Originally Posted by kiwi2
Originally Posted by grigorianvlad
Yeah, I understand, but I am trying to understand this logic behind "isolated bass and treble sections" in the pic above. How are they isolated? The amp output is just one post. Does the wire do isolation by itself? There has to be some logic behind this statement, however flawed. Is there?
It is the separation of the different current demands that a woofer or tweeter draw. It's the same if you were to take a 12v car battery and connect a 100w headlight bulb with its own run of wires back to the terminals and at the same time a mw accessory like a navigation device unit with its own run of wires back to the terminals.
There are some not-obvious but relevant problems with this example.
The light bulb and the nav gear take power at the same frequency. DC The woofer and tweeter by definition operate in different bands. Seems subtle, but it isn't. Because the nav and the light take power at the same frequency, they interfere with each other. Because the woofer and tweeter take power at different frequencies they take power independently, and would only interfere with each other if the wire were nonlinear. But copper, aluminum and all other common conductive materials are highly linear.
Whether or not it makes a difference is debatable
The debate can be and was resolved by analysis and confirming measurements. There is a measurable effect but it is so tiny that...
but that is the idea behind it.
The actual idea is "buy wire" that can only cause problems. I don't know how many amps were fried by biwiring done wrong, but it was a lot more than one!
Realise when a driver coil moves backwards and forwards through its magnetic field that it creates a back current. If you can separate that from the other drivers then you can theoretically reduce crosstalk.
The back current idea seems to lead to a lot of futile thinking, of which bi wiring is just one. It's valid but it seems to lead many astray. Another way to look at the same same facts is to realize that the counter-EMF causes the impedance of the speaker driver to increase because it counters the flow of current from the amp. Because speakers are passive and the Law Of The Conservation of Energy, the counter-EMF can never be larger than the applied EMF. So, while it can raise the effective impedance of a 4 ohm speaker to 40 ohms, it can't raise it to infinityor make the speaker's impedance negative.Edited by arnyk - 10/16/13 at 4:00am