Clipfix Audacity

Clip Fix... attempts to reconstruct clipped regions by interpolating the lost signal. It is only likely to be effective for repairing lightly clipped audio.

Accessed by:Effect > Clip Fix...

I tried the clip fix effect from Audacity but it didn't really help. May someone have tipps how to increase the quality of the voices or is the recording so bad that it can't be rescued? Log in or sign up to leave a comment Log In Sign Up. Contribute to audacity/audacity development by creating an account on GitHub.

Threshold of Clipping (%)

How close to the maximum sample magnitude any sample must be to be considered clipped.

If processing is slow, select only a few seconds of clipped audio at a time.
This effect assumes that the audio is clipped at the same dB level for both positive and negative peaks. If either the top or bottom of the waveform is successfully reconstructed but not both, try applying DC offset correction before applying Clip Fix.

Reduce amplitude to allow for restored peaks (dB)

This enables you to reduce the amplification of the current selection (default is -9 dB) to provide headroom for the clip-fixed reconstruction.

Buttons

Clicking on the command buttons give the following results:

gives a dropdown menu enabling you to manage presets for the tool and to see some detail about the tool. For details see Manage presets
plays a short preview of what the audio would sound like if the effect is applied with the current settings, without making actual changes to the audio. The length of preview is determined by your setting in Edit > Preferences > Playback, the default setting is 6 seconds.
applies the effect to the selected audio with the current effect settings, but unlike the effect runs in debug mode. This is primarily of use when writing or editing Nyquist plug-ins.
- In addition to the normal plug-in behavior, a 'debug window' opens to display error messages, normally the debug window will be empty
applies the effect to the selected audio with the current effect settings and closes the dialog
aborts the effect and leaves the audio unchanged, closing the dialog
brings you to the appropriate page in the Manual, this page

Links

|< Index of Effects, Generators and Analyzers

There are only a couple main reasons clipping is present in an audio. One is that the audio has been “overproduced” or, for a better lack of terminology, is battling against others in the loudness wars. The second is that it has been recorded at too high of a volume or has been processed in a way that also pushed its boundaries beyond the audible spectrum.

In today’s post we walk our readers through the process of using our favorite free, open source audio editing software for PC, aka Audacity to fix this clipping and restore the recording to a normal, non-distorted state!

How would I use this tutorial? If your audio sounds too loud or is noticeably distorted, and when looking at the waveform, appears similar to the image below rather than the one above, this tutorial will show you exactly how to repair the audio as best as possible, without having to re-record!

Before starting: Looking for Setup instructions? Our recent Audacity 2.0.0 for Windows Installation Tutorial should do the trick!

For today’s walk-through, we’ll be applying the Clip Fix effect using Audacity 2.0.0 (Windows 7) as run on Parallels; a virtual machine booted in ‘coherence mode’, running on a MacBook Pro.

Step 1: MP3 Download

Already have your file ready to go on your desktop? Skip to Step 2!

Before one can edit their AudioAcrobat recording in Audacity, the first step is to make sure that the file resides on the hard drive of the computer on which editing will be performed.

1. Login to your AudioAcrobat account
2. Click Audio (L)
3. Click the Title of the Audio you wish to Download
4. Click Download Audio

Clipfix.ny Audacity

Looking for Expanded Steps? Try HERE.

Step 2: Open in Audacity

Now that the file our readers wish to edit is on their computer’s hard drive, they will want to open the file with Audacity. Right-click the file and choose Open With and select Audacity from the list. Don’t see it listed? Open Audacity from Programs folder in the Start menu. Open the software and click File >> Open, selecting the audio to be edited.

Once the file opens in Audacity, our readers will see something like this:

Listen to the above clip!

Step 3: Highlight, Amplify

This part is really simple but extremely necessary. Click and drag with the mouse cursor over the area you want to apply the effect, or for those keyboard enthusiasts out there, use Shift + Left / Right arrow keys to make your selection.

Prior to applying the Clip Fix effect, you will want to bring the volume of your source file down far enough to leave room for the interpretation and repair of the boosted (clipped) peaks. To do this, we will use the Amplify effect. Since we’ve previously covered the Amplify effect in full detail, we will share only the essentials in today’s tutorial.

For the Amplify effect, our readers will want to select Effect >> Amplify as seen below:

Immediately after selecting Amplify, the following pop-up window will appear:

By default, the Amplification (dB) value will display a positive number. Change this number to a value of negative 10.0 dB, as seen above, and click OK.

Step 4: Highlight, Clip Fix

If for any reason the waveform isn’t already highlighted, go ahead and do so at this time.

For the Clip Fix effect, our readers will want to select Effect >> Clip Fix as seen below:

Immediately after selecting Clip Fix, the following pop-up window will appear:

For today’s example, we’ve left the settings at their defaults, but please feel free to experiment with the value / slider seen above to fine-tune the effect to your liking.

Threshold of Clipping [%] is defined as “how close to the maximum sample magnitude any sample must be to be considered clipped” and can either close the window of focus (raising the percentage to be closer to 100%) or open this window even further by lowering the % to be closer to 0%.

Here’s what our audio looks like after applying the above settings:

Click to Enlarge

Step 5: Highlight, Amplify, Export

Making sure that the audio is highlighted, we will again apply the Amplify effect as seen in Step 3, except this time we will not be modifying the Amplification(dB),and leaving it at the default (positive) value, which will in turn raise the volume as much as possible without clipping.

Here’s what our waveform looks like after applying the Amplify effect yet again:

Listen to the above clip!

When satisfied, select File >> Export to save the newly edited version and head over to AudioAcrobat in an internet browser to begin the upload process.

Aside: Notice how the finished clip sounds less distorted during the loudest parts? This is by design, and confirms that the tutorial was successfully completed, thus restoring the audio to a state in which the listener is able to hear the full audible spectrum without any distortion.

Audacity Reduce Clipping

Well that was quick … we’ve already walked through the process of downloading/opening our file, applying the Amplify and Clip Fix effects using Audacity 2.0.0 for Windows 7 and exporting the file for upload to the Web … and yet it seems as though we had just begun. If you agree, go ahead and click the ‘Previous Post’ link beneath this article to continue the joyride!

Did you get stopped somewhere in the process? Make sure you have LAME correctly setup then shampoo, rinse and repeat the steps listed above. Success will be yours!