killer bass solo. When the bass is right I then listen to the attack of bass and drums after the solo. Once done, I go to piano (cut 2 of Gould's Hindemeth CD for example) for any fine tunning. This is followed by cello and classical guitar. IMO all of these instruments need proper setup of a sub that goes down to 20Hz to sound right.
My experience is that HT and music work best with completely different LF settings. How much of a boost is required for "best" HT will vary with the extension, type of loading and placement that the subs have to offer. Trying to find one setting that is a good blend between the two different formats is very tough and usually a compromise at best.

As far as integration goes for music, one should mount the subs pretty close to the mains ( if at all possible ). This presents a more stable image, less localization problems and minimizes the time delay differences between each cabinet. Using large full range speakers for every channel is by far the best solution but most people aren't willing to sacrifice the necessary amount of "acreage" to do so.

Once you achieve the proper blend between your mains and the sub(s) for music, one can simply introduce more LF boost for movies as they see fit. Toggling between two different settings is not that difficult in most cases, especially if you have some type of programable processor.

If using powered subs, simply dialing up the gain on the sub amp is a quick and dirty approach. That is, so long as you remember where the settings are. Making a paper template with several different preset marks and taping it to the control panel on the sub can also be done quite easily. This gives you an instant reference for various settings ( rock / classical / jazz / movies, etc... ) with minimal fuss and no worries about memory loss : ) Sean
Psychic, Danner, and Sean all make excellent points, and I'll add only a few minor comments. First, however, I'll second the "do it by ear" method of adjusting the subwoofer output. I have two Vandy 2WQ subs that I use in conjunction with Vandy 3A Sig main speakers.

In the 2WQ sub's manual, Vandersteen says to integrate the sub(s) with the main speakers by playing a good recording of the acoustic bass that features a "walking" bass solo going up and down the frequency scale. As the frequency of the bass notes pass through the crossover point (typically around 80 Hz), there should be no discernable change in the volume of the bass. I have used both walking bass solos and organ recordings (such as Wilson Audio's recording of the organ at St. Mark's Cathedral in Seattle) to tune the deep bass response.

With regard to subwoofer response in HT applications: there IS a significant bass boost in the THX standard, so if you want MUSICALLY accurate bass, don't use the "Avia Guide" or "Video Essentials" DVD to adjust your subwoofer.

If you have a sub that has an adjustable "Q", such as the Vandy 2WQ's, you can turn the "Q" up for home theater, and down for audio.
If it sounds boomy, it probably is crossed over too high. My sub is crossed over at 63HZ. And it seems about right for my system. You may want to go lower.