Subject: Re: [ecasound] ecasound and tape hiss...
From: Kai Vehmanen (k_AT_eca.cx)
Date: Wed Jan 16 2002 - 20:46:14 EET
On Tue, 15 Jan 2002, Peter King wrote:
> is there a sensible way to use ecasound to remove tape hiss from
> audiofiles ripped from analog tape? A band-reject filter might do
> it if it were sufficiently narrow, but I can't seem to identify the
> frequency of tape hiss. If anyone can tell me how to do this, I'd
Removing noise is not an easy task and usually requires lot of
case-specific experimentation and fine-tuning. Sometimes plain frequency
filtering (bandreject, or even low/high pass) is enough, while sometimes
using a noise gate (like -enm) is better (usually when the noise is only
audible on the otherwise silent moments).
Useful tools (in addition to those mentioned by Dave):
- anoi, denoi, dnr; http://www.sci.fi/~mjkoskin/
- Steve's eq plugins (w/ ecasound for instance)
Btw; ecasound's default effect presets include a preset
called 'gate_noisegate_delanalog', which is
actually just '-enm:0.20,0.1,1000,50,0'. I've used
to remove some hiss... but it won't necessarily
work without tuning for other audio data. One
good way is to launch ecasound in interactive and
play with the effect params while playback is
active. Assiging an controller can also be useful:
add a slow envelope that sweeps the whole spectrum
with a bandreject filter...
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