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  #1   Report Post  
Pete Snyder
 
Posts: n/a
Default Dynaco A25 XL Speaker - Need crossover diagram.

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!

Pete )
  #2   Report Post  
Tim Padrick
 
Posts: n/a
Default Dynaco A25 XL Speaker - Need crossover diagram.

How are they positioned with respect to the floor, side walls, and back
wall?



"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!

Pete )



  #3   Report Post  
Tim Padrick
 
Posts: n/a
Default Dynaco A25 XL Speaker - Need crossover diagram.

How are they positioned with respect to the floor, side walls, and back
wall?



"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!

Pete )



  #4   Report Post  
Tim Padrick
 
Posts: n/a
Default Dynaco A25 XL Speaker - Need crossover diagram.

How are they positioned with respect to the floor, side walls, and back
wall?



"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!

Pete )



  #5   Report Post  
Tim Padrick
 
Posts: n/a
Default Dynaco A25 XL Speaker - Need crossover diagram.

How are they positioned with respect to the floor, side walls, and back
wall?



"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!

Pete )





  #6   Report Post  
Arny Krueger
 
Posts: n/a
Default Dynaco A25 XL Speaker - Need crossover diagram.

"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.


  #7   Report Post  
Arny Krueger
 
Posts: n/a
Default Dynaco A25 XL Speaker - Need crossover diagram.

"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.


  #8   Report Post  
Arny Krueger
 
Posts: n/a
Default Dynaco A25 XL Speaker - Need crossover diagram.

"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.


  #9   Report Post  
Arny Krueger
 
Posts: n/a
Default Dynaco A25 XL Speaker - Need crossover diagram.

"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.


  #10   Report Post  
Dick Pierce
 
Posts: n/a
Default Dynaco A25 XL Speaker - Need crossover diagram.

"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.


  #11   Report Post  
Dick Pierce
 
Posts: n/a
Default Dynaco A25 XL Speaker - Need crossover diagram.

"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.
  #12   Report Post  
Dick Pierce
 
Posts: n/a
Default Dynaco A25 XL Speaker - Need crossover diagram.

"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.
  #13   Report Post  
Dick Pierce
 
Posts: n/a
Default Dynaco A25 XL Speaker - Need crossover diagram.

"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.
  #14   Report Post  
Terry E. Dwyer
 
Posts: n/a
Default Dynaco A25 XL Speaker - Need crossover diagram.

Dick Pierce wrote:
"Arny Krueger" wrote in message ...

"Pete Snyder" wrote in message
.com

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.

I have never looked at the A25XL crossover but I did measure a complete
system 2 yrs ago;the woofer has a 2nd order rolloff at 1.5khz as seen in
a nearfield measurement so there must be at least an inductor to give
the 1st 6db/octave;the 2nd 6db could come from the natural rolloff of
the 10" WFR.
An OHMETER reading at the box input terminals gave 4.7 ohm.

A complete Quasi-Anechoic measurement had -3/-10db points at 63/44hz
with respect to the midband.


  #15   Report Post  
Terry E. Dwyer
 
Posts: n/a
Default Dynaco A25 XL Speaker - Need crossover diagram.

Dick Pierce wrote:
"Arny Krueger" wrote in message ...

"Pete Snyder" wrote in message
.com

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.

I have never looked at the A25XL crossover but I did measure a complete
system 2 yrs ago;the woofer has a 2nd order rolloff at 1.5khz as seen in
a nearfield measurement so there must be at least an inductor to give
the 1st 6db/octave;the 2nd 6db could come from the natural rolloff of
the 10" WFR.
An OHMETER reading at the box input terminals gave 4.7 ohm.

A complete Quasi-Anechoic measurement had -3/-10db points at 63/44hz
with respect to the midband.




  #16   Report Post  
Terry E. Dwyer
 
Posts: n/a
Default Dynaco A25 XL Speaker - Need crossover diagram.

Dick Pierce wrote:
"Arny Krueger" wrote in message ...

"Pete Snyder" wrote in message
.com

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.

I have never looked at the A25XL crossover but I did measure a complete
system 2 yrs ago;the woofer has a 2nd order rolloff at 1.5khz as seen in
a nearfield measurement so there must be at least an inductor to give
the 1st 6db/octave;the 2nd 6db could come from the natural rolloff of
the 10" WFR.
An OHMETER reading at the box input terminals gave 4.7 ohm.

A complete Quasi-Anechoic measurement had -3/-10db points at 63/44hz
with respect to the midband.


  #17   Report Post  
Terry E. Dwyer
 
Posts: n/a
Default Dynaco A25 XL Speaker - Need crossover diagram.

Dick Pierce wrote:
"Arny Krueger" wrote in message ...

"Pete Snyder" wrote in message
.com

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.

I have never looked at the A25XL crossover but I did measure a complete
system 2 yrs ago;the woofer has a 2nd order rolloff at 1.5khz as seen in
a nearfield measurement so there must be at least an inductor to give
the 1st 6db/octave;the 2nd 6db could come from the natural rolloff of
the 10" WFR.
An OHMETER reading at the box input terminals gave 4.7 ohm.

A complete Quasi-Anechoic measurement had -3/-10db points at 63/44hz
with respect to the midband.


  #18   Report Post  
Tim Padrick
 
Posts: n/a
Default Dynaco A25 XL Speaker - Need crossover diagram.

An inductor in parallel with a tweeter, without a series capacitor, would be
seen by the amp as a short at low frequencies. A cap in series with a
woofer would roll off the low frequencies.

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.



  #19   Report Post  
Tim Padrick
 
Posts: n/a
Default Dynaco A25 XL Speaker - Need crossover diagram.

An inductor in parallel with a tweeter, without a series capacitor, would be
seen by the amp as a short at low frequencies. A cap in series with a
woofer would roll off the low frequencies.

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.



  #20   Report Post  
Tim Padrick
 
Posts: n/a
Default Dynaco A25 XL Speaker - Need crossover diagram.

An inductor in parallel with a tweeter, without a series capacitor, would be
seen by the amp as a short at low frequencies. A cap in series with a
woofer would roll off the low frequencies.

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.





  #21   Report Post  
Tim Padrick
 
Posts: n/a
Default Dynaco A25 XL Speaker - Need crossover diagram.

An inductor in parallel with a tweeter, without a series capacitor, would be
seen by the amp as a short at low frequencies. A cap in series with a
woofer would roll off the low frequencies.

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.



  #22   Report Post  
Arny Krueger
 
Posts: n/a
Default Dynaco A25 XL Speaker - Need crossover diagram.

"Tim Padrick" wrote in message


An inductor in parallel with a tweeter, without a series capacitor,
would be seen by the amp as a short at low frequencies. A cap in
series with a woofer would roll off the low frequencies.


Agreed, and that leaves some non-simple problems to solve.

AFAIK the very few commercial designs with an inductor in parallel with the
tweeter use a tweeter that is more efficient than the woofer, and put a
resistor in series with the inductor/tweeter combination. Still not a pretty
picture.


  #23   Report Post  
Arny Krueger
 
Posts: n/a
Default Dynaco A25 XL Speaker - Need crossover diagram.

"Tim Padrick" wrote in message


An inductor in parallel with a tweeter, without a series capacitor,
would be seen by the amp as a short at low frequencies. A cap in
series with a woofer would roll off the low frequencies.


Agreed, and that leaves some non-simple problems to solve.

AFAIK the very few commercial designs with an inductor in parallel with the
tweeter use a tweeter that is more efficient than the woofer, and put a
resistor in series with the inductor/tweeter combination. Still not a pretty
picture.


  #24   Report Post  
Arny Krueger
 
Posts: n/a
Default Dynaco A25 XL Speaker - Need crossover diagram.

"Tim Padrick" wrote in message


An inductor in parallel with a tweeter, without a series capacitor,
would be seen by the amp as a short at low frequencies. A cap in
series with a woofer would roll off the low frequencies.


Agreed, and that leaves some non-simple problems to solve.

AFAIK the very few commercial designs with an inductor in parallel with the
tweeter use a tweeter that is more efficient than the woofer, and put a
resistor in series with the inductor/tweeter combination. Still not a pretty
picture.


  #25   Report Post  
Arny Krueger
 
Posts: n/a
Default Dynaco A25 XL Speaker - Need crossover diagram.

"Tim Padrick" wrote in message


An inductor in parallel with a tweeter, without a series capacitor,
would be seen by the amp as a short at low frequencies. A cap in
series with a woofer would roll off the low frequencies.


Agreed, and that leaves some non-simple problems to solve.

AFAIK the very few commercial designs with an inductor in parallel with the
tweeter use a tweeter that is more efficient than the woofer, and put a
resistor in series with the inductor/tweeter combination. Still not a pretty
picture.




  #26   Report Post  
Dick Pierce
 
Posts: n/a
Default Dynaco A25 XL Speaker - Need crossover diagram.

"Tim Padrick" wrote in message ...
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


An inductor in parallel with a tweeter, without a series
capacitor, would be seen by the amp as a short at low
frequencies. A cap in series with a woofer would roll off
the low frequencies.


Too bad you didn't try to understand or analyze the circuit.

If you were to put JUST a tweeter and JUST an inductor in parallel
across an amp, you'd be right, but that's VERY clearly, from the
topology above, NOT what is happening. You cannot look at a circuit
and simpy pick little pieces of it and expect a quick analysis based
on one piece to give you a coherent picture of the whole. Let's, in
fact, do a more complete analysis and see what is REALLY happening

We'll make some simplifying assumption just to make the analysis
easier: we'll replace XWoofer and XTweeter with resistive loads
RWoofer and RTweeter.

Start at frequencies well below the crossover point. At these
frequencies the impedance of shunt capacitor CWoof is very high,
and that of the shunt inductor LTweet is very low. As a result,
the current flows through the woofer leg (RWoofer) and through
the inductor LTweet) And the amplifier sees, essentially, the
woofer as the load.

Now, at high frequencies well ABOVE the crossover point, the
impedance of the shunt capacitor CWoof is very low and that of
the shunt inductor LTweet is very high. As a result, the current
flows through the shunt capacitor (CWoofer), bypassing the woofer
and flowing through the tweeter leg. And the amplifier sees, essentially,
the tweeter as the load.

Around the crossover, the impedance of the two shunt reactances
LTweet and CWoof) are about the same, and are also about the same
as the impedances of the woofer and tweeter (assuming we don't pick
values out of thin air, like I did). In such a condition, equal
amounts of the current flow through each leg of the mesh, meaning
the power to the woofer and tweeter are about the same. And the load
seen by the amplifier is the parallel combination of the woofer mesh
and tweeter mesh.

Contrary to your analysis at NO point does the amplifier EVER see
a short circuit.

Let's in fact do a more precise analysis. I have adjusted the
values to something a bit more practical, aiming for a 1 kHz
crossover. Here's the new circuit:

* Series crossover analysis
Vin 1 0 AC SIN 1.0 0.0

CWoof 1 2 25UF
RWoof 1 2 8

LTweet 2 0 1MH
RTweet 2 0 8

.AC OCT 3 20 20K
.PRINT AC VDB(1, 2) VDB(2,0)
.END

Now, here's the output response across the woofer terminals
and the tweeter terminals, plotted every 1/3 octave:

Frequency Woofer Tweeter
Response Response
---------- -------- --------
20 Hz 0.0 dB -36.1 dB
25.2 0.0 -34.1
31.7 0.0 -32.1
40 0.0 -30.1
50.4 0.0 -28
63.5 0.0 -26
80 0.0 -24
101 0.0 -22
127 0.0 -19.9
160 0.0 -17.9
202 0.0 -15.8
254 0.0 -13.7
320 0.0 -11.6
403 0.0 -9.4
508 -0.1 -7.3
640 -0.4 -5.2
806 -0.9 -3.3
1020 -1.9 -1.8
1280 -3.4 -0.9
1610 -5.3 -0.3
2030 -7.4 -0.1
2560 -9.6 -0.0
3230 -11.8 0.0
4060 -13.9 0.0
5120 -16 0.0
6450 -18.1 0.0
8130 -20.1 0.0
10200 -22.1 0.0
12900 -24.2 0.0
16300 -26.2 0.0
20500 -28.2 0.0

As you can see, the response problems you predict simply do not
happen.

Now, as to the assertion of there being a "short circuit" across the
amplifier, let's look at the impedance:

Frequency Impedance
---------- ---------
20 Hz 8 Ohms
25.2 8
31.7 7.99
40 7.99
50.4 7.98
63.5 7.97
80 7.96
101 7.93
127 7.89
160 7.83
202 7.74
254 7.61
320 7.41
403 7.16
508 6.84
640 6.51
806 6.25
1020 6.15
1280 6.26
1610 6.53
2030 6.87
2560 7.18
3230 7.43
4060 7.62
5120 7.75
6450 7.84
8130 7.9
10200 7.93
12900 7.96
16300 7.97
20500 7.98

At no point does the impedance EVER drop below 6 ohms. Hardly a short
as you claim. Let's even look at DC, where the inductor impedance is
0 and the capacitor impedance is infinite: the imepdance of the total
cricuit is that of the woofer. At infinite frequency, where the
impedance of the capacitor is 0 and the inductor is infinite, the
impedance is that of the tweeter.
  #27   Report Post  
Dick Pierce
 
Posts: n/a
Default Dynaco A25 XL Speaker - Need crossover diagram.

"Tim Padrick" wrote in message ...
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


An inductor in parallel with a tweeter, without a series
capacitor, would be seen by the amp as a short at low
frequencies. A cap in series with a woofer would roll off
the low frequencies.


Too bad you didn't try to understand or analyze the circuit.

If you were to put JUST a tweeter and JUST an inductor in parallel
across an amp, you'd be right, but that's VERY clearly, from the
topology above, NOT what is happening. You cannot look at a circuit
and simpy pick little pieces of it and expect a quick analysis based
on one piece to give you a coherent picture of the whole. Let's, in
fact, do a more complete analysis and see what is REALLY happening

We'll make some simplifying assumption just to make the analysis
easier: we'll replace XWoofer and XTweeter with resistive loads
RWoofer and RTweeter.

Start at frequencies well below the crossover point. At these
frequencies the impedance of shunt capacitor CWoof is very high,
and that of the shunt inductor LTweet is very low. As a result,
the current flows through the woofer leg (RWoofer) and through
the inductor LTweet) And the amplifier sees, essentially, the
woofer as the load.

Now, at high frequencies well ABOVE the crossover point, the
impedance of the shunt capacitor CWoof is very low and that of
the shunt inductor LTweet is very high. As a result, the current
flows through the shunt capacitor (CWoofer), bypassing the woofer
and flowing through the tweeter leg. And the amplifier sees, essentially,
the tweeter as the load.

Around the crossover, the impedance of the two shunt reactances
LTweet and CWoof) are about the same, and are also about the same
as the impedances of the woofer and tweeter (assuming we don't pick
values out of thin air, like I did). In such a condition, equal
amounts of the current flow through each leg of the mesh, meaning
the power to the woofer and tweeter are about the same. And the load
seen by the amplifier is the parallel combination of the woofer mesh
and tweeter mesh.

Contrary to your analysis at NO point does the amplifier EVER see
a short circuit.

Let's in fact do a more precise analysis. I have adjusted the
values to something a bit more practical, aiming for a 1 kHz
crossover. Here's the new circuit:

* Series crossover analysis
Vin 1 0 AC SIN 1.0 0.0

CWoof 1 2 25UF
RWoof 1 2 8

LTweet 2 0 1MH
RTweet 2 0 8

.AC OCT 3 20 20K
.PRINT AC VDB(1, 2) VDB(2,0)
.END

Now, here's the output response across the woofer terminals
and the tweeter terminals, plotted every 1/3 octave:

Frequency Woofer Tweeter
Response Response
---------- -------- --------
20 Hz 0.0 dB -36.1 dB
25.2 0.0 -34.1
31.7 0.0 -32.1
40 0.0 -30.1
50.4 0.0 -28
63.5 0.0 -26
80 0.0 -24
101 0.0 -22
127 0.0 -19.9
160 0.0 -17.9
202 0.0 -15.8
254 0.0 -13.7
320 0.0 -11.6
403 0.0 -9.4
508 -0.1 -7.3
640 -0.4 -5.2
806 -0.9 -3.3
1020 -1.9 -1.8
1280 -3.4 -0.9
1610 -5.3 -0.3
2030 -7.4 -0.1
2560 -9.6 -0.0
3230 -11.8 0.0
4060 -13.9 0.0
5120 -16 0.0
6450 -18.1 0.0
8130 -20.1 0.0
10200 -22.1 0.0
12900 -24.2 0.0
16300 -26.2 0.0
20500 -28.2 0.0

As you can see, the response problems you predict simply do not
happen.

Now, as to the assertion of there being a "short circuit" across the
amplifier, let's look at the impedance:

Frequency Impedance
---------- ---------
20 Hz 8 Ohms
25.2 8
31.7 7.99
40 7.99
50.4 7.98
63.5 7.97
80 7.96
101 7.93
127 7.89
160 7.83
202 7.74
254 7.61
320 7.41
403 7.16
508 6.84
640 6.51
806 6.25
1020 6.15
1280 6.26
1610 6.53
2030 6.87
2560 7.18
3230 7.43
4060 7.62
5120 7.75
6450 7.84
8130 7.9
10200 7.93
12900 7.96
16300 7.97
20500 7.98

At no point does the impedance EVER drop below 6 ohms. Hardly a short
as you claim. Let's even look at DC, where the inductor impedance is
0 and the capacitor impedance is infinite: the imepdance of the total
cricuit is that of the woofer. At infinite frequency, where the
impedance of the capacitor is 0 and the inductor is infinite, the
impedance is that of the tweeter.
  #28   Report Post  
Dick Pierce
 
Posts: n/a
Default Dynaco A25 XL Speaker - Need crossover diagram.

"Tim Padrick" wrote in message ...
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


An inductor in parallel with a tweeter, without a series
capacitor, would be seen by the amp as a short at low
frequencies. A cap in series with a woofer would roll off
the low frequencies.


Too bad you didn't try to understand or analyze the circuit.

If you were to put JUST a tweeter and JUST an inductor in parallel
across an amp, you'd be right, but that's VERY clearly, from the
topology above, NOT what is happening. You cannot look at a circuit
and simpy pick little pieces of it and expect a quick analysis based
on one piece to give you a coherent picture of the whole. Let's, in
fact, do a more complete analysis and see what is REALLY happening

We'll make some simplifying assumption just to make the analysis
easier: we'll replace XWoofer and XTweeter with resistive loads
RWoofer and RTweeter.

Start at frequencies well below the crossover point. At these
frequencies the impedance of shunt capacitor CWoof is very high,
and that of the shunt inductor LTweet is very low. As a result,
the current flows through the woofer leg (RWoofer) and through
the inductor LTweet) And the amplifier sees, essentially, the
woofer as the load.

Now, at high frequencies well ABOVE the crossover point, the
impedance of the shunt capacitor CWoof is very low and that of
the shunt inductor LTweet is very high. As a result, the current
flows through the shunt capacitor (CWoofer), bypassing the woofer
and flowing through the tweeter leg. And the amplifier sees, essentially,
the tweeter as the load.

Around the crossover, the impedance of the two shunt reactances
LTweet and CWoof) are about the same, and are also about the same
as the impedances of the woofer and tweeter (assuming we don't pick
values out of thin air, like I did). In such a condition, equal
amounts of the current flow through each leg of the mesh, meaning
the power to the woofer and tweeter are about the same. And the load
seen by the amplifier is the parallel combination of the woofer mesh
and tweeter mesh.

Contrary to your analysis at NO point does the amplifier EVER see
a short circuit.

Let's in fact do a more precise analysis. I have adjusted the
values to something a bit more practical, aiming for a 1 kHz
crossover. Here's the new circuit:

* Series crossover analysis
Vin 1 0 AC SIN 1.0 0.0

CWoof 1 2 25UF
RWoof 1 2 8

LTweet 2 0 1MH
RTweet 2 0 8

.AC OCT 3 20 20K
.PRINT AC VDB(1, 2) VDB(2,0)
.END

Now, here's the output response across the woofer terminals
and the tweeter terminals, plotted every 1/3 octave:

Frequency Woofer Tweeter
Response Response
---------- -------- --------
20 Hz 0.0 dB -36.1 dB
25.2 0.0 -34.1
31.7 0.0 -32.1
40 0.0 -30.1
50.4 0.0 -28
63.5 0.0 -26
80 0.0 -24
101 0.0 -22
127 0.0 -19.9
160 0.0 -17.9
202 0.0 -15.8
254 0.0 -13.7
320 0.0 -11.6
403 0.0 -9.4
508 -0.1 -7.3
640 -0.4 -5.2
806 -0.9 -3.3
1020 -1.9 -1.8
1280 -3.4 -0.9
1610 -5.3 -0.3
2030 -7.4 -0.1
2560 -9.6 -0.0
3230 -11.8 0.0
4060 -13.9 0.0
5120 -16 0.0
6450 -18.1 0.0
8130 -20.1 0.0
10200 -22.1 0.0
12900 -24.2 0.0
16300 -26.2 0.0
20500 -28.2 0.0

As you can see, the response problems you predict simply do not
happen.

Now, as to the assertion of there being a "short circuit" across the
amplifier, let's look at the impedance:

Frequency Impedance
---------- ---------
20 Hz 8 Ohms
25.2 8
31.7 7.99
40 7.99
50.4 7.98
63.5 7.97
80 7.96
101 7.93
127 7.89
160 7.83
202 7.74
254 7.61
320 7.41
403 7.16
508 6.84
640 6.51
806 6.25
1020 6.15
1280 6.26
1610 6.53
2030 6.87
2560 7.18
3230 7.43
4060 7.62
5120 7.75
6450 7.84
8130 7.9
10200 7.93
12900 7.96
16300 7.97
20500 7.98

At no point does the impedance EVER drop below 6 ohms. Hardly a short
as you claim. Let's even look at DC, where the inductor impedance is
0 and the capacitor impedance is infinite: the imepdance of the total
cricuit is that of the woofer. At infinite frequency, where the
impedance of the capacitor is 0 and the inductor is infinite, the
impedance is that of the tweeter.
  #29   Report Post  
Dick Pierce
 
Posts: n/a
Default Dynaco A25 XL Speaker - Need crossover diagram.

"Tim Padrick" wrote in message ...
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


An inductor in parallel with a tweeter, without a series
capacitor, would be seen by the amp as a short at low
frequencies. A cap in series with a woofer would roll off
the low frequencies.


Too bad you didn't try to understand or analyze the circuit.

If you were to put JUST a tweeter and JUST an inductor in parallel
across an amp, you'd be right, but that's VERY clearly, from the
topology above, NOT what is happening. You cannot look at a circuit
and simpy pick little pieces of it and expect a quick analysis based
on one piece to give you a coherent picture of the whole. Let's, in
fact, do a more complete analysis and see what is REALLY happening

We'll make some simplifying assumption just to make the analysis
easier: we'll replace XWoofer and XTweeter with resistive loads
RWoofer and RTweeter.

Start at frequencies well below the crossover point. At these
frequencies the impedance of shunt capacitor CWoof is very high,
and that of the shunt inductor LTweet is very low. As a result,
the current flows through the woofer leg (RWoofer) and through
the inductor LTweet) And the amplifier sees, essentially, the
woofer as the load.

Now, at high frequencies well ABOVE the crossover point, the
impedance of the shunt capacitor CWoof is very low and that of
the shunt inductor LTweet is very high. As a result, the current
flows through the shunt capacitor (CWoofer), bypassing the woofer
and flowing through the tweeter leg. And the amplifier sees, essentially,
the tweeter as the load.

Around the crossover, the impedance of the two shunt reactances
LTweet and CWoof) are about the same, and are also about the same
as the impedances of the woofer and tweeter (assuming we don't pick
values out of thin air, like I did). In such a condition, equal
amounts of the current flow through each leg of the mesh, meaning
the power to the woofer and tweeter are about the same. And the load
seen by the amplifier is the parallel combination of the woofer mesh
and tweeter mesh.

Contrary to your analysis at NO point does the amplifier EVER see
a short circuit.

Let's in fact do a more precise analysis. I have adjusted the
values to something a bit more practical, aiming for a 1 kHz
crossover. Here's the new circuit:

* Series crossover analysis
Vin 1 0 AC SIN 1.0 0.0

CWoof 1 2 25UF
RWoof 1 2 8

LTweet 2 0 1MH
RTweet 2 0 8

.AC OCT 3 20 20K
.PRINT AC VDB(1, 2) VDB(2,0)
.END

Now, here's the output response across the woofer terminals
and the tweeter terminals, plotted every 1/3 octave:

Frequency Woofer Tweeter
Response Response
---------- -------- --------
20 Hz 0.0 dB -36.1 dB
25.2 0.0 -34.1
31.7 0.0 -32.1
40 0.0 -30.1
50.4 0.0 -28
63.5 0.0 -26
80 0.0 -24
101 0.0 -22
127 0.0 -19.9
160 0.0 -17.9
202 0.0 -15.8
254 0.0 -13.7
320 0.0 -11.6
403 0.0 -9.4
508 -0.1 -7.3
640 -0.4 -5.2
806 -0.9 -3.3
1020 -1.9 -1.8
1280 -3.4 -0.9
1610 -5.3 -0.3
2030 -7.4 -0.1
2560 -9.6 -0.0
3230 -11.8 0.0
4060 -13.9 0.0
5120 -16 0.0
6450 -18.1 0.0
8130 -20.1 0.0
10200 -22.1 0.0
12900 -24.2 0.0
16300 -26.2 0.0
20500 -28.2 0.0

As you can see, the response problems you predict simply do not
happen.

Now, as to the assertion of there being a "short circuit" across the
amplifier, let's look at the impedance:

Frequency Impedance
---------- ---------
20 Hz 8 Ohms
25.2 8
31.7 7.99
40 7.99
50.4 7.98
63.5 7.97
80 7.96
101 7.93
127 7.89
160 7.83
202 7.74
254 7.61
320 7.41
403 7.16
508 6.84
640 6.51
806 6.25
1020 6.15
1280 6.26
1610 6.53
2030 6.87
2560 7.18
3230 7.43
4060 7.62
5120 7.75
6450 7.84
8130 7.9
10200 7.93
12900 7.96
16300 7.97
20500 7.98

At no point does the impedance EVER drop below 6 ohms. Hardly a short
as you claim. Let's even look at DC, where the inductor impedance is
0 and the capacitor impedance is infinite: the imepdance of the total
cricuit is that of the woofer. At infinite frequency, where the
impedance of the capacitor is 0 and the inductor is infinite, the
impedance is that of the tweeter.
  #30   Report Post  
Arny Krueger
 
Posts: n/a
Default Dynaco A25 XL Speaker - Need crossover diagram.

"Dick Pierce" wrote in message
om
"Tim Padrick" wrote in message
...
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


An inductor in parallel with a tweeter, without a series
capacitor, would be seen by the amp as a short at low
frequencies. A cap in series with a woofer would roll off
the low frequencies.


Too bad you didn't try to understand or analyze the circuit.

If you were to put JUST a tweeter and JUST an inductor in parallel
across an amp, you'd be right, but that's VERY clearly, from the
topology above, NOT what is happening. You cannot look at a circuit
and simpy pick little pieces of it and expect a quick analysis based
on one piece to give you a coherent picture of the whole. Let's, in
fact, do a more complete analysis and see what is REALLY happening

We'll make some simplifying assumption just to make the analysis
easier: we'll replace XWoofer and XTweeter with resistive loads
RWoofer and RTweeter.

Start at frequencies well below the crossover point. At these
frequencies the impedance of shunt capacitor CWoof is very high,
and that of the shunt inductor LTweet is very low. As a result,
the current flows through the woofer leg (RWoofer) and through
the inductor LTweet) And the amplifier sees, essentially, the
woofer as the load.

Now, at high frequencies well ABOVE the crossover point, the
impedance of the shunt capacitor CWoof is very low and that of
the shunt inductor LTweet is very high. As a result, the current
flows through the shunt capacitor (CWoofer), bypassing the woofer
and flowing through the tweeter leg. And the amplifier sees,
essentially, the tweeter as the load.

Around the crossover, the impedance of the two shunt reactances
LTweet and CWoof) are about the same, and are also about the same
as the impedances of the woofer and tweeter (assuming we don't pick
values out of thin air, like I did). In such a condition, equal
amounts of the current flow through each leg of the mesh, meaning
the power to the woofer and tweeter are about the same. And the load
seen by the amplifier is the parallel combination of the woofer mesh
and tweeter mesh.

Contrary to your analysis at NO point does the amplifier EVER see
a short circuit.

Let's in fact do a more precise analysis. I have adjusted the
values to something a bit more practical, aiming for a 1 kHz
crossover. Here's the new circuit:

* Series crossover analysis
Vin 1 0 AC SIN 1.0 0.0

CWoof 1 2 25UF
RWoof 1 2 8

LTweet 2 0 1MH
RTweet 2 0 8

.AC OCT 3 20 20K
.PRINT AC VDB(1, 2) VDB(2,0)
.END

Now, here's the output response across the woofer terminals
and the tweeter terminals, plotted every 1/3 octave:

Frequency Woofer Tweeter
Response Response
---------- -------- --------
20 Hz 0.0 dB -36.1 dB
25.2 0.0 -34.1
31.7 0.0 -32.1
40 0.0 -30.1
50.4 0.0 -28
63.5 0.0 -26
80 0.0 -24
101 0.0 -22
127 0.0 -19.9
160 0.0 -17.9
202 0.0 -15.8
254 0.0 -13.7
320 0.0 -11.6
403 0.0 -9.4
508 -0.1 -7.3
640 -0.4 -5.2
806 -0.9 -3.3
1020 -1.9 -1.8
1280 -3.4 -0.9
1610 -5.3 -0.3
2030 -7.4 -0.1
2560 -9.6 -0.0
3230 -11.8 0.0
4060 -13.9 0.0
5120 -16 0.0
6450 -18.1 0.0
8130 -20.1 0.0
10200 -22.1 0.0
12900 -24.2 0.0
16300 -26.2 0.0
20500 -28.2 0.0

As you can see, the response problems you predict simply do not
happen.

Now, as to the assertion of there being a "short circuit" across the
amplifier, let's look at the impedance:

Frequency Impedance
---------- ---------
20 Hz 8 Ohms
25.2 8
31.7 7.99
40 7.99
50.4 7.98
63.5 7.97
80 7.96
101 7.93
127 7.89
160 7.83
202 7.74
254 7.61
320 7.41
403 7.16
508 6.84
640 6.51
806 6.25
1020 6.15
1280 6.26
1610 6.53
2030 6.87
2560 7.18
3230 7.43
4060 7.62
5120 7.75
6450 7.84
8130 7.9
10200 7.93
12900 7.96
16300 7.97
20500 7.98

At no point does the impedance EVER drop below 6 ohms. Hardly a short
as you claim. Let's even look at DC, where the inductor impedance is
0 and the capacitor impedance is infinite: the imepdance of the total
cricuit is that of the woofer. At infinite frequency, where the
impedance of the capacitor is 0 and the inductor is infinite, the
impedance is that of the tweeter.


Thanks for the lesson in reciprocity!




  #31   Report Post  
Arny Krueger
 
Posts: n/a
Default Dynaco A25 XL Speaker - Need crossover diagram.

"Dick Pierce" wrote in message
om
"Tim Padrick" wrote in message
...
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


An inductor in parallel with a tweeter, without a series
capacitor, would be seen by the amp as a short at low
frequencies. A cap in series with a woofer would roll off
the low frequencies.


Too bad you didn't try to understand or analyze the circuit.

If you were to put JUST a tweeter and JUST an inductor in parallel
across an amp, you'd be right, but that's VERY clearly, from the
topology above, NOT what is happening. You cannot look at a circuit
and simpy pick little pieces of it and expect a quick analysis based
on one piece to give you a coherent picture of the whole. Let's, in
fact, do a more complete analysis and see what is REALLY happening

We'll make some simplifying assumption just to make the analysis
easier: we'll replace XWoofer and XTweeter with resistive loads
RWoofer and RTweeter.

Start at frequencies well below the crossover point. At these
frequencies the impedance of shunt capacitor CWoof is very high,
and that of the shunt inductor LTweet is very low. As a result,
the current flows through the woofer leg (RWoofer) and through
the inductor LTweet) And the amplifier sees, essentially, the
woofer as the load.

Now, at high frequencies well ABOVE the crossover point, the
impedance of the shunt capacitor CWoof is very low and that of
the shunt inductor LTweet is very high. As a result, the current
flows through the shunt capacitor (CWoofer), bypassing the woofer
and flowing through the tweeter leg. And the amplifier sees,
essentially, the tweeter as the load.

Around the crossover, the impedance of the two shunt reactances
LTweet and CWoof) are about the same, and are also about the same
as the impedances of the woofer and tweeter (assuming we don't pick
values out of thin air, like I did). In such a condition, equal
amounts of the current flow through each leg of the mesh, meaning
the power to the woofer and tweeter are about the same. And the load
seen by the amplifier is the parallel combination of the woofer mesh
and tweeter mesh.

Contrary to your analysis at NO point does the amplifier EVER see
a short circuit.

Let's in fact do a more precise analysis. I have adjusted the
values to something a bit more practical, aiming for a 1 kHz
crossover. Here's the new circuit:

* Series crossover analysis
Vin 1 0 AC SIN 1.0 0.0

CWoof 1 2 25UF
RWoof 1 2 8

LTweet 2 0 1MH
RTweet 2 0 8

.AC OCT 3 20 20K
.PRINT AC VDB(1, 2) VDB(2,0)
.END

Now, here's the output response across the woofer terminals
and the tweeter terminals, plotted every 1/3 octave:

Frequency Woofer Tweeter
Response Response
---------- -------- --------
20 Hz 0.0 dB -36.1 dB
25.2 0.0 -34.1
31.7 0.0 -32.1
40 0.0 -30.1
50.4 0.0 -28
63.5 0.0 -26
80 0.0 -24
101 0.0 -22
127 0.0 -19.9
160 0.0 -17.9
202 0.0 -15.8
254 0.0 -13.7
320 0.0 -11.6
403 0.0 -9.4
508 -0.1 -7.3
640 -0.4 -5.2
806 -0.9 -3.3
1020 -1.9 -1.8
1280 -3.4 -0.9
1610 -5.3 -0.3
2030 -7.4 -0.1
2560 -9.6 -0.0
3230 -11.8 0.0
4060 -13.9 0.0
5120 -16 0.0
6450 -18.1 0.0
8130 -20.1 0.0
10200 -22.1 0.0
12900 -24.2 0.0
16300 -26.2 0.0
20500 -28.2 0.0

As you can see, the response problems you predict simply do not
happen.

Now, as to the assertion of there being a "short circuit" across the
amplifier, let's look at the impedance:

Frequency Impedance
---------- ---------
20 Hz 8 Ohms
25.2 8
31.7 7.99
40 7.99
50.4 7.98
63.5 7.97
80 7.96
101 7.93
127 7.89
160 7.83
202 7.74
254 7.61
320 7.41
403 7.16
508 6.84
640 6.51
806 6.25
1020 6.15
1280 6.26
1610 6.53
2030 6.87
2560 7.18
3230 7.43
4060 7.62
5120 7.75
6450 7.84
8130 7.9
10200 7.93
12900 7.96
16300 7.97
20500 7.98

At no point does the impedance EVER drop below 6 ohms. Hardly a short
as you claim. Let's even look at DC, where the inductor impedance is
0 and the capacitor impedance is infinite: the imepdance of the total
cricuit is that of the woofer. At infinite frequency, where the
impedance of the capacitor is 0 and the inductor is infinite, the
impedance is that of the tweeter.


Thanks for the lesson in reciprocity!


  #32   Report Post  
Arny Krueger
 
Posts: n/a
Default Dynaco A25 XL Speaker - Need crossover diagram.

"Dick Pierce" wrote in message
om
"Tim Padrick" wrote in message
...
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


An inductor in parallel with a tweeter, without a series
capacitor, would be seen by the amp as a short at low
frequencies. A cap in series with a woofer would roll off
the low frequencies.


Too bad you didn't try to understand or analyze the circuit.

If you were to put JUST a tweeter and JUST an inductor in parallel
across an amp, you'd be right, but that's VERY clearly, from the
topology above, NOT what is happening. You cannot look at a circuit
and simpy pick little pieces of it and expect a quick analysis based
on one piece to give you a coherent picture of the whole. Let's, in
fact, do a more complete analysis and see what is REALLY happening

We'll make some simplifying assumption just to make the analysis
easier: we'll replace XWoofer and XTweeter with resistive loads
RWoofer and RTweeter.

Start at frequencies well below the crossover point. At these
frequencies the impedance of shunt capacitor CWoof is very high,
and that of the shunt inductor LTweet is very low. As a result,
the current flows through the woofer leg (RWoofer) and through
the inductor LTweet) And the amplifier sees, essentially, the
woofer as the load.

Now, at high frequencies well ABOVE the crossover point, the
impedance of the shunt capacitor CWoof is very low and that of
the shunt inductor LTweet is very high. As a result, the current
flows through the shunt capacitor (CWoofer), bypassing the woofer
and flowing through the tweeter leg. And the amplifier sees,
essentially, the tweeter as the load.

Around the crossover, the impedance of the two shunt reactances
LTweet and CWoof) are about the same, and are also about the same
as the impedances of the woofer and tweeter (assuming we don't pick
values out of thin air, like I did). In such a condition, equal
amounts of the current flow through each leg of the mesh, meaning
the power to the woofer and tweeter are about the same. And the load
seen by the amplifier is the parallel combination of the woofer mesh
and tweeter mesh.

Contrary to your analysis at NO point does the amplifier EVER see
a short circuit.

Let's in fact do a more precise analysis. I have adjusted the
values to something a bit more practical, aiming for a 1 kHz
crossover. Here's the new circuit:

* Series crossover analysis
Vin 1 0 AC SIN 1.0 0.0

CWoof 1 2 25UF
RWoof 1 2 8

LTweet 2 0 1MH
RTweet 2 0 8

.AC OCT 3 20 20K
.PRINT AC VDB(1, 2) VDB(2,0)
.END

Now, here's the output response across the woofer terminals
and the tweeter terminals, plotted every 1/3 octave:

Frequency Woofer Tweeter
Response Response
---------- -------- --------
20 Hz 0.0 dB -36.1 dB
25.2 0.0 -34.1
31.7 0.0 -32.1
40 0.0 -30.1
50.4 0.0 -28
63.5 0.0 -26
80 0.0 -24
101 0.0 -22
127 0.0 -19.9
160 0.0 -17.9
202 0.0 -15.8
254 0.0 -13.7
320 0.0 -11.6
403 0.0 -9.4
508 -0.1 -7.3
640 -0.4 -5.2
806 -0.9 -3.3
1020 -1.9 -1.8
1280 -3.4 -0.9
1610 -5.3 -0.3
2030 -7.4 -0.1
2560 -9.6 -0.0
3230 -11.8 0.0
4060 -13.9 0.0
5120 -16 0.0
6450 -18.1 0.0
8130 -20.1 0.0
10200 -22.1 0.0
12900 -24.2 0.0
16300 -26.2 0.0
20500 -28.2 0.0

As you can see, the response problems you predict simply do not
happen.

Now, as to the assertion of there being a "short circuit" across the
amplifier, let's look at the impedance:

Frequency Impedance
---------- ---------
20 Hz 8 Ohms
25.2 8
31.7 7.99
40 7.99
50.4 7.98
63.5 7.97
80 7.96
101 7.93
127 7.89
160 7.83
202 7.74
254 7.61
320 7.41
403 7.16
508 6.84
640 6.51
806 6.25
1020 6.15
1280 6.26
1610 6.53
2030 6.87
2560 7.18
3230 7.43
4060 7.62
5120 7.75
6450 7.84
8130 7.9
10200 7.93
12900 7.96
16300 7.97
20500 7.98

At no point does the impedance EVER drop below 6 ohms. Hardly a short
as you claim. Let's even look at DC, where the inductor impedance is
0 and the capacitor impedance is infinite: the imepdance of the total
cricuit is that of the woofer. At infinite frequency, where the
impedance of the capacitor is 0 and the inductor is infinite, the
impedance is that of the tweeter.


Thanks for the lesson in reciprocity!


  #33   Report Post  
Arny Krueger
 
Posts: n/a
Default Dynaco A25 XL Speaker - Need crossover diagram.

"Dick Pierce" wrote in message
om
"Tim Padrick" wrote in message
...
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


An inductor in parallel with a tweeter, without a series
capacitor, would be seen by the amp as a short at low
frequencies. A cap in series with a woofer would roll off
the low frequencies.


Too bad you didn't try to understand or analyze the circuit.

If you were to put JUST a tweeter and JUST an inductor in parallel
across an amp, you'd be right, but that's VERY clearly, from the
topology above, NOT what is happening. You cannot look at a circuit
and simpy pick little pieces of it and expect a quick analysis based
on one piece to give you a coherent picture of the whole. Let's, in
fact, do a more complete analysis and see what is REALLY happening

We'll make some simplifying assumption just to make the analysis
easier: we'll replace XWoofer and XTweeter with resistive loads
RWoofer and RTweeter.

Start at frequencies well below the crossover point. At these
frequencies the impedance of shunt capacitor CWoof is very high,
and that of the shunt inductor LTweet is very low. As a result,
the current flows through the woofer leg (RWoofer) and through
the inductor LTweet) And the amplifier sees, essentially, the
woofer as the load.

Now, at high frequencies well ABOVE the crossover point, the
impedance of the shunt capacitor CWoof is very low and that of
the shunt inductor LTweet is very high. As a result, the current
flows through the shunt capacitor (CWoofer), bypassing the woofer
and flowing through the tweeter leg. And the amplifier sees,
essentially, the tweeter as the load.

Around the crossover, the impedance of the two shunt reactances
LTweet and CWoof) are about the same, and are also about the same
as the impedances of the woofer and tweeter (assuming we don't pick
values out of thin air, like I did). In such a condition, equal
amounts of the current flow through each leg of the mesh, meaning
the power to the woofer and tweeter are about the same. And the load
seen by the amplifier is the parallel combination of the woofer mesh
and tweeter mesh.

Contrary to your analysis at NO point does the amplifier EVER see
a short circuit.

Let's in fact do a more precise analysis. I have adjusted the
values to something a bit more practical, aiming for a 1 kHz
crossover. Here's the new circuit:

* Series crossover analysis
Vin 1 0 AC SIN 1.0 0.0

CWoof 1 2 25UF
RWoof 1 2 8

LTweet 2 0 1MH
RTweet 2 0 8

.AC OCT 3 20 20K
.PRINT AC VDB(1, 2) VDB(2,0)
.END

Now, here's the output response across the woofer terminals
and the tweeter terminals, plotted every 1/3 octave:

Frequency Woofer Tweeter
Response Response
---------- -------- --------
20 Hz 0.0 dB -36.1 dB
25.2 0.0 -34.1
31.7 0.0 -32.1
40 0.0 -30.1
50.4 0.0 -28
63.5 0.0 -26
80 0.0 -24
101 0.0 -22
127 0.0 -19.9
160 0.0 -17.9
202 0.0 -15.8
254 0.0 -13.7
320 0.0 -11.6
403 0.0 -9.4
508 -0.1 -7.3
640 -0.4 -5.2
806 -0.9 -3.3
1020 -1.9 -1.8
1280 -3.4 -0.9
1610 -5.3 -0.3
2030 -7.4 -0.1
2560 -9.6 -0.0
3230 -11.8 0.0
4060 -13.9 0.0
5120 -16 0.0
6450 -18.1 0.0
8130 -20.1 0.0
10200 -22.1 0.0
12900 -24.2 0.0
16300 -26.2 0.0
20500 -28.2 0.0

As you can see, the response problems you predict simply do not
happen.

Now, as to the assertion of there being a "short circuit" across the
amplifier, let's look at the impedance:

Frequency Impedance
---------- ---------
20 Hz 8 Ohms
25.2 8
31.7 7.99
40 7.99
50.4 7.98
63.5 7.97
80 7.96
101 7.93
127 7.89
160 7.83
202 7.74
254 7.61
320 7.41
403 7.16
508 6.84
640 6.51
806 6.25
1020 6.15
1280 6.26
1610 6.53
2030 6.87
2560 7.18
3230 7.43
4060 7.62
5120 7.75
6450 7.84
8130 7.9
10200 7.93
12900 7.96
16300 7.97
20500 7.98

At no point does the impedance EVER drop below 6 ohms. Hardly a short
as you claim. Let's even look at DC, where the inductor impedance is
0 and the capacitor impedance is infinite: the imepdance of the total
cricuit is that of the woofer. At infinite frequency, where the
impedance of the capacitor is 0 and the inductor is infinite, the
impedance is that of the tweeter.


Thanks for the lesson in reciprocity!


  #34   Report Post  
Dick Pierce
 
Posts: n/a
Default Dynaco A25 XL Speaker - Need crossover diagram.

"Arny Krueger" wrote in message ...
"Tim Padrick" wrote in message


An inductor in parallel with a tweeter, without a series capacitor,
would be seen by the amp as a short at low frequencies. A cap in
series with a woofer would roll off the low frequencies.


Agreed, and that leaves some non-simple problems to solve.


No it doesn't.

AFAIK the very few commercial designs with an inductor in parallel with the
tweeter use a tweeter that is more efficient than the woofer, and put a
resistor in series with the inductor/tweeter combination. Still not a pretty
picture.


Sorry, but you're both pretty clueless as to what was described.
This is hardly an uncommon crossover design, and was fairly
well described 3 decades and more ago, for example, Small, R. H.,
"Constant Voltage Crossover Design," Proc IREE Australia vol 31
(1970), reprinted in J. Audio Eng. Soc. 1971 Jan:

"the series network in Fig 10b [EXACTLY the topology I
described] in inherently advantageous because tolerances
in the component values, both in the crossover and in the
termination, will have no effect on the total network
voltage response. Because the drivers are connected in
series across the amplifier output, the sum of the voice-
coil voltages must always be equal to the driving voltage."

As both explained AND demonstrated in my other response to these
assertions, it is hardly a "non-simple problem," indeed, it is
no problem at all, having some significant advantages.

How about actually LOOKING at the circuit and UNDERSTANDING it?
  #35   Report Post  
Dick Pierce
 
Posts: n/a
Default Dynaco A25 XL Speaker - Need crossover diagram.

"Arny Krueger" wrote in message ...
"Tim Padrick" wrote in message


An inductor in parallel with a tweeter, without a series capacitor,
would be seen by the amp as a short at low frequencies. A cap in
series with a woofer would roll off the low frequencies.


Agreed, and that leaves some non-simple problems to solve.


No it doesn't.

AFAIK the very few commercial designs with an inductor in parallel with the
tweeter use a tweeter that is more efficient than the woofer, and put a
resistor in series with the inductor/tweeter combination. Still not a pretty
picture.


Sorry, but you're both pretty clueless as to what was described.
This is hardly an uncommon crossover design, and was fairly
well described 3 decades and more ago, for example, Small, R. H.,
"Constant Voltage Crossover Design," Proc IREE Australia vol 31
(1970), reprinted in J. Audio Eng. Soc. 1971 Jan:

"the series network in Fig 10b [EXACTLY the topology I
described] in inherently advantageous because tolerances
in the component values, both in the crossover and in the
termination, will have no effect on the total network
voltage response. Because the drivers are connected in
series across the amplifier output, the sum of the voice-
coil voltages must always be equal to the driving voltage."

As both explained AND demonstrated in my other response to these
assertions, it is hardly a "non-simple problem," indeed, it is
no problem at all, having some significant advantages.

How about actually LOOKING at the circuit and UNDERSTANDING it?


  #36   Report Post  
Dick Pierce
 
Posts: n/a
Default Dynaco A25 XL Speaker - Need crossover diagram.

"Arny Krueger" wrote in message ...
"Tim Padrick" wrote in message


An inductor in parallel with a tweeter, without a series capacitor,
would be seen by the amp as a short at low frequencies. A cap in
series with a woofer would roll off the low frequencies.


Agreed, and that leaves some non-simple problems to solve.


No it doesn't.

AFAIK the very few commercial designs with an inductor in parallel with the
tweeter use a tweeter that is more efficient than the woofer, and put a
resistor in series with the inductor/tweeter combination. Still not a pretty
picture.


Sorry, but you're both pretty clueless as to what was described.
This is hardly an uncommon crossover design, and was fairly
well described 3 decades and more ago, for example, Small, R. H.,
"Constant Voltage Crossover Design," Proc IREE Australia vol 31
(1970), reprinted in J. Audio Eng. Soc. 1971 Jan:

"the series network in Fig 10b [EXACTLY the topology I
described] in inherently advantageous because tolerances
in the component values, both in the crossover and in the
termination, will have no effect on the total network
voltage response. Because the drivers are connected in
series across the amplifier output, the sum of the voice-
coil voltages must always be equal to the driving voltage."

As both explained AND demonstrated in my other response to these
assertions, it is hardly a "non-simple problem," indeed, it is
no problem at all, having some significant advantages.

How about actually LOOKING at the circuit and UNDERSTANDING it?
  #37   Report Post  
Dick Pierce
 
Posts: n/a
Default Dynaco A25 XL Speaker - Need crossover diagram.

"Arny Krueger" wrote in message ...
"Tim Padrick" wrote in message


An inductor in parallel with a tweeter, without a series capacitor,
would be seen by the amp as a short at low frequencies. A cap in
series with a woofer would roll off the low frequencies.


Agreed, and that leaves some non-simple problems to solve.


No it doesn't.

AFAIK the very few commercial designs with an inductor in parallel with the
tweeter use a tweeter that is more efficient than the woofer, and put a
resistor in series with the inductor/tweeter combination. Still not a pretty
picture.


Sorry, but you're both pretty clueless as to what was described.
This is hardly an uncommon crossover design, and was fairly
well described 3 decades and more ago, for example, Small, R. H.,
"Constant Voltage Crossover Design," Proc IREE Australia vol 31
(1970), reprinted in J. Audio Eng. Soc. 1971 Jan:

"the series network in Fig 10b [EXACTLY the topology I
described] in inherently advantageous because tolerances
in the component values, both in the crossover and in the
termination, will have no effect on the total network
voltage response. Because the drivers are connected in
series across the amplifier output, the sum of the voice-
coil voltages must always be equal to the driving voltage."

As both explained AND demonstrated in my other response to these
assertions, it is hardly a "non-simple problem," indeed, it is
no problem at all, having some significant advantages.

How about actually LOOKING at the circuit and UNDERSTANDING it?
  #38   Report Post  
Arny Krueger
 
Posts: n/a
Default Dynaco A25 XL Speaker - Need crossover diagram.

"Dick Pierce" wrote in message
om
"Arny Krueger" wrote in message
...
"Tim Padrick" wrote in message


An inductor in parallel with a tweeter, without a series capacitor,
would be seen by the amp as a short at low frequencies. A cap in
series with a woofer would roll off the low frequencies.


Agreed, and that leaves some non-simple problems to solve.


No it doesn't.


Please see my post from 8:23 EST this morning.


  #39   Report Post  
Arny Krueger
 
Posts: n/a
Default Dynaco A25 XL Speaker - Need crossover diagram.

"Dick Pierce" wrote in message
om
"Arny Krueger" wrote in message
...
"Tim Padrick" wrote in message


An inductor in parallel with a tweeter, without a series capacitor,
would be seen by the amp as a short at low frequencies. A cap in
series with a woofer would roll off the low frequencies.


Agreed, and that leaves some non-simple problems to solve.


No it doesn't.


Please see my post from 8:23 EST this morning.


  #40   Report Post  
Arny Krueger
 
Posts: n/a
Default Dynaco A25 XL Speaker - Need crossover diagram.

"Dick Pierce" wrote in message
om
"Arny Krueger" wrote in message
...
"Tim Padrick" wrote in message


An inductor in parallel with a tweeter, without a series capacitor,
would be seen by the amp as a short at low frequencies. A cap in
series with a woofer would roll off the low frequencies.


Agreed, and that leaves some non-simple problems to solve.


No it doesn't.


Please see my post from 8:23 EST this morning.




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