Originally Posted by Desert Pilot
This morning, I ran Audyssey XT32 and have a question about subwoofer trim.
System: Marantz AV8805 pre/pro. Parasound Halo A52+ amplifier. SVS Ultra (L,C,R,SL,SR) and 2 SVS SB13 Ultra subwoofers. I listen to multichannel surround music (classical and jazz) and, of course, watch movies.
SW Level matching was about 75 to 78db. Audyssey set the subwoofer trim to -10 and -10.5. I would like extra bass so I changed the trim to -5 and -5.5. Is this the best procedure or should I leave the trim set by Audyssey and turn up the subwoofer volume about 5db?
What you did was just fine! There are a couple of variables here that I think are worth mentioning, though. If you think that either of the variables might apply in your circumstances, then I will make a suggestion. A lot depends on your listening volumes. If you rarely go over about -15 or so, with your master volume, then the variables will be less important.
First, there may be times when a movie doesn't seem to have as much audible or tactile bass that you will want to increase your subwoofer volume. As long as your master volume isn't much above -15, you could still use your trim controls to add another couple of decibels. Ideally, I wouldn't go much above -5, at higher master volume levels.
Second, if you ever feel that your SB13's are straining, you can actually achieve higher max output levels with those subwoofers, if the gain control is set closer to the max. Your current subwoofer boost is fairly modest, so again, unless your master volume level is high for a movie with a good deal of low-bass, that shouldn't be a problem. But remember, that if you are using DEQ, it will also be adding it's own subwoofer boost. It boosts the bass in all of the channels, and boosts most at subwoofer frequencies.
If either of those variables I listed is a concern to you, you could compromise by raising the gain levels (equally) on the two subs and dropping your trim levels down to about -8. You would just be seasoning to taste here, as you did when you raised the trim levels by 5db. That would give you several decibels of room to move either up or down in subwoofer volume by just using your AVR remote.
To reiterate my first sentence, what you did was perfectly fine. It is only if you want to allow yourself a little more margin that you might consider doing what I suggested. I like to tell people that although the advice in the Guide represents best practice recommendations, this really isn't something to obsess about too much. And then I remember that I am talking to fellow AVS members, where OCD is SOP.