thank you
BertusResistors
Resistors are again benign, although they will always contribute heat if dissipating any power. While non-inductive resistors are available and are recommended, the error introduced by a normal (slightly inductive) resistor will typically be far smaller than the normal production differences between supposedly identical loudspeaker drivers. Any errors introduced will generally not be apparent within the audio band. The inductance of most power resistors is such that the wiring may introduce greater errors than the resistors themselves, given that each 10mm of (straight) wire adds about 5nH of inductance to the circuit.
Bear in mind that some 'non-inductive' resistors are identical to 'ordinary' resistors except for the non-inductive marking and the price. I've seen and measured some so marked and compared them with the same value of standard wire-wound resistor, only to find no worthwhile difference whatsoever. This does not mean that all suppliers of non-inductive resistors are cheating, but some most certainly are.
It is important to ensure that the power rating for all resistors is well above (preferably double) the expected average power to which they will be subjected. This is much lower than a full power steady state (sinewave) analysis might indicate, but it may be necessary to experiment a little during the final tweaking phase.
Naturally, any resistor that gets hot cannot be glued to the crossover board with hot-melt adhesive, and ideally should be clamped with a metal bracket to help dissipate heat and ensure that vibration cannot move the part - this may cause the lead(s) to eventually fracture. Rattles inside the box are definitely not desirable either!
by Jake Hertz
by Jake Hertz
by Jake Hertz