Sub Calibaration?

Discussion in 'Speakers' started by timZa, Jun 4, 2006.

  1. timZa

    timZa Stunt Coordinator

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    I got a radio shack spl meter, and set my speakers up at 75db. i set my sub at 85 dbs. reading on the net, it says about 3 dbs over the rest of the speakers. as it is 85 seems to low for me. is this a matter of preference or a must to prevent damage to the sub? my sub out is at 0db and my sub volume is about a 1/4 way up.
     
  2. Robb Roy

    Robb Roy Supporting Actor

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    Tim,

    I'm not sure what you used to calibrate to those levels, but your sub is probably quite hot (about 13 dB hot). A lot of people when they first calibrate feel the sub is a bit low because they expect the bass to dominate the sound, rather than blend with it. This happens a lot with music. There could also be any number of setup issues preventing proper performance (assuming you have a capable subwoofer). Here are a couple of links to look at. One goes through using Avia to calibrate (which I would suggest) and the other is a list of common setup problems.

    http://www.robbroy.net/HT/AviaSubCalibration.cfm

    http://www.robbroy.net/HT/SubwooferErrors.cfm

    Good luck!

    -Robb
     
  3. timZa

    timZa Stunt Coordinator

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    Robb, thanks for the reply and links. 2 questions i can't seem to find on the net. i calibrate using my receivers tones. i put volume at level of 75 on volume because this is the highest i turn up receiver. now it says to put input
    level to sub at -5 for calibration, do i leave it there after i calibrate it? also which do i turn up and down for the proper db, the sub volume or the recivers input level to sub? thanks.
     
  4. Robb Roy

    Robb Roy Supporting Actor

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    Tim,

    During calibration, set the level at -5 (assuming a range of -10 to +10) and use the sub’s gain to calibrate. Once calibrated, don’t touch the sub’s gain knob, and use the receiver’s levels to adjust bass as desired. The reason you do this is you can always put the receiver’s levels back to -5 to know you are at reference level, and you know just how hot you have things when you bump it up.

    -Robb
     
  5. Vader

    Vader Supporting Actor

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    Derek
    Tim, keep in mind that if you use the auto-on circuit on the sub (assumingthat yours has one), the lower the AVR setting, the less sensitive the sub to bass signals to turn on (or stay on). I set my subs (Dual SVS 20-39 PC+) to 1/3 gain, and calibrated using the AVR to -2.0 (flat, not hot). Following what Robb said, if you have a problem with the sub not sensing bass as it should, back off on the gain and compensate with the AVR level settings. There is nothing magical about -5, so long as you pick an AVR level you know is reference (just like there is nothing magical about setting your AVR to MV 00 to calibrate*, just so all your channels are calibrated correctly relative to each other).

    * the 'MV 00' is simply to provide a common point of reference between other systems; "apples-to-apples", if you will.

    Also remember that, if you are using your AVR tones to calibrate, all speaker levels should be equal. The only times you should calibrate the sub to 10 dB over the others are a) if you are using the DVE sub tones (which are 10dB too hot), or b) if running 10dB hot is what you are aming for (personal preference). Since you are using the AVR tones, calibrate to 75 dB across the board (73 dB for the sub, as the Rat Shack meter reads about 2 dB lower than the actual SPL level of the pink noise), and adjust the sub from there, depending on how hot you want it (if at all).
     
  6. timZa

    timZa Stunt Coordinator

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    Robb and Dereck, thank you very much for clearing that up!
     
  7. Robb Roy

    Robb Roy Supporting Actor

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    Derek,

    You bring up a good point. The -5 is just a good starting point that allows for plenty of room to increase the level as well as limit any distortion introduced by the receiver. If a sub has trouble "waking up", then increasing the level at the receiver is the obvious way to go. I'll talk to Ed about including a caveat on the -5 recommendation.

    -Robb
     
  8. Brian_cyberbri

    Brian_cyberbri Stunt Coordinator

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    Yeah, it's just a starting point. I have my receiver sub level at 0 and the sub's gain at 1/2 way between 0 and the first of 6 marks to max. My sub has a lot of power and the gain knob is really sensitive, so I found this to be the easiest combination to get calibrated just right.

    My other speakers are set to: -3, -4, -3, -2, -2 (around from front left). This is using Avia to set 0 on my dial to 85dB.
     

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