Understanding sub response in a room...

Discussion in 'Archived Threads 2001-2004' started by Chris Demaree, Jul 23, 2001.

  1. Chris Demaree

    Chris Demaree Stunt Coordinator

    Nov 3, 2000
    Likes Received:
    - SVS 20-39pc
    - Outlaw Audio 1050 receiver
    - Paradigm Titan v2 (mains), CC-170 (center)
    - Energy Take2 (surrounds)
    - Sony KV36-FV26
    - Toshiba sd-2200
    Currently the signal to the sub is set at -12dB. The crossover is set to 80hz. The sub placement is between the TV and the right, front speaker. Test tones measure the sub output at about 4dB's higher than my other speakers (from the listening position). The 150hz to 20hz sweep on the AVIA disk brought to my attention a large spike in output centered around 50hz. I don't want to move the sub back to the room corner (behind the right, front speaker) because the sub's output becomes too much for the rest of my system, and it picks up a slight hum. If I place the sub in the corner, set the signal to -0db and turn the amp down to 50% the output sounds distorted?? at levels the current setting/placement is loud and clear.
    Do I have to use an external equalizer (BFD or ART equivalent) to reduce the MAJOR spl increase at 50hz?
    Why does my SVS sound ..distorted (not sure how to describe the actual sound, but it isn't pretty) with a normal input signal and the internal amp set to 50%?
    Would moving the SVS to a different spot in the room change the spl spike at 50hz (possibly making things worse, maybe better)?
    The room is 12'x13'x8', opens up into the kitchen and has an open doorway to the rest of the house.
    Any and all comments are appreciated, thanks!
  2. Brian Fellmeth

    Brian Fellmeth Supporting Actor

    Jul 30, 2000
    Likes Received:
    Double check that the PC's amp boost switch off- that could be part of the 50Hz peak. As for your other question aboout the sub being distorted. try reposting with SV in the title to get TV or Ron's attention or e-mail them.
  3. Deane Johnson

    Deane Johnson Supporting Actor

    Jan 27, 1999
    Likes Received:
    I probably can't help you with the distortion problem other than to say that the first thing I would look for is some portion of the audio chain being over driven, that is being hit with too much level. That may be what happens when you set your output to 0 level and the sub amp to 50%. I have no experience with your receiver's output level, just guessing.
    The 50 Hz room spike comes as no surprise. That's generally the area in which they occur. I doubt you would have any luck eliminating it by moving the sub around. It almost has to be taken out with an equilizer. The more complicated method of taking it out is with room modifications such as bass traps, etc., something most of us aren't going to go to the trouble and expense to do.
    The external equalizer in the sub circuit can be a very effective fix.
    The BFD is more flexible and more complicated to operate. The ART unit is simpler to operate and less flexible. The major difference with the flexiblility of the BFD is that you can move the center frequency of the cut or boost around and you can vary it's width.

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