Recording The Robo-Kit
Producer Kent Sparling is a multi-instrumentalist, composer, and film mixer/sound designer with several big credits to his name, including Sofia Coppola’s Lost In Translation, Spike Jonze’s Adaptation, and James Cameron’s Titanic. Over the years we have also worked together on a number of independent music CDs, mostly for Vanessa Lowe, Kent’s wife and music-making partner. For our most recent studio outing — Lowe’s Stars Of Bean Hollow — Sparling devised a “robo-kit” to supply unique percussive underpinning.
The components of the robo-kit are a programmable drum machine, computer recording software, an amplified playback system that routes drum-machine tracks to small speakers, plus standard (and non-standard) parts of an ordinary drum kit, which are miked in a room. No sticks were harmed in the making of this record! This is the story of how it was done.
After producing three Vanessa Lowe albums with the unfettered creative energy of Tobias Hawkins on drums and percussion, it was decided that the current recording should be focused more on the voice and songwriting, and that the rhythmic backing would exist in a supporting role. It seemed clear that to ask a primarily improvisational drummer to lay down simple quarter-note hats and 2/4 kicks and snares inspired by soul and country-and-western records would be akin to harnessing up an Arabian racehorse to a country doctor’s buggy. Clearly, another plan was called for.
As far back as 1987, with songwriting partner Matt Rohr, Sparling had experimented with feeding keyboard and drum-machine sounds out to real-world “modifiers,” and recording the augmented sound on a separate track, to be blended with the original, “dry” signal. There is something unmistakable about real instruments in real environments moving air molecules — call it “energy,” “excitement,” or “juju” — which is too often lacking in modern music.
By blending drum machine sounds and the close and room mikes of the real drum kit, Sparling envisioned a way to craft an organic drum sound that would support perfectly Lowe’s original songwriting and her inventive rhythmic finger picking on acoustic guitar. Thus, our robo-kit was born.
With only a little prior knowledge of techniques for recording drums triggered by speakers, there was some trial and error involved in the setup of our robo-kit recording session at Guerrilla Recording in Oakland, California. First, trigger parts for kick and snare were programmed into a Yamaha RX5 drum machine, using both the “factory preset” sounds as well as others from the “Jazz” and “Electronic” Voice ROM cartridges issued by Yamaha in 1988. These patterns were recorded on separate tracks into Pro Tools sessions, syncing the RX5 to Pro Tools using MIDI clock.
For several of the songs, duplicate trigger sources were recorded for both kick and snare, as well as additional percussion parts, using sounds from Native Instruments’ Kontakt sampler. Finally, discreet click tracks and hi-hat guide tracks were recorded, so the players could listen to a mock-up of the finished full rhythm, or any submix of their choice (more click, less kick-snare, etc.) while recording.
The next step was to route our kick and snare trigger sounds to an amplifier and two transducers, which would each “excite” a single drum. We had a small battery-powered Dayton Audio DTA-1, 15W “T-Amp,” which gave us a stereo input on a hacked 1/8" mini plug, and outputs on speaker-wire terminals. The T-Amp was ideal for percussion sounds because of its reputation in the “hi-fi” world as being an extremely good amplifier for reproducing fast transients. One of the hardest parts of the process was field stripping RCA cables to make the proper wiring connections — a little more planning ahead of time will save you studio time on this part of the rig.
To trigger the drums with our prerecorded sounds we used an old Radio Shack 5" dual-driver speaker, set face down on the top of the snare drum, and for the kick we used a Sonic Impact 5029 Soundpad, which is basically a “stick-on speaker.” The Soundpads have a standard magnetic speaker coil which is attached to a sticky-backed piece of cardboard — when you stick the cardboard to a large, thin, vibrating surface, such as a sheet of metal or a window or a kick drumhead, the sound is transferred to that surface as though it were the speaker cone — perfect for our kick drum trigger. We placed the Soundpad on the kick head right about where the beater would hit from the kick pedal.
Getting the tracks routed out of a Digi 002 rack, with easily accessible level control for the kick and snare speakers, proved to be an additional challenge. What we settled on was to route a rough mix of the music tracks — including the robo-kit mikes being recorded, as well as copied drum machine tracks — to the studio monitors, while simultaneously routing the drum machine tracks from the headphone output jack on the Digi 002 to the T-Amp in the drum room. Since there were only two signals being sent (kick and snare) this was easily accomplished by running a single stereo headphone extension cable out from the control room.
The headphone level control on the Digi 002 rack allowed us the convenience of making volume adjustments to the levels being sent to the drums, while monitoring the resulting tones from the control room. This saved us a lot of trips down the hall to the drum room! Adjustments to the levels being sent to the individual kick and snare tracks could also be made within Pro Tools, of course, and this was done when we sent a blend of more than one drum machine sound to trigger the real drums. Not surprisingly, in this part of the process we found that adjusting the volume level of the trigger tracks had a dramatic effect on the attack, tonality, and resonance of the actual drums.