Sub Volume Adjustment Question

Technically the opposite is true and easier to keep reference for flat or otherwise, once the sub receives voltage from the pre/pro that's it, lose the paranoia and pump it up on the receiver not on the sub YMWV too many variables at play for otherwise.

If you can keep the sub level below the 0/neutral level on the receiver, that's usually best. Ie., if the sub range on the receiver goes from -10 to +10 with 0 as neutral, around -5 to -3 is a good range to start out at. Then adjust the sub's gain knob when you calibrate to the proper level. Then you know the sub's gain level + your receiver level is at the calibrated level (balanced, or +1 or +2dB hot, for example). Then if you want to bump up the bass a few dB you still know where to return it to on the sub.

WebEffect, as I'm sure you know, whatever sounds better is the correct setting. Personally, I've never noticed a difference in where the volume came from. But, as Cyberbri says, I do happen to have my preamp set at -6 on the sub level. I find this makes on the fly adjustment between movies easier.

If the signal level from the pre-pro is low with a high gain at the sub, then the sub will be amplifying the noise/hum from the prepro and cable along with the signal. Best to set the level from the prepro around neutral and turn down the gain at the sub...

So what initial setting should you put the sub on before you calibrate levels with the receiver? 25%? 50%?

Do you need to autocalibrate? I'd set the prepro on 0 (assuming that's mid-range -- no adjustment) for the sub channel, then adjust the gain at the sub to hit the target level on your spl meter.

Let me clarify -- above post is advising to manually calibrate, if that's an option. If it's necessary to autocalibrate, pick a relatively low setting on the sub (you don't want to blow it out) and see where autocalibrate sets the receiver sub channel adjustment. If it sets it high then turn up the gain at the sub and re-autocalibrate. If autocalibrate sets the receiver low, then turn down the sub gain and recycle. You'll converge on an acceptable setting with a couple of attempts.

Depends on your sub. I would start with the volume set to 0. If you have a constant audible sub level noise going, then get behind the sub, and adjust accordingly. I've never had reason to turn my sub up past the first or second dot on the volume indicator. As for calibrating my sub level on my preamps channel level adjust, I find it worthless when matching it to the other speakers. Use an SPL meter or your ears.

So the goal would be to have the sub set at a volume where the receiver sub channel is at 0, correct?

The level on the receiver can be at 0, -3, -5, whatever. As long as the combination of the level on the receiver and the level of the sub's gain get you your desired calibrated level. But it's a good idea to keep it in the receiver at a level even with or slightly below that of the speakers so you don't send a clipped signal to the sub.

In line with cyberbri's advice, try setting the sub level adjust in the receiver to match that of the front L/R channels, then dial in the right spl (or whatever sounds best to you) by fine tuning at the sub.

I would go with this advice.

The other advantage of this technique is that with some some subs it may be necessary to have a higher signal level coming in from the pre/pro or receiver in order to "wake up" the sub from hibernation if you are using an "auto-on" setting.

I was having that issued with my SVS 20-39 PC+ with a Denon receiver. At lower volumes, the sub would stay muted, then suddenly kick in. By increasing the input signal in the Denon, that issue is minimized.

Auto-calibration is useful to the novice sans meter, in the final stages of tweaking and nailing the last note it's basically useless. Rereading the original query and his only response, the OP needs to lose predetermined impressions and get acquainted with BM 101, a good start on the journey might be acquired HERE The journey of a thousand miles starts with the first step...in the right direction

Good point. Also worth mentioning is that many receivers today have a midnight mode. Selecting this option when listening at low volume levels particularly on non digital sources like tv audio or using Prologic surround helps eliminate this problem.

Ian

That makes sense to me, thanks!

This post is good read but still needs some clarification on the following:
When starting to callibrate, what should be gain set to on the subwoofer initially (min,mid,max)?
When we get the right callibration, if we try to increase the gain will that affect the callibration or not?
What is the good idea - Increase the gain on subwoofer to maximum or set the gain low but increase the db on the receiver?

Thanks

low -- see post #9



yes



see post #6

Excellent, Thanks a lot.

my 2 cents.....

Just got a denon 987 and used audessey to calibrate my PC Ultra and MBM-12.

The problem I was having was that the auto calibrate would turn the Sub managment level to -12 out of -12-12+. This was with following audessey's recommendation of turning the gain on the subwoofers to halfway up prior to calibration. -12 is next to off. So I figured the subs were too powerfull with the gains set halfway up initially, So I backed them down 1/4 to about 10 on the dial. Did the auto calibrate again, and wound up with -12 in the Denon. I then manually did Spl measurements and found that the MBM was boosted over the SVS. Probably because the SVS wasn't really accounted for by the tones in audessey. In a way this was good, because then audessey would do too much to equalize the lower bass below 50 hz. My SVS was crossed to the MBM at 50hz. The MBM was crossed in the AVR to 100hz. next up I did some tone spl readings with a CD I made up and recorded various Frq's. I found that I needed to turn back the MBM gain a bit, down to about 9:45 and boost the Ultra to about 12 (half way). Running the FRQ CD I found that that most of the spl readings were pretty close, not flat by any means but good enough for my taste.
Curious, I ran the speaker tone test in the Denon and everyting matched perfect. So the audessey was spot on for the speaker calibration just not the sub. But because of my adjustments, the sub got matched perfectly.

Now to run every speaker at the exact spl including the sub, the denon remains at -12 subwoofer, this includes having decreased the gain on the MBM and increased the gain on the PC Ultra. Because I like the low end boosted for a nice house curve and personal taste, I adjust the denon sub level from -12 to -9 for HDTV and for DVD's to about -7 for Dolby Digital. DTS around -9.
Like a previous poster stated, if I leave it at -12 the auto-on, on the subs won't kick in until the volume is boosted high and then backed down again.

the setup now Sounds really good but took alot of measuring and trial and error.

Mainly because of the 2 Subs crossed at different points.

I found that Audessey was pretty accurate in its readings including tones and distance. Not sure if I like the sound when it's activated though. Seems to push mid-bass alot and roll off the lows by about 3 dbs.

Just my thoughts....