Let me start off by saying, yet again, that the 'everyone is one bar' music collaboration project is a brilliant idea. I just wish it wasn't so difficult for an average fan to participate, because for sure we'd have a lot more cool and interesting mixes if people had the tools and knowledge to be able to contribute.
It seems like most people are using GarageBand - fine if you have a Mac, which not everyone does.
Other people are musicians and have ProTools and/or an actual studio at their disposal.
And the rest of us...well, we either gave up at the outset, or we're struggling with other tools to find a way to participate.
I don't have a Mac but I do have an iPad, so I downloaded GarageBand on that and played with the stems there for a few days. I managed to record some vocals (that should be "vocals" with really big air quotes LOL) and add them to a track, so that was fun :-)
Unfortunately when the stems are imported, GarageBand assigned them the 'Audio Recording' track source thingy, so I don't get any of the editing controls you'd get if the stems were recognized as guitars or bass or keys. In the end I had to bag the GarageBand for iPad idea, it wasn't getting me anywhere.
Then I tried Audacity, which is a free software for audio mixing, but the options aren't great and it doesn't come with any loops or instruments to work with.
Next I heard about Adobe Audition, and downloaded the free 30 day trial. I had some difficulty figuring it out, so I asked my neighbor (who knows ProTools and GarageBand) if he could show me what the options were - he wasn't familiar with Audition, but given his other experience, he was able to figure it out and show me how it all works. I've also watched some tutorials on YouTube. So far, so good.
Now I have 12 days left of my Audition trial, and I'm only just getting started..! And I don't have a proper microphone, so I can't re-record the vocals I wanted to add, although my neighbor says he has one somewhere. The key is him finding it before my software trial is over ;-) The world is probably better off without my vocals though!
All this to say that it's not exactly easy for the average person to jump in and play along, even if you really want to. Speaking for myself, it has been a lot of effort just to get the right tools in place and learn how to use them.
With time getting short, I am focusing on 'Control Park' and possibly 'Your Voice Needs Subtitles'. At this point I'll be really pleased if I can get just one decent mix together to submit :-)
EDIT: I just finished my first premix! It came out ok for a first try, I already uploaded it and feel a bit relieved to have done at least one that I like. The rest is (cup)cake(s)!