Newbie - Vented Shiva with PE 300-796

Discussion in 'Archived Threads 2001-2004' started by Forrest, Feb 20, 2003.

  1. Forrest

    Forrest Auditioning

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    I have been reading this forum for a number of months and have decided to take the plunge and build a ported Adire Alignment Shiva tuned to 20 Hz. A few weeks ago, I bought the PE 300-796 amplifier as it was on sale for $100.

    I have built the box and am about to install the amplifier, but before I do, I would like to modify R26 and R27 to tweak for my set-up.

    What dB of bass boost should I modify the amplifier for a vented 85l box tuned to 20Hz?

    Thanks in advance,
    Forrest

    PS the 300-796 is apparently the same as the 300-794 except for a 6dB bass boost at 30 Hz
     
  2. Andrus_R

    Andrus_R Stunt Coordinator

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    No clue what yer talking about [​IMG] but mine has bypass switches to disable Bboost. Vendor rec me 1db boost around 25 hz for my sbb4 temp design. I've yet to start[​IMG] coz i broke my mid finger on the day i was gonna start [​IMG] [​IMG] .

    Ohh the irony. [​IMG]
     
  3. Jeffrey Noel

    Jeffrey Noel Screenwriter

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    Forrest, the amp should have shipped with the values of resistors you need to replace to eliminate the boost. With that design, I highly doubt you'd want any boost anyway. It'll be quite loud and go quite low! Believe me!!
     
  4. Ryan Schnacke

    Ryan Schnacke Supporting Actor

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    I'd probably go with the no-boost values that the 300-794 uses:

    R27=120k
    R26=56k

    This will give you a cutoff frequency of 19.4Hz for the rumble filter. That should work well with a tuning frequency of 20Hz. You won't have to worry about subsonics bottoming your woofer. I've built a spreadsheet to determine resistor values for any boost/frequency combination and I'll be happy to run some numbers if you decide you want something specific.
     
  5. Forrest

    Forrest Auditioning

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