postgap, pregap, pauses on audio cd/ddp vs mp3 version


when burning an audio cd/DDP of some songs I have recorded, using the audio montage, I can let the cd wizard add post- and pregaps + pauses automatically. So I guess I have to edit the audio files so there is no silence at all before or after the track, before I import it in the montage and use the cd wizard function? Correct me if I am wrong?

But then I also wonder, if I want to do a version of each song for itunes/spotify, then I guess I render an MP3 version. Is there a function for letting the program automatically add the post-, pregap, for a track, or do I have to edit it manually for each track?


A few things:

  1. Don’t render an mp3 version for iTunes/Spotify. The digital distributor you choose will require a 16-bit/44.1k WAV and all the various encoding is handled after that from the WAV. Mastering 101. Also, sites like Bandcamp and SoundCloud as well as “Mastered For iTunes” can accept 24-bit and higher sample rates so you have that option too.

  2. Regarding the spacing, I use what WaveLab calls CD Track Splice Markers in my montage instead of separate end/start markers. To me it simplifies many things and I think having gaps between the end and start marker is an old practice and best forgotten when it comes to standard album mastering.

A CD Track Splice Markers lets you insert what appears and acts as one marker between the songs. It’s less to manage and then you can be certain the spacing between songs is the same on the CD/DDP version and any rendered WAV or mp3 files.

That being said, there is a new option in WaveLab 9 if you check the “Options” section in the render Ribbon tab that lets you include the gaps between markers in either the end of the last track or the start of the next track. I believe the unofficial standard is including the pause at the end of the previous track.

See the attached screen shot about that new option.

Regarding the CD Wizard, it’s probably best to trim your songs up first, and then use the CD Wizard to place the markers, then fine tune the marker placements as needed. If you use CD Track Splice markers, it’s my opinion that things are much more simple and one of the brilliant features of WaveLab.

Also, in order to make sure your DDP track IDs match the rendered WAV or mp3 files perfectly (down to the sample), it’s best to use the CD Wizard to “Quantize Markers to Nearest CD Frame” at the very last step after all your other work is done. Just uncheck all the options in the CD Wizard except “Quantize Markers to Nearest CD Frame” and run the CD Wizard again. Especially if you have some overlapping songs or crossfades, you’ll want to be sure that the track markers are quantized so you can be sure the CD/DDP and rendered files are 100% identical. If the markers are not quantized by you in the montage, they will be force quantized when the DDP or CD is made and you could have a slight discrepancy with the track timings. Most times this is not a noticeable issue but in some cases it can cause issues so my practice is to just always do it.
Screen Shot 2016-11-08 at 8.47.26 AM.png

Hi Justin, thanks for the info!

Just to be sure I understand this process correct:

When letting wavelab automatically generate post- pregap and pauses, it automatically generates 2 seconds pauses between all tracks. In addition to that, it also adds 32 cd frames of silence after first start marker, 15 cd frames of silence efter each other track start marker, 3 cd frames of silence before each track end marker, and 60 cd frames of silence before last track end marker. See attached pic.

I am unsure exactly what cd frames is and why it is measured in cd frames instead of milliseconds, but I guess this pauses and gaps that is automatically inserted is some form of ”standard” measurements that needs to be inserted.

If I use the method that you advice me to, and use splice markers to generate pauses between all songs, my first question is, do I set it up somewhere in the program so these pauses is 2 seconds?

My other question is, I only get the pauses by doing it that way? The other gaps that is taken care of automatically by the cd-wizard, do I have to insert those gaps manually in some way? If so, how is the best way to do that, and how do I find out how much milliseconds those measurements are? (cd frames measures)


There are a lot of options in the CD Wizard but you don’t always need to use them. I suggest importing the clips and arranging them in the correct order, trimming and fading the heads and tails as needed, adjusting the space and flow between each song/clip as needed manually. From here on out, the spacing between songs should stay the same (unless you or your clients changes their mind about the spacing between songs).

Now you need to insert markers. I basically always use the settings as you see in the new attachment. It doesn’t change the spacing of the clips at all as I’ve already dialed that in manually. Depending on how you have your clips trimmed, you may want to fine tune the placement of the CD Track Splice Marker so that the track doesn’t have an abrupt start. Roughly 200ms before the first audio appears is my default but maybe some people go tighter. It’s a long story but my clips are already processed in another DAW and before I export them to bring into WaveLab I pad the clips with 200ms of digital black silence so that when I load the clips into WaveLab and generate CD track splice markers at the starts of the clips, there is a nice short buffer built in. I know this doesn’t help you but worth noting.

If your CD Track Splice Markers end up too close to the first note, you can use a command in the Markers Functions Tab called “Move Multiple Markers”. This will let you move the makers back from the clip starts in milliseconds but it doesn’t move the clips themselves. I don’t use any of the markers adjustments in the CD Wizard box.

Then, once everything is just as you want it, it’s best to go back to the CD Wizard and choose only “Quantize Markers to Nearest CD Frame” to make sure the CD Track Splice Makers are placed on a CD frame to ensure 100% sample accurate marker continuity between the CD/DDP version and simply rendering WAV files from the montage. Also check that Quantizing the markers didn’t put the marker in a bad spot which mostly applies to any songs that overlap or crossfade.

Thanks Justin. I will read this in more detail, and try it in wavelab, and maybe come back to this post if I have any questions if its ok! Thanks again!

No problem. From what I can tell, I think you may have been overthinking it. Just arrange the clips as needed, use the CD Wizard to apply the markers of your liking and fine tune from there as needed. The CD wizard doesn’t need to change the clip timings, I think it’s best done manually so you know what it is and how it feels.

Back the the original question…CD Track Splice Markers make the gaps when rendering irrelevant but if you do like to use gaps between markers, check the two new options in the Render tab and that should take care of it.

Hi again Justin! Just got to ask you this: If I use the splice markers between songs, but I choose options -> include pause after track. Then the spacing between the songs won’t be the same on the cd/ddp version and any other rendered version I guess? If I want it to be the same I have to just use splice markers, without pause, and instead trim the file in a way that the pause after the song is “built in” in the file?

I’ll have to double check but I’m 99.9% sure that if you are only using splice markers, the option to include pause before or after track is not relevant. One thing you could try is to render a WAV of each track, then make a new montage track and load the rendered files back to that new test track. You should see that the waveforms are in sync with the original files. If not, something went wrong.

Excuse me if this is a dumb question, but when you write that its not “relevant”, do you mean that if I include a pause, the pause doesn’t change the wav file then?

I mean that if you use CD Track Splice Markers instead of having a gap between an end and start marker, there is no gap to factor in when rendering files vs. making a CD/DDP, so the setting doesn’t make a difference. This is the beauty of the CD Track Splice markers. There are no gaps, you just place the splice marker where you want it and the majority of the space between songs lives on the previous track if you put the CD Track Splice marker close to the start of the next song.

I think the best thing for you is to render your WAV or mp3 files, and then load them into the montage on a new track, and then look at the sync timing to make sure the new files match what you see in the montage with the original clips and track markers.

Just for clarity, the pause after the wav doesn’t have to be included in the wav file itself. As an example: Take a first song 1 from 0:00 to 3:00, then add a 2 second pause, then add song 2 of 2:00 and song 3 of 4:00, with also a 2 second pause in between. At 0:00 there will be a CD track start marker, at 3:02 a CD splice marker, then at 5:04 another one and at 9:04 there should be a CD track end marker. Each individual song as an mp3 will now be respectively 3:02, 5:02 and 4:00 long, with the silence at the end. |wwwww |wwww |wwwwww|


Yes, a good point that maybe I wasn’t clear about. When you render regions as CD Tracks, the only thing that matters is the markers. These are the sections being rendered regardless of what the source WAV file clip looks like. You can have a 2 minute WAV file clip and then 2 seconds of silence after it before the CD Track Splice Maker.

When you render Regions/CD Tracks, the two seconds of silence between the end of the WAV file and the CD Track Splice Maker are automatically included.

Ah, then I guess its a good thing to render all versions from the same montage setting using splice markers, as we talked about in out other thread. In that way audio cd/ddp and all rendered files will become identical.

But while talking about that. Is it important that the cd/ddp version an all the other rendered files is identical? (Except that it sound the way that was planned) I read somehere it was important because of this “gracenote” database, which I am very confused about :S.

I think that clients would want the same listening experience for the CD and the digital distribution version, so it’s important to keep the song spacing identical unless it’s requested to be different. Sometimes I have people that want more song crossfades on the vinyl pre-master but that is unrelated to this really.

Gracenote Database identifies albums by the number of tracks and their respective lengths so yes, if the CD versions and digital distribution versions are different, there could be some troubles with the album being recognized by Gracenote.