How To Properly Bi-Amp (Sonic Frontiers Line 2 to Two Amps to power Infinity Kappa 9's)


I recently purchased a pair of pristine Infinity Kappa 9's and I am looking to biamp them. I have a pair of Kappa 7's that are using a Behringer Europower EP4000 amp and it works great.  The Ep4000 cannot handle the 9's.

I am confused as to how to split the signal coming from my preamp for proper bi-amping. Do I just buy a split balanced or RCA cable? I feel like this would compromise the signal... Or do I use the additional outs on my preamp? My preamp is a Sonic Frontiers Line 2. I believe it has two stereo XLR outs and two RCA outs.

Please let me know.

...also, what is an powerful enough, extremely holographic, silky sweet amp for the mids and top section of the Kappa 9's? Suggestions would be greatly appreciated.

Thanks,
Brett
8b96c43b e6a2 44b2 9680 9f170d281699brettmcee
brettmcee
I am confused as to how to split the signal coming from my preamp for proper bi-amping.
You need a crossover between your preamp and amplifiers to biamp properly. There are many to choose from ... Bryston, Marchand, Pass, Behringer ...
Thanks for your reply.  The Infinity Kappas already have a crossover setup specifically for bi-amping. I do not think I need an additional external crossover, although it would increase the efficiency in amplification. 
One of the Crown XLS amps I am using has an internal crossover and I will employ it.

Still, how would one split an output signal from the preamp to feed the two amps? Should I just use the multiple outs from the preamp?
brettmcee
Still, how would one split an output signal from the preamp to feed the two amps? Should I just use the multiple outs from the preamp?
To take advantage of biamplification, you really need an xover between your preamp and amplifiers. That will not only allow you to set the xover frequency, but will allow you to adjust for differences in gain between the two amplifiers.

@brettmcee,

Use the multiple outputs of your preamp, that’s what they design for. In most cases, vertical biamping gives your the best possible results i.e. using one stereo amp per speaker. If you choose to use two seperate brand amps, external crossover is highly recommended as @cleeds pointed out.

If your amp has XLR inputs, I would recommend using XLR cables.

I am also bi-amping my speakers with a class D amp (ATI-543NC) for bass and a tube amp (ARC VT-80) for mid’s and high’s.
You don't need a crossover to bi-amp. You do need a crossover to get the most out of it.

The other issue is the SF preamp. If you split the output, to a pair of amps you may fall below the recommended minimum impedance.

Also, it may be worth while investigating online mods for those speakers. Some of the Infiinity speakers had really awkwardly designed crossover with terrible impedance curves, which put undue stress and limited output on amplifiers.

Best,


E
So, as I was examining the crossover, and thinking to myself "There has to be someone who has improved these..." I found this:

http://www.befr.ebay.be/itm/NEW-Infinity-Kappa-7-8-9-Speaker-Crossover-Filter-Network-Kappa7-Kappa8-...

Based on my own experience modding old speakers, I really like the approach they took. The improvement in the impedance will be far better than biamping (of any kind) could do.

Best,

E