Attempting to fix clipping on an album.

[DarthLowBudget]

Hey everyone, it's my first time on this forum, so go easy on me.

I'm attempting to fix the clipping issues on the Rush album Vapor Trails. So far I've taken my CD and ripped the .wav files to my desktop for editing. Before anyone says this is a lost cause, I have found a set of instructions on the web for doing this in Cool Edit Pro/Audition. I've listened to a 30 second sample of the results of this process and the effect is noticeable to my ears. The instructions were put together by a pair of Rush fans who are also audio editors. They are fairly simple, but require me to use software I don't have. Because I don't want to dabble in anything even slightly less than legal (although I must admit I'm not entirely clear on the legality of editing a CD I have purchased for personal use only) I've decided to attempt this procedure utilizing only freeware editing software. I've been messing around in Audacity for a little while for various purposes but I've never attempted anything like this.

Basically I was hoping someone could take a look at these instructions and help translate them into Audacity for me, or at least point me in the direction I should be looking in as far as plugins and settings.

The instructions are as follows:

The process created to remove the digital distortion/clipping or "crackle" (adversely affected the louder sections of VT) is summarized below.

Convert to 32-bit

Run Cool Edit Pro 'Clip Restoration ' ('Restore Normal' preset) except with a -2.6dB setting.

Run WavesMasters 'L2 Ultramaximizer' ( http://www.waves.com ) with the following settings: -1.3 dB Threshold, 0 dB Out Ceiling, ARC Enabled, Quantize = 16-bit, Dither = Type1, Shaping = Ultra)

Repeat steps 2 and 3

Convert to 16-bit and Save

Now I don't know if these things are even remotely possible with freeware plugins, so maybe I'm wasting my time, but any improvement in audio quality would be nice (the album has a pretty good deal of clipping going on), so any thoughts on other ways of accomplishing something similar would be greatly appreciated.

Thanks in advance,

DLB

[steve]

I've heard about the problem with this album, but I've not heard the album itself, so I've no idea how well this "restoration" will work.
Basically, to do the equivalent of the suggestions but using Audacity:
1) Convert to 32 bit
2) Amplify by a negative amount (probably around -10dB)
3) Split the album into tracks and export as 32 bit WAV files
4) Import one track and run ClipFix (available in Audacity 1.3.6) - do not try and run it on the entire album in one go because it will take forever, and probably crash.
5) Repeat step 4 for each track (restart Audacity between processing each track)

6) Restart Audacity, import all the tracks.
7) Apply "Amplify" to all tracks at the same time.
8) Use "fast lookahead limiter" (available as a free plug-in for Audacity).

[DarthLowBudget]

So I figure I'll basically just run Clip Fix at the standard 95% threshold, but then when I amplify, how far do you think I should push it? Obviously not back up enough that the peaks get clipped again.

Oh, and where can I snag the "fast lookahead limiter"?

[steve]

The defaults on ClipFix will probably be about right but you may need to experiment.

The Amplify will not allow you to make it clip again, unless you explicitly tell it to, so just use the default setting.

The "fast lookahead limiter" is included with the LADSPA effects pack: http://audacityteam.org/download/plugins
You will need to experiment with the settings on this - basically the idea is just to compress some of the peaks that you have created with ClipFix, not to increase the amount of compression/ limiting that is present in the recording as the original recording has (apparently) been overly maximized already. Try input gain of about 2dB, and limit to -0.5dB

(Experiment on a short section and adjust as necessary. Ctrl + Z = Undo)

[DarthLowBudget]

Ok, so those settings already seem to be a doing a world of good. The first track is already more listenable. When I start tweaking around more it should be even better. I found it was helpful to actually do the clip fix and limiter steps twice, as suggested in the original instruction for audition. When listening I notice that most of the crackling that was present in the loud sections of the track are largely gone, and there also seems to be slightly more depth to the recording (well not much, but it sounds slightly less flat). Given the insane amount of compression introduced during the original mastering process, I doubt it will ever sound as good as it could, short of an official remaster, but at least now I may be able to listen to the thing over headphones without cringing.

[agaraffa]

Hope nobody minds but I'm bringing this old thread back. I'm brand new here and just started trying to get some dynamics out of some of my squashed albums using Audacity. Just wondering if anyone has any additional tips. Here is my process...

- Open album as one complete FLAC file into Audacity
- Amplify album to adequate level (normally around -10 dB)
- Run Clip Fix using the default "Threshold of Clipping %" of 95 (since I have the complete album in one file I select about 10 minutes at a time)
- Amplify album back up using a "New Peak Amplitude %" of -0.1

I've given up hope that the music industry is ever going to do the right thing and master some of these recording properly so I'd like to get the best results possible using in-home tools. Just wondering if anyone has any tips, critiques, or alternate methods that may provide better results.

Thanks.

[waxcylinder]

Our main tips are encapsulated in the workflow tutorial in the Manual: http://manual.audacityteam.org/o/man/sa ... ation.html

WC