diff options
| author | Ryan Billing <ryjobil@gmail.com> | 2013-10-04 01:57:00 +1300 |
|---|---|---|
| committer | Michael Giacomelli <giac2000@hotmail.com> | 2013-12-15 22:24:08 +0100 |
| commit | d0918b98fa0cfba21208a4fb5ed153687b8f02c3 (patch) | |
| tree | 006ef2bb902dfd83101fbfa3fe63b07f47d9e8e6 /docs/CREDITS | |
| parent | 5b5f0755d6d7fd9e3fdfdb479caeb7fafd0a9960 (diff) | |
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>
Diffstat (limited to 'docs/CREDITS')
| -rw-r--r-- | docs/CREDITS | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/docs/CREDITS b/docs/CREDITS index b78c44904b..94e8df2706 100644 --- a/docs/CREDITS +++ b/docs/CREDITS @@ -632,6 +632,7 @@ Vanja Cvelbar Richard Quirk Kirill Stryaponoff Roman Poltoradnev +Ryan Billing The libmad team The wavpack team |