KSN 1038 as a "Super Tweeter"

You might be interested in the post called "Pi implementations of quartz piezoelectric tweeters", and in the links to other threads that are contained in this post. As for a specific sugegstion, you might try this:

=== 10kHz Filter ===

Series Capacitance = 1.0uF
Parallel Resistance = 16 ohms


freq     resp
=============
20kHz   -1 dB
10kHz   -3 dB
 5kHz   -7 dB
2.5kHz  -13dB

That will give you some subtle "sparkle" and is probably what you're looking for.

Alternately, I'll describe the exact filter you've asked about, which is a first order 20kHz network. If this is what you want, you'll need a capacitor that's exactly half as big as the one listed above. So you'll want a 16 ohm resistor across the tweeter, and a 0.47uF capacitor in series with the tweeter/resistor connection.

This will give the following response curve:

=== 20kHz Filter ===

Series Capacitance = 0.47uF
Parallel Resistance = 16 ohms


freq     resp
=============
20kHz   -3 dB
10kHz   -7 dB
 5kHz   -13dB
2.5kHz  -19dB

A KSN 1038 using this second filter might add some "air," but it will be crossing over pretty high.

In either case, choose only polypropylene film and metal foil capacitors. Don't use electrolytics, tantalums or other metalized film components. Actually the metalized film parts are acceptable for larger values, but capacitors with values this low are inexpensive and easy to find having metal foil. So you can afford the best at a buck and a half. On the resistors, use only non-inductive parts. You'll probably have little trouble with 16 ohms, since 4, 8 and 16 ohms are common values for non-inductive resistor manufacturers.

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