Freaky speaker experience:


I have the Nuforce 9SE pre's and amps. I had them attached to my Focal JMLABS 936; bi-wired at the speaker but single ended at the amp. They sounded soooo crappy (tinny, bright, fatiguing) that I was ready to toss them off the second floor window. :) Could'nt understand. For kicks, I single wired it using the original jumpers. Now they sound awesome. About 10 cd's later still awesome.????? They sound different but as good as my Totom Mani's. Any ideas about the bi-wiring? Too much juice going to the high end?
cepages
I am going to have my wife try and trick me by bi-wiring and not bi-wiring; good suggestion. I want to make sure this is real. Plus play more music. But it was such a change that I believe it is real and not what I hope is real. I hated to think that I had to sell those huge heavy things in this market.....

No I tripple checked and the wiring has always been in phase.
Al- in your opinion when the speaker jumper is removed to bi wire would that change driver impedances the amp sees as now the crossover is presenting different cap and inductor values to the amp driving them which happens to be the same for both woofers and high frequencies;maybe that seperation of the drivers is causing a strange impedance presentation to his amps? Just a thought.
i had the same experience happen to me with my infinity renaissance 90's, when i was buying speaker wire i wanted to get two identical sets so that they would sound the same so i spoke with the manufacturer before buying the wires and he told me that when you bi wire the current of your amp gets divided between the two wires and that only half the current would get to the woofers and half to the highs and he told me that he does not like to bi wire speakers, of course i did not believe him and bought the two sets of wires so that i could bi wire, well i have to say that the speakers had more detail and sounded clearer but they lost most of their dynamics and had no punch, i hated the sound of them, i too liked them better with a single wire, i though that maybe speakers that are harder to run ( need more current) like the ren 90's sound better with the single wire and maybe the manufacturer was right in that the current gets divided between the two wires when bi wired, then i added a second amp and bi amped the speakers and what a difference, they sound clear like when they where bi wired but now have all the punch and dynamics you could ask for, i could not believe the difference i was hearing, if i where you i would try to bi amp your speakers you won't believe the difference.
greg
Rleff -- Interesting thought, but I wouldn't think so. From the amp's perspective, the speaker load impedance should appear to be the same in both cases, with the VERY slight exceptions that:

-- The total wire resistance and inductance, being greater in the non-biwired configuration, would cause the amp to see a VERY slightly heavier load in the biwired configuration.

-- The amp would see a VERY slightly greater amount of load capacitance in the biwired configuration.

-- The amp would have to deal with a VERY slightly greater amount of back-emf from the woofer section in the biwired configuration, because a VERY slightly greater fraction of it would be absorbed by the high frequency section of the speaker in the non-biwired configuration.

But I would think that all of those differences would be extremely minute, probably not audible at all, and certainly not enough to account for what Cepages seems to be describing. And having the amp deal with woofer back-emf, rather than the mid/tweeter parts of the speaker, normally improves rather than degrades the sound.

In saying these things I'm assuming, of course, that the wires do not have extreme, outlandish values of either resistance, inductance, or capacitance.

Greg said:
he told me that when you bi wire the current of your amp gets divided between the two wires and that only half the current would get to the woofers and half to the highs

He mis-stated that to you. What happens when you biwire is that the low frequency part of the crossover network in the speaker, being in series with the low frequency wires between the speaker and amp, keeps the high frequencies from going through the low frequency wires. And the high frequency part of the crossover network in the speaker, being in series with the high frequency wires between the speaker and amp, keeps the low frequencies from going through the high frequency wires. The result is less interaction between high frequency and low frequency currents, which normally results in a slight benefit. Also, as I noted above, back-emf from the woofer is conducted entirely to the amplifier, rather than some fraction of it being conducted to the mid/high speaker elements.

It's easy to understand how bi-wiring can result in either slight improvement or no improvement, but frankly I have no idea how it could result in significantly worse sound (assuming, again, that the cables have reasonably conventional parameters).

Regards,
-- Al