Calibration, Avia test tones, 80 hz xover, B&W N804 mains, SVS subs

Discussion in 'Archived Threads 2001-2004' started by MarkFrab, Apr 17, 2002.

  1. MarkFrab

    MarkFrab Agent

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    I think there may be something wrong with my pre/pro bass management. It seems like the mains get the full-bandwidth signal regardless of the small/large speaker setting or the xover setting. The sub seems to get redirected bass only if the main speakers are set to small.

    On the Avia disc, on sub calibration menu, the test where, by channel, it plays an alternating high-freq pink noise and low-freq pink noise - what is the freq range on the lower signal? Does it go above 80hz?

    When I play the Avia low-freq sweep (200-20), with mains set to small and xover at 80, sub amp turned off, I get 85db output at a fairly even level down to about the mid-30 hz region (the nominal -3db bass limit of the N804 is 38hz). I get the same results regardless of the speaker size setting. This is wrong, isn't it?

    If I have a correct grasp of the situation, the xover should output a -3db signal at 80hz, and with a 12db/octave slope the signal should be -15db at 40hz, right? So [rant]no way[/rant] should I be getting 80ish db at 35hz - even if there happens to be a huge standing wave at the listening position, which I haven't investigated.

    My real problem is that with all speakers set to small with an 80hz xover, the "lower" pink noise is about 6-8db higher for the front speakers. The center and rear surrounds are consistant in level. My center is the HTM-1, which, compared to the N804s, has a nominal -3db bass limit of 42hz. Don't ask about the rears. :b

    The mains and center are bi-wired, and if I disconnect the woofer inputs on the mains, the test tones play at a steady 85db for all channels for both high and low freq pink noise signals. Doesn't this point to a problem with the bass management?

    Thanks for any help you can give!
     
  2. MarkFrab

    MarkFrab Agent

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    After talking to the tech people at the manufacturer, I found out how to do a reset of my processor, which seemed to fix the problem. I've still got a slight bass boost for the main speakers, however.

    I think I'm going to re-calibrate the bass level to the mains, ignoring the dip from the other speakers. Anyone see a problem with this?

    However, I'm still interested in learning what the freq range on the "sub" tone is. Does anyone have this information?

    Regards.
     

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