Re: [ecasound] reverbs

New Message Reply Date view Thread view Subject view Author view Other groups

Subject: Re: [ecasound] reverbs
From: Kai Vehmanen (
Date: Sat Sep 11 1999 - 15:58:50 EEST

On Fri, 10 Sep 1999, Jeremy Hall wrote:

> ecasound -i /tmp/in.raw -o /tmp/out.raw -efs:1000,500 -efr:1000,500 -c
> sounds similar to a 56K audio stream and is a bit quieter. In contrast,

Well, in this case it's just what it should sound like as...:

ecasound -i /tmp/in.raw -o /tmp/out.raw -efr:1000,500 -c

does nothing to the signal in 1.5.9/10.

> -ev:
> as noted before, -ev can produce some strange results, do we wrap
> counters?

Hmm, strange in what way? Counters are reseted with every
call of "estatus". Otherwise they will wrap after about 27 hours
of sample data... this shouldn't be a problem. ;)

> The statistics table is hard to understand.

Well, this I admit. :) It's _very_ messy. I needed a quick&dirty
way to adjust the input signal level (in console mode!).
As ecasound wasn't publically released back then "-ev" did
the job nicely.

> enm: I think I am not setting it up right.

Check /usr/local/share/ecasound/singlechain_effect_presets ...
There should be at least one working noise-gate preset.
Btw; you can get some weird rhytmic effects if you use
low-frequency oscillators to control the noisegate parameters.
You can't do this with your average rack-multieffect! ;)

> (audiofx) Mono noise gate enabled; threshold level 75.0000%, threshold
> time 40.0000 ms, attack 80.0000 ms, hold 75.0000 ms and release 75.0000
> ms.

This won't sound so good as it treats everything below 75%
(100% = max amplitude) as noise.

> -ep: works as advertised, but decreases volume

Yep, this should have been fixed a long time ago. In 1.5.11
"-epp" won't affect the volume level.

> [jhall@pongo jhall]$ ecasound -i /tmp/in.raw -eft:80
> - [ Chainsetup/Adding a new chain operator ]

These will be gone in 1.5.11r5. I'm rewriting some parts of
the effect-API and it will have a new way to handle
effect configurations (internally). When ecasound was just a
simple command line util, it wasn't a big deal if it dumped
core when invalid command line arguments were given, but now this
will have to change.
> -etf: doesn't make a signifficant diff on a stereo signal and that is whta
> I am testing with now

Same problem as with "-efr" (bandreject filter). Doesn't do
anything (1.5.0->1.5.10 versions).

> -ef1: produces a high squeal

This is under work (a bit experimental, -efs and -efb should
be used instead). I might drop this altogether.

> -efb: produces strange results no matter what its options are

Hmm, this works fine with me. I'll have to test it some more.

> -efh and -efl
> they seem to do something that is sortta right, but I am hearing pitches
> around 400 to 500hz when I set -efh of 1000 but they may be overtones I'll
> test with a sine wave later.

Yes, these should also work, but are not perfect.

> gotta go, will continue the evaluation later, but a friend is here.

Thanks! This has been __very__ helpful. Most of ecasound's effect
code dates back to 1997-1998. I've been aware of the problems,
but other issues (multitracking, qtecasound, etc) have taken
all my time.

Kai Vehmanen <> -------- CS, University of Turku, Finland
 . - linux audio processing
 . - ambient-idm-rock-... mp3/ra/wav

New Message Reply Date view Thread view Subject view Author view Other groups

This archive was generated by hypermail 2a24 : Sat Sep 25 1999 - 19:41:11 EEST