In my experience...
Bi-wiring: Use 2 sets of cables from the amps to the M/H terminals and to the L terminals on the speakers. Of course, this uses the passive XO inside the speakers. I didn't notice any benefits.
Bi-amping #1: Use 2 IDENTICAL amps, one for the M/H terminals and the other for the L terminals on the speakers. Tried using the passive XO inside the speakers. I didn't notice any real benefits in my setup.
Bi-amping #2: Use 2 DIFFERENT amps, a SS amp that has tube qualities for the M/H terminals on the speakers, and a SS amp for the L terminals on the speakers. Again, tried using the passive XO inside the speakers. Definitely sounded "different," but in my particular case, the gain of the two amps were different so there was unevenness in the FR of the speakers (which led to...).
Bi-amping #3: Use 2 DIFFERENT amps, a SS amp that has tube qualities for the M/H terminals on the speakers, and a SS amp for the L terminals on the speakers. Added an active XO between the preamp and power amps. This allowed me to match gain in the different amps. Also, due to the high pass filter in the active XO, the amp connected to M/H terminals would only be amplifying the M/H frequencies, while due to the low pass filter in the XO, the amp connected to the L terminals would only be amplifying the L frequencies (this is what I see as the main benefit of bi-amping). This was tried with the passive XO still in the speakers. I noticed some improvements and definite differences in sound, especially fiddling with slopes, crossover points, phase, etc.
Bi-amping #4: Use the same setup as #3 above but removed the passive XO in the speakers. Tried different settings on the active XO. I noticed much bigger changes, better control, and - more importantly improvements in my setup.
Personally, my bi-amp setup allowed me to use an amp better suited for M/H frequencies for those frequencies and an amp with bass slam for those L frequencies. By having an active crossover upstream of the amps, these amps were not being required to amplify the full bandwidth signal. Instead, each amp is only presented with the signal needed for the job - either the M/H frequencies or the L frequencies.
Compare the above situation with a passive XO in the speakers that is downstream of the amps. All amps are then required to amplify the full bandwidth signal, only to have most of that signal discarded at the passive XO's filter networks.
By bi-amping with an active XO, you are able to dedicate the amps for specific parts of the signal, thereby getting (hopefully) optimum performance.
YMMV.
So, IMHO, bi-amping does take a lot of time, patience, and listening to dial in, and requires investment in an active XO, additional amps, and measuring equipment to get the most benefits. But the differences in sound that an active XO or passive XO can impart in a system really needs to be heard.
But Bi-amping isn't for everyone. If you're a person that wants to plug it in and just listen, it may not be for you. Indeed, it's not as simple as adding additional amps or even adding an active XO. There's a lot more to it than that. I got confused a lot and did a lot of trial and error even after reading about XO theory. But if you like tweaking and getting that last bit of enjoyment out of a system, you may want to give it a try.
Also, bi-amping is nothing new. People having been bi-amping since the 80s as far as I know (pro and consumer). More so now perhaps because people are creating their own DIY speakers.
Have fun listening!
Bi-wiring: Use 2 sets of cables from the amps to the M/H terminals and to the L terminals on the speakers. Of course, this uses the passive XO inside the speakers. I didn't notice any benefits.
Bi-amping #1: Use 2 IDENTICAL amps, one for the M/H terminals and the other for the L terminals on the speakers. Tried using the passive XO inside the speakers. I didn't notice any real benefits in my setup.
Bi-amping #2: Use 2 DIFFERENT amps, a SS amp that has tube qualities for the M/H terminals on the speakers, and a SS amp for the L terminals on the speakers. Again, tried using the passive XO inside the speakers. Definitely sounded "different," but in my particular case, the gain of the two amps were different so there was unevenness in the FR of the speakers (which led to...).
Bi-amping #3: Use 2 DIFFERENT amps, a SS amp that has tube qualities for the M/H terminals on the speakers, and a SS amp for the L terminals on the speakers. Added an active XO between the preamp and power amps. This allowed me to match gain in the different amps. Also, due to the high pass filter in the active XO, the amp connected to M/H terminals would only be amplifying the M/H frequencies, while due to the low pass filter in the XO, the amp connected to the L terminals would only be amplifying the L frequencies (this is what I see as the main benefit of bi-amping). This was tried with the passive XO still in the speakers. I noticed some improvements and definite differences in sound, especially fiddling with slopes, crossover points, phase, etc.
Bi-amping #4: Use the same setup as #3 above but removed the passive XO in the speakers. Tried different settings on the active XO. I noticed much bigger changes, better control, and - more importantly improvements in my setup.
Personally, my bi-amp setup allowed me to use an amp better suited for M/H frequencies for those frequencies and an amp with bass slam for those L frequencies. By having an active crossover upstream of the amps, these amps were not being required to amplify the full bandwidth signal. Instead, each amp is only presented with the signal needed for the job - either the M/H frequencies or the L frequencies.
Compare the above situation with a passive XO in the speakers that is downstream of the amps. All amps are then required to amplify the full bandwidth signal, only to have most of that signal discarded at the passive XO's filter networks.
By bi-amping with an active XO, you are able to dedicate the amps for specific parts of the signal, thereby getting (hopefully) optimum performance.
YMMV.
So, IMHO, bi-amping does take a lot of time, patience, and listening to dial in, and requires investment in an active XO, additional amps, and measuring equipment to get the most benefits. But the differences in sound that an active XO or passive XO can impart in a system really needs to be heard.
But Bi-amping isn't for everyone. If you're a person that wants to plug it in and just listen, it may not be for you. Indeed, it's not as simple as adding additional amps or even adding an active XO. There's a lot more to it than that. I got confused a lot and did a lot of trial and error even after reading about XO theory. But if you like tweaking and getting that last bit of enjoyment out of a system, you may want to give it a try.
Also, bi-amping is nothing new. People having been bi-amping since the 80s as far as I know (pro and consumer). More so now perhaps because people are creating their own DIY speakers.
Have fun listening!