If you end up with two 50w amps, one great for midrange and tweeters and one great in bass, you can biamp them beause, low bass is unidirectional and only quantity matters.
Atleast I was trying out the above. Did not succeed because of the reasons mentioned.
The amps in question were musichall which was great in midrange and highs and NAD 2400 which was great in bass.
Let me explain in as simple a way as possible without too many terminologies
You are talking about passive biamping. the crossover is already set by the manufacturer, In most 3 way FS speakers the lowest woofer is not crossed at under 80hz, it is usually at 150 hz or 200 hz. at this high a wavelength bass is directional.
Unless offcourse you have one hell of a behemoth FS speaker which actually houses a Passive Subwoofer Driver - In that case the story is entirely different as the manufacturer would set the crossover of the subwoofer driver at 80hz or lower
Anyway when the speakers we are talking about is the front channels it does not make a difference if the bass is directional or not. Since it is in the front of the listening position. Quantity is not everything unless offcourse you want to drown all the other freq with Bass. In that case its better to just add a subwoofer and be done with it.
Anyway
Lers take for example a 3 way generic brand speaker run without biamping /biwring
(Example) 2* 6.5 woofers and a tweeter FS speaker
The 2 woofers would have different crossover points.
First woofer (the lowest one) crossover is at 200hz, so any freq 200 hz and below that the amp sends will go to this driver
Second woofer ( the middle one) crossover is usually at 1000-1500 hz so any freq that the amp sends under 1500hz right up to 200hz will go to this driver.
Tweeter anything above 1500hz fq the amp sends will go to the tweeter.
Now when you biamp the speaker, most manufactures have designed the crossover inside the speaker that it will segregate the bass and mid bass freq drivers as one unit and the tweeter as a second unit. ( Also called Passive Biamping)
And this is the case probably with your speakers
So with 2 amps running in tandem biamp to your speaker.
The 2 woofers in the example above will take the load from one AMP ( 40hz to 1500hz) and the tweeter (1500hz to 20khz will take the load from the second amp.
And this is probably what happened in your case. that's why the NAD played the entire bass as well as midrange and the music hall probably only played the Treble freq
Ideally you should not be using 2 different amps to biamp - because gains have to be matched - however if your preamp does it, its a different story. Or else you would have bass
Anyway to overcome this what is actually required is an active crossover connected to each of your drivers in the loudspeaker and if you know the Parameters of each driver you can then use the active crossover to segregate frequencies going into each speaker driver from each amp. (It is complicated but very much doable) This is Active Biamping
That is why in my post to corelement, I asked to him to try biamping and the result would be dependent on the crossover network in the speaker.
