Sonotube powering options for dual AV-15's

Discussion in 'Archived Threads 2001-2004' started by Scott Parker, Jan 2, 2003.

  1. Scott Parker

    Scott Parker Agent

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    Okay, I'm thinking of building a sealed 300L sonotube with 2 AV-15's. I'm wondering about the best way to power this thing.

    I already have a 350w plate amp so I could buy one more and use 350w at 4ohms for each driver. Then I could take the sub out of the receiver and go into 1 plate amp and then hook the line out into the line in on the next plate amp. Or I could ome off my sub with a splitter and have one go to each plate amp. Which do you think would perform better.

    I could also buy a RMX1450 and run 450watt at 4 ohms in each driver. Or should I bridge the amp at 900 watts and into an 8 ohm load?

    What would you guys do?
     
  2. JimPeitersen

    JimPeitersen Second Unit

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    Scott,
    Buying another plate amp would be the most cost effective solution (try these - www.rythmikaudio.com). You could also pick up an inexpensive pro amp and run two 4 ohm stereo subs (musciansfriend is having a great sale on Nady and Crown amps). Either way, you should be happy with the results.
    JP
     
  3. Bryan Michael

    Bryan Michael Supporting Actor

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    how god is nady? compared to crown,and samson? thanks
     
  4. JimPeitersen

    JimPeitersen Second Unit

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    I believe this has been discussed before, but I think that either QSC or Crown made the Nady amps as an OEM manuf. They are most likely solid (but noisy) no-frills pro amps.
    JP
     
  5. Scott Parker

    Scott Parker Agent

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    Yeah those rythmic and nady amps are pretty cheap. Are those Crown amps that much better to warrant the price difference? It seems like I could just get a Nady at 2x750watts 4 ohms and be done with my power troubles, at only $369.

    Do you guys run into any ohm trouble splitting the sub out from your receiver? Or is it better to daisy chain the amps?

    Thanx for the replies guys
     
  6. Ryan Schnacke

    Ryan Schnacke Supporting Actor

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    Daisy chaining the plate amps only works if the line out from the plate amp is not high-pass filtered. The parts express plate amp spec sheets claim that the line out is not filtered, but in reality it is for those amps. I'd experiment with the line out on the plate amp you have to find out if its high-passed. Its usually something pretty obvious like Fc > 100Hz.

    There's usually no problem splitting the line out and sending to two amps. I've split mine to 3 plate amps with no problems. People tend to exaggerate the issue of impedences on the line output. Most inputs are 20kohms or more. And a good output circuit will have an output impedence of 1kohms or less. So lets say you've got a cheap, 2kohm output and you go from driving one 20k input to 2 20k inputs. Driving one input you're passing 91% of the voltage amplitude. Driving two you're passing 83%. Not a big loss.

    The problem I see more frequently is having enough output voltage from your receiver's subwoofer output to drive a pro amp. The pro amp inputs are designed to work with a larger voltage swings and sometimes you'll see posts where guys just can't drive them hard enough to really use their power. That's the whole reason that SVS co-created their "black-box".
     
  7. Scott Parker

    Scott Parker Agent

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    Thanks Ryan,
    Yeah I've heard of many people having trouble using their pro amps. Is there a sure fire way of telling if you will have trouble or not? I probably will just stay with the plate amps as I've had good success with those. Do you think a 350watt per AV-15 will be enough to reach Xmax?

    One more question. I'm using LspCad to get a rough estimate of the SPL Curve. When I put in 600watts when I'm using 2 drivers, does that mean 600watts for each or both? Because Xmax can be reached with 600w.
     

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