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

Bi-amping need not be complicated and difficult. And, it can be cheaper than replacing stock speaker-level x/o parts with those pricey boutique ones.

Really the only one’s who should engage in this are those who have speakers specifically designed with active crossover in mind (pro speakers), or who can build their own speakers anyway.

Everyone else is probably going to do it wrong and is far better off with a single amp solution.

Best,
E

@erik_squires 

bdp24 said..  Beside the advantage of a bi-amped speaker presenting an impedance of less variation to each of the two power amps than one amp sees from a non-bi-amped speaker

This is what I think he is saying. 

The advantage of a bi-amped speaker is that is presents an impedance of less variation to the individual power amps than what one amplifier has to deal with when the high and low drivers are strapped together. 

I think this is easy to confirm. Just think of capacitors and inductors hooked together vs them not. 

I dont see why you say this statement is not true. Seems true to me. I believe bdp is saying that the high and low terminals driven together are a much more difficult load than the high and low terminals strapped together. 

Really the only one’s who should engage in this are those who have speakers specifically designed with active crossover in mind (pro speakers), or who can build their own speakers anyway.

Everyone else is probably going to do it wrong and is far better off with a single amp solution

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Well they have my permission and I am willing to help. Ye of little faith. 

Is it soooooooo hard to buy a woofer and a tweeter, divide the signal before the amps, choose appropriate amps. 

As far as I am concerned, speaker level crossovers where an ok solution when one had only one amplifier. Now we have lots of ampifiers. A 6,12,18 db/octave analog crossover is childs play. 

@bdp24 

Being able to get rid of the speaker-level crossover parts is one of the two reasons for bi-amping (doing so has at least the potential for producing a worthwhile improvement in the sound quality of a loudspeaker). The other is, as Roger Modjeski said above, to separate the low frequencies from the mids/highs in the amplification (giving each it’s own amp, of course), thereby decreasing the potential for the creation of IM distortion in the amp(s).

Bi-amping need not be complicated and difficult. And, it can be cheaper than replacing stock speaker-level x/o parts with those pricey boutique ones. Not only that, you can use a brute-force amp on the woofers if you want, with a nice tube amp for the mids and highs. I first bi-amped with a pair of Magneplanar Tympani T-I loudspeakers in 1973, using the ARC passive x/o designed specifically for that task. Nelson Pass makes a great electronic x/o, but it’s not cheap. Fortunately he also makes (or made, it has just been discontinued) a modestly-priced 2-way x/o, the First Watt B4. It provides 1st/2nd/3rd/and 4th order filters in 25Hz increments from 25Hz to 3200Hz. All discrete (no opamps, no ic’s), retail price $1500. Reno Hi-Fi may have one left, I don’t know. For DIY’ers, it will soon be available as a kit

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Thank you bdp. I am in total agreement. We may have to do some education on this. There are many crossovers out there. My Beveridge RM-3 shows up now and then for a few hundred dollars.

I have recently made some 2nd and 4th order Linkwitz-Riley PC boards that use a quad op amp. I will supply a TL-074 but any quad opamp will work. 

IMO, parametric equalizer pair with active crossover can make a huge improvement!

@erik_squires 

Hi, Ive been reading your blog. Do you really feel this way about stereophile.  Hearing aids? Trick? What is the "stereophile curve
"?

  For a long time I've had trouble matching up Stereophile reviews with my experience of the same speakers. I think I've found the reason why. They aren't reviewing speakers at all. They are reviewing hearing aids pretending to be speakers. This is why they are so expensive. What I mean is that the speakers Stereophile praises would only sound good to some one with hearing loss between 7kHz and 15 kHz, which I lack. It's clear that completely different manufacturers have taken advantage of this "trick."

I'm calling this trick the "Stereophile Curve" and the more I go back in time to look at megabucks speakers rated highly, the more apparent the truth of this curve becomes. Of course, the alternate, benign explanation is that the reviewers have all bought the B&W studio heritage hype, and they have become accustomed to thinking of the B&W 800 series speakers as a neutral reference, which, objectively, they can't be.