Question about LFE level and auto on circuitry

Discussion in 'Archived Threads 2001-2004' started by Darren_T, Jul 25, 2002.

  1. Darren_T

    Darren_T Second Unit

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    Since I calibrated my new Tempest with my system I have noticed the auto on circuitry doesn't trip until my volume reaches a certain level. While calibrating I turned my PE 250W amp gain up to about 10:00 and had to reduce the level on my receiver to -10 to -12. This combination doesn't seem to send enough of a LFE signal to the amp to turn it on until I reach moderate volumes. If I turn the amp to "on" it comes on and there is audible bass so I would figure the amp should turn on by itself. While troubleshooting I changed the configuration a bit. I turned the sub amp to about 9:00 or about 1/4 gain and then set my LFE level on the receiver to 0. This seems to turn the amp on just fine at the lowest levels and results in similar output.


    Is this typical? Will my sub amp be under-performing because of this? I had assumed that any signal to the LFE would trip the auto-on circuitry. Am I mistaken?

    Thanks.

    Darren
     
  2. Dave Poehlman

    Dave Poehlman Producer

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    You may want to look at where the crossover knob is set on the sub. Make sure it is set well above your LFE frequency.

    On an off topic note: I have a cheap MCM sub amp I use in my living room that is wired through the high level inputs and out to the L & R speakers. If my receiver is off and I tap the cone of the woofer on one of my bookshelf speakers, the voice coil apparently generates enough current to switch the amp on. Kinda neat.
     
  3. Darren_T

    Darren_T Second Unit

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    I have the crossover set to it's highest level...120hz I believe.

    Darren
     
  4. Brian Bunge

    Brian Bunge Producer

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    Darren,

    That's exactly how I usually suggest calibrating a sub with a plate amp. Set it to about 1/4 the way up (or 9:00 on the dial) and then adjust your sub out from your receiver to calibrate.

    I've used mine that way for several years and it's worked just fine.

    Brian
     
  5. Rob Lloyd

    Rob Lloyd Stunt Coordinator

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    I've done the same with mine - About 1/4 gain and around -2 on my receiver. Crossover is at 120hz. Never noticed it not turning on.

    You might want to try a signal splitter. Some claim it helps but I think you would need even less gain with it. I haven't tried it yet.
     
  6. Darren_T

    Darren_T Second Unit

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    Hmmm...didn't think of that. I have a signal splitter but I broke the pin off of one end. I'll have to replace it...is a Y pretty much the same thing? I have a THX certified Monster LFE cable that has a splitter on it which is the splitter I toasted. I know the splitter made quite a difference on my velodyne but I thought it was the type of amp it had.
    He he...funny thing is the Monster cable can't make much difference because I wired my LFE in the house with RG6 DIY cables...spent 75 bucks on that dang monster cable before I wired the house. [​IMG]
    Darren
     

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