Newbie sub question

Discussion in 'Archived Threads 2001-2004' started by JohnMM, Sep 7, 2001.

  1. JohnMM

    JohnMM Stunt Coordinator

    Jan 3, 2001
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    Can someone explain this to me in somewhat of layman's terms? (FYI: room=1300cf, subs calibrated w/AVIA).
    1) I have an Infinity BU-120 sub. It sounds OK, not as much impact as I would like.
    2) I borrowed a Velo CT-120. It sounds better, getting closer to the impact I would like.
    3) I'm considering an SVS 20-39. From what I've read, I'm hoping it will give me the impact I would like.
    I can appreciate that there are many factors that influence the quality of a sub's output, and I don't want to get into that. I am more interested in how (or not) the following figures from Tom Nousaine correlate to points 1 thru 3 above:
    infinity bu-120: 100db/32hz, 90db
    velodyne ct-120: 101db/20hz, 87db
    svs 20-39cs: 109.5/20hz, 105.8db
    To put it another way, how do T Nousaine's figures above correlate to my unscientific findings that the velo has more impact than the infinity; and that the svs will blow them both away?
  2. Tom Vodhanel

    Tom Vodhanel Cinematographer

    Sep 4, 1998
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    the 20hz output of the 20-39cs was 91dB(105.8 was recorded at 25hz).
    remember, that's not maximum output...but max output using a 10% thd limit. THis has little to do with the frequency response of a unit.(TN notes that too...usually nearfield and at the listening position).
    Generally, the lower and flatter a subwoofer can play...the more *tactile/impactful* it will seem. Another key issue is the subwoofers ability to maintain it's response signature as the volume levels increase. A subwoofer that might measure flat to 20hz at 90dB...could show a severe rolloff an octvae higher(40hz) when the SPLs are increased to more HT representative levels.

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