Separate tracks in the mix?

[Horrorwitz]

Anyone else have this problem?

[alatham]

Yes, I have this problem, but only under one condition.

If I change the sample rate of the exported files, Audacity introduces errors into the exported file.

For instance, when I start with an 11.025 KHz file, and split it using your method into (2) 44.1KHz WAV files, I get an glitch between the two files.

However, if I start with a 44.1KHz file and end up with 2 44.1KHz files, it works just fine.

Are you converting to a new sample rate when exporting? Audacity has a known bug during sample rate conversions.

[Horrorwitz]

I appreciate the tip. I imported a 44.1KHz sound file. I put a label at the beginning and dropped another label in the middle during a long solid tone. Then I "multiple exported" it as a wav file with the default sample rate set to 44100 Hz. When I played it back there was still a gap there though. Am I still doing something wrong?

Most of the sound files I am using are wav files taken from CDs or mp3 files. Ultimately I want to burn the final mixed tracks onto a CD.

[Horrorwitz]

I tried it with mp3 files as well, importing and exporting them the same and still get the the gaps.

[Horrorwitz]

This is driving me nuts! There has to be a way to do crossfades without having those gaps other then just not inserting labels.

[steve]

Saving as mp3 will always cause this to happen - it is not to do with Audtion but is a "feature" of mp3. If you want "gapless tracks" you must use wav not mp3.

Nero also creates gaps between tracks by default. To prevent this from happening you need to edit the track properties to set the delay to 0 seconds (default = 2 seconds). Unfortunately this can not be set as a default in Nero - you have to remember to do it each time. It is not possible to set the first track to 0 seconds due to limitations of the CDR format, but this does not matter as a 2 second gap before the first track i not noticeable. (Other CD burners work in a similar way, but you may need to consult the manual for the specific software that you are using).

[alatham]

horror,

you said:

When I played it back there was still a gap there though.

What program were you using to play the file back? Did you re-import them into Audacity and add them to the same track? If I do that I can't hear any glitches between the two files, but if I add both to Windows Media Player I get a blip between the two.

Steve is right about mp3s.

If you want to make a CD with no gaps between tracks, listen to Steve, but also be aware that the WAV files need to be cut at a CDDA frame. What this means is that a CD stores data as "frames," If you convert a WAV file to CDDA format to burn it, it will fill up the end of the last frame with zeros, resulting in a small gap. But if you use Audacity to cut the files at the edge of a CDDA frame, you can get perfect gapless playback in a CD player. In order to do that, at the bottom of Audacity's main screen, you need to change those three displays to show CDDA frames (instead of HH:MM:SS), then you need to turn on Snap To (in 1.2.6 this is in the Edit -> Snap To menu, in 1.3.4 the option is next to those three displays at the bottom of the screen). Now any time to set the cursor it will snap to the nearest CDDA frame and you can cut each track perfectly.

[steve]

Thanks alatham, I didn't realise that Audacity had "snap to frames".

Generally I have used zero crossing point at a quiet part of the music for splitting tracks, even without snapping to frames this provides acceptable results as, even in a worse case scenario, there would be a little less than 2 frames gap (< 26ms), which would be negligible. However, frame snapping is better as you should then be able to split tracks anywhere without gaps.

[alatham]

Right, Steve.

But that reminds me of one more thing. After the files are split at a CDDA frame, the first and last 10 milliseconds of each track should be faded in and out, since the likelihood of a zero crossing coinciding with a CDDA frame is quite small.

Fading the first and last 10 milliseconds will get rid of any possible clicks between tracks and should be more or less impossible to hear.

[steve]

I think that if you split on a CDDA frame you don't need to split at a zero crossing, as, since there is no gap, the end of one track and the beginning of the other will match, hence no click.