Does anyone know how this big copper coil is called?
It's part of a subwoofers crossover.
Thanks in advance!

 

It is an inductor.

 

It is an inductor. (Also known as a choke.) It will be in series with the low frequency speaker (Woofer.) to filter out the high frequencies.

Les.

 

the combination of the Capacitor, the big black thing lol and the coil form a filter

 

For audio frequencies, especially for subwoofer crossovers (AND high power), you need a passive, low loss filter. That means inductors and capacitors. For the inductors, they will be HUGE at those frequencies. To be low loss, that means that they will be even HUGER! As everyone has pointed out, that big copper thingy is an inductor. And although inductors are used as chokes, in this case it is wound to be very close to a designed value so as to resonate with the capacitor, which is also a precision device. A choke has a wide range of values that work, while in a filter, a PRECISION value is required.

 

Thanks for all your replies,
this really cleared things up a lot for me