SPL meter speaker calibration--help!

Discussion in 'Home Theater Projects' started by Stephen Gladwin, Jun 10, 2005.

  1. Stephen Gladwin

    Stephen Gladwin Stunt Coordinator

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    On the recommendation of this board's members, I went out and bought the Radio Shack SPL meter (the analog kind, no less) and just ordered the AVIA dvd online. I was playing around with the meter tonight and just trying with my receiver's test-tones. I think I'm using the meter properly (have it set for 80db, set to "C" and "slow", standing aside when I measure), but no matter how much I crank the volume on my receiver, my LR speakers never seem to get up very far on the meter. My center comes through loud and clear though and can reach "0" on the meter. My LR speakers always seem at lower volume. I checked to see if they were out of phase, but the connections seem OK (no pos/neg mismatches). **The goal is to get all LCR speakers to "0" on the meter, right?

    What am I doing wrong? Do I need to fool with the level controls for each speaker? Strangely, my receiver only allows me to adjust the db level on the center; I can only adjust the balance on the LR speakers.
     
  2. Adil M

    Adil M Supporting Actor

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    The goal is usually 75 or 85 db.
    Avia recommends 85 db which is +5 at the "80" setting.

    * Excellent clarification below. The key is that all speakers are balanced.
     
  3. Wayne A. Pflughaupt

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    Stephen,
    Yes, the idea is to get all the speakers at the same volume. If you can’t turn up the L/R loud enough to match the center, just turn down the center speaker to match the L/R. It will accomplish the same thing.

    Regards,
    Wayne A. Pflughaupt
     
  4. Clinton McClure

    Clinton McClure Casual Enthusiast
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    Wayne is correct. I have a Yamaha RX-V995 and that is how I had to calibrate. I have no individual level controls for my mains (only a left/right balance knob), so I balanced them so that they both read 72dB on the meter (I don't think it really matters what decibel level you calibrate them to as long as they are all the same volume). I then adjusted the center and surround level controls to match the decibel level.

    Most people will recommend to set your sub about 10dB hotter than the rest of your speakers but I have quite a bit of air to move in my room so my sub (Paradigm Servo-15) is referenced to 92dB vs the 72dB reference for the rest of my rig.
     
  5. Bob McElfresh

    Bob McElfresh Producer

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    If you have your L/R/Center in a straight line - the L/R speakers are several feet farther away which means their volume will be lower.

    You should also play with angle by turning the L/R speakers inwards to point more towards the center seat. Some speakers have a sharp drop-off to the side and this will help increase their apparent volume.

    A small laser-pen is a nice tool to help see where the speakers are pointing. You may be suprised at how far off you are just doing things by eye-ball.
     

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