Axiom Home Page Forums General Discussion Advice from Axiom Owners Bi amplification

Chris, Blue Jeans is a no-nonsense outfit, but I noticed that in the discussion of lower capacitance for the cables no numbers for the magnitude of the improvement in the high frequency roll-off were given. In the past I made some rough calculations with such lower capacitance numbers, using typical output impedance and cable lengths, and found that the magnitude was less than a tenth of a dB at 20KHz. So, I'm inclined to consider this to be a measurable but audibly insignificant factor.

As I said, if you're using the analog stage of the CD player, then a better model can improve the sound. I noticed quite an improvement from a 1st gen Sony DVD player to 2007 flagship Pioneer Elite model. But any player which can completely get the bits off the disc and hand them to the receiver in digital form will sound the same as any other model performing the same task.


It is pretty much a required feature of any high-end speaker. If Axiom didn't include them it would be a "con" on every review. Hopefully it adds very little to the price.

I did the math in my head real quick and came up with about the same number. But at 90kHz, you know for those 192/24 DTS-HD MA Blu-rays... Oh, that's about a full dB then.

Well at least BJ took an idea and ran with it, and don't really charge that much more for the LC-1 than they do for the Belden Brilliance video cable.

Thankfully I'm done with analog interconnects now anyway. At least until I get my separates...

When are you planning on moving to separates?

After I complete my 7.1 of Axiom--which should be around the end of the year. I'm going to connect an amp (still leaning toward the 7700 from Outlaw) to the pre outs of my current receiver.

How would one physically go about bi / tri-amping a set of speakers? If you need a crossover independent from the speakers, I’m unclear how to achieve this. I always though the binding posts were tapped off the speaker internal wiring where they needed to be, negating the need for any crossover.

I have an extra 5 X 200 amp to use with my Rotel 1080. My speakers have binding posts for tri-amping. I’d like to give this a try. If needed, I also use an LFMB – although I’m unsure how I’d incorporate this into the equation.

Mike, I didn't really follow the "negating" supposition, but an external crossover(usually electronic)has to be placed prior to the amplifiers so that each amplifier only gets an input of the desired frequency range. Once that is done and the crossover is taken care of, the internal crossover in the speaker has to be removed or at least bypassed by rewiring so that the signals from each set of speaker terminals go straight through to the appropriate driver. Very few home users actually have gone to the trouble of bi-amping, which as Alan has pointed out is of more significant benefit in professional applications involving mega-wattage.

OK… I get it now, I think. Not real sure why something so simple evaded me. If I were to common the output of the pre amp and send that to three different amplifiers to power my speakers with the binding post jumpers removed, each driver would then get the full amplified, full frequency signal – right? I would need the external crossover to output a frequency range signal for amplification to each separate amp. So my next question, provided I’m following this correctly, are there external crossovers available for purchase for the purpose of bi / tri-amping?

There are some "active crossovers" made by such companies as Rane and Behringer. I've been looking into this option vs a passive crossover if I try a DIY project(tower speakers). I'm most intrigued by the Behringer crossover so far, esp the Ultradrive Pro which is upgradeable and can create virtually any type of crossover. This combined with 3 modest amps like the A500's and you're on your way...

Look at pro-audio crossovers. For Behringer they are DCX and DBX products I believe. The DCX2496 is very popular for people running multiple subs and MBMs because it is very inexpensive.

You might try posting on a forum like diyaudio.com to see what people recommend. For some reason, folks there think the DCX is ok for subs, but not as an active crossover on regular speakers.