rockbox/manual
Ryan Billing d0918b98fa DSP Compressor: Sidechain, Exponential Atk/Rls
This is an improvement to the current compressor which I have added
to my own Sansa Fuze V2 build.  I am submitting here in case others
find it interesting.

Features added to the existing compressor:
Attack, Look-ahead, Sidechain Filtering.
Exponential attack and release characteristic response.

Benefits from adding missing features:
Attack:
Preserve perceived "brightness" of tone by letting onset transients
come through at a higher level than the rest of the compressed program
material.

Look-ahead:
With Attack comes clipping on the leading several cycles of a transient
onset.  With look-ahead function, this can be pre-emptively mitigated with
a slower gain change (less distortion).  Look-ahead limiting is implemented
to prevent clipping while keeping gain change ramp to an interval near 3ms
instead of instant attack.

The existing compressor implementation distorts the leading edge of a
transient by causing instant gain change, resulting in log() distortion.
This sounds "woofy" to me.

Exponential Attack/Release:
eMore natural sounding.  On attack, this is a true straight line of 10dB per
attack interval.  Release is a little different, however, sounds natural as
an analog compressor.

Sidechain Filtering:
Mild high-pass filter reduces response to low frequency onsets.  For example,
a hard kick drum is less likely to make the whole of the program material
appear to fade in and out.  Combined with a moderate attack time, such a
transient will ride through with minimal audible artifact.

Overall these changes make dynamic music sound more "open", more natural.  The
goal of a compressor is to make dyanamic music sound louder without necessarily
sounding as though it has been compressed.  I believe these changes come closer to this goal.

Enjoy.  If not, I am enjoying it

Change-Id: I664eace546c364b815b4dc9ed4a72849231a0eb2
Reviewed-on: http://gerrit.rockbox.org/626
Tested: Purling Nayuki <cyq.yzfl@gmail.com>
Reviewed-by: Michael Giacomelli <giac2000@hotmail.com>
2013-12-15 22:24:08 +01:00
..
advanced_topics Corrected typo '%Play' with 'Play' on line 407 2012-10-05 17:23:48 +02:00
appendix fix the eq settings in the manual 2013-02-09 23:27:22 +11:00
configure_rockbox DSP Compressor: Sidechain, Exponential Atk/Rls 2013-12-15 22:24:08 +01:00
frontpage Move various logo files to a single location. 2011-06-04 20:31:11 +00:00
getting_started Manual: fix minor error with D2 OF filenames 2013-04-20 14:41:12 +01:00
intro Update manual copyright information for 2013. 2013-02-08 23:12:56 +01:00
main_menu [Fuze+][Keymaps] keymaps for radio and recorder update 2013-07-16 15:06:31 +02:00
platform Docs: Manual entry for touchpad settings. 2013-12-08 01:31:41 +01:00
plugins [Fuze+][Keymaps] Application and viewer keymaps update 2013-07-18 20:24:06 +02:00
rockbox_interface Update manual for Clip Zip 2013-02-02 13:53:30 +01:00
working_with_playlists Remove duplicate note from manual. 2012-01-02 10:52:34 +00:00
booktabs.sty The WPS section of the manual now reflects the wiki. Added booktabs.sty for prettier tables. Changed the way we get sans serif fonts as well. 2006-03-08 15:04:36 +00:00
credits.pl The credits file now also has underscores, which need to be escaped in LaTeX. 2007-05-19 21:05:20 +00:00
gsearch.js Manual: add search box to HTML output. 2011-06-19 15:43:41 +00:00
LaTeX.Rules Filter LaTeX output for errors. 2012-06-19 21:32:10 +02:00
latexfilter.pl Filter LaTeX output for errors. 2012-06-19 21:32:10 +02:00
Makefile Manual: make sure output folder exists to fix -j. 2012-07-03 22:53:36 +02:00
Makefile.pdflatex Manual: add search box to HTML output. 2011-06-19 15:43:41 +00:00
mkidx.ist Add style file for index. 2006-10-25 18:28:09 +00:00
optional.sty Rockbox manual in LaTeX initial commit. New option 'manual' added to configure. Some platforms (eg recorderv2, fmrecorder) produce the same manual target, so either can be selected from the configure script. 2006-02-06 07:25:25 +00:00
pdfdraftcopy.sty Manual: Apply dos2unix to replace CR+LF end-of-line with LF 2009-12-10 19:56:53 +00:00
preamble.tex Manual: Add version information to page footer. 2011-06-19 09:41:09 +00:00
rockbox-html.cfg Manual: add search box to HTML output. 2011-06-19 15:43:41 +00:00
rockbox.tex Add the identifying header 2010-03-27 16:02:39 +00:00
spellcheck.sh Update spellcheck script. 2011-08-09 23:14:41 +00:00
spelldict.pws Update spellcheck script. 2011-08-09 23:14:41 +00:00