Arny Krueger wrote:
wrote in message
oups.com...
Hi All,

Something that I've been thinking about for a while with
the design of
speaker crossovers, but don't have the necessary knowledge
to calculate
or figure out, is this:

If you were to take, for example, an 18dB/oct Butterworth
high pass/low
pass crossover for a two way system, could you synthesize
the same
summed electrical response (and therefore the on axis
response) in
terms of amplitude and phase response if you were to lower
the Q of the
high pass section, and raise the Q of the low pass section
from their
standard 0.707, without changing anything else ?

No. While you can play with Q's to get small areas of the
response curve with similar slopes, over the ranges
required, the basic properties of the filters come to the
forefront.

I'm not sure that you follow what I'm asking. I'm not asking for the
individual responses of the filters to be the same, as that is
obviously impossible - if they're different, they're different.

What I'm asking is if there is a way to achieve the same summed
response from a different combination of high/low pass filters, where
ONE of the individual sections has a better transient response at the
expense of the other.

My example was to take an 18dB/oct Butterworth, and alter things so
that the high pass section has an improved transient response at the
expense of a worse transient response for the low pass section, but
with the same (or similar) transient response as the original design
for the summed response.

Surely this is not so different from a subtraction based crossover
where one half is a standard filter and the other slope is derived from
a difference signal ? (Although admitedly, that approach is limited to
active designs...)

Any takers ?

Regards,
Simon