"Arny Krueger" wrote in message ...
"Pete Snyder" wrote in message
om
As a followup to my earlier positing about weak bass from my recently
purchased Dynaco A25XL speakers (not A25's - but A25XL !!), I am
searching for an article/review on these A25XL's that would include a
diagram or description of the crossover. I just want to assure myself
that somewhere back in time that a previous owner did't muck around
with the cross-overs and perhaps cause the weak bass that I now
encounter. (Remember that I even replaced the original woofers with
SEAS' current replacement for the Dynaco driver but with NO
improvement!!)

Thanks for any help!

All you need to know is that in a simple 2-way crossover, the capacitor if
any goes in series with the tweeter, and the inductor if any goes in series
with the woofer.

Not so. IN a series-pass crossover, the inductor would be in parallel
with the tweeter and the capacitor in series with the woofer. Two
SPICE files indicate the topological differences. First, the more
common parallel model (assume MyWoofer and MyTweeter are both
appropriate Spice sub circuit models of the woofer and tweeter, and
ignore the fact that the values may or may not be appropriate):

* Parallel crossover net list
Vin 1 0 AC SIN 1.0 0.0

Lwoof 1 2 1MH
Xwoof 2 0 MyWoofer

Ctweet 1 3 8UF
XTweet 3 0 MyTweeter

Now, the same as a series-pass model:

* Series crossover net list
Vin 1 0 AC SIN 1.0 0.0

Cwoof 1 2 8UF
Xwoof 1 2 MyWoofer

LTweet 2 0 1MH
XTweet 2 0 MyTweeter

Two very different topologies

This is not to say the A-25 is one or the other, but beware a
generalization like:

"All you need to know is that in a simple 2-way crossover,
the capacitor if any goes in series with the tweeter, and
the inductor if any goes in series with the woofer."

There is nothing that intrinsically requires a simple crossover
to be designed in this fashion.