Subject: Re: [ecasound] trouble panning with -epp
From: Bill Allen (ballen_AT_mail.serve.com)
Date: Tue Oct 23 2001 - 14:04:39 EEST
On Tue, 23 Oct 2001, Kai Vehmanen wrote:
> On Mon, 22 Oct 2001, CLOTILDE Guy Daniel wrote:
>
> >> I've got 3 single channel tracks that I want to pan across the left to
> >> right sound field. I'm using the following ecs script:
> > ----cut-------
> > -f:16,1,44100
> > -a:1 -epp:0 -ea:500 -i:sax1.wav -ea:500 -erc:1,2 -epp:0
> > -a:2 -epp:50 -ea:500 -i:trumpet1.wav -ea:500 -erc:1,2 -epp:50
> > -a:3 -epp:100 -ea:500 -i:trombone1.wav -ea:500 -erc:1,2 -epp:100
> > -a:all -f:16,2,44100 -o:alsa,default
> > ----cut-------
>
> You have the right idea. The minimum setup to do panning of mono-files
> would be:
>
> --cut--
> -a:1 -i:sax1.wav -erc:1,2 -epp:0
> -a:2 -i:trumpet1.wav -erc:1,2 -epp:50
> -a:3 -i:trombone1.wav -erc:1,2 -epp:100
> -a:all -f:16,2,44100 -o:alsa,default
> --cut--
>
> The actual signal chain is something like ('---' = mono channel)
>
> sax1.wav |--'1'---- erc ----| epp |---\
> \-----| |---\\
> \\
> trumpet1.wav |--'2'---- erc ----| epp |------- | alsa,default
> \-----| |------- |
> //
> trombone1.wav |--'3'---- erc ----| epp |---//
> \-----| |---/
>
> The critical points are:
>
> - ecasound automatically notices that the three
> input files are mono files
> - chains contain mono signal until -erc operator,
> which transforms the chain into a stereo chain
> - now -epp works as excepted
> - chains are mixed to the alsa device channel-wise
>
> If you leave out the -erc effect, chains will still be converted to
> stereo, but on each chain, only the first channel (left) will contain any
> audio from the input files.
>
>
Thanks to both of you for the replies which I have tried and do work. I
have to admit that I'm a little confused by it though. From the man page:
-------------------
-epp:right-%
Normal pan effect. Balance value of 0 means to pan signal fully left and
100 fully right. If the panned signal is a stereo signal, left and right
channels aren't mixed together. Use the -erm and -erc effects to force
conversion to mono before panning.
-------------------
That implied to me that I needed to use mono signals for the horns to get
them to pan correctly, but your responses seem to imply that only stereo
signals pan correctly. What am I missing here (other than a brain :-)
Bill
BTW: I love ecasound. As someone else sort of said, keep coding so I can
keep playing the sax!
-- To unsubscribe send message 'unsubscribe' in the body of the message to <ecasound-list-request_AT_wakkanet.fi>.
This archive was generated by hypermail 2b28 : Tue Oct 23 2001 - 13:55:28 EEST