Using the RDA-7 for 5 speakers

[Jon SS]

If you only have a 5.1 set up and are using the RDA-7 amp is it possible to use 2 of the power amp's channels (bi-amp) for each of the front speakers thereby using 300W for the 2 fronts and 150W for the centre and each surrond. If so, how do you do this?

Many thanks

[Burke Strickland]

Yes it is doable, if...

1) you have speakers that are truly "biwireable / biampable" with separate terminals for the upper range and lower range drivers (usually "jumpered" when only using a single wire and amp).

2) you have an active external crossover between your pre/pro and the power amp.

The RDA-7 owner manual explicitly states that two amp channels must NOT be run in "parallel" to the same speaker, which is what you would be doing if the speaker has only one set of terminals for the speaker cable connection and have two amp channels connected to the single terminal on a given speaker.

a single speaker should never be connected in parallel to both the right and leftchannel terminals simultaneously.

If you don't use an external active cross-over and tried using Y-adaptor/splitters instead to feed the amps, you would be sending the same signal to both amps and overdriving the speaker drivers (assuning you used separate terminals) since you would be feeding a full range signal to both sets of drivers without the benefit of any crossover, or connecting the power amps "in parallel" to the same termninals which we have already noted is a "no-no".

The external active crossover would be connected to the L/R outputs of your pre/pro and then the separate high/low signals for each channel would be routed to two of the RDA-7's amps for each channel and from there connected to the high/low speaker terminals.

Hope that helps. Good luck!

Burke

[Jon SS]

Burke,

What is an external crossover? If I get the RDA-7 I would be using the RDC-7 balanced outputs.

Thanks for the help, some of the tech stuff is a bit confusing.

[Burke Strickland]

Jon -

An external crossover is a separate component that electroncally separates the high frequencies from the low frequencies so that each speaker driver only gets the bandwidth it is designed to handle. Typically your speakers have an internal passive crossover to do that job after receiving the signal from the amplifier. But if you "bi-amp" and connect the wires to the speaker's bi-amp terminals, the internal crossover is bypassed, so an external one must be used. If you are using the balanced outputs from the RDC-7 then you would need an external crossover designed to handle that kind of connection.

More information on biamping and the use of external crossovers (just found those recently -- long after I had already written my little missive above):

http://www.djsociety.org/Bi-Amp.htm

http://www.audiovideo101.com/learn/articles/speakers/speakers19.asp

Good luck!

Burke

[Jon SS]

Thanks, the info was excellent!