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

Since my HK3480 has outputs for two sets of speakers I'm wondering if there would be any improvement in sound if I would use them to bi amplify my M80's or is it necessary to get a separate amp to do so?

There will be no benefit with passive biamping. Neither with the H/K or separate amps. Use the 3480 as is.

Asher, that would not be true bi-amping. Besides, why do you think you need to bi-amp your 80's anyway? True bi-amping can be costly to get the appropriate equipment, and you would have to remove the passive crossovers in the 80's, which probably is not a good idea.

That would actually be lowering the impedance the M80s presented to the receiver, I believe--a bad idea.

No, it would still follow the same impedance curve. It would be no different than having the binding post straps in place. Just removing the straps wouldn't change the characteristics of the speakers.

No, it is best to bi-wire........far less costly than bi-amping.

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Better if ya have M80s though.

hope these guys didn't scare you off Asher.

Arthur(welcome back), your 3480 doesn't have provision even for the phony "bi-amping" that some of the multi-channel receivers advertise, using the back surround channels. The provision in the 3480 is simply an internal splitter to the same two output channels, allowing two sets of speakers to be driven in parallel. There's no electrical difference regardless of which set(or both)of terminals that you use, and it isn't bi-amping.

Actual bi-amping requires separate amplifiers with an external crossover before each amplifier so that each amplifies only a limited frequency range. The internal speaker crossover has to be bypassed.

Your 3480 has a quite powerful amplifier and it's highly unlikely that you're using its full power capacity.

After 38 years of using hi-end equipment and being immersed in hifi using some systems that included bi & tri-amping, bi & tri-wiring and megabuck cables - I will go on line stating that in double blind listening tests (with millisecond A/B switiching +/- 0.5dB) there is NO IMPROVEMENT WHAT SO EVER, MEASURABLE OR AUDIBLE achieved by simply using more wire UNLESS you are using wire that is too thin for your speaker run in the first place.
In electronically measurable terms (and even audible ones) biwiring is simply not going to improve your set-up one iota. It may assuage an advertising-riddled mind; it may impress the less knowledgeable audiophile, but the actual results are that you will pay money for nothing at all. Nada, Nyet, Bupkus. Biwiring money is better spent in many other areas (more music for example).

Bi-amping is a different kettle of fish and some speakers (none of Axioms in my tests M22, MP 60 or MP 80) may do better with them but it is a very difficult road to travel with the need for perfectly matching amplifiers as the only surefire way to achieve good results.

The Axioms I use in two fo my four systems simply will not benefit from either bi-wiring or biamping unless your amplifiers are very anemic or you desire enough dynamics and volume to have yourself arrested for making a disturbance in any neigbourhood except a farm house in the middle of nowhere. All the Axioms I have tried and bought are plenty loud to the point of being able to cause your eardrums to distort under the SPL and cause dmage to the one thing that all things stereo cannot be purchased or repaired - your ears!

If you want to improve the sound on the cheap start by getting the best speakers you can afford; ones that your existing pre and amp (if its specs are good and you'ŗe happy with it) can power. Next buy a great source component. Spend a bit on the best CD palyer you have read or heard about in a price range that you can cope with. There is some stunning gear coming from China these days that takes a backseat to no one. You can also throw out all the cheap (or otherwise) analogue RCA interconnects you have and contact someone like Cable Solutions to have sets of perfectly shielded digital coaxial cables made for you. These can be used on all analogue signal runs but do an audibly better job at 1/10 the price I have foolishly spent in the past on exotic cables from MIT, NBS etc.

Good luck and happy listening,
Dr. A. Venkmann

I agree with everything you said up to buying the best CD player. I say take that extra money and go to the next level up on a receiver or pre/pro, and get an every-day DVD/Blu-ray player. Ditch the analog interconnects for a digital connection. Now all the player has to do is get the bits off the disc without error, and the receiver does the rest.

I'm lucky to be poor enough that I was able become educated before I dropped money on "Transparent Cable" which I thought would be the best thing ever. Sorry to hear you were able to go down the MIT road.

And welcome to the board!

I bought transparent cable once. Kept tripping over it though...

I accidentally unplugged the transparent cable that powered my invisible fence and my invisible dog ran off. I put posters everywhere. No one has seen him.

I covered your invisible posters with my missing 10 dollar bill poster. No one seems to have seen my money either.

I thank everyone for their thoughtful and intelligent responses to my question.
Speaking about improving the sound of my audio systom,I am definitely not a believer in all the snake oil cures promoted by many in the high end crowd.However I recently purchased a Music Fidelity V Dac which has been highly reviewed in the audio media.Even though I was inclined to be skeptical as to whether there would be any imrovement in sound to my system but purchased it on impulse for $299.I hooked it up to my Sony 2000ES SACD player and lo and behold the sound that emerged from my M80's made them sound like some very high end speakers i've audioned in the salons.
I have over 2000 red book classical cd's as well as over 200 SACD's and the sound of my cd's was of a much higher quality then that of the SACD's.I was truely astounded.
The only downside is that I can't use the Sony for SACD's on my Sony because of the V DAC.I now use a Oppo 970 as my source for them.I would like to reiterate that the improvement in sound was not minimal but highly discernible not only by myself but many others.
Disclaimer:I have no vested connection with Musical Fidelity in any way or form.

"Cable Solutions...perfectly shielded digital coaxial cables made for you. These can be used on all analogue signal runs"
Just to clarify, are you recommending using their coaxial shielded digital cable for analog signal transfer?

I agree with your general statement about starting out with the best speakers one can afford (as high as 65-70% of the budget). I did not think a CD player could make much difference, except recently, but this could be colored by my expectations and psychological bias.

I have recently asked Alan at Axiom about biamping M80s and his response was very similar to that from johnk; i.e., need for active external cross-over and likely no audible improvement. He added that large, concert venues with multi-driver arrays were a different situation where multi-amping with carefully set active cross-overs would make a lot of difference.

That is what he was recommending. Using the digital cables which are capable of handling frequencies in the MHz range; makes for very nice analog interconnects. Except for one thing: Digital, and video interconnects are designed for a 75 Ohm impedance match. The sending and receiving jacks on analog audio equipment are not matched, so throwing out that 75 Ohm requirement allows one to change the geometry of the cable, and achieve lower capacitance, which can improve the high-frequency roll-off. Blue Jeans Cables has done just this with their LC-1 cabling.

How is your CD player connected to your receiver? If it is by digital I'd say there is some placebo effect possible. But there can be an improvement from one model to another when using the analog output stage.

If I had a million dollars,
And a very big room...

Chris, The CD player is connected by analog output to the preamplifier. I use BJ cables (they seem to be passing the electrons just fine ) Placebo effect still possible.

If bi-amping or bi-wiring M80s makes no difference, then I suspect the dual sets of binding posts are included for those who believe there is a difference.

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.

Hey Adrian. According to a long thread on the A500 either on avsforum or audioholics there can be quality issues with the A500.

Tks, I'll check it out.

I still find it odd that this technology has been around at affordable prices for a long time in the mobile audio side, but remains rather esoteric in the home environment. My Alpine head unit in my SUV has active 3-way parametric crossovers in the digital domain. It is great to be able to change the crossover point from 80 at -12db to 63 at -18 if that works better in your setup, or as you replace speakers. I confess, i leave the passive crossover network in place on my expensive separates just make sure i don't screw it up by accident.

Surprised this simple bit of code/chipset has not been dropped into a decent Denon AVR for real use of the 19 amps they are dropping into their AVRs these days.

And the speaker companies would love it - just think how many DIY'ers would blow the tweeter across the room seeing if it could handle a 1000 hz signal! It would open a whole new market for replacement parts.

Charles, just a point re amplifier terminology relevant to your "19 amps" comment. A receiver has just one amplifier with multiple output channels. So, despite the terminology in some manuals, a receiver can't "bi-amp", even if some of its 7 or 9 channels(the 19 channels will be in next year's "upgrade") aren't being used otherwise.

No, I fully realize that. I just mean that its a tricky addition to allow people to do custom cross over setups as discussed above. Agreed, it gives no extra power, etc. But you could build a custom speaker and not mess with a complex passive crossover if they had the digital crossover network I'm referring to routed via ch 1&2 - high, ch 3&4 mid, ch 5&6 mid-bass, ch 7&8 bass, etc. And if done in for pre-amp outs, you could set up a true bi-tri-curious configuration.