McIntosh MC901's internal active crossover & speaker's internal passive crossover

@erik_squires what you're essentially claiming is that any speaker that can be biwired can also be biamplified - that the two terms are interchangeable. That's simply mistaken and, as I noted, easily tested with a DMM or VOM.

erik_squires

Almost all speakers I’ve seen with 2 sets of inputs and external jumpers separate the crossovers internally.  Otherwise, why have jumpers??

Agreed, biwiring doesn't make much sense and neither do the jumpers. When you biwire, you do not send the full amplifier output to the tweeter, do you? Of course not, you'd blow the bugger out. It still goes through the speaker's x-over. It's easy to verify with a DMM - just check for continuity. Spendors used to be wired that way, IIRC, and it always puzzled me.

A biwirable speaker provides a separate path for lo and hi frequencies, but they are still joined electrically at the xover. A biamplified speaker provides electrically isolated paths for the two frequency bands. That's the difference between the two.

erik_squires

A properly wired speaker for bi-wiring separates out the crossover sections entirely internally.

This is mistaken. What you have described is a speaker designed for biamplification. Biamplifying and biwiring are two different things.

If you connect both outputs of a Mac901 amplifier to a speaker not intended for biamplfication, you’re going to have problems. Big time.

carlsbad2

... the Mc901.  It is a hybrid amp that wants to drive your woofers with solid state and your mids and tweeter with tube.  To do this your speakers have to be set up for biwiring ...

No, the speakers need to be made for biamplifying. Biwiring and biamping are two different things. If you connect both MC901 outputs to a biwired speaker, you'll blow the amp.