Does impedance of a speaker change when one bi-amps?

@byfwyne

So the bottom line is that there seems to be something to be said for light loading.

It was rather obvious to me from the start. The tubes love it.

Does anyone have any questions about why it works so well? The distortion reduction is usually 5 to 1 or more and the damping (regulation) doubles. Noise goes down 3 dB. All you give up is imaginary headroom.

When I tried to run my ESLs off a high quality integrated I learned a lot. For instance the rated power is only deliverable into a resistive load. Anything reactive shut the amp down and a message came up "check for shorted speaker wires" That speaks volumes. The amp thinks anything below X ohms is a short.

Yep. ESL's are basically giant capacitors. 1/3 of an ohm at the top of the spectrum is not unheard of. Fortunately there's very little music power at 20kHz, but it is not an easy load in general.

Thanks for the interest. My Int is A Hegel H360 and the speakers are Revel salon2's. Though I chose the unit to go with the salon1's I had at the time i'm happy with the synergy with the new speakers and now i've had the Hegel just over a year and the new speakers since march I did manage to trip the thermal protection once. I know heat kills and I horizontally bi-amped my R105/3's successfully in the past. The 2nd amp made a big difference with the kef r105/3 speakers really filling out the bottom end. 

The current .7 series Maggies have series crossovers, and are therefore not candidates for bi-amping. The .6 and earlier have parallel crossovers, and can be bi-amped. An electronic x/o is used in place of the external one supplied by Magnepan with the 3.6, and the speaker benefits greatly from bi-amping. Not just for the benefits mentioned above (eliminating the possibility of amplifier IM distortion, etc.), but because instead of one, brute-force amp on all the speaker’s drivers (Maggies need lots of current), two smaller, perhaps better-sounding amps can be used. A ss on the bass panels, a tube on the mid/tweeter is a favorite combination, one I myself employ with my Tympani T-IVa’s. Some long-term Maggie user/owners have therefore chosen to stay with the older models (the .6 is a favorite), primarily to be able to bi-amp.

For the record, almost all passive crossovers also include some form of EQ. If you plan to remove and replace a passive crossover you need to be prepared to do both.

A local speaker builder brought over a pair of his speakers without crossover for me to play with bi amping. The drivers are a $225 Scanspeak woofer and $60 Tweeter. $225 woofers only show up in $10,000 speakers. Most of the price of a complete speaker is in the cabinet and margin for the dealer. When an interested party took at a $10,000 speaker, priced out the components and found the drivers plus crossover to be about $1,000 or less. Its just the economics of the speaker business.

The drivers my local guy had chosen had such flat response that no EQ is needed nor does he build any into his series crossover. The impedance was amazingly constant and he feels this is the main virtue of his speaker. If a speaker has a flat impedance curve then damping is not so big an issue. Good drivers have pretty flat response, that is what you are paying for. 

I have never found a need to add EQ to a bi-amp system if the drivers are good quaity. Besides, in a bi-amp system you already have a woofer and tweeter control (you need only one) to adjust the tonal balance which I do at my own pleasure. The knob is right next to the volume control which I also adjust for my own pleasure. Its all so simple, but so hard to get across. I have to climb the wall of marketing just to get someone's ear.