I always see 2 spools of wire inductors in every cross over what do they do,I also noticed they are almost always next to a resistor.
I always see 2 spools of wire inductors in every cross over what do they do,I also noticed they are almost always next to a resistor.
Jeff :UBERTHREADKILLER
Low pass filter.
Sometimes they have a resistor in circuit to stabilise the speaker drive unit impedence.
Chris
Common sense isn't anymore!
In the case of an inductor feeding a bass/mid it rolls off the treble. An inductor has a property known as inductive reactance & effectively what this means is that the resistance of the coil of wire increases the higher the frequency goes - so it rolls off the treble because it's in series with the bass/mid!
In the case of a tweeter it will be in parallel with the tweeter & as it's resistance increases with frequency it will tend to shunt less power to ground the higher the frequency goes In co-operation with a capacitor this will increase the power to the tweeter as the frequency increases.
Resistors are generally on the tweeter side as these tend to be a bit more efficient than bass/mids
Bests, Mark
"We must believe in free will. We have no choice" Isaac Bashevis Singer
Passes them on.
Chris
Common sense isn't anymore!
Ok,so inductance creates the roll off,I always thought caps did that.
Jeff :UBERTHREADKILLER
Caps are hi-pass.
Chris
Common sense isn't anymore!
Capacitors do the opposite Well no, they do create a rolloff but in the opposite sense
Capacitive reactance as it's known creates a reducing impedance (resistance) with increasing frequency.
So imagine your bass/mid again, it has a choke (inductor) feeding it in series & a capacitor shunting the driver. As frequency increases the choke will increase in its AC resistance & the capacitor will decrease in it's AC resistance - it creates a steeper rolloff
In the case of a tweeter being fed in series from a capacitor & having an inductor shunting it you get this... As the frequency decreases the capacitor displays more AC resistance thus rolling off the power to the driver & the inductor also has less AC resistance also creating a steeper rolloff..
Bests, Mark
"We must believe in free will. We have no choice" Isaac Bashevis Singer
It seems a miracle speaker crossovers work at all.
What alot going on for so few parts.
Jeff :UBERTHREADKILLER
Jeff it gets worse as no drive unit has a fixed impedance, they all vary all over the place as well which can bugger up the crossover frequency & driver phase. As you can imagine this make things more complicated
& just to make things even worse the driver sensitivity varies over frequency as well
So yeah, it's a minefield out there
This is why I like electronic crossovers as they are accurate. A whole lot of problems get left behind
Bests, Mark
"We must believe in free will. We have no choice" Isaac Bashevis Singer