Re: DynamicsCompressorNode

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On 05/02/2013 03:17 AM, Frederick Umminger wrote:
> Soft-clipping will add distortion to the sound whereas a good 
> compressor/limiter will not.

Well, it depends on the amount of clipping that goes on. Also,
clipping is unavoidable even with a compressor, so it's probably a
good idea to to it smoothly anyway.

Compressors also have their own artefacts, especially full-band ones.
For example, if there's a low frequency burst, it'll modulate any high
frequencies present in the signal. So for large excursions,
compressors may be unavoidable, but it we can avoid those,
soft-clipping may be a better option. One important advantage of
(soft-)clipping is that when there are no overflows, it does not cause
any artefact at all.

> Head room is often the best way to prevent clipping,but it can
> conflict with a desire to maximize the loudness. Without an
> enforced standard for head room there is an inevitable creep 
> towards 0 dB FS. With regards to this, perhaps the Web Audio API
> should somehow incorporate the proposed game console loudness
> standard ( http://gameaudiopodcast.com/ASWG-R001.pdf ), which is
> based on proven television loudness standards, I'm not sure how
> this could be enforced though, other than through dynamics
> processing within the browser.

Well, I would say that at least having a standard level would go a
long way. That's actually what I've been trying to specify for WebRTC
audio: http://tools.ietf.org/html/draft-ietf-rtcweb-audio-01#section-4
Of course, being able to actively enforce it (e.g. running some level
control on any signal that exceeds the limit) might be even better.

For example, there could be a -20 dB "maximum average level", above
which a slow-acting AGC would trigger to maintain the average at no
more than -20 dB.

	Jean-Marc
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.13 (GNU/Linux)
Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/

iQEcBAEBAgAGBQJRgsx2AAoJEJ6/8sItn9q9QMcH/1t1NImwzM7gT9J1PC+xUsSh
S9Ei9+3H95bceCNEzGNBZvFFGzgGT3J0thaPgcPNTOYPEImCYQO0DhDRXLaayTHt
7PtuuVjCLRJGDMQxWePPrAALJhtokaSqx3/QfJQTQEfYRf5mowiwCgGahFcFqfcx
OPJvonzbRgSTlxgVq14cU1Dk8kNnoMCfYrEOyu/yHbZEtaPgAGenOXJTPE/is3PY
W1Yz5eQfo1fh4VVqOZLyva2wEW9q6suAS7fk200DaLytdY7LYc3MCOTnZ8GFO7bg
p2Fbb/LkkhgG8t9l3UfC5Txu/6nBXwarmaoBmMcB9JPqevRmiQCvns9uaNyUFDE=
=XOEn
-----END PGP SIGNATURE-----

Received on Thursday, 2 May 2013 20:29:07 UTC