Hi guys.

You may also know about this but I accidentally found online docs for how a Rock Band song is downmixed for the game. It gives a clue to how it's all put together. And for stems lifted directly from a song archive explains why they are so loud and why instruments cross mix into another track.

The main page is here. It details preparing the stems, midi data, packing it and testing. As well as other information on the process.


Here below it guides on how to bounce down the stems from the parent DAW into 44.1 WAV 16. There is a particular focus on Reaper here which they use to demonstrate preparing the stems. Which have some processing to give them some mastering based on the album mix. And expected to sound as close to the album mix when mixed together. This could be awkward if the album mix sounds foreign compared to the single mix if it was remixed before release.

The drums are usually separated into kick, snare and rest. But can be as one stem. Then the bass, keyboard, lead and backing vocals with the rest in a backing track. For reference there is also dry 16Khz dry vocal tracks specified, a CD mix and a stem mix.

If you noticed that in some stems a guitar crosses over to another track this explains why. As there is the main playable stem that must remain playable. So if an instrument changes focus to keep the player active it will cross fade into the main track and the other instrument will fall into a backing track. Such as a rhythm and lead guitar. Players will know about this.


Finally in my review is this guide below. This explains why those "Rock Band stems are so loud!" The nicely levelled stems are taken then normalised, compressed and put through a limiter to a -0.5 dB ceiling. So they hit the wall. A brick wall limiter. There is a brief mention of attenuation and a tool called Magma that puts it all together. Apparently they are purposely made "too" loud to account for other sounds in the game. But I would have expected the game mixer to take care of that. A music game that can't mix music? Seems like it's doing X to fix Y to me. :-)

They give a tutorial on tempo mapping that goes into a MIDI track. And using some custom key shortcuts they made for Reaper that makes use of transients. One marker per bar is expected and at most one marker per beat. There is also the count in. In the usual case this will be two bars in the "1, 2; 1, 2, 3, 4" style that is taken from the first two bars of the actual song. In case it starts on an off beat, such as on the 4, it can be put on the final 4 in the count in. Meter changes are also included. I wonder what happened to the original tempo map from the master session and why it's not included in the bounce down? Doing it by hand is annoying. Still, it's easier with a clean kick track, and it can be automated with clean transients. Otherwise time to get out a dedicated beat detector.

On top of the MIDI encoded tempo map there are also other MIDI tracks that are used to code game events. With things like beat, events and venue track. That all specify different events during the game play, from beat rhythm to crowd control and camera in venue.


Well I hope this was enlightening. Didn't mean to review the site, just provide the links, lol. With this extra information it helps to understand RB stems and their quirkiness. Now I wonder, given the stems are made to go at full blast, what happened to the volume information? If the game is designed to mix the stems so it sounds like the album mix, and the stems are all maxed to the same level, how does it level it off to match? I'm interested if this information and if it can be tabled with the stems. Though might be easier from earlier releases like RB3 where the song archive can be directly extracted. :-)