Gain/Volume Setting on 20-39 PC+

kberg · August 2003

I noticed in SVS' manual that in one section, "Getting ready to start now", it says (as part of the calibration process)...

"...ensure your subwoofer's volume control is set 1/4 to 1/3 up to start".

Then, in the section where the manual discusses "Gain", it says...

"Start calibration with the sub's volume 1/2 to 3/4ths of the way up".

I'm familiar w/ calibration using the RS SPL meter, but was still curious as to what the first statement means as related to the second. Right now at post calibration my gain is set to slightly above 1/4 of the way up. What is meant by the second statement, or am I missing something here?

Dr. Spec · August 2003

The Indigo plate amps were almost too sensitive and resulted in adequate volumes at 1/4 for most people. For some reason that seemed to bother customers, so SVS and Indigo have made running changes to the input sensitivity of the plate amp, which should result in a higher volume setting.

Anyway, the contradiction in wording is a mistake that SVS will be correcting over time.

Since the overall subwoofer volume during calibration is a function of the plate amp volume setting, the subwoofer level control in the AVR, and the Master Volume setting in the AVR, the only thing that really matters in the end is a proper calibration level.

Set your Master Volume to 00 (or w/e setting you will use for calibration), and set the subwoofer level to -5 (on a scale of -10 to +10), and simply adjust the plate amp volume until the sub SPL comes into line. Don't worry about where it ends up.

Run the sub just a tad hot (maybe 3 dB) for HT and flat for music. Remember, the RS meter reads a bit low on the sub tone, so the true SPL on the sub tone will be higher than what the meter is saying. If you are using 75 dB for the surround channels, I'd go with 76-77 dB on the sub tone, and that will be about 78-79 dB in reality.

If you want it a little hotter, go ahead and shoot for 77-78 dB on the meter, but much more than that will sound unrealistic.

Remember, the SVS does not need to be run overly hot to compensate for a lack of true low end (like the Infinity). Even run flat for HT, and even at a low volume, the SVS will impress with its clean extension and power and accuracy.

Resist the urge to overcalibrate (I know, it's fun to feel the power and almost unlimited headroom), and give your ears time (a few weeks) to adjust to true accurate bass and you will find yourself naturally gravitating to a "mildly warm" setting for HT and a flat setting for music.

The accuracy of this sub will astound you as the weeks, and the movies, and the songs pass. The only bad thing about SVS is that it spoils you and you can't bear to listen to "ordinary" subs anymore.

Doc

kberg · August 2003

Excellent, Doc. Thanks for the explanation. I figured I was ok on my calibration, just confused by the SVS contradiction. I think I'm a dB or two too hot right now, so I'm going to bring it down a bit.

I have both the DD and DTS versions of LOTR, so I want to see what I measure out at with each on the ring drop.

Kev

Dr. Spec · August 2003

I am calibrated to Dolby Reference Level 85 dB with Avia at Master Volume 00.

I have the sub running about 3-4 dB hot.

The absolute loudest I can play LOTR-FOTR EE DTS 6.1 Discrete is -10 Master Volume. At that volume, the six surround channels are almost painfully loud.

Depending on my location in the room, I'm hitting 120-125 dB bass peaks (115-120 on the meter) at Master Volume -10.

The PC+ is not capable of that kind of volume, so work up to the loud stuff carefully. Even though the Plus driver is rugged, it has limits and they can be exceeded because the sub is so clean.

In your room, you might be able to make the PWC on the ring drop with a few dB to spare. Leave all ports open and the SS filter set to 20 Hz. If the sub sounds like it is straining, be sensible and back off. The PC+ does have very high limits, though.

Remember, the $30 RS meter isn't that good at displaying fast bass peaks at very low frequencies and high volumes.

Doc

kberg · August 2003

Ok. I think that before I even reach the reasonable extremes of the PC+ I'll be rattling **** off the mantle.

Since you had the PC+, what kind of comfortable bass peaks were you getting on the ring drop again, without doing any damage (somewhere around 112 dB?)?

Dr. Spec · August 2003

Originally posted by kberg
Ok. I think that before I even reach the reasonable extremes of the PC+ I'll be rattling **** off the mantle.

Since you had the PC+, what kind of comfortable bass peaks were you getting on the ring drop again, without doing any damage (somewhere around 112 dB?)?

I agree, you will be rattling **** off the shelves. :cool:

I was able to hit 112-114 dB peaks on the meter (117-119 actual) without bottoming or damage. The PB2+ has about a 5-6 dB advantage over the PC+, or about twice the clean output.

My room is 2000 ft3 (roughly), and that is 10 feet from the sub. If your room is bigger, drop those numbers a bit.

Doc

kberg · August 2003

Doc,

I can't recall where you said this, but just tonight while watching a bit of Monsters Inc. w/ the kids, I was pleasantly surprised by how subtle the SVS is when it needs to be, then (as you said) all of a sudden, WHAM!, it almost knocks you off the couch! All of the "electrical surge" scenes, as with most others - simply awesome.

This is VERY COOL! :cool:

Dr. Spec · August 2003

SVS calls this a linear FR/SPL/THD relationship. The FR looks the same at all volumes within the safe operating range of the sub and THD stays remarkably low even when the going gets tuff.

Many subs are measured at low volumes and the curves look great. Crank them up to loud HT levels and the curves go to hell, the extension falls off badly, and distortion skyrockets.

Not so with the SVS.

If you have Daredevil, play the barfight in DTS. You will flip over how much subsonic information is actually present in that scene. Stuff you will feel pressurizing the room but that is at the lower limits of your hearing - really an amazing reference DVD. And when he gets whomped in the face three times with the pool cue, hang on!

Doc

faster100 · August 2003

alright, now i'm buying daredevil.. I rented it but doc is making me wanna see it again and again with the SVS

kberg · August 2003

Originally posted by Dr. Spec
If you have Daredevil, play the barfight in DTS. You will flip over how much subsonic information is actually present in that scene.

Doc

Saw Daredevil at the theater but don't have it on DVD, but now I feel I should at least rent the thing!

Oh, and yet another fascinating discovery. Music is just not the same anymore, either. Have you ever heard of Switched-On Bach by Walter (now Wendy, but we won't get into that here!) Carlos? That CD has some serious bass that was all unheard of before, but no more! If you've never heard it and want to, just let me know.

faster100 · August 2003

Originally posted by kberg
Saw Daredevil at the theater but don't have it on DVD, but now I feel I should at least rent the thing!

Oh, and yet another fascinating discovery. Music is just not the same anymore, either. Have you ever heard of Switched-On Bach by Walter (now Wendy, but we won't get into that here!) Carlos? That CD has some serious bass that was all unheard of before, but no more! If you've never heard it and want to, just let me know.

I never heard it, why? we talking sending a burned copy for preview? :cool:

Gain/Volume Setting on 20-39 PC+

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