Any use of a subsonic filter for my ported PSB Image 6T mains?

Discussion in 'Archived Threads 2001-2004' started by Chris PC, Apr 24, 2002.

  1. Chris PC

    Chris PC Producer

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    I play my ported front mains full range without my subwoofer fairly often. My fronts are rated -3 dB at 32 hz anechoic. I wonder if there is any wasted power going to these speakers somewhere in the bottom octave of 16-32hz? Would there be any use to me in using a subsonic filter of some kind, say below 20 hz to remove some of the bottom most octave that might be sucking amp power for no good reason? Or does the steep slope of the ported design avoid wasted power?

    What I imagine is that the amp and speaker are voicing the bottom octave, even though its a few dB below the frequency response and not heard, thereby wasting power.
     
  2. Harold_C

    Harold_C Stunt Coordinator

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    It's a very good idea to use a subsonic filter on any vented loudspeaker. Control of cone excursion is lost below system resonance. You will signifcantly reduce cone excursion with a subsonic filter.
     
  3. Chris PC

    Chris PC Producer

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    Any suggestions for where and what kind of subsonic filter I could use?
     
  4. Harold_C

    Harold_C Stunt Coordinator

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    No. Unfortunately. I did a little searching for an add-on subsonic filter a while back and didn't find one.

    You would have to be using a separate power amplifier, because a decent subsonic filter will be a line-level device. You can do it passively at the speaker input, but I probably wouldn't go that route at frequencies as low as you would need.

    Many receivers have a lo-cut filter. I know Pioneer does, but it's at 40 Hz which is too high. That's really intended to protect a cheapo subwoofer.
     
  5. Chris PC

    Chris PC Producer

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    Fair enough. I guess sealed speakers don't suffer as much with this problem?
     
  6. Richard Burzynski

    Richard Burzynski Second Unit

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    SVS just came out with the "black box" which has subsonic filter builtin. This piece is no joke in terms of sound quality as it is OEM'd by Marchand (the fancy crossover people). Only thing is, I don't know if this is a mono only piece, meaning you would have to buy 2 inorder to hook up to your stereo mains. Maybe Tom will chime in if he sees the post.

    Rich B.
     
  7. Chris PC

    Chris PC Producer

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    Thats interesting. Good point. I wasn't fully aware of that.
     

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