AVR-3803 audio calibration

Discussion in 'Archived Threads 2001-2004' started by Jamey F, Jan 27, 2003.

  1. Jamey F

    Jamey F Stunt Coordinator

    Joined:
    Dec 20, 2002
    Messages:
    200
    Likes Received:
    0
    Trophy Points:
    0
    I'll agree with your suggestion to adjust speakers' levels with the same frequency by the SPL meter. You can get an idea on subs, but definately listen and set it more by ear. I adjusted my sub according to the meter and it produced more low bass than I wanted so I had to cut it back a bit. Music sounded off and DVD's had long spells of just rumbling bass way in excess of what should be. Instead of adding feeling to the effect it just distracted from it. Turning the sub down about 3-4 db below what was measured on the meter seemed to give a more realistic measurement. I'm probably going to move my sub from it's corner location and redo the calibration test. I think it's not the best placement for midbass. The lowest frequencies may be getting too much of a boost in the corner. In any case, there is a strong need to adjust the sub's level by ear because of the large difference in perception of LFE's and room placement.
     
  2. jeff_coil

    jeff_coil Stunt Coordinator

    Joined:
    Dec 3, 2002
    Messages:
    157
    Likes Received:
    0
    Trophy Points:
    0
    Hi Mike my analog SPL meter has taken a dive. Would you recommend the new digital or replace with another analog?
     
  3. BrianWoerndle

    BrianWoerndle Supporting Actor

    Joined:
    Feb 19, 2002
    Messages:
    794
    Likes Received:
    0
    Trophy Points:
    0
    The analog Radio Shack SPL meter is not very accurate at low levels. At 20hz you have to add 7 db to the reading for the correct value. (I think, the correction values are posted on the HTF somewhere, do a search to find them) I am not sure how accurate the new digital meter is, but that could be part of the problem. I calibrate with the meter first, then tweak the volume up until I am happy.
     
  4. BrianWoerndle

    BrianWoerndle Supporting Actor

    Joined:
    Feb 19, 2002
    Messages:
    794
    Likes Received:
    0
    Trophy Points:
    0
    Mike, Glad you got it to where you like. You have learned so many lessons in sound by just experimenting. Most people do not realize how many factors affect the sub. People just want to add another sub, or place it anywhere, and then it doesn't sound as good. Your post would be a great answer to many questions reguarding multiple bass sources and placements. You have encountered a number of bad problems all in the same room (square, multiple bass sources, phase, cancellation, reflections).
     
  5. Brian L

    Brian L Cinematographer

    Joined:
    Jul 8, 1998
    Messages:
    2,943
    Likes Received:
    27
    Trophy Points:
    1,610
    Had a nice detailed reply going, but IE went T.U. Oh well, I will keep it short.

    I have found that the test software contributes greatly to the stability of the readings. The best I have used for tweaking a sub is from Bass Machanics.

    They have tones in 1 Hz increments from 99 hertz on down. The discs can be found at Parts Express.

    Using this CD with a Infinity RABOS SPL meter yielded dead-nutz stable readings. Perfect for EQ'ing a sub.

    BGL
     

Share This Page