My guess is that you won't gain much performance by going the passive bi-amp route, especially if you intend to use an identical Yamaha, because both amps would be running full-range. However, if the Yamaha amps can be bridged for monoblock configuration, resulting in twice the power output, then you could use a pair as single bridged monoblocks, one to drive each speaker. That would give you a bit more headroom. If you were going to use an active crossover and bypass the speaker's internal passive crossover's then bi-amping would be more advantageous from a performance perspective. There are some other possibilities worth considering, such as using a different, higher-quality amp to drive the mid/top with the existing passive networks; or using different hook-up wire to the respective bass and mid/treble sections, biwired to the same amp but optimized for driving the different frequency ranges of the two respective speaker sections. Good Luck!
Joelm, actually, after I reviewed the power output specs on your Yamaha amp, you probably wouldn't benefit from adding more power -- but you may benefit much more by merely using a bi-wire configuration with a better quality high-power amp, like a Sunfire, for example. Sell the Yamaha or use it just for the bass section. :)
Thanks for your input. After I posted this question I did some more searching in the archives and Google and I am now a bit better educated on the subject. I think you are 100% correct in your assessment of what would be worth doing or not. As a low-buck tweek I might just bi-wire the MX-1000.
The next step up that would be worth making would be to add another MX-1000 with an active crossover (I assume it would have to be matched with the internal crossover in the speakers almost exactly or a loss of signal would result) The Yamaha cannot be bridged so that is not an option. I wish it was. As a follow up can you recommend a good active crossover? I don't know if you are familiar with the Infinity Kappa 9, but it has 2 front firing ribbon tweeters a 3" dome mid, 5" dome mid, 2 12" woofers and a rear firing tweeter and rear radition from the 3" dome. ( a total of 6 powered drivers ) Frequence response is 29Hz-45kHz Crossover frequencies are 80Hz,800Hz,4500Hz. Any crossover would have to fit within those specs I would imagine. I need something component size, non-rack mountable.
It is interesting that you mentioned the Sunfire. I am seriously considering trying to find a good deal on a Sunfire Signature Stero amp (600wpc) The 600wpc is at 0.5% THD. A much higher (mathmatically speaking anyway) distortion level than I am seeing with my Yamaha (it is only part of the story I know) What output do you think the Yamaha would put out at 0.5% THD? Or what could I expect out of the Sunfire at 0.003% THD? Thanks again for your input! I have just recently found this site and it is just wonderful to have this resource available!
If your woofer section crosses at 80 Hz you can probably get away with using a Paradigm X-30 active crossover to split at around that frequency or thereabouts. They can be bought new for around $200 and would be fun to play with. You probably would not need to defeat the internal crossover's on the Infinity's -- just tune the X-30 to your taste by ear. As for the distortion figures on the amps, don't worry about that so much. The Sunfire, with the higher rated distortion will probably sound much better than the lower distortion Yamaha -- because the large amount of negative feedback employed to achieve the low distortion figures has other deleterious effects on the sound quality that don't show up in the specs. I believe it skews the phase characteristics which destroys the coherency and authenticity of the sonic presentation. In my experience, this is far more audible than the small increase in measured distortion.
I have a pair of Infinity Kappa 8's that are biiwired. First of all, don't bridge any amp into this load. Bridging effectively halves the ohmage. There is also a switch on the back of these speakers to change the ohm rating to four ohms; start with that. I hear a definite improvement when bi-wiring vs single wiring even with only one amp. Don't use cheap Monster bi-Wires on these speakers they sound terrible. Use MIT or a higher end Monster. Next tubes are very good with these speakers for the highs. The lows really do like Transistors. The second amp if used will relieve the mid-tweeter amp from running out of power so you may hear a difference (I've never tried it). I still have the Kappa eights running with a modified adcom gfa555. I run another bi-amp set up with a separate electronic crossover. The electronic crossover and multiple amps give the sound an almost effortless sound.
Plato- I think that one of the 12" woofers crosses over at 80hz and the other crosses over at 800hz. But I could be wrong about that. Kappa 6 and Kappa 7 (both 3-driver speakers) crossover at 800hz and 4500hz. The have a simpler system of 10(or 12") woofer, 3" polydome, emit tweeter. I am a bit confused with the Kappa 8 however it is the same as the Kappa 7, but adds the 5" dome. And it crosses over at the same freq as the "9" So maybe you are
right and the double 12" drivers are for 80hz and below? That would leave the 5" dome for 80-800hz, the 3" dome for 800-4500hz and the two (actually 3, including the back) emit tweeters (one in front is an "EMIT K" the other is a "SEMIT K") at 4500 and above. I wonder when you bi-amp where the split is. It could be 80hz or 800hz. Time will tell I suppose if I can ever get the guy to find boxes that will allow me to double box them and get them on a plane. I wish I was there........
Dannylw---- Thanks for the insite on the Kappa 8 bi-wiring. Where do your 8's split with the bi-wire? As far as speaker wire goes I am going to get rid of my 16 gauge Radio Shack special "monster type" cable I am running my 7's with. I just bought a spool of Phoenix Gold ZEROpoint Reference II inner space reference speaker cable. It is 10 gauge with a clear outer jacket. It has a copper stranded wire and a silver stranded wire. I assume it is copper to red(+) when I connect it. Is that correct? I think I will try bi-wiring like you said and see what that sounds like.
Regardless of the power rating of your Yamaha, those speakers WILL suck up a lot of power. The more that you have, the cleaner, clearer, louder and less stressed it will sound all things being equal. As previously mentioned, DO NOT bridge an amp into a very low impedances unless the amp is built like an absolute tank. In terms of comparing the Sunfire Signature to your Yammie, that is NOT a comparison at all. I have run a Yamaha M-80 ( their best amp that they ever made as far as most people are concerned ), so i know pretty much what to expect out of the amp that you have. Keep in mind that the Signature is rated for 1200 wpc @ 4 ohms, which is much closer to what your speakers will actually be. For reference purposes, i replaced a bi-amped system consisting of 400 wpc for the top end and 500 wpc for the bottom end with a Sunfire Signature doing 1200 wpc full range. The Signature literally STOMPED the biamped system in terms of clarity, detail, air, etc... At extremely high volumes, the bi-amped system started to get "pinched" sounding due to amplifier compression whereas the Sunfire never seemed to strain in the least and always sounded effortless, even when playing louder than the other system could achieve. The only place that the biamped system was a slight winner over the Signature was in bass slam. Not to take anything away from the Signature, but my "little" Perreaux's will stomp on most amps when it comes to this specific area. While you can use 10 gauge stuff that you just bought for the woofers, I would look for something else to use on the tope section. Try to avoid "zip cord" type wires as they don't do very well with upper midrange and treble response but are fine below appr. 2 Khz or so. Sean
I'm sure the low pass is 80HZ with biwiring. (I removed the wire and listened.) A few years ago I used to use an electronic crossover to handle the below 50HZ signal and that cleaned up the midrange. For single amp use you need a high current amp with these speakers. It doesn't need really high power.
The kappa 9,i agree with most of the above it's good advice ,but don't focus so much on wattage,get yourself a good high CURRENT amp like tke plinus 250,bryston4b,parasound hca 3500 'with out knowing your budget or sonic taste,the 9's could get very bright and harsh with the wrong component's upsstream,i would use a tube preamp and 1 quality amp.never heard any improvment's when i biamped my 9's.good luck.
I agree with gts87. These speakers are merciless if the upstream components are bright. In many ways they are similiar to Thiels in the quality they demand. By the way I agree with his choice of amps too. Throw Conrad Johnson in there as a good choice.