CD Gaps

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phaworth
Posts: 8
Joined: Tue May 13, 2008 8:42 pm

CD Gaps

Post by phaworth »

I haven't actually burned a CD yet but it seems like the gap between tracks has to be the same length every time? Is there a way to vary the length of the gap? For example, could I set the gap time yo zero and insert silence at the begimning of each track for the amount of time I want?

Thanks,
Pete

Gerard Bik
Posts: 353
Joined: Fri Nov 10, 2006 9:04 pm

Re: CD Gaps

Post by Gerard Bik »

phaworth wrote:I haven't actually burned a CD yet but it seems like the gap between tracks has to be the same length every time? Is there a way to vary the length of the gap? For example, could I set the gap time yo zero and insert silence at the begimning of each track for the amount of time I want?

Thanks,
Pete
Gaps can be 0 sec between tracks on a cd. In Toast the pause can be set per track. The newer iTunes can burn continuous.
Haven't burned with Amadeus yet.

When you want to put the silence inside your track, wouldn't it be more practical to put it at the end?
regards

phaworth
Posts: 8
Joined: Tue May 13, 2008 8:42 pm

Post by phaworth »

Actually, I can't find a specific way to insert silence into a track. I think I have to do it by sliding the sound in the second document over by however many seconds of silence I want and then positioning a marker somewhere in that gap. Is that right?

As for whether the silence should be at the end of one track or at the start of the next, I'm not really sure but I think normally when you hit the CD button that goes to the next track, you go to the gap between the tracks so that's why I was thinking of putting it at the start of each track.

Pete

Gerard Bik
Posts: 353
Joined: Fri Nov 10, 2006 9:04 pm

CD Gaps

Post by Gerard Bik »

Actually, I can't find a specific way to insert silence into a track. I think I have to do it by sliding the sound in the second document over by however many seconds of silence I want and then positioning a marker somewhere in that gap. Is that right?

As for whether the silence should be at the end of one track or at the start of the next, I'm not really sure but I think normally when you hit the CD button that goes to the next track, you go to the gap between the tracks so that's why I was thinking of putting it at the start of each track.

Pete
"Generate silence" is the last entry in the Effects menu. It inserts the silence at the insertion point.

I would like my music to start as soon as I hit the play button. That's why I would put the pause at the end.

I recommend buying some cheap cd-r's and give it a try. Burn and learn!.

gerards regards
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Sonic Purity
Posts: 82
Joined: Sat Nov 10, 2007 11:58 pm
Location: Pasadena, California, U.S.A.

Post by Sonic Purity »

phaworth wrote:As for whether the silence should be at the end of one track or at the start of the next, I'm not really sure but I think normally when you hit the CD button that goes to the next track, you go to the gap between the tracks so that's why I was thinking of putting it at the start of each track.
Here’s an ASCII drawing version of how it theoretically works (simplified):

…end of Track 1 (index 1 or higher) | Track 2 Index 0: silence | Track 2 Index 1: Start of audio for Track 2…

The vertical bars | indicate the transition points. Standard audio CD players jump to the start of Index 1 of the next (or previous) track. When this is actually done in practice, if one watches the single-track elapsed time counter as the machine plays straight through, it will count up to the end of Track 1, then show Track 2 and have a negative count down to zero (-0:02, -0:01 etc.) during the pregap, then when it hits Index 1 where the start of the actual audio for Track 2 lives (the point where the player goes when it jumps), it counts up from 0 seconds as expected.

Now, many people don’t care or don’t get the concept, so it is extremely common to not see negative counts when there is silence between tracks. In this case, there is silence at the end of Track 1 (in this example, and if there is indeed silence between the tracks).

As we do not live in a perfect world, and CD players do not always hit (in my example) Track 2 Index 1 at exactly the correct point, it is common practice to have some “space” between Track 2 Index 1 and the actual start of audio. In CD mastering programs like Roxio Jam, one can insert an offset to create this few milliseconds of silence. Or, a very small slice of silence may be at the beginning of the source file. Jam also allows a similar offset at the end of a track, so no actual silence is necessary there.

Nothing i have written is tied to whether or not the pregap (the Index 0 negative count, when it exists) contains sound or is silent. It is very possible to have a “live” recording where Track 1 ends when the song ends, then as the audience bursts into applause we are in Track 2 Index 0, then the moment before the next song actually starts we hit Track 2 Index 1. This setup allows nice transitions in shuffle/program modes and when doing manual jumping around. It is also fine to let the applause be part of Track 1 and have a 0 second pregap for Track 2, and this is indeed common.

There do exist a couple of 1st. generation audio CD players from the early 1980s (any surviving ones which work are likely in museums) which mute the audio during Index 0 pregap negative count times, which is one reason that commercial labels got out of the habit of using the negative counts with audio. I was fixing these things (CD players) professionally, daily from when they were introduced until leaving the repair field in 1995, and there are very, very few of these players which were ever made. I personally use the pregap when it makes logical sense, and put audio in it when needed.

Many reading this may not be aware of Index points. This is IMO a nice feature of the original CD-DA system which rapidly fell into disuse. The idea was that, for example, one could have a song (or movement of a classical piece) with its usual track number, and then have other seekable subdivisions within that track where properly-equipped audio CD players could jump directly. These points could be the start of a new theme within a movement, a guitar solo, or any number of other salient change points of a song. Or, as i will be working with today or soon, the current track may contain interviews, and the index points mark the start of each different interviewee. Hardware support for Index points in audio CD players started to become rare in the late 1980s, sadly… one reason i hold onto my 2nd. and 3rd. generation mid-1980s players with full Index point support.

To date, i do this work in older versions of Adaptec or Roxio Jam on an OS 9 system. I very much look forward to the day when Amadeus Pro supports converting one color of marker to track change points and another color of marker in the file to Index points >1, so i can have one master file for a CD and use Amadeus Pro to directly write a Red Book compliant CD with full index point glory! So far, i have not written any CDs from within Amadeus Pro, as it does not (yet) meet my needs. As it (and many other software options) uses Apple’s disc writing code in Mac OS X, there may be limitations on what can be done, yet i do not believe that having Index points >1 is one of those limitations.
))Sonic((

phaworth
Posts: 8
Joined: Tue May 13, 2008 8:42 pm

Post by phaworth »

Wow, thanks for the great explanation of the index marks, etc. I'm going to have to play around with Amadeus to see the best way to get all this working.

As a separate question. I carefully set up markeres for all the start points of each track and then "flattened" the file before burning the CD. In the flattened document, there are no visible markers. Does that mean when I burn the CD it will end up as one big track? And if so, why on earth weren't the markers brought forward into the flattened file.

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