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sub amp [message #51011]

Mon, 23 April 2007 20:55

tmoore
Messages: 15
Registered: May 2009

Chancellor

Would an inexpensive plate amp such at the Dayton unit from parts express be sufficent to drive the 3 pi subwoofer? Are there other inexpensive options?

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Re: sub amp [message #51012 is a reply to message #51011]

Mon, 23 April 2007 22:57

Wayne Parham
Messages: 18686
Registered: January 2001

Illuminati (33rd Degree)

I'd run it with an amp rated 100 to 400 watts RMS into a 4Ω load. There are plenty inexpensive amps that will work. The 100, 240 or 500 watt plate amps sold by Parts Express will do just fine. If you add a cooling plug and some sort of a heat sink, you can run the 1000 watt plate amp.

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Re: sub amp [message #51020 is a reply to message #51012]

Tue, 24 April 2007 19:17

tmoore
Messages: 15
Registered: May 2009

Chancellor

Does it matter if the driver and port are facing into the room or can they be downfiring? If so how high off of the floor should the sub be positioned?

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Re: sub amp [message #51022 is a reply to message #51020]

Tue, 24 April 2007 20:21

Wayne Parham
Messages: 18686
Registered: January 2001

Illuminati (33rd Degree)

You can point them downward but it will change the acoustic/pneumatic loading on the driver slightly, so response will be affected. To know what degree and therefore how far is "best" is entirely empirical and depends on other boundaries too, like whether in an open space or near a corner. Don't take this to be words of discouragement; Far from it, I think it's a good idea. Floor loading is like corner loading. What I am saying is that there are more variables involved than just a set figure. That said, there is one figure I can suggest, and that is don't get further than 1/4λ away from a boundary at the crossover point, which is about 2 feet. If you must be further than that from a nearby boundary, try to keep it further than 1/4λ of the lower cutoff, which is 14 feet. You're usually limited by the ceiling at 8 feet. That makes a notch at 35Hz, which is still pretty good.

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Re: sub amp [message #51025 is a reply to message #51011]

Fri, 27 April 2007 07:51

colinhester
Messages: 1349
Registered: May 2009
Location: NE Arkansas

Illuminati (3rd Degree)

I'm currently building two 3 Pi subs, and I think I'm going with the 250 watt plate amp w/ remote control from parts express. However, I do not know if this particular amp has the on/auto-on feature. Personally I hate the auto-on setting. I'm giving up my 1000 watt plate amp for this very reason. There is nothing more annoying than hearing it kick on in the middle of a piece......C