Track 'n' Stack is a Drupal module that allows community members to collaborate on audio projects. At any time, registered users can participate to Audio projects in progress or create new ones. Each project is owned by its Author, who is the person who created the piece by uploading its first file. The Author is responsible for keeping the mixdown up to date by creating a new mixdown and posting it on the web site at every participation. You can work with the audio file format of your choice (MP3, Ogg, FLAC, WAV, ...) but the only one that is compatible with the Flash audio player used to play audio files in Drupal is MP3 at a sample rate of 11, 22 or 44KHz. If you want to use MP3 or an other lossy compressed file format, you should read the following paragraph. Otherwise or if you don't really care about this, jump to the section 1.

Most lossy audio compression schemes add a small amount of silence (i.e. gap) to the beginning of a track. This gap may cause timing problems when adding tracks over tracks. Unfortunately, most MP3 encoders don't store the amount of delay or padding for later removal. Also, the encoder delay may vary from encoder to encoder, making automatic removal difficult. More recent compressed audio formats (such as Ogg Vorbis) have been designed to address this problem and can therefore produce gapless audio. If you still want to use MP3, I suggest to use LAME (for Windows, for Mac) to encode/decode your tracks. This free software stores the gap information (called encoder delay) in the file header on encoding and automatically remove the gap on decoding.

The instructions below outline the various operations to perform. Please read them carefully.

1- Adding Tracks to Pieces in Progress

Enter your username and password to log on the website. In the menu on the left, under your user name, you will see "Audio". This leads to a list of pieces which are currently available on the web site. To show pieces under development, click on the sub-menu option "Browse in progress" (below, in pink).

If you click on the title, you will be able to see the piece's properties and an history of all tracks that have been submitted thus far for this piece.

You can listen to a preview of the current state of the piece by using the embedded player. When you find a piece you want to work on, click on "Check out" (above, in pink) to prevent other users from being able to work on the piece while you are making your track. Participants have the choice to download a mixdown of the tracks that have been submitted thus far or download each of them individually. Once a piece is "Checked Out", no one will be able to access it until the person who checked it out checks a new track in. If the person who checked out the file does not provide a track within three days, the lock expires and the piece becomes available for editing once again.

Once you have checked out the file, you must create a new track and then upload it by returning to the Audio section, locating the song you are working on (use the "Browse in progress" sub-menu option) and clicking on "Check in" (above, in pink).

You will be asked to locate new tracks (up to three) on your disk. This may also include text or MIDI files if you think it would be helpful to next participants.

2- Creating and Managing your own Piece

Authorized users can start a piece by clicking on "Audio" under the "Create Content" menu. If this option is not available, you are only allowed to add tracks to pieces in progress. This opens up a form that you must fill out (mandatory fields are in pink):

Leave all other settings to their default values and then click on "Submit". This creates a new piece that can now be seen by visiting the "Audio" option in the menu on the left.

Once someone has added a new track to a piece that you have initiated, you will receive an e-mail telling you that a new track is available. You are then responsible for making a new "working" mix of all of the tracks that have been received so far. This mix does not have to be excellent: it only has to be good enough to allow the next person to create a new track for the piece. To upload your new mix:

• Click on your piece to see its properties¹



¹ If you won't keep the new track, click on the delete button and the piece will again be available to new submissions.

• Select the Edit tab, at the top



• Check "Approve last checkin from username" (above, in pink) under Track'n'Stack
• If you feel that a piece has enough tracks and you won't any new submissions, uncheck "Allow others to collaborate" otherwise skip to the next step
• Select the new mixdown under Audio File - Replace with a new file (above, in pink)
• Click on "Submit"

Once done, author of the last checkin will receive an e-mail telling him that his checkin has been approved and is now part of the mixdown.