3 Jul
2012
3 Jul
'12
6:41 p.m.
Hello, all,
Here's a question for the fine DSP and accoustic experts on this list. I
need to apply different processing (mostly reverb and compression) to
different bandwidths of the frequency spectrum on a given track. How
would I go about using filters to implement crossovers as flat as
possible? Most plugins do not actually seem to tell what their rolloff
curve is.
Thanks.
Cheers,
s.M.
--
3 Jul
3 Jul
6:59 p.m.
On Tue, Jul 3, 2012 at 11:41 AM, S. Massy <lists(a)wolfdream.ca> wrote:
Hello, all,
Here's a question for the fine DSP and accoustic experts on this list. I
need to apply different processing (mostly reverb and compression) to
different bandwidths of the frequency spectrum on a given track. How
would I go about using filters to implement crossovers as flat as
possible? Most plugins do not actually seem to tell what their rolloff
curve is.
Thanks.
Cheers,
s.M.
Your choices are limited by the bandwidth and center frequencies you choose.
When you choose the quality factor to get a certain phase/magnitude
characteristic, that determines your bandwidth:cutoff freq ratio for
resonant filters.
I would defer to more experienced members on the list--but I think
your best choice is to use 2nd order low-pass/high-pass pairs with
Q=0.5. That will get you a reasonable (but not perfect)
reconstruction and nice flat response.
To get perfect reconstruction--with the limitation of 1-octave band
filters--you can use wavelets and their associated mirror quadrature
filters.
Chuck
7:04 p.m.
Does the SWH plugins not include a crossover?
IIRC anyway! -H
On Tue, Jul 3, 2012 at 5:41 PM, S. Massy <lists(a)wolfdream.ca> wrote:
Hello, all,
Here's a question for the fine DSP and accoustic experts on this list. I
need to apply different processing (mostly reverb and compression) to
different bandwidths of the frequency spectrum on a given track. How
would I go about using filters to implement crossovers as flat as
possible? Most plugins do not actually seem to tell what their rolloff
curve is.
Thanks.
Cheers,
s.M.
--
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http://lists.linuxaudio.org/listinfo/linux-audio-user
10 p.m.
On Tue, Jul 03, 2012 at 12:41:58PM -0400, S. Massy wrote:
Hello, all,
Here's a question for the fine DSP and accoustic experts on this list. I
need to apply different processing (mostly reverb and compression) to
different bandwidths of the frequency spectrum on a given track. How
would I go about using filters to implement crossovers as flat as
possible? Most plugins do not actually seem to tell what their rolloff
curve is.
* The outputs of first order xover filters will add to exactly the
input signal. But you only have 6 dB/oct and hat may or may not
be enough, depending on the application.
* If you want steeper (higher order) filters one solution is to
us the Linkwitz-Riley type. Outputs add to a perfectly flat
frequency response, but the phase response of the recombined
signal is not linear. It won't matter in most cases.
For ready-to-use L-R filters, get zita-lrx1. It provides up to
four bands using 4th order filters (i.e. 24 dB/oct).
Ciao,
--
FA
A world of exhaustive, reliable metadata would be an utopia.
It's also a pipe-dream, founded on self-delusion, nerd hubris
and hysterically inflated market opportunities. (Cory Doctorow)
10:12 p.m.
On Tue, Jul 03, 2012 at 08:00:21PM +0000, Fons Adriaensen wrote:
On Tue, Jul 03, 2012 at 12:41:58PM -0400, S. Massy
wrote:
Thanks, Fons, very helpful as
usual.
Cheers,
S.M.
Hello, all,
Here's a question for the fine DSP and accoustic experts on this list. I
need to apply different processing (mostly reverb and compression) to
different bandwidths of the frequency spectrum on a given track. How
would I go about using filters to implement crossovers as flat as
possible? Most plugins do not actually seem to tell what their rolloff
curve is.
* The outputs of first order xover filters will add to exactly the
input signal. But you only have 6 dB/oct and hat may or may not
be enough, depending on the application.
* If you want steeper (higher order) filters one solution is to
us the Linkwitz-Riley type. Outputs add to a perfectly flat
frequency response, but the phase response of the recombined
signal is not linear. It won't matter in most cases.
For ready-to-use L-R filters, get zita-lrx1. It provides up to
four bands using 4th order filters (i.e. 24 dB/oct).
4529
days inactive
4529
days old
linux-audio-user@lists.linuxaudio.org
5 comments
4 participants
participants (4)
-
Charles Henry -
Fons Adriaensen -
Harry van Haaren -
S. Massy