This is a tutorial by Noah Roberts...
How To Paricipate in a Jam
I have twice been asked how these things work so I decided to write something up. I have only been in a couple and mixed one, but I get the gist down...maybe others will correct my mistakes.
First thing an overview of how the "forum" jam thing works. Someone decides to host a jam (from now on called "the host") and lays out a set of segments. The host also selects the backing track and provides the rest of the participant access to the track; usually before the decide to be participant so they can listen and see if they want to join. People choose from those segments and it is usually just a first come first serve but of course the host decides that. Once this is done, participants send their entries to the host, usually via email but whatever method the host has set up for transfer. The host then mixes all the entries together, with the backing track, and posts it to "Completed Jams" for everyone to hear.
Of course, the host might set up the whole thing to work differently, but generally this is how they go.
Now the question is, "Yeah, but how do I do all that?" Well, that is the hard part isn't it... The following describes use of Audacity to participate in one of these things. I don't use audacity myself, but it is available to almost everyone so is a good choice to base this tutorial on. I will also describe what works for me as a host, other hosts may differ in submission guidelines.
What I want, as host, is a two file set from participants. The first file contains a 128bit mp3 with a 44.1kHz sample rate. This is just basically a CD quality audio file with all the http://www.soundclick.com/bands/songInf ... 60519stuff
I can't hear anyway taken out of it (debatable of course). This file contains only your playing, meaning I can only hear you in it, except for the first couple of seconds which will contain part of the backing track so that I can line up the parts; this section usually has drum clicks in it. The beginning section might need to provide themselves and a later section of the track for alignment if they start playing right away; you must leave your part clean so I can take the clicks out of your track without damaging your submission.
The second file is a low quality mp3 of your section with the backing included; this provides an extra layer of certainty so I can be sure the tracks ligned up how the participant hears them. A good setup for this file is a 64bit mp3 at 44.1kHz.
The actuall steps:
First open audacity and import the backing track. You do this through the project menu and select "Import audio..."; then just select the mp3 file. This will bring up a stereo track in the project space. Then just hit record and start playing when your time comes in. You should see something like this:
After you are done you might see something like this (only yours will probably be more constant from the beginning unless you do some cutting):
At this point you want to provide your two files. First make the low quality sample by selecting your section and exporting as wav or mp3. Select all tracks by holding down shift as you select. Choose "Export selection to mp3" (or wav).
Before exporting you will want to adjust your mp3 settings if you are exporting to mp3 (you need lame for that otherwise save to wav and convert after).
Then select the very beginning of the backing track and choose trim out of the edit menu (or select all but the beginning and choose cut). This will take out the rest of the track.
Export to wav or mp3 again, but this time choose "Export to mp3" (or wav).
Then send both files to the host and wait for them to finish the mix and post it.
I hope this tutorial helps somewhat...