external xo

[pwiner]

I would like to place my speakers passive xo's in my equipment cabinet so it will be easier to tweek (as time permits). But it got me thinking. I was planing to put them in a wooden box. But what about nearby metal from the amps, etc in the equipment rack, or even worse the large power transformers in the amps.

Rod Elliot <A HREF="http://sound.westhost.com/lr-passive.htm">http://sound.westhost.com/lr-passive.htm</A> recomends that inductors be 50mm away from any metal. But what about stray magnetic fields from the power transformers?

Any thoughts or links greatly appreciated!

[Pete Schumacher ®]

> I would like to place my speakers passive
> xo's in my equipment cabinet so it will be
> easier to tweek (as time permits). But it
> got me thinking. I was planing to put them
> in a wooden box. But what about nearby metal
> from the amps, etc in the equipment rack, or
> even worse the large power transformers in
> the amps.

> Rod Elliot
> <A HREF="http://sound.westhost.com/lr-passive.htm">http://sound.westhost.com/lr-passive.htm</A>
> recomends that inductors be 50mm away from
> any metal. But what about stray magnetic
> fields from the power transformers?

> Any thoughts or links greatly appreciated!

magnetic fields drop rapidly with distance. Unless you're sitting them next to the deflection coil of a CRT or right next to a crappy power transformer, you should be fine.

Placing inductors near metal will have varying effects. Near high iron content steel, you could see the inductance change appreciably (like an iron cored inductor). Otherwise, near something non-ferrous or non-magnetic (like aluminum) the effect will be negligible in the audio band. As you move higher in frequency, you could see the inductor mutually couple with any conductive surface and create eddy currents that will alter the impedance. But at audio frequencies, it's not really an issue. Just keep them away from magnetic materials and you'll be fine.