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Stupidity Exposed! Ignorance Revealed! [message #16584] Sat, 05 June 2004 10:50 Go to next message
wunhuanglo is currently offline  wunhuanglo
Messages: 912
Registered: May 2009
Illuminati (2nd Degree)
OK, so I'm an idiot, but I can't find a fully satisfactory answer on my own so I'm asking for a little info.

The Klipsch crossovers used on the "real" line of speakers (Type A, Tpye AA) have what look to be bell transformers in them. Are these really transformers for impedence matching (or some other purpose I can't imagine) or are they just inductors built into frames for mounting purposes?

Thanks for any help.

Re: Stupidity Exposed! Ignorance Revealed! [message #16586 is a reply to message #16584] Sat, 05 June 2004 13:37 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18786
Registered: January 2001
Illuminati (33rd Degree)
Klipsch uses autotransformers in their crossovers. Autoformers do provide step-up/step-down/impedance matching just like regular transformers but without the DC isolation provided by a transformer. Klipsch uses the autotransformers for level matching, like an L-Pad.

Re: Autotransformers - Thanks Wayne! [message #16588 is a reply to message #16586] Sat, 05 June 2004 21:38 Go to previous messageGo to next message
wunhuanglo is currently offline  wunhuanglo
Messages: 912
Registered: May 2009
Illuminati (2nd Degree)
.

A follow-up question? [message #16589 is a reply to message #16588] Sun, 06 June 2004 08:45 Go to previous messageGo to next message
wunhuanglo is currently offline  wunhuanglo
Messages: 912
Registered: May 2009
Illuminati (2nd Degree)
Thanks Wayne, that made it somewhat clearer. But what I'm still uncertain about is where the inductors are?

All I've ever seen about DIY crossovers is that they're LCR networks, and what I'm used to seeing is an obvious air core inductor. But in the Klipsch design they must be using the self-inductance of the transformer somehow?

That seems pretty difficult, because it seems to me that the inductance in the secondary is going to vary by what tap you use, and the essentially paralled inductors of the primary and secondary are going to have variable interactions depending on the size of the secondary selected?

I found some indication in the patent referenced in the URL that the inductance of the transformer is used as part of the low-pass filter. But I get the impression from the patent that the ratios in that transformer are fixed, not user selectable as in the Klipsch. Does Klipsch simply accept the variations as a compromise to achieve lower losses than they'd have from using resistors to pad the input?

Maybe this is all to complicated for somebody who never got past Ohm's Law!



Re: A follow-up question? [message #16590 is a reply to message #16589] Sun, 06 June 2004 14:51 Go to previous message
Wayne Parham is currently offline  Wayne Parham
Messages: 18786
Registered: January 2001
Illuminati (33rd Degree)
Transformers and autotransformers are coils and so have inductance. That can be used to form a low-pass or band-pass filter. What I'd suggest is to model the schematic(s) in Spice to see the signal output for each driver. Might be an interesting exercise.

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