Ampdog
R.I.P. 23 June 2022
Since the subject has come up again under different threads, I have a question stemming from ignorance of commercial practice. The reply might be interesting to others having perhaps followed the wrong route.
But first to differentiate. Bi-amping in HT mostly seem to refer to using two amplifiers (channels) in bridged mode, thus getting 2 - 4 times increase in available output. That practice is not the subject here.
What I am referring to is frequency selective bi-amping, as typically replacing cross-over filters. From the point of proper loudspeaker control and seamless cross-over it is generally known that this is the preferred method (especially for the low frequency channel), at the expense of an extra amplifier. But the danger, especially with loudpseakers suitable for bi-wiring, lies in that the uninitiated might simply connect the h.f. amplifier channel to the tweeter loudspeaker terminals and the l.f. amp to the woofer terminals, with internal cross-over components still in place as for bi-wiring.
In commercial practice, how often does this happen? I have never seen a loudspeaker with two sets of input terminals/channel and a switch to switch out the internal cross-overs for bi-amping. (But as said before, I am not au faix with commercial loudspeakers.)
To complete the point for those not in the know (I see that engineers will always explain): With frequency selective bi-amping the cross-over is electronic (already somewhere inside the amplifiers proper), and should not be used with another filter still present on the loudspeaker. Further, isolating only say the h.f. side of a passive loudspeaker filter (removing the bridging plates) and using this as a load for an amplifier is looking for trouble, as the filter input below its pass-band is nowhere near say 8 ohm resistive (more or less), and can cause severe instability in the particular amplifier, etc. - similar for the l.f. side.
Just wondering where frequency selective bi-amping is used, do dealers take the trouble (or do clients know) to disconnect the loudspeaker internal cross-over conponents and connect the drivers directly to the provided input terminals?
Croak, others?
But first to differentiate. Bi-amping in HT mostly seem to refer to using two amplifiers (channels) in bridged mode, thus getting 2 - 4 times increase in available output. That practice is not the subject here.
What I am referring to is frequency selective bi-amping, as typically replacing cross-over filters. From the point of proper loudspeaker control and seamless cross-over it is generally known that this is the preferred method (especially for the low frequency channel), at the expense of an extra amplifier. But the danger, especially with loudpseakers suitable for bi-wiring, lies in that the uninitiated might simply connect the h.f. amplifier channel to the tweeter loudspeaker terminals and the l.f. amp to the woofer terminals, with internal cross-over components still in place as for bi-wiring.
In commercial practice, how often does this happen? I have never seen a loudspeaker with two sets of input terminals/channel and a switch to switch out the internal cross-overs for bi-amping. (But as said before, I am not au faix with commercial loudspeakers.)
To complete the point for those not in the know (I see that engineers will always explain): With frequency selective bi-amping the cross-over is electronic (already somewhere inside the amplifiers proper), and should not be used with another filter still present on the loudspeaker. Further, isolating only say the h.f. side of a passive loudspeaker filter (removing the bridging plates) and using this as a load for an amplifier is looking for trouble, as the filter input below its pass-band is nowhere near say 8 ohm resistive (more or less), and can cause severe instability in the particular amplifier, etc. - similar for the l.f. side.
Just wondering where frequency selective bi-amping is used, do dealers take the trouble (or do clients know) to disconnect the loudspeaker internal cross-over conponents and connect the drivers directly to the provided input terminals?
Croak, others?
