Pops and clicks in playback during editing

Audacity 3 Help Forum GNU/Linux
1

I use Audacity 2.05 on Ubuntu Studio 14.04.
After a while of editing (that could be somewhere between 5 or 10 minutes after starting, forementioned problem occurs.

I attempted to record the sounds that I hear, but I could only by using my external recording device. (There seems to be no other sound recording program on Ubuntu that doesn’t use Jack)
https://soundcloud.com/muziektaal/cracks-during-playback-in-audicity/s-8IBas#t=0:10

You can still hear the cracks though, that have an electrical feel to it. Really annoying during the editing process. This doesn’t always occur, by the way. I tried to edit with one earlid of my headphones off. After a while, some loud beeps are also present. And after like 20 minutes of click and beeps, all is silent again.

What can it be? I tried every option for “Input device”, checked the volume control for wrong settings, but I could not figure it out.

Is there any log that I can see through what happens? What to check?

EDIT #1:
There is a similarity with the topic “Static during playback”: https://forum.audacityteam.org/t/static-during-playback/34663/1 (I just didn’t know how to call the sounds)

This what my audio device looks like:
00:01.1 Audio device: Advanced Micro Devices, Inc. [AMD/ATI] Wrestler HDMI Audio
00:14.2 Audio device: Advanced Micro Devices, Inc. [AMD] FCH Azalia Controller (rev 01)

Kernel information:
Linux
[] 3.13.0-35-lowlatency #62-Ubuntu SMP PREEMPT
[] x86_64 x86_64 x86_64 GNU/Linux

Processor:
AMD E2-1800 APU with Radeon™ HD Graphics

2

I’ve tried to work on another file. It seems that I don’t get to hear the static cracks now.
Since it has been quite a while that I heard them, I can try to think loudly what might have caused this.

Both projects are interviews (length about 1-2,5 hours). Long, anyway.

The project that brings the static cracks, is an interview that I recorded using my Zoom H4N, the Zoom device encoded it directly to MP3.
The audio was imported in Audacity afterwards. I noticed a disbalance on the interview track and the songs I recorded on location. I tried to fix it first by running the standard compressor plugin. Afterwards I cut / seperated the interview parts from the songs, and put the music on different tracks. Then, I converted the stereo interview track completely to mono, including the blank spaces in between. As far as I can remember the cracks started occuring from then on.

The other project file contains only spoken word, directly recorded with Audacity on my ASUS laptop using an external analog audio mixer, using the microphone plug. For now, I will continue to edit this interview, I’ll get back if I might encounter the cracks here aswell.

So what could’ve happened when I converted from stereo to mono? Is that conversion the cause of all this?

3

USB Audio Devices don’t much like going through USB hubs with other equipment. That’s a sure way to cause noise problems.

Koz

4

using an external analog audio mixer, using the microphone plug.

That’s another way to cause problems. Mixer connections are robust, powerful and stereo. Mic-In is usually delicate, sensitive and mono.

800×613 54.2 KB

That’s a Behringer UCA202.

Koz

5

EDIT #1:
I’ve been editing this project that was recorded using my old Behringer Xenyx mixer for over an hour now, and all went pretty smooth.
So far it seems it was the project with the imported MP3’s that caused the trouble. What doubles it, is that I’ve been recording audio both using USB-mixers (and my Zoom on USB) and this old Behringer one successfully without having these ‘cracks’ / ‘statics’ on playback

So it is still only the project that I worked on previously, the one I uploaded the recording of.
My guess is still that something must’ve gone wrong when I converted some of the original stereo mp3-audio (that had been succesfully loaded into the Audacity project) to mono. Any ideas what that might have been?

6

I moved this to a new topic. You do not have the same machine as the other person whose topic you joined, and that topic turned out to be a playback issue on the computer.

You mean “2.0.5”.

The best way to record computer playback on Ubuntu is usually to use Pulse Audio Volume Control. See Tutorial - Recording Computer Playback on Linux - Audacity Manual .

See Why do I hear clicks when I remove or paste audio, or at the start or end of the track? for good editing practices like cutting on zero crossing points.

As stated there, the imported files may possibly have been recorded with DC offset . This may cause clicks when you edit. After importing files from the same source, use Effect > Normalize… with DC offset removal enabled before starting editing.

Record with Zoom to WAV if you can. MP3 is lossy. Audacity will decompress the MP3 to PCM when you edit it, so you are not saving disk space on the computer.


Gale

7

Dear Gale,

Thanks for your explanation. I must admit that I’m working with Audacity for over three years now, and that I understand the basic principles of editing interviews and making manual edits of songs. So to say, I am sure these “static pops and beeps” have nothing to do with that.

As I mentioned before in this thread, this problem occured after merging one stereo track to one mono track. After merging (and, by the way, removing some background noise) I both compressed (and normalised) the audio.

Of course, as you mentioned I tried to normalise the audio again (and remove DC offset), but unfortunately the static popping sound still occurs.

You seem like an experienced forum user, do you or anyone else recognise these static pops?
Here’s the link again for an impression: https://soundcloud.com/muziektaal/cracks-during-playback-in-audicity

8

I tried another option I thought of earlier: exporting all the audio, and then importing it into a new project. That fixed the problem of the cracks, but now, of course I have only one track left and I need to make the cuts all over again.

Fact is, in some way an Audacity project can go corrupt. I still wonder what caused this, so perhaps it can be fixed in the future. For now, I stick to my hypothesis. If anyone wants my project for debugging or study purposes, I am happy to share it. Any way I can help the Audacity team developing, I would be happy doing so.

9

Of course, if you have a project with the stereo interview track (without clicks) and music track, and can tell us steps to corrupt the audio we will be happy to investigate it.

If you Edit > Undo the stereo to mono conversion, does the problem go away, but reappear if you redo the conversion?

We would need you to open File > Check Dependencies… in the project, copying in any files listed there, then save and close your project in undamaged state. Make a zip of the AUP file and the _data folder and include a text file giving us the steps to create the distortions.

Are you saying for example that the disturbance at 26.15 seconds in your Soundcloud file is not in the original recording? That file is stereo, not mono.


Gale

10

The file doesn’t have any dependencies. (I just did the check)
Since I closed the file and shut down my computer in the meantime, I can’t undo/redo.

I will try to reproduce the error using parts of the original recordings in a new project. This will take some time, though.
By the way, in my forum profile, I noticed that I posted about this a few years ago, too. I was using a desktop computer, back then.

11

I tried to reproduce the static cracks, using the same original audio file. In this case I imported just one of the four MP3’s.

Step 1. Import the MP3-file into a new project.
Step 2. Change the balance so that the audio is in balance.
Step 3. Cut out (CTRL-I) part of the audio (in my case the Sun-Ra song) and put it on a new (stereo) track.
Step 4. Normalise the first audio part containing the interview (stereo channels not seperately, -0,1 db)
(for the research, I tried editing the file here, cut bits and pieces away, using fade in/fade out for tiny parts of audio so I can cut ERRRR’s off)
Step 5. Converted the two audio parts on the “interview” track to mono. Part of is was empty, so it was filled up with “blank audio” where the song was put on the new track.
Step 6. Put back the balance.
Step 7. Select the ‘blank audio’ and cut it out using CTRL-ALT-K
(for the research I started doing the editing again, and just before I thought I would have to think of another possible step, the first static cracks came in. Which is normal, I can restart Audacity and work for a few minutes without the cracks, and then, they show up).

The static crack have three louder cracks on the right channel, and one softer crack on the left channel. The come along every 5 seconds. After a while, loud beeps are heard.

IMPORTANT: If I start playing the audio track at a point of silence, the static cracks disappear. Strange. Impressive, but strange.

12

The Soundcloud recording was terrible. I don’t believe all those bangs were due to editing. Please refer to an exact point in time on that sound file that you think is a click that Audacity permanently added.

Thanks, but those aren’t steps to reproduce that we could use, without a project to look at.

CTRL + I (as in “eye”) does Split, not “cut out”.

How you are “converting to mono”? It could be important.

No Audacity editing could create beeps where there were none before.

Every 5 seconds sounds like it could be the length of an Audacity “audio block file”.

It would be much simpler if you would provide a project that is ready to show the problem after we perform certain steps in it.

You now seem to be suggesting it isn’t an editing problem, if the clicks are not there immediately after converting to mono but then appear later.

Exact layout of tracks could be important. If tracks are offset from time zero with only white space (not a flat line) before the audio starts, this could create noise if you play where there is white space. That issue is reported sometimes on Mac OS X.

Please use Help > Audio Device Info… in Audacity and post the complete information from there.

Are you choosing the pulse playback device in Device Toolbar? If so, what happens if you quit Audacity then launch Audacity from the terminal with the pulse latency set in an environment variable?

env PULSE_LATENCY_MSEC=30 audacity

What happens if you set the playback and recording device in Device Toolbar to an ALSA (hw) choice?


Gale

13

Okay, you’re pulling my leg a bit here. English is not my motherlanguage, and I am very willing to spend time to assist and help, but please understand that my terminology is not completely conform your knowledge of the English language. Above all, I use the Dutch version of Audacity. Then again, thanks for your assistance.

Anyway, back to business. I will try to reply to your remarks one by one.

Soundcloud recording
All I can say about the “bangs” (I called them cracks / static pops), is that they were coming from Audacity. I’m not making them up. They weren’t in the original recorded audio. I will replace the audio file on Soundcloud with a new one, I just reopened the project as I write. This time I will record from the laptop speakers in stead of the headphones.

I’ve put a new recording online. In the first part (audio interview) I just let the audio roll, every 5 seconds the “crack” is heard. In the second part (the crazy free jazz track) I skip through the audacity project. Every time the audio starts to play, the sound is heard. If I turn down the volume, the crack also goes down in volume. When turned up, the volume of the crack goes likewise. I didn’t get the beeps this time.
https://soundcloud.com/muziektaal/cracks-during-playback-in-audicity/s-8IBas

Reproducing steps
Of course I can send you the project file! I already offered, but I don’t have any address to send it to. Or I don’t know a place to put it.

I converted to mono by selecting different audio parts on one track and then Chose
Tracks (Sporen) => From stereo to mono (Van stereo naar mono).

Beeps
I’m indeed suggesting that it isn’t an editing problem. I suppose it is the way Audacity handles and sends out audio from these specific audio “packages”. Something in the project files makes Audacity behave as such. I thought the ‘audio block file’ had a length of 6 seconds? That’s why I counted the length of it. Please note, that by skipping through the track, everytime the audio starts playing, this “crack” is heard.

Layout
I don’t understand this part of your explanation. The problem returned in a different track layout (i.e. another project that I specially created for troubleshooting). Perhaps this is what you mean.

Audio device information

==============================
Default capture device number: 4
Default playback device number: 4
==============================
Device ID: 0
Device name: HD-Audio Generic: HDMI 0 (hw:0,3)
Host name: ALSA
Input channels: 0
Output channels: 8
Low Input Latency: -1,000000
Low Output Latency: 0,005805
High Input Latency: -1,000000
High Output Latency: 0,034830
Supported Rates:
    32000
    44100
    48000
    88200
    96000
    176400
    192000
==============================
Device ID: 1
Device name: HD-Audio Generic: ALC269VB Analog (hw:1,0)
Host name: ALSA
Input channels: 2
Output channels: 2
Low Input Latency: 0,005805
Low Output Latency: 0,005805
High Input Latency: 0,034830
High Output Latency: 0,034830
Supported Rates:
    44100
    48000
    96000
    192000
==============================
Device ID: 2
Device name: hdmi
Host name: ALSA
Input channels: 0
Output channels: 8
Low Input Latency: -1,000000
Low Output Latency: 0,005805
High Input Latency: -1,000000
High Output Latency: 0,034830
Supported Rates:
    32000
    44100
    48000
    88200
    96000
    176400
    192000
==============================
Device ID: 3
Device name: pulse
Host name: ALSA
Input channels: 32
Output channels: 32
Low Input Latency: 0,008707
Low Output Latency: 0,008707
High Input Latency: 0,034830
High Output Latency: 0,034830
Supported Rates:
    8000
    9600
    11025
    12000
    15000
    16000
    22050
    24000
    32000
    44100
    48000
    88200
    96000
    176400
    192000
==============================
Device ID: 4
Device name: default
Host name: ALSA
Input channels: 32
Output channels: 32
Low Input Latency: 0,008707
Low Output Latency: 0,008707
High Input Latency: 0,034830
High Output Latency: 0,034830
Supported Rates:
    8000
    9600
    11025
    12000
    15000
    16000
    22050
    24000
    32000
    44100
    48000
    88200
    96000
    176400
    192000
==============================
Device ID: 5
Device name: /dev/dsp
Host name: OSS
Input channels: 16
Output channels: 16
Low Input Latency: 0,008707
Low Output Latency: 0,008707
High Input Latency: 0,034830
High Output Latency: 0,034830
Supported Rates:
==============================
Selected capture device: 4 - default
Selected playback device: 4 - default
Supported Rates:
    8000
    9600
    11025
    12000
    15000
    16000
    22050
    24000
    32000
    44100
    48000
    88200
    96000
    176400
    192000
==============================
Available mixers:
==============================
Available capture sources:
==============================
Available playback volumes:
==============================
Capture volume is emulated
Playback volume is emulated

Devices
Changing devices does not get rid of the static cracks during playback. I haven’t tried launching Audacity from the terminal using that code. I haven’t got time for that now. I need to focus on other tasks.


As I said, I would be happy to hand you the project file that I created for repeating the steps. But then, I need somewhere to send it to.

14

If you can make a ZIP archive containing both the .AUP file and the _data folder, then you could post it to a free file sharing service such as sendspace.com and post a link here.

15

The “default” device you are choosing in Audacity for playback and recording is in fact pulse.

I would definitely try launching Audacity with

env PULSE_LATENCY_MSEC=30 audacity

What setting do you have for “Audio to buffer” in the Audacity Recording Preferences? That setting affects playback too.


Gale

16

I’ve encountered the same error in another project. I’m sorry I haven’t replied earlier, I’ve had some terrible weeks altogether. This is just a message that I’ve returned with working on the problem.

I uploaded a sample project to Sendspace: https://www.sendspace.com/file/lrq212 If you still want to test using that project, be my guest.

Fact is, in the project I’m working on now, I haven’t converted any track from mono to stereo or the other way around. So it seems the problem lies elsewhere.
I will try to start Audacity using the command line you suggested. [ env PULSE_LATENCY_MSEC=30 audacity ] I will report back any results. If I haven’t seen the statics returning during the editing process, I will let you know when I’m done. If that happens, I consider the problem solved. I will likely be done editing somewhere around Monday.

17

Thanks. What are the exact steps to perform after opening the project that make it do what you want us to see?


Gale

18

Sorry, I’ve been busy again. It’s the time of the year again.

About the example project
The steps to reproduce, just take the steps I mentioned in this thread earlier.


I ran Audacity using the augmented PULSE_LATENCY, and this what I got from started (doesn’t look all clean):

(process:3688): GLib-GObject-WARNING **: Attempt to add property GnomeProgram::sm-connect after class was initialised

(process:3688): GLib-GObject-WARNING **: Attempt to add property GnomeProgram::show-crash-dialog after class was initialised

(process:3688): GLib-GObject-WARNING **: Attempt to add property GnomeProgram::display after class was initialised

(process:3688): GLib-GObject-WARNING **: Attempt to add property GnomeProgram::default-icon after class was initialised
ALSA lib pcm_dsnoop.c:618:(snd_pcm_dsnoop_open) unable to open slave
ALSA lib pcm_dmix.c:1022:(snd_pcm_dmix_open) unable to open slave
ALSA lib pcm.c:2239:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.rear
ALSA lib pcm.c:2239:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.center_lfe
ALSA lib pcm.c:2239:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.side
bt_audio_service_open: connect() failed: Verbinding is geweigerd (111)
bt_audio_service_open: connect() failed: Verbinding is geweigerd (111)
bt_audio_service_open: connect() failed: Verbinding is geweigerd (111)
bt_audio_service_open: connect() failed: Verbinding is geweigerd (111)
ALSA lib pcm_dmix.c:1022:(snd_pcm_dmix_open) unable to open slave
Cannot connect to server socket err = Bestand of map bestaat niet
Cannot connect to server request channel
jack server is not running or cannot be started
Expression 'ret' failed in 'src/hostapi/alsa/pa_linux_alsa.c', line: 1736
Expression 'AlsaOpen( &alsaApi->baseHostApiRep, params, streamDir, &self->pcm )' failed in 'src/hostapi/alsa/pa_linux_alsa.c', line: 1904
Expression 'PaAlsaStreamComponent_Initialize( &self->capture, alsaApi, inParams, StreamDirection_In, NULL != callback )' failed in 'src/hostapi/alsa/pa_linux_alsa.c', line: 2171
Expression 'PaAlsaStream_Initialize( stream, alsaHostApi, inputParameters, outputParameters, sampleRate, framesPerBuffer, callback, streamFlags, userData )' failed in 'src/hostapi/alsa/pa_linux_alsa.c', line: 2840
Expression 'stream->playback.pcm' failed in 'src/hostapi/alsa/pa_linux_alsa.c', line: 4611
Expression 'stream->playback.pcm' failed in 'src/hostapi/alsa/pa_linux_alsa.c', line: 4611

And during the editing, I encountered a continuous buffer underrun.

ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred

et cetera

19

Try a higher number in the PULSE_LATENCY_MSEC command. For example:

 env PULSE_LATENCY_MSEC=100 audacity
20

Hey Steve,

I will try your suggestion. I’ve got another of those cracking projects, this time I managed to do a better recording (better mixer, so now it’s direct from source).

The recorded session were originally one recording.
The recording starts with a song. The static pops are clearly hearable.
After that, there are a few minutes of empty space (no audio blocks). The pops are still hearable.
Then, a new audio recording starts. Somehow, the pops seize to be heard.

Skipping back to the song, there are no pops and clicks where they were heard earlier on this recording.

https://soundcloud.com/muziektaal/cracks-during-playback-in-audicity/s-8IBas