Chris Capel's Dynamic Compressor

Share your Audacity/Nyquist plug-ins here, or test drive the latest plug-ins submitted by Audacity users.

After testing a plug-in from this forum, please post feedback for the plug-in author.
Post Reply
steve
Site Admin
Posts: 81227
Joined: Sat Dec 01, 2007 11:43 am
Operating System: Linux *buntu

Chris Capel's Dynamic Compressor

Post by steve » Thu Jul 21, 2011 7:56 pm

Sadly, Chris passed away on 15th March 2011.

In his legacy he left the latest beta version of his famous dynamic compressor (commonly known as "Chris's Dynamic Compressor").
We are able to post it here as it was licensed under the MIT license.
;;Permission is hereby granted, free of charge, to any person obtaining a copy
;;of this software and associated documentation files (the "Software"), to deal
;;in the Software without restriction, including without limitation the rights
;;to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
;;copies of the Software, and to permit persons to whom the Software is
;;furnished to do so, subject to the following conditions:

;;The above copyright notice and this permission notice shall be included in
;;all copies or substantial portions of the Software.

;;THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
;;IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
;;FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
;;AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
;;LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
;;OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
;;THE SOFTWARE.
Note that this is beta software and has not yet been tested by anyone in the Audacity Team.
More information to follow.
Attachments
compress-b1.ny
(18.93 KiB) Downloaded 6824 times
9/10 questions are answered in the FREQUENTLY ASKED QUESTIONS (FAQ)

steve
Site Admin
Posts: 81227
Joined: Sat Dec 01, 2007 11:43 am
Operating System: Linux *buntu

Re: Chris Capel's Dynamic Compressor

Post by steve » Fri Jul 22, 2011 12:54 pm

The algorithm used in the 1.2.7 beta version is slightly changed from previous version, with the addition of the following parameters:
"Compress bright sounds" [0/1]
"Boost bass sounds" [0/1]

To get the same results with 1.2.7 as the default 1.2.6 version settings, set "Hardness" to 0.25861 and "Compress bright sounds" to "No".

The default values in 1.2.7 beta are:
Compression level: 0.5
Hardness: 0.611
Floor: -32
Noise gate falloff: 0
Renormalize: 0.99
Compress bright sounds: 1
Boost bass sounds: 0

Personally I don't think that the perceptual modelling (the "Compress bright/bass sounds") is quite right yet. The idea is that it makes the compressor follow the way in which hearing responds to volume at different frequencies, but in my tests I find that a more natural sound is produced without this feature (ie with the 1.2.6 version).
Anyone else?

steve
Site Admin
Posts: 81227
Joined: Sat Dec 01, 2007 11:43 am
Operating System: Linux *buntu

Re: Chris Capel's Dynamic Compressor

Post by steve » Fri Jul 22, 2011 2:43 pm

Here's the beta version with the advanced options enabled.
This can be installed at the same time as the regular 1.2.7 beta version and will appear in the Effect menu as "Compress dynamics (advanced)..."
Attachments
compress-b1a.ny
(18.94 KiB) Downloaded 1537 times
9/10 questions are answered in the FREQUENTLY ASKED QUESTIONS (FAQ)

Trebor
Posts: 9875
Joined: Sat Dec 27, 2008 5:22 pm
Operating System: Windows 8 or 8.1

Re: Chris Capel's Dynamic Compressor

Post by Trebor » Thu Jul 28, 2011 10:42 pm

steve wrote:Personally I don't think that the perceptual modelling (the "Compress bright/bass sounds") is quite right yet. The idea is that it makes the compressor follow the way in which hearing responds to volume at different frequencies, but in my tests I find that a more natural sound is produced without this feature (ie with the 1.2.6 version).
Anyone else?
The shape of equal loudness curves does depend on the loudness ...
400px-Lindos1.svg.png
400px-Lindos1.svg.png (42.22 KiB) Viewed 27950 times
http://en.wikipedia.org/wiki/Equal-loudness_contour

So any corrections Chris has applied can only be correct when played at a particular volume.

[Chris included this link slightly different version of equal loudness curves in the plugin]


The inverse of ISO 226 (below red) may be worth a try ...
400px-Lindos3.svg.png
400px-Lindos3.svg.png (42.01 KiB) Viewed 27949 times
http://en.wikipedia.org/wiki/A-weightin ... _equipment
Chris's corrections.png
Chris's corrections.png (5.22 KiB) Viewed 27912 times
Chris's corrections don't agree with inverse of ISO 226

theRamenNoodle
Posts: 22
Joined: Fri Oct 22, 2010 8:41 pm
Operating System: Please select

Re: Chris Capel's Dynamic Compressor

Post by theRamenNoodle » Fri Aug 12, 2011 8:10 pm

I host a "how-to" podcast about podcasting and using Audacity and would highly recommend Chris's Dynamic Compressor for podcasters and other Audacity users.

In Chris's memory, and with his dad's help, I am hosting Chris's Dynamic Compressor on my own site. I found a bug in the 1.2.7 beta, so I'm currently offering just 1.2.6, but I keep a copy of 1.2.7 also on my server.

http://theaudacitytopodcast.com/chriss- ... -audacity/

If you'd like to contribute some documentation (especially illustrated), or work on improving the project, please contact me.

steve
Site Admin
Posts: 81227
Joined: Sat Dec 01, 2007 11:43 am
Operating System: Linux *buntu

Re: Chris Capel's Dynamic Compressor

Post by steve » Thu Aug 18, 2011 6:03 pm

theRamenNoodle wrote: I found a bug in the 1.2.7 beta,
If you could give details we can probably fix it.
9/10 questions are answered in the FREQUENTLY ASKED QUESTIONS (FAQ)

theRamenNoodle
Posts: 22
Joined: Fri Oct 22, 2010 8:41 pm
Operating System: Please select

Re: Chris Capel's Dynamic Compressor

Post by theRamenNoodle » Fri Aug 19, 2011 3:06 pm

I'll have to play with it again to get better details. But from my memory, 1.2.7 wouldn't normalize the audio after compression, if something was set a certain way. I'll test and get back with you. Thanks for offering to help! I'll host any updates on my site, too.

http://theaudacitytopodcast.com/chriss- ... -audacity/

By the way, Chris's dad has given me the complete archive of Chris's website, and we're working to transfer the domain to me so people can still easily find it. I'll be updating the above URL (if it posts this time) with Chris's original documentation and will be happy to include any revisions or additions.

steve
Site Admin
Posts: 81227
Joined: Sat Dec 01, 2007 11:43 am
Operating System: Linux *buntu

Re: Chris Capel's Dynamic Compressor

Post by steve » Fri Aug 19, 2011 3:24 pm

theRamenNoodle wrote:from my memory, 1.2.7 wouldn't normalize the audio after compression,
That may just be an effect of the new "perceptual loudness model" feature ("Compress bright sounds" is enabled by default in 1.2.7). As with "ReplayGain" and other "perceptual loudness" models, this will override the peak amplitude setting. If that feature is not selected, then peak normalizing should work as previously.
9/10 questions are answered in the FREQUENTLY ASKED QUESTIONS (FAQ)

hedera
Posts: 72
Joined: Thu Oct 25, 2007 10:47 pm
Operating System: Please select

Re: Chris Capel's Dynamic Compressor

Post by hedera » Mon Apr 09, 2012 11:27 pm

Now that Audacity 2.0 is out (yay!), can we assume that Chris' 1.2.6 version will run with 2.0? How about the beta, 1.2.7? I'd be interested to test the beta. Yes, I did try to answer this question in the FAQ and the wiki and I don't see it.

theRamenNoodle
Posts: 22
Joined: Fri Oct 22, 2010 8:41 pm
Operating System: Please select

Re: Chris Capel's Dynamic Compressor

Post by theRamenNoodle » Mon Apr 09, 2012 11:28 pm

Yes, it works fine with 2.0. I've been using and recommending 1.2.6 with Audacity 1.3.x beta for a while. Audacity 2.0 is just Audacity 1.3 final (with new bugs, which I'm working to document).

Post Reply