How? Could I not wire as follows:
Terminal + of coil 1 to channel 1 +
Terminal - of coil 1 to channel 1 -
Terminal + of coil 2 to channel 2+
Terminal - of coil 2 to channel 2 -
If the amplifier is not bridged internally, aren't all minus terminals on the amplifier referred to the same ground potential? If so why use the ground terminal of an other channel?
Assuming it is, what's the benefit of using the terminals of the 3rd and 4th channel over just connecting it 'nornally'?
Yes, that's correct.
I was saying that you can't talk about an advantage because this is the only possible connection, so you have no choice (we're talking about an amplifier connected internally in bridge).
You can have an advantage when you have the possibility to choose one of two available conditions.
However, if you follow this type of connection, the problem of filtering remains.