First 5 seconds of Export buzzing

Audacity Help Forum macOS
1

Hello,

I’m currently running Audacity 2.0.5 on my Mid-2013 13-inch MacBook Air (base model) running OS X Mavericks Version 10.9.1.

I am editing sermons for my church to publish onto the local radio. I used to have an '09 Macbook Pro running OS X 10.8 and ran Audacity 2.0.5 on it with no exporting issues at all. Unfortunately, that computer crashed completely and I’ve since upgraded to my current Macbook Air in which I’ve been experiencing issues. With my new laptop, I’ve been editing sermons that have three separate tracks, that in total exact to a final time of 27:50. Whenever I export the sermon (whether MP3 or WAV), the first 5 seconds of the published file have a crackling sound. I am not certain as to why this keeps happening, but it is quite frustrating and any advice is more than greatly appreciated.

I’ve tried isolating the problem, but haven’t fully figured things out, so here are some other notes that I’ve observed
-Whenever I install Audacity, usually the first time I export with it, my final MP3 file comes out perfect. Any following times I export, I get the beginning 5 second crackle
-With that said… I’ve installed 3 different versions of Audacity (2.0.3, 2.0.4 and 2.0.5) with the same issue across the board
-I’ve exported each individual track separately into MP3 format and had absolutely no issues with them
-I’ve exported to WAV both before and after installing LAME to observe if the crackling occurred. It still did :frowning:

In summary, I’ve come the following conclusion(s): The version of Audacity makes no difference upon the issue, the LAME plug-in is not the culprit of the issue, and lastly I can technically keep installing/deleting Audacity to export my final product, it is just very frustrating as I edit multiple times a week.

So I’m not certain if this is a general incompatibility issue between Audacity and OS X Mavericks 10.9.1, an issue with my files when arranged into multiple tracks (as each exported individually just fine), or something else.

I hope I offered a thorough enough explanation, and do greatly appreciate any advice. Also I have read a similar issue: https://forum.audacityteam.org/t/static-distortion-on-export/30123/1
but the solutions offered me no help unfortunately.

Thank you for your time,
Ryan

2

Does it happen if you export the first clean show and then export exactly the same show only change one character in the filename?

We’re going to want to hear that crackle but you can only upload about two seconds of WAV sample to the forum. Do you have any online file service available?

I don’t know about going much further without hearing the problem.

Koz

3

Watch your email.
Koz

4

Probably not good news - Mavericks and Mac Book Pro seem to have issues with audio.

What playback device are you using - make and model number?

Do you hear the crackling if you play the exported file in iTunes or only if played in Audacity? If only in Audacity, have you tried changing Audio to Buffer in Audacity’s Recording Preferences? Try reducing buffer as well as increasing it.

That doesn’t make much sense unless you are importing the exported MP3 back into Audacity and then exporting that, in which case you will get more loss of quality with every export.

Are the subsequent WAV exports worse than the first one?

Are you making other changes in that project between the first and subsequent exports?

Are any or all of the track starting after time zero? If so have you tried selecting all the tracks then Tracks > Mix and Render?

What happens if you open the Audacity Preferences, go to Quality on the left, then under “High-quality conversion”, set “Dither” to None?


Gale

5

The poster discovered a work-around when he was arranging to provide much longer sound clips. He prepared some of the work for delivery to me and the problem vanished. I’ll cross-post the dialog.
Koz

6

On a first-pass inspection, we know that all Audacity does on Export is add up all your tracks and shovel them out the door. This can give you overload and clipping problems and is the author of the “Normalize Whole Project” project. The real question is why it only happens in the first five seconds.

Turning the right-brain creative side loose: it took five seconds to realize that the sermon was too loud and to reach over and pull the mixer down slightly. If automatic, that’s the attack time of the mixer. Koz

7

Which was…?

Or if it was excessive volume from mixing tracks together that are too loud when combined, why does it only happen in the first five seconds and not after that? Or did the poster stop listening after five seconds?

Several other people on Mac have complained about crackling/buzzing/distortion in the first few seconds only, usually caused by not all tracks starting at zero and solved by Mix and Render. Why it only gets reported on Mac I do not know.


Gale

8

Hello again,

First off, I apologize for my tardiness in response, but I greatly appreciate your help very much! This is an incredible forum overall and again really appreciate the feedback and care.

What playback device are you using - make and model number?
Do you hear the crackling if you play the exported file in iTunes or only if played in Audacity? If only in Audacity, have you tried changing Audio to Buffer in Audacity’s Recording Preferences? Try reducing buffer as well as increasing it.

Gale the crackling occurs only in exported format, regardless of my output device. I’ve listened to my exported MP3 and WAV on my Mac, another Mac and on my iPhone, and it still produced a crackle. Interestingly, when I playback the project for editing directly in Audacity there is no crackle, which again knocked out the possibility of the raw files I was working with being the culprit (and other reported errors with the crackling confirm that).

As for your next question

Are the subsequent WAV exports worse than the first one? Are you making other changes in that project between the first and subsequent exports?

From my experience, no, they’re all the same in sound quality and all crackle the same exact way for the first 5 seconds. I am also making no project changes to subsequent exports.

As for what Koz said, my only real workaround (which is still fairly practical) is to just composite all of my separated tracks and arrange them in another project as one uniform track.

Thanks again and feel free to keep asking questions, I hope to be better in my replies.
Ryan

9

Does the audio of all the tracks start at time zero (0 on the Timeline)?

How are you “compositing” them? Do you use Tracks > Mix and Render to do that? If export will cause a crackle, Mix and Render should.

Are all your Quality settings as here?

If not, please give the settings that differ.


Gale

10

I, too, am having the same problem with Audacity on my 13" mid 2013 MacBook Air.

Model Name: MacBook Air
Model Identifier: MacBookAir6,2
Processor Name: Intel Core i7
Processor Speed: 1.7 GHz
Number of Processors: 1
Total Number of Cores: 2
L2 Cache (per Core): 256 KB
L3 Cache: 4 MB
Memory: 8 GB

As an example, the audio from our radio show today–went out live on-air clean. Was clean on the MP3 recording device. When I dumped it into Audacity and exported as MP3, WAV, anything else, for online posting, crackle became audible in first part (and seemingly randomly throughout). But it’s not because the audio is maxing out, it seems to be something else. Here’s a link to the SoundCloud, where you can hear the crackle in the first 5 seconds. https://soundcloud.com/bunewsservice/bostons-saint-patricks-day

Any assistance would be greatly appreciated (and I apologize if this particular post might not the right place for this).

Jamie

11

Which version of Audacity exactly? Please see the pink panel at the top of this page.

Was this on one track in Audacity, or were there multiple tracks?

If there are multiple tracks that don’t all have audio starting at time zero, you could try generating a little silence at the start of each track.

Do you have high-quality dither set to “Shaped”?

If not, try that .


Gale

12

You’re talking about that light ticking in the background, right? Mavericks? Did you upgrade to 10.9.2?
Koz

13

There is also some kind of squeaky distortion near the start, which I assume is compression damage.

However some people who had audio tracks not starting at zero found that the Audacity exports added distortions.

Either way, you and I can hear the ticks in the SoundCloud example. So the damage is in the exported file and it’s not a playback problem as I understand it.


Gale

14

Thanks, Gale and Koz,

Sorry about that – I’m using Audacity version 2.0.5. My OS x is version is 10.9.2.

Yeah, the crackle sound seems to be introduced only after exporting from Audacity, not on the original file.

There were two tracks, the second of which didn’t start at zero, as you mentioned. I just generated silence all the way back to zero on that track. On export, it seems to have worked! No more crackle on the final MP3.

I’ll be working on more sound in the next few weeks, so I’ll try that trick and see if it continues to work.

Many thanks,

Jamie

15

I too have had this problem with Audacity 2.0.5 and Mac OS X 10.9.2 and with a high-quality dither of “Shaped”.

It seems to happen only in multi-track sessions where one track starts later than the other. Adding silence to those later tracks so that they all start at the same time fixes it.

I have an AUP project and exported MP3 this problem, if anyone would like to hear or play with it.

-Ken

16

By all means if can you post a link to the project, Ken, we’ll look at it. Set it up so that with Real-time dither set to “None” and High-Quality dither set to “Shaped”, you can hear the problem in the project then export WAV and hear the problem in the exported WAV.

Do you have MacBook Pro?

If you can reproduce the problem in 2.0.5, what happens if you open that project in 1.3.13 ( http://audacity.googlecode.com/files/audacity-macosx-ub-1.3.13.zip ) ? That was the last version that rendered white space between time zero and first audio.


Gale

17

Gale,

Thanks for the quick reply! I do indeed have a MacBook Pro, purchased November 2013.

Here is the Audacity file w/exported WAV, both exhibiting this behavior:

https://drive.google.com/file/d/0B15Dl3_IicZ7Y3VlVW5ONE9KdFU/edit?usp=sharing

This project file sounds fine in Audacity 1.3.13, which also exports a flawless WAV.

-Ken

18

Thanks, Ken. I can reproduce a playback problem in the project and in your exported file on my Mac Mini from 2013 on OS X 10.9.2. Audacity 2.0.2 ( http://audacity.googlecode.com/files/audacity-macosx-ub-2.0.2.zip ) does not have the problem but 2.0.3 ( http://audacity.googlecode.com/files/audacity-macosx-ub-2.0.3.zip ) and later do show the problem.

But in 2.0.3 or later I have not managed to export a 16-bit WAV that renders the playback problem, either with “High-quality Conversion” dither off or on.

It seems both project tracks are in your exported file. Are you using File > Export or File > Export Selection? Can you please post an image of your Quality Preferences (Audacity > Preferences then choose “Quality” on the left)?

Other things I found:

  • If in the upper track I delete the audio that does not start at zero (leaving an empty track), the playback problem goes away.
  • If I undo the delete then mute the upper track, the playback problem goes away.
  • If I unmute the upper track then move it below the audio track that starts at zero, the playback problem goes away.
  • If I generate silence from time zero to 1 second in the upper track then play both tracks, the playback noise starts after 1 second.
  • Audio to buffer settings make no difference.

@Ken, in 2.0.5 can you export 16-bit WAV (without changing Quality Preferences) with the upper track moved down? To do that, drag the track down with the mouse where you see “32-bit float” in the track. Does that WAV have the noise?

Do you agree that 2.0.2 does not show the playback or export problem?

@others, can you please try the project in 2.0.6-alpha on other versions of OS X? I tried on Windows 7, there is no playback problem.



Gale

19

Gale,

My latest tests with the file I provided, in both Audacity 2.0.2 and 2.0.5, is that the static can be heard the first time I play back the file, but not on subsequent playbacks (unless I close and reopen the file).

I can export a WAV with the static in 2.0.5 but not 2.0.2. After swapping track positions, I cannot export a staticky WAV in 2.0.5. Swapping track positions eliminates the static entirely in 2.0.2 but not 2.0.5. Even with tracks swapped, 2.0.5 can still export a staticky WAV. I am using “Export”, not “Export Selection”.

Here are my audio quality settings.

The file I provided is an excerpt from a much larger recording that’s several gigs in size and has more tracks. That file seems to exhibit the static more consistently.

-Ken

20

Thanks for testing. On my Mac mini, in 2.0.5 or 2.0.6-alpha, the playback is noticeably less crackly first time, then subsequent times is extremely crackly in the first 5 seconds or so, then intermittently crackly thereafter. I presume the relevance of 5 seconds or so is that this is the first audio block file at 32-bit float.

What happens if you restart 2.0.5, open the project then export, without playing the project? Is the WAV still ticky?

I’m not quite clear from the above whether you can ever export a ticky WAV from 2.0.5 after swapping track positions. Does it vary - some exports with swapped tracks are crackly and some not?

If you don’t swap the tracks in 2.0.2, is the export still ticky, whether or not you play the project?

You have dither enabled for export in http://tinypic.com/r/2w4a4ia/8 , as is default. Can you try setting the second “Dither” setting (under High-quality Conversion) to “None” and then export from 2.0.5 without tracks swapped. That does not stop the crackle for me.


Gale