Recording - July 2010 - 26

All the drum-replacement plug-ins, and The illusion is complete most commercial sampled kits, use sample-layering—this means that multiple Once we’d seen to all of the above recorded samples of the same drum, issues, we auditioned the songs with the being hit at several different levels from softest to hardest, are assigned to the same key, and the different dynamic samples are chosen by the MIDI Velocity (1–127) of the trigger signal, which is derived from the relative levels of the notes in the original audio track being replaced. The alternative approach is to use a single loud sample, and use velocity-controlled envelope and filter adjustments to simulate the same response. All of the drum-replacement plug-ins use the first method, and have the ability to load in a collection of dynamically-varied samples for each drum to be replaced, and, ideally, some adjustment of the velocity-response curve that controls their selection (Figures 10–12). Our custom drum Instrument mostly uses method two, and is already set up to provide natural dynamic variation from MIDI trigger notes (Figure 13). Figure 13: The custom EXS-based drum Instrument in Logic: shown are a collection of snare samples of different performance variations, the matrix-modulation section of the EXS that controls velocity response, and randomization programming in the Environment. • Random variations: One of the dead giveaways of a sampled drumkit vs. a real kit is when the same sample (say, on the backbeat of a steady groove) triggers over and over, identical on every hit. With a real kit, no two hits ever sound exactly alike—slight variations in angle and striking position cause slight variations in tone, attack, and sometimes apparent pitch, especially noticeable when hard rimshots are being played repeatedly on the snare. Our custom kits have this built-in as well, from slight random pitch variation to semi-random selection of ever-so-slightly different sampled hits of the same drum, for a highly natural degree of tonal variety. All of the plug-ins also offer this option, sometimes as an alternative to other variations (apTrigga), but usually in addition to dynamic variations, with the option of alternate hits at every dynamic level. Drumagog offers not only randomized alternate samples but also “positional” variations (when the stick hits the drum near the center vs. near the edge of the drumhead, for a thinner tone), and left-hand/right-hand variations as well (Figure 14).
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From hit to hit With snare drums, there is the additional tonal variation of center-hit (stick hitting drum head only) vs. rimshot (stick hitting head and rim together, for a much sharper, louder crack). Backbeats are often played as rimshots, for a really cutting tone, but triggering faster figures, even with a softer rimshot sample, would sound unnatural—those kinds of figures are usually played on the drumhead only. This also needs to be factored into the assignment and fine-tuning of the dynamic velocity response of the snare samples, based on the drummer’s original performance. Our kits allowed additional adjustments after the main replacement was done, by

sets have separate recordings of these techniques, though they may not match the precise timing of the originals in a drum-replacement scenario. Other times, the choice might be made to not have these quieter notes replaced, and use the ones in the original track. Drumagog has a cool feature for this called Stealth Mode, which will let elements like this be heard by letting the original track bleed through only between triggered replacement hits.

re-assigning the MIDI trigger notes to different pitches, which would then trigger differently performed snare/ rimshot variations, giving us greater control in tweaking the replacement track for more natural-sounding accents and fills. Ultimate subtleties Again, with the snare drum, very soft, rapid notes are often played leading into or coming out of a harder hit (drags and ruffs), or sometimes as in-between notes to make a simple pattern more interesting without cluttering it up too much (ghost notes). These notes often run together (with the buzzing snares throughout) rather than sounding like discreet taps. They’re easily missed in the detection stage, and if assigned to samples that are a little too solid in their attacks, they can make the drummer sound amateurish, like he doesn’t have a fine-enough touch to execute such techniques with the proper subtlety. Our kits incorporate this at the lowest velocity-trigger levels. Some drum sample

Figure 14: Drumagog’s options for natural variation: dynamic (velocity), random, positional, and alternate L/R-hand; all can be active simultaneously. other instruments brought up in (very) rough mixes, and were generally pleased with the results. Switching back and forth between the original kick and snare and the replacement versions, there was a much greater solidity to the grooves and patterns, but the new sounds blended well with the original toms and cymbals. Since we wanted to preserve all of the nuances of the drummer’s performance, there was still quite a bit of manual tweaking to be done to correct any remaining small latencies or other timing offsets, which Yianni set out to do. At the time this article was submitted, the mixing was still ongoing, so I’ve yet to hear the finished results, but even the roughs suggested that the drum sound was going to provide a really solid underpinning for the music.

Recording - July 2010

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