rpm 2012 post-mortem, track 5: specific impulse

Specific impulse (usually abbreviated Isp) is a way to describe the efficiency of rocket and jet engines. It represents the derivative of the impulse with respect to amount of propellant used, i.e., the thrust divided by the amount of propellant used per unit time.”

This is definitely the most song-ish track on the album; it could easily work with lyrics, if I’d had time to write them. I started this on day 14, when I was starting to get in to a bit of a rut, but I sat down at the keyboard and started playing around with a Rhodes sound, and eventually got a nice chord progression going. I revisited it a few times after that, but I didn’t end up fleshing it out until days 27 and 28.

Originally I’d planned to make this more of an electronic track, so once I had the chords down (using LinuxSampler and the jRhodes3 soundfont) I added the bass, using a slowly-pulsating patch (more of a slow “whum… whum…” than a clich├ęd dubstep “wubwubwub”) made in TAL NoiseMaker. Then, the Salamander Drumkit was released, and I was so impressed when I played with it that it inspired me to go with a more acoustic feel.

I had some segments of melody sketched out alongside the chords, but it took some time to flesh it out across the track and then add the solo in the final section. Though I mixed things up a bit by using sustained chords in some sections and more rhythmic chords in others, it was still hard to add enough progression with just the Rhodes, bass, and drums, so I added an organ part, using AZR-3, to fill out the second half of the track.

There’s the start of a good track here, I think, but I wasn’t super-happy with what I was able to do with it within the 29 days. The main problem is with the melody line — I don’t think its arrangement fits well with the rest of the track, and the playing in the solo was a bit rough. The electronic bass doesn’t sit terribly well with the rest of the track, either.

I was surprisingly happy with the drums, though, given their simplicity — all those round-robin samples in the Salamander mean that you still get some natural variation, even when you’re just repeating the same note over and over. If I can come up with some lyrics, or just some better ideas for the instrumental arrangement, it might be worth revisiting this track.

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