VX-10 calibration issues

Discussion in 'Speakers' started by Kevin Co, May 29, 2003.

  1. Kevin Co

    Kevin Co Extra

    Dec 31, 2002
    Likes Received:
    I’m having difficulty calibrating my Velodyne VX-10 sub on my Yamaha 5560 receiver. I’m new to Dolby Digital and this is my first 5.1 system, so I’m sure I’ve made some fundamental mistake. I’ve done the Avia calibration for my mains (Boston 361’s) and center (Boston CRC) with no problems. I’ve calibrated them to 75dB and all are within +/- 0.5dB of each other. I’ve done the basic subwoofer level calibration in Avia and end up with my sub level trim at –17.5dB with the subwoofer’s volume set at ¾ of max. All speakers are set to “SMALL” and “BASS” is set to “SWFR”. I’m having three separate (but possibly related) issues:
    1) During the Avia low frequency sweep, the SPL rapidly varies from about 76dB to 66dB
    2) There is a noticeable hole from about 105 Hz to about 65 Hz where the SPL drops to below 60dB. There is also a similar hole from about 147 to 150 Hz.
    3) When performing the “Low Frequency Pink Noise, 6 Channel Pan” the LFE consistently drops about 5dB in SPL. This is with the LFE setting on the receiver at 0dB (maximum) leaving me no adjustment.

    Some further notes and observations:
    1) I’ve connected the sub with a single RCA cable to the “L” input. I’m not sure if I need to use a splitter or not.
    2) The “Subwoofer Phase Warble Sweep, Left-Front” seems to indicate that I have the phase correct.
    3) I used all Left-front Avia sweeps for my measurements.
    4) The variable crossover setting on the VX-10 seems to have no effect at all on the frequency hole that I’m experiencing. I’ve tried it all the way up to 200Hz with little change. The receiver’s internal crossover is 90Hz.

    I can’t imagine that these issues are all the result of bad placement, especially the LFE level drop. Anyone have any suggestions, theories, etc.

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