Pop/Click Noise when applying effects or trimming

[mangoesbananas]

I hope someone can help resolve this issue that I'm experiencing with Audacity, which happens with both the stable & unstable versions of Audacity, and it happens on any XP or Vista computer I try it on...

- When I apply an effect to an audio file, suddenly there are click/pop noises at the start & end of the segment that the effect was applied to.
- This even happens when simply deleting a few seconds off the front end of a file.
- Trying to do a small fade-in on top of the newly-added click noise doesn't change anything
- Trying to remove the newly-added noise by using the click removal effect does nothing
- Trying to remove the newly-added noise by using the Normalize DC Offset effect does nothing
- Actually, even if I time-shift the audio file several seconds to the right, and then I start playing from the far-left of the screen (well before the file even begins), the click noise is still there!

Any help or advice would be much appreciated!

Many thanks...

[kozikowski]

This can happen if you have DC or battery voltage mixed in with your sound. It's fairly common to have cheaper digitizers do this by accident. I have two cheap microphone USB adapters with the same model number. One does it, one doesn't.

You can Apply Effects > Normalize > Remove DC (only)

Which can create problems depending on show content, or a formal High Pass Filter...

Effects > HiPass Filter (24dB 10Hz)

This one does a very nice job, but the first half-second or so of the show can't be used and can fail if you have a very large show and a modest computer.

You need to do these before you start editing. Once the clicks and pops appear, they are permanently baked into the show.

Koz

[steve]

Actually, even if I time-shift the audio file several seconds to the right, and then I start playing from the far-left of the screen (well before the file even begins), the click noise is still there!

And the click is still where?

Using Audacity 1.3
If you generate a 3 second tone and split it into 3 pieces - move one piece so that it start at t=10 seconds, the middle piece so that it starts at t=4 seconds and the first piece so that it starts at t=1.5 seconds. Apply a fade-in/fade-out to each clip and play the entire track. Any clicks? Is there anything you can do to make it click?

[mangoesbananas]

Thanks to both of you for replying. I'm not sure if kozikowski's answer applies to my exact problems, since the fixes you mentioned didn't seem to help, so I will type out the exact routine I follow...

- I record audio (either live or through the line-in input) on my Edirol R09-HR.
- I transfer the file to either my XP or Vista computer and then drag the file into Audacity (either the stable or unstable version).
- I press the Play button in Audacity. The start of the file sounds totally clean.
- I highlight & delete the first few seconds of dead space from the file so the music will start immediately at the start of the file.
- I press the Play button in Audacity, and there is now a loud 'pop' sound when play begins.
- Even if I time-shift the file to the right, the pop still happens - not at the start of the actual file, but just when the Play needle starts to move from the far-left of the Audacity window (in the gray area that doesn't even have any music file in it). From this behaviour, it seems the pop isn't on the file itself....however, if I export the file, it certainly is.
- These same pop sounds happen at the start & finish of most of the effects I add to a file....including when I use "Fade In" at the start of a file.

Regarding what 'stevethefiddle' wrote, I have followed your instructions, and although the original 3-second tone file started cleanly (no pops), once I split and moved the three sections and applied the fade-ins and fade-outs, there is now a pop when I hit the Play button. As you instructed, the first audio file doesn't start till 1.5 seconds, but the pop is heard at 0.0 on the timeline. That's how it is for the other files after I trim the dead space at the beginning. There is always that pop - even when I time-shift the audio file to the right.

I hope this helps make it clearer what is happening, and I thank you or anyone for any help they can offer....!

[steve]

Regarding what 'stevethefiddle' wrote, I have followed your instructions, and although the original 3-second tone file started cleanly (no pops), once I split and moved the three sections and applied the fade-ins and fade-outs, there is now a pop when I hit the Play button. As you instructed, the first audio file doesn't start till 1.5 seconds, but the pop is heard at 0.0 on the timeline. That's how it is for the other files after I trim the dead space at the beginning. There is always that pop - even when I time-shift the audio file to the right.

Curious - I have a theory, but first...

1) There is just 1 pop?
2) The pop is at the very beginning of the track?
3) The pop is also saved when you Export the track and play it in a different media player on a different computer?

4) If you zoom in really close so that you can see the individual samples, and look at the first sample on the track, is there any "pop" visible? (if there is, then a screen shot would be nice).

[mangoesbananas]

Thanks for writing back. To answer your questions...

1. Yes, there is just one pop.
2. The pop is at the very beginning of the track.
3. The pop is also heard on the exported file, no matter what computer or player it's played on.
4. If you zoom in very close, absolutely nothing shows up where the pop is! And, as I said, if I time-shift the file to the right a few seconds, the pop is still heard at 0.0 when the player is started at 0.0 (and it's still on the exported file).

All in all, it's very odd indeed.

Also, it happens with effects that are added. For instance, if there's a solo note in the middle of a file that I highlight and then choose "Change Pitch", there are then pops at the start and end of the effect. Certainly not an ideal scenario for clean audio-editing, so I'm hoping there's a solution.

Many thanks again for any help you can offer...

[steve]

1. Yes, there is just one pop.
2. The pop is at the very beginning of the track.
3. The pop is also heard on the exported file, no matter what computer or player it's played on.
4. If you zoom in very close, absolutely nothing shows up where the pop is! And, as I said, if I time-shift the file to the right a few seconds, the pop is still heard at 0.0 when the player is started at 0.0 (and it's still on the exported file).

Could you Export this file in WAV format - check that you are still getting the pop, and post it on the Internet and send a link (the forum will not accept WAV files)
If you don't have a web-site, you can use http://www.sendspace.com/ or a similar free service.

You could also send an example of a file where you have used other effects, but I am particularly interested in this one that just uses a generated tone and fade-in/out.
(please keep the files down to less than 20 seconds - WAV files are BIG).

[kozikowski]

This is a thing on DC being in your show by accident...

http://wiki.audacityteam.org/index.php? ... Management

I swear you have all the symptoms of battery voltage being in places where it shouldn't.

If you put your show on the timeline and move the cursor to the left into the tool area left, it will turn into a magnifier. It will boost the magnification vertically and let you see deviations between what you have and where "zero" should be. If you record dead silence -- put the recorder under a pillow and press record -- your line and the zero line should be the same.

It doesn't take too much up and down deviation to make editing impossible.

Are you trying to record productions in 24-bit? Audacity has a history of odd problems in 24-bit.

Koz

[steve]

I swear you have all the symptoms of battery voltage being in places where it shouldn't

A quick look at the Exported file will immediately answer that one.

[mangoesbananas]

Thanks so much to you both for all your insights. I was away from my computers yesterday evening, and will also be most of today, but I'll get those files you requested uploaded by the end of today. By the way, yes, I am recording in 24-bit, 96kHz. Do you think that's the entire problem? If so, is there a way I can still use that quality for recording, but not have the problems?

Many thanks again...