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BI-AMP/WIRE basics? INFINITY KAPPA 9

Help-
I am getting a pair of INFINITY KAPPA 9's and I guess they are notorious power hogs so I am considering bi-amping them. I understand they are set up for that, with jumpered binder posts. But I have no knowledge of what the benifits of bi-amping might be. Even if you bi-amp aren't the amps still working the entire frequence range? Is the benifit that the ohm load will be greater and therefore less likely to overdrive the amp? The speakers are rated at 340 watts RMS at 4-6 ohms, but I have read that it can drop to 1 ohm on certain frequencies. The amp I have is a Yamaha MX-1000 and I will be buying another identical one if I bi-amp. The specs on the MX are as follows----RMS 260 @ 8 ohms 0.003 THD / 295 @ 6 ohms 0.007 THD /330W @ 4 ohms 0.02% THD. Dynamic Power 450 @ 8 ohms / 560 @ 6 ohms / 740 @ 4 ohms / 960 @ 2 ohms / 1000 @ 1 ohm. What kind of performance increase might I see by bi-amping. And this may seem like a silly question, but what exactly is bi-wiring? Obviously if you bi-amp you need to run 2 sets of wires, but does bi-wire mean running 2 sets of wires to the
same amp? If you do, do you run them to the A terminals or 1 to A and one to B? It sounds like it could create problems possibly. My pre-amp is a YAMAHA CX-1000 that has 2 sets of outputs. I have 1 going to the MX-1000 now and one going to the line leads for a powered sub. I still plan on running the sub, but now I will need 3 outputs what do I do? ANY help would be greatly appreciated. I realize my equipment may not compare to what most of you guys run, but it is the best I can afford right now. Help me make the most of it. Thanks you guys (I appreciate the feedback on my "shipping heavy speakers" post. I have chosen to use DELTA AIR FREIGHT based on your recommendations. I think it will be safe,cheap, and fast)
a71spud
plato
1,543 posts
 
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!
plato
1,543 posts
 
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. :)
a71spud OP
29 posts
 
Plato-

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!
plato
1,543 posts
 
Hello Joelm,

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.
dannylw's avatar
dannylw
172 posts
 
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.
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