2. amps-preamps
  3. 135981-2164

Bi-wiring to 4 and 8Ω speakers

I use Parasound JC 1 monoblocks LCR, each of which has two pair of speaker terminals.  I'm wondering about connecting one pair to the 4Ω LF terminals of a KEF Reference 107/2 and the other pair to the 8Ω terminals of an LS50.  There would be no connection to the HF terminals of the 107/2.  Would mixing impedances in such a way endanger the JC 1s?  The goal is pairing the magnificent LF of the 107/2s with the modern MF/HF of the Uni-Q LS50s.

In a couple of weeks I expect to audition a pair of 207/2s and Reference 3s, both of which use Uni-Q for MH/HF.  Have yet to hear Blade 2s.

db
dbphd

Showing 2 responses by erik_squires

erik_squires
16,732 posts
 
So I've been doing some reading. Those speakers rely on an active EQ circuit, the KUBE, that adjusts the signal levels before the amplifier. 

Of course, this would make the resulting output quite unusable for other speakers. 

https://www.stereophile.com/floorloudspeakers/550/index.html

Best,

Erik 
erik_squires
16,732 posts
 
Hi Dbphd,

Sounds messy. 

Parallel impedance divides. When speaker makers do this, the crossovers prevent impedance dividing. That is, the tweet, midrange and woofer don't seem to be in parallel to the amplifier's sense of impedance (more or less). 

Without that, the basic resistance formula is like this R = 1 / ( 1/Ra + 1/Rb ...) so, roughly:

R = 1 / ( 1/4 + 1/8 ) = 2.7 Ohms. 

A pretty low value. 

Also, there is no level matching. Again, something crossover designers do for you. The level of one speaker may be far different than another. 

So, in general, I'd say no, don't do this.  If you were going to use a pair for say, one pair in your pool, another in your bedroom, this approach would be OK if the resulting impedance was high enough. 

What you really want to do in this case is use an active crossover, and separate amps for each speaker. 

Best,

E
More to discover