Wayne Parham Messages: 18784 Registered: January 2001
Illuminati (33rd Degree)
Just to clarify: I think Bill's suggestion "to go with Erse steel core when it comes to deep bass" is good, but only when it really is "deep bass". If midrange runs through the coil, it needs to be an air-core coil. I think a good rule of thumb is to limit iron-core coils to woofer circuits used below 300Hz, maybe 500Hz tops. Above that, the inductance required is small enough that an air-core coil is not all that large anyway. Helps reduce hysteresis and saturation, and the resulting intermodulation distortion that is caused by it.