Subsonic filter

Discussion in 'Speakers & Subwoofers' started by MikeKaz, May 27, 2003.

  1. MikeKaz

    MikeKaz Stunt Coordinator

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    I want a line level high pass filter that will cut out everything below 15 or maybe 20 hz. Is there anything out there that's fairly descent but doesnt cost $160 like the SVS box?
     
  2. Geoff L

    Geoff L Screenwriter

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    Not the perfect fix (no phase adjustment or other controls) but relativley inexpensive compared to a speciality unit like the SVS Black Box or Digims 30.

    You might look into FMOD's:::
    FMOD is an active crossover simulator and is considered better (according to Harrison Labs) than an expensive electronic crossover that requires power to operate...

    I'm speaking of Harrison Laboratorys FMOD ~{line level crossovers}~. They make both LP and HP FMOD's...

    20hz is the lowest they make I belive. 12-db per octave crossover slope and are compatible with all RCA type input amps. 10-volt maximumn RMS input, can be coupled and for a steeper slope 24-db using two 12-db units.
    Install the FMOD into the seperate amps RCA-in or powered subs plate amps RCA-in. If using a Y-cable, plug the FMOD into the female single in on the Y and attach sub cable to the end of the FMOD female RCA in.

    Constuction:
    24-kt over brass construction and USA made. 2-per pack and 25.90 threw Partsexpess, cheapest I've seen them...

    I know many use them in car audio for changing crossover slopes or steeping them..

    Regards
    Geoff
     
  3. Frank Carter

    Frank Carter Screenwriter

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    The FMods Geoff mentioned is the only thing I can think of.
     
  4. Ellen

    Ellen Stunt Coordinator

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    Are you at all handy at reading schematics and wiring up circuits from them? If so, you might check out the Subsonic / Rumble filter project at Rod Elliot's web site. While I haven't built this particular circuit, I have built other esp projects with much success.
     
  5. RichardHOS

    RichardHOS Second Unit

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    I second Ellen's suggestion on Rod Elliot's design. FMOD's can work well, or not so well, depending on the input and output impedance of your amp and preamp, respectively. A powered active crossover (rumble filter) based on Rod Elliot's design should have the best combination of sonic attributes (distortion, phase, slope, etc.).
     
  6. Ditto on Rods projects. I might have to try this one [​IMG]
     
  7. Geoff L

    Geoff L Screenwriter

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    If Mike has the skills to build Rods unit, than yes, certainly the better way to go no question!!!!

    But if not, the FMOD's are easy to use and very resonable in price for quick plug and play situation. My uderstanding is they work very well and could be returned if they do not get it for his appliction.
    The weight of a 2-pack are next to nothing, so return shipping costs would be next nothing.

    I plan to pick a pair up just to play with myself in my next order for an up-coming DIY sub this winter.

    At their cost I'll find a use for them and if don't care for them, a car audio buddy will buy them from me for sure.

    Hope the ideas brought forth by (Ellen especialy) and I, give you some lower dollar hopes! [​IMG]

    Best of luck
    Geoff
     
  8. Kevin C Brown

    Kevin C Brown Producer

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    How come no company makes one of these? [​IMG] I'd be interested in one too, but at or less than $50. Adjustable low freq limit (10, 15, 20 Hz). Don't need all the functionality of the SVS/Marchand box...
     
  9. MikeKaz

    MikeKaz Stunt Coordinator

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    Thanks everyone. I just might end up getting those FMODs. One benefit is that since they come in pairs, I'll be able to get that 24db/octave slope for my single subwoofer line. I can read that wiring schematic fine, but I'm not sure how id actually build it, i've never made a circuit before (Do I mount it on a piece of wood, an empty circuit board, a block of cheese...?). Maybe I'll give it a shot some day though.

    Regards
    Mike
     
  10. MikeKaz

    MikeKaz Stunt Coordinator

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  11. Kevin C Brown

    Kevin C Brown Producer

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  12. MikeKaz

    MikeKaz Stunt Coordinator

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  13. Geoff L

    Geoff L Screenwriter

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    Kevin

    I posted it already up top.

    Go here and type FMOD $25.00 a pair and they carry the attenuators their also.

    Geoff
    Edit: Seems someone beat me to it with a direct link...
     
  14. Kevin C Brown

    Kevin C Brown Producer

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    Cool, I found another place for $28.99 or something. Awesome!
     
  15. MikeKaz

    MikeKaz Stunt Coordinator

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    I think I'm definately gonna go with the ESP projects. Around $30 for the filter and power supply boards, then I just have to buy a bunch of capacitors and Op-Amps, solder them on and I'm ready to roll. Not too bad.
     

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