Calibrating reference level w/ SVS sub & Sony 4ES

Discussion in 'Archived Threads 2001-2004' started by TonyTone, Nov 7, 2002.

  1. TonyTone

    TonyTone Supporting Actor

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    The equipment in question--SVS 25-31 PC+, Sony DA4ES. When I calibrate the sub volume using VE and RatShack SPL with receiver volume set at -20.0 dB (max 0 dB) and sub located approx. 6 ft from the listening position (6 ft value also inputted into receiver), I find that I have to set the receiver's LFE output level at -15.0 dB (-20 to +10 range) and the SVS volume knob at 2 clicks (out of 8) past minimum in order to hit the VE 75 dB reference level on the SPL.

    So...even though I can set sub reference at 75 dB and granted that the sub is fairly close to the listener as it is, why do I get the feeling that the LFE output is gonna be pretty low (volume-wise) when I listen at "normal" levels, e.g. receiver volume set between -50 dB and -30 dB? I mean, the SVS' volume knob is only 1/4 (meaning I could crank the knob quite a ways if I wanted lots of LFE output) and the LFE output level on my receiver is set at only -15 dB; not only that, the LFE trim on the Sony is set to -5 dB (-20 to 0 range, IIRC). I can only imagine how much more bass, albeit distorted, I could get if I cranked the LFE level on both the receiver and the SVS to just only the midpoint on the adjustment scale.

    So I guess what I'm trying to get at is this:

    Which is more preferable--lower receiver reference volume with higher speaker level adjustments, or higher receiver reference volume with lower speaker level adjustments, when calibrating, and why?
     
  2. TonyTone

    TonyTone Supporting Actor

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    bump...anyone?
     
  3. Edward J M

    Edward J M Cinematographer

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    Could you explain the difference between the LFE volume control (which you have set at -15) and the LFE trim control (which you have set at -5) on your receiver?

    It is preferable to have the LFE volume control on the negative side, but avoid extremes at both ends of the spectrum. I'm told too low of a setting (-20 for you) may unnecessarily increase the S/N ratio of the LFE pre-out signal. Too high of a setting (+10 for you) may result in LFE pre-out signal compression problems. Your current setting of -15 seems fine, but maybe you could select -10 and recalibrate. Overall SVS recommends that you stay in the negative zone about "halfway" between 0 and the minimum, which for you would be -10.

    Beyond that, once you have achieved 75 dB on the sub test tone, you are at "reference" (or even a bit above with the Rat Shack meter, which tends to read about 2 dB low on the sub test tone), regardless of how "low" the sub amp volume and/or the receiver settings may seem. This is a common occurance with a powerful sub like the PC+ only being 6 feet from your SPL meter. Beleive me, you won't be "missing out" on anything - if the signal calls for it, the sub amp will deliver its full power, despite the "2 clicks out of 8" setting.

    Once you fire up your system, you will see for yourself. If you listen at more sedate levels (like -30 or -50) feel free to temporarily increase the LFE volume at the receiver a bit if you need more punch. But as you get close to reference (-20 for you), you won't need to - the place will be rockin'!

    Regards,

    Ed
     

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