Click & pop hunting tips needed

[Tapehead]

I've had some success with more obvious ones but there are two or three slight clicks where I can't locate any obvious defect in the waveform.

I can locate the general area when zoomed out but the more I zoom in whilst playing back the quicker waveform flies by so that doesn't really help narrow it down. So then I slow down the playback speed but at slower speeds I can't hear the click

Zooming in horizontally and vertically and manually scrolling the general area doesn't show up any obvious defect in the waveform and also involves what seems like a few miles of wavy lines at that magnification.

[DVDdoug]

That can be tough... Have you tried Click Removal effect over a section that's big enough to include the defect?


For cleaning-up vinyl records, I use a program called Wave Repair ($30 USD after free trial).

It has a spectral view that shows the frequency spectrum over time (unlike the Audacity where spectral view which shows the spectrum of your selection)). A vinyl click will usually show-up as a white line.* (The clicks & pops don't always stand-out, and your clicks may not be so obvious.) You can zoom-in on the click in spectral view, and then switch to the normal waveform view.

CORRECTION - As Trebor says, Audacity's Spectrogram from the drop-down track menu will show the same thing as Wave Repair. (Analyze - Plot Spectrum won't help.)

There is also a feature called "Play Around", which skips-over your selection. So if you can still hear the click, it's not in your selection. Sometimes you can select a longer section with the click and then start zooming-in and moving your selction around while using Play Around to find the click.

Once you've found the click, there are several repair methods (besides re-drawing the waveform), and you don't have to see the defect to repair it.

Wave Repair is not perfect but it does a perfect job on most clicks & pops. It's designed for vinyl records, but I've used it on other sources when there is a short-duration defect.





* Now that I think about it there are some color selection options, so the line may not be white but it should be contrasting.

[Trebor]

I've had some success with more obvious ones but there are two or three slight clicks where I can't locate any obvious defect in the waveform.

Try Audacity's spectrogram view , rather than waveform view ...


http://manual.audacityteam.org/o/man/tr ... _menu.html

Clicks are more obvious on the spectrogram because of their high-frequency content ...

click shows on spectrogram.gif (80.21 KiB) Viewed 1030 times

[steve]

Another vote for Spectrogram track view.

This is a track I've been working on recently. You can clearly see a click in the left (upper) channel, indicated by the red vertical line:

firsttrack001.png (262.65 KiB) Viewed 1017 times

[Gale Andrews]

There is a page in the Wiki: Click removal using the Spectrogram view that will help you use the Spectrogram for click removal.

This page will move to the Manual from 2.0.6 onwards.


Gale

[Tapehead]

At last! Got the little blighters. Using the spectrogram makes life a lot easier

Thanks very much everybody for your help.,

After locating the clicks I used a variety of draw tool, brush tool (alt+click) and repair to smooth out the waveforms. I used the draw pencil to roughly smooth out the glitches with long sweeps using the edge of my laptop touchpad as a kind of rulerand then the brush to smooth out any of my freehand wobbles or misalignments. Just using the brush tool alone can be RSI inducing,

One of the clicks was actually made up of three different red lines, another was more of a less distinct spread out red splodge so I used Repair for that one. The area was far too wide for the number of samples Repair would accept so I highlighted a section - repaired - highlighted the next section - repaired and so on.

Very pleased with the outcome.

p,s Is there a shortcut or facility to automatically flatten out a waveform line between two points or induce a curve instead of a spike?

p.p.s Why does the zoom have to be so high before the draw tool can be used?
Because often (even after also vertically zooming) the shape of the waveform is lost and the glitch - which is obvious at slightly lesser zoom levels - can no longer readily be seen

[kozikowski]

To address a problem you had about two-thirds of the way up the thread, no the blue waves do not have to "fly by." I set Auto Update the Display when I'm recording to make sure I'm getting a proper performance, but I turn that off immediately when editing. I'll put the view exactly where I want it, thanks. I don't need any help.

Audacity > Edit > Preferences > Tracks > [_] Update Display... (de-select)

Koz

[Trebor]

p,s Is there a shortcut or facility to automatically flatten out a waveform line between two points or induce a curve instead of a spike?

A low-pass filter will smooth the waveform , you may have to use repair on the ends of the section where a low-pass equalization has been applied ...

low-pass equalization (applied twice) smoothes waveform.gif (104.98 KiB) Viewed 992 times

[steve]

p,s Is there a shortcut or facility to automatically flatten out a waveform line between two points or induce a curve instead of a spike?

If that is for repairing small clicks, then there is the "Repair Tool" http://manual.audacityteam.org/o/man/repair.html

p.p.s Why does the zoom have to be so high before the draw tool can be used?

Because the Draw tool acts on individual samples.
I'm guessing that you have a "feature request" in mind for it to do something when zoomed out?

[waxcylinder]

Like DVDdoug I also use a piece of third party software. Like you I used to use the spectrogram view with the draw tool and latterly the Repair effect. - but than Koz pointed me in the direction of Brian Davies' ClickRepair (for which I am eternally grateful to him [Koz and Brian that is], as it has saved me huge amounts of time and produced excellent results with my LP transfers).

See this sticky thread: http://forum.audacityteam.org/viewtopic.php?f=28&t=1994

WC