To Bi-wire or not?

You've changed two things at once (cable type, and bi-wiring instead of single-wiring), which makes it hard to provide a meaningful response. I suggest that you try the Blue Jeans cables single-ended, with the jumpers in place, preferably with the high and low frequency wires in parallel, or if that is not feasible then using the low frequency wires and leaving the high frequency wires unconnected.

Bass performance can be compromised by some combination of high cable resistance per unit length (i.e., too small a gauge, meaning an AWG number that is too high), long cable length, low speaker impedance, and/or high amplifier output impedance. Let us know as many of these parameters as you can, and we'll be in a better position to help.

You'll also be interested in the following current thread:

http://forum.audiogon.com/cgi-bin/fr.pl?cspkr&1247016622

Regards,
-- Al

Hi Greg -- How long are the cables? What is the gauge of the wire used in the single-wire configuration? And what is the gauge of the wire which carries the low frequencies in the bi-wire configuration?

Regards,
-- Al

Okeeteekid -- I looked into the Kappa 9's a bit. As you realize, but others may not, and assuming that you are using the "extended/normal" switch in the back in the "extended" position, at bass frequencies they are perhaps the most difficult speaker load ever devised by mankind.

In that mode, which seems to be the one most commonly preferred, they go down below 0.8 ohms at some bass frequencies, causing them to be widely known as amp killers.

Your 12 foot round-trip run of 12 gauge wire has a resistance of only about 0.02 ohms, which is negligible even in comparison to the 0.8 ohms. But I calculate that approximately 0.2 ohms of resistance anywhere in the path would result in a 2db bass loss. You shouldn't have that much resistance if all of the joints between cables, terminations, jacks, etc. are well-made and are not oxidized, but when we are dealing with such low levels of resistance being significant, who knows?

In any event, considering how uniquely difficult that speaker is in the bass region, I would not make any generalizations from your observations about bi-wiring that are applicable to anything other than your own setup.

Regards,
-- Al

Okeeteekid,

Here's a theory I just thought of: You are not really losing bass in the bi-wire configuration; you are just getting better bass damping (meaning tighter, more well-controlled bass), for reasons I'll explain below. That would very conceivably produce the slight measured loss in bass response that you have found (I presume using test tones), and on musical material could very conceivably produce a subjective impression of less bass.

The reason that may be happening is as follows:

In the bi-wire configuration, back-emf from the low frequency drivers is conducted directly (and only) back to the amplifier, which in your case has an extremely good damping factor (i.e., an extremely low output impedance). So the back-emf is absorbed there very effectively.

In the single-wire configuration, some small fraction of the back-emf from the low frequency drivers is conducted through the jumpers into the mid-frequency drivers, where it will not be effectively damped (because the impedance is much higher than at the amplifier output), and, more significantly, WHERE IT WILL PRODUCE SOUND THROUGH THE MID-FREQUENCY DRIVERS, ADDING TO THE SOUND PRODUCED BY THE LOW FREQUENCY DRIVERS.

So you may indeed be getting measurably more bass in the single-wire configuration, but bass which is the result of back-emf effects and is therefore less accurate!

Regards,
-- Al