Question about Bi Amping

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Bi-amping adds big power, which is always a GOOD thing. You could take it to the next level by inserting a DSP crossover/EQ upstream, and bypassing the passive crossovers in the speakers-- this would be a REALLY GOOD thing :)
 
You could take it to the next level by inserting a DSP crossover/EQ upstream
Theoretically, YES active bi-amping is the ultimate solution. But only if your system is designed with bi-amping capability from the start, like the Monolith, or the one from Sanders Sound Systems. Otherwise, I am still on the fence with inserting DSP crossover in between pre-amp and amp. Why add more complexity into the signal chain unnecessarily: Analog-to-Digital conversion, DSP processing, Digital-to-Analog conversion. If I have a pure digital system, then a digital preamp with DSP crossover makes sense. But, having analogue source, my hesitation is with the extra A-D and D-A conversion in the chain. And we have not touched on the quality of these conversion stages, or the DSP implementation. IF I were to go down this path, I'd probably go with analogue crossover from Marchand Electronics. Given that I have a good preamp, I would probably go with their passive line-level crossover, built to the ReQuest's specs.
and bypassing the passive crossovers in the speakers
This is where I draw the line since I am all thumbs when it comes to modifying circuitry, especially a complex one in my ML ReQuest speakers. Yes, I have seen the DIY instructions on this site, but I prefer to leave things well enough alone. Obviously, there are other members who have successfully modified their crossover for actively bi-amping. I am not one of them. To sum things up in my case: since I don't intend to bypass the speakers' crossovers, inserting the active crossover into the signal chain is a moot point.
 
I have a pair of B&W speakers with an active 24db/octave crossover and bi-amping.
The speakers were not originally cabled for bi-amping, so I had to do some modifications to by-pass the original passive cross-over.
Bottom line : I was never able to identify a significant difference due to bi-amping alone.

Bi-amping + a very well tuned DSP may be a very different story, but it is not the kind of improvement anybody can do after buying off the selves loud-speakers, only the manufacturer is really in a position to do that with a true benefit (like B&W with the $60 000 Nautilus).
The theory of the benefits of bi-amping is very well explained there :
Benefits of Bi-Amping (Not Quite Magic, But Close) - Part 1
Benefits of Bi-Amping (Not Quite Magic, But Close) - Part 2

Bi-amping offers benefit ONLY when the amplifier starts clipping. A powerful enough amplifier will not show ANY benefit.
And a DIGITAL powerful amplifier will run cool too (contrary to Class A / B).
Personally I use an old Tripath amplifier, but the Hypex NC1200 will likely be a good match to Martin Logans due to its low output impedance (2x1200W(2Ω)).
 
Implementing active crossovers and multiple amps only pays off if you can then REMOVE the lossy, passive crossover elements from between the amp and speaker. There's not much point if you don't get the caps and inductors out of there. That will, of course, very much change the character of the loudspeaker, and you may not like the result...... If you get the crossover tweaked just right, it might turn out way better. The pursuit could take days, weeks, .....months!
 

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