Before uploading your MP3 file(s) that will be used by the drummer to play-along with, there are a few important things to remember.

• Encode your MP3 files at 128 kbps Also, your MP3s should be the same sample-rate that your Project is. So if your Project is 44.1kHz, then your MP3 should also be 44.1kHz, encoded to 128kbps.
• Make sure the MP3 file(s) you send starts at the absolute beginning of your song file Even if there are empty measures, or measures that you are not playing anything before the song starts, the MP3 file should reflect the very beginning of your song/Project, which is 1:01:000 (Measures:Beats:Ticks). Your recording program may use a slightly different way to describe the very beginning, but just make sure the MP3 starts at the exact beginning time of your song/project file. By telling us the exact tempo of your project file, and giving us an MP3 that starts at the absolute beginning, we can easily line up your MP3 track into our recording program.
• Make sure you have told us the correct bit-depth and Sample-Rate of your project You should have done this when you filled-out the Studio Checklist in Step 1. Do not change the bit-depth or sample-rate of your project after you have created your MP3 file(s). This will throw off the timing of the final drum tracks we send you, and they will not line-up with your other tracks in your song/project.
• Play good scratch tracks After choosing a tempo of your project, play the scratch tracks you will be sending us very tightly to the click/metronome (or some other track or loop that is in perfect sync with the measures and beats of your project). This will allow the drummer to use your scratch track to get a good "feel" of the groove of the song. We recommend that you play the most simple parts that get your ideas across to the drummer. Then after you receive your final drums tracks you can go back and record all the rest of your tracks using the drum tracks as your timing source (this is of course how a band would normally play). Also you should redo all the tracks you used as the scratch tracks for the MP3.
• Mix your scratch tracks suited for the drummer Before you create the MP3 of your scratch tracks, mix them so that the most important instrument is loudest. This will most likely be the bass or the guitar. If the bass has the feel you're after, then make that the loudest. If your rhythm guitar has the feel, make that track the loudest. (Of course you could be using a different instrument, such as a piano). If you have a scratch vocal track, include it in your MP3, but it should be quiet to very-quiet in the mix.
• Include a click with your scratch MP3 file ONLY at the beginning By telling us the exact tempo of your song, we can create our own click tracks to use. But it can be useful to us if you include a click at the beginning of your MP3s, before you start to play. In other words, your MP3s should have a click on the quarter notes starting at the very beginning (1:01:000), for maybe two or four measures (or however many bars you want), then when your music comes in you can drop the click.

  Here is an example of a good MP3 scratch track.

• Submitting a second MP3 Since you are allowed to upload two MP3 files, you can use the second as a reference track for the drummer. This may be short example of the drum grooves you have in mind for the song, or a full length drum performance of maybe a Midi drum track you already put together that you would like the drummer to try and duplicate. If it's a full length track, make sure to follow the instruction above so that the MP3 file lines up correctly with your scratch track.
• Important: Again, even though we recommend you redue your scratch tracks after you receive your final drum tracks, it's very important you play as tightly as possible to the click/metronome when creating your scratch tracks. This will enable the drummer to play tighter and create better drum tracks for you.