[Rocky'sDad]

Hi all.  I'm considering purchasing some ACI speakers and have some questions about bi-amping.  It seems from what I've read and viewed on the website that most, if not all, ACI speakers are built with a single set of binding posts, so bi-amping or bi-wiring is not possible.  Is that right?  If so, could Mike or someone else explain why that decision was made or the general considerations of the capability of bi-amping in speaker design.  Is it a myth that speaker performance is improved by bi-amping or is it that the improvement is not sufficient to justify the cost of having two sets of binding posts.  Any general information on this topic would be much appreciated.
Rocky'sDad

[guest]

The subject of biamping is controversial to say the least.  Let me give you a short answer of what I believe is the truth based on what the more scientific side of the high end would be.
If you are seeking to get more power out of your amplifier by supplying another similar amplifier and biamping, don't bother.  If your amp is capable of driving the speakers impedance load adequately, there is no gain with biamping.  In other words, 2 stereo 100 watt amplifiers would still give only 100 watts to the speaker.  Each amp sees the same signal on the input side, and the same load on the speaker side, so how could it be any different.
If your amplifier is having a little trouble with the impedance of the bass unit, let's say, and your amplifier's ability to cleanly play the midrange and highs is affected, then biamping could give you some small benefit, but it would not be great.  I would recommend just getting a better amplifier under this scenario.
If you want to combine two different sonic signatures as a goal of your biamp, like solid-state on the bass and tubes on top, this makes sense.  It's not the way I would go, but to each his own.
I have seen biamping effectively done when you want to equalize each drive unit near the crossover, without affecting the other drive unit.  A friend of mine biamped a sloppy midrange unit and tweeter, equalized the midrange only, leaving the tweeter alone.  Very effective.  
I have not found any reputable amplifier or loudspeaker manufacturer who disagrees with any of these statements.  By the way, I don't come up with this stuff on my own, but I have very patient knowledgeable friends who have pounded this into my head for the last 20 years.
Bottom line,
Get better loudspeakers, get a better amplifier, buy more concert tickets, take your wife to dinner, buy more ACI stuff !I heard the Sapphire at CES this year and I was absolutely stunned!)

Thanks for listening!   Dan

[Mike Dzurko]

Dan did a great job with his reply. My feeling is that generally I'd rather put the money into ONE set of the best cables, and ONE best amp than split the $$$ in two.

Bi-amping makes more sense if it is done at line level, with line level crossovers . . . but that is a whole other piece of cake.

Adding a second set of binding posts adds to the cost for everyone, but only about 10% of the users choose to use it.

Having two sets of posts means that about 90% of the folks will be using jumpers rather than bi-wire, and now we're adding an additional contact, not something that is desirable.

Our speaker models are designed to not only sound great, but to be relatively easy loads for any amplifier to drive. There are many great choices of amplification that will work well, and you won't need to have two amps, just one good one  

[larry99]

I was powering my VMPS RM-30's with a single NAD2700 (2 channels @ 150Wpc) When I looked at the price of upgrading my speaker cables it was cheaper to buy a second NAD2700 ($350 for a nice used one) and get really short speaker cables. The RM-30 have a bi-wire capability so I ran the left channel to the woofers and the right to the mid/tweeter section. As expected and as pointed out above, there was no increase in volume. I did notice that the mid's and high's sounded much cleaner at high volumes. I believe this is due to the amplifier looking at a higher impedance loads and the total amplifier current being cut in half since each amp was only driving one speaker. I did not add an electronic cross-over, just let the speakers cross-over do their thing.