Posting information about the current status of Triggering, Midi, Positional Sensing, and Drum Modules in 2013.
A commercial drum "brain" module does a few things:
- Plays the drum sample so you can hear it
- Converts the input trigger voltage to a MIDI note
- Detects how hard the drum/cymbal was hit (velocity)
- Detects where the drum/cymbal was hit. The common vernacular is "positional sensing" but that is not an accurate term, it really is "radius inference".
The major disadvantage with commercial drum modules is that usually you can NOT use your own drum samples! Sure you can tweak parameters to modify the sound but that isn't close to using a complete custom sound. Yup, even on those "high end" Roland modules. :-/ The other limitation is that the built-in drum sounds are sound artificial well, because they are. They don't sound "full" like a real acoustic set. There are comparisons on YouTube such as the "Roland TD-12 sound vs Superior Drummer 2.0" that demonstrate how much "richer" using real drum samples are.
There are a couple of cheaper hardware solutions that go by the name TMI - Trigger Midi Interface - a device that separate the drum sample playback from the conversion of the input trigger voltage to MIDI. The rationale is that you will use software (a program on your PC/Mac) to "mix" the drum samples in real-time.
Sorted from most expensive to least expensive:
- Rolands TMC-6 www.rolandus.com/products/details/224
- Alesis Trigger | iO www.alesis.com/triggerio
- DIY megaDrum www.megadrum.info/
- DIY microDrum microdrum.altervista.org/blog/
The commercial TMI devices do NOT support positional sensing as the drum companies want to upsell you an expensive drum module for that capability! The DIY megaDrum does support positional sensing but the firmware is sadly proprietary and closed source -- the community is very active though. The microDrum is based entirely on the Ardruino open hardware and is open source however, at this time, it does not support positional sensing; its community is extremely small.
The disadvantage of triggered MIDI is the latency. The total time it takes from when you physically hit the pad to the time the drum sample is produced. Acoustic drums obviously don't have this latency, but the tradeoff is that instead of having access to unlimited sounds you are limited to just a few, along with the lack of good volume control.
Standard MIDI only has a baudrate of 31250 due to it being serial. It is possible to use the higher baud of 11520 but that requires custom firmware/hardware. Some TMI devices will output directly to USB to help minimize the latency.
The popular drum samplers are:
- Toontrack's "Superior Drummer" or "EZDrummer"
- XLN Audio's "Addictive Drums"
- Native Instruments' "Abbey Road"
Other software DAW (Digital Audio Workstation) that might be of interest:
- Fruity Loops
For more deatils see wikipedia "Digital_audio_workstation"
Another acoustic solution is that you CAN trigger MIDI from any audio source using software:
- eTrigger www.etrigger.net/ (which was a rewrite of its predecessor "edrum monitor")
- AudioFront's "dsp Trigger" www.audiofront.net/dspTrigger.php
One can even pre-trigger to really minimize the latency!