Way to limit max bass signal while leaving low volume alone?

Discussion in 'Speakers' started by Jon Carlson, Feb 13, 2007.

  1. Jon Carlson

    Jon Carlson Extra

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    I don't even know if what I'm looking for is possible.

    I installed 4 Aura Pro Bass Shakers in my sofa about 6 months ago to help with the illusion of bass when watching movies at low-to-moderate volume. And I'm completely satisfied with their performance for that task.

    And when I watch a movie with the volume cranked up (when the wife is gone) my sub does a credible job on its own. Unfortunately, with the volume turned up I find the shakers distracting during loud bass passages, so much so that I sometimes turn them off.

    Is there a circuit or something I could build which will let a low-to-moderate bass signal through, while limiting the signal during loud passages. I'm talking about an RCA cable feeding an amp powering the shakers.

    I'm looking for something cheap since I'm unemployed. Replacing the Bass Shakers with better tactile transducers isn't an option at this point.

    Let me know your thoughts.

    Thanks,
    Jon
     
  2. John Garcia

    John Garcia Executive Producer

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    Are you not using them with a separate amp now? That would be the way IMO, if you aren't. Maybe an old stereo receiver with a remote control so you can independently control their volume.
     
  3. Jon Carlson

    Jon Carlson Extra

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    John, Thanks for the reply. I don't think I was clear. I'm powering the 4 shakers with an old plate subwoofer amp. My issue is that I want a way to diminish the shaking at loud volume while leaving low-to-moderate volume shaker effects untouched, i.e. I want to limit the signal that's passed to the amp powering the shakers, but only during loud sub passages.

    I split the rca sub-out signal from my receiver between a 150-watt amplifier for the bass shakers and 700-watt amp for my subwoofer.
     
  4. John Garcia

    John Garcia Executive Producer

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    I got what you were asking, just not whether you were driving them off a separate amp. I can't think of a device that does what you say, though there may be one.

    That's why I suggested a receiver to power them with remote control instead of a manually adjusted amp, that way you at least have the ability to adjust them on the fly if desired without having to go over to the amp and turn the knob. Maybe just a cheap preamp between the sub amp and the receiver?
     
  5. MikeNg

    MikeNg Second Unit

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    You could run the signal through a compressor/limiter. The louder the signal coming in, the softer the signal going out. Is that what you are after?

    I can't help you in trying to build something like this. You can get one used pretty cheap online like from eBay. I don't know of a 'cable' that does this sort of thing...

    Mike
     
  6. Jon Carlson

    Jon Carlson Extra

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    Mike,

    I didn't know what they were called, but it sounds like a compressor/limiter is exactly what I need. I'll check ebay prices over the coming weeks.

    Thanks.
     
  7. Jean D

    Jean D Screenwriter

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    Im really shocked that a 150 watt amp powers 4 shakers that much. my father in law had some issues using a 250 watt amp with 3 Auro pro shakers and ultimately bought a new amp to drive them. The amp kept clipping out on us. I forget the exact reason but it had to do with 4 ohm vs 8 ohm and 3 shakers.
     
  8. Jon Carlson

    Jon Carlson Extra

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    I don't mean to imply the shakers are highly effective at loud volumes, at least in my environment. For me they're a way to enhance bass effects while volumes are reasonably low, and my actual sub's volume is also low. The shakers do a nice job for that.

    But when I watch an action movie at high volume, the shakers call attention to themselves by unrealistically vibrating the couch, an effect I didn't like. It didn't seem to enhance the bass, it just seemed gimmicky. I was looking for a way to automatically limit the max volume fed to the shakers' amplifier, and it looks like a compressor/limiter will do that.

    Thanks to all who replied.

    Jon
     
  9. Wayne A. Pflughaupt

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    Since you’re looking for a cheap one, look for the Alesis model on eBay. It’s a low-end pro model, not highly regarded in pro-audio circles, but for what you need, it’ll be fine. Just make sure the one you get comes with a manual, so you'll know how to set it up.

    Regards,
    Wayne A. Pflughaupt
     

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