Description
Seismograf is a PIC based drum module featuring coding by Jetroid. There is currently a choice of two PICs which may be used with Seismograf, ‘BD‘ and ‘SD‘. As you might expect, BD contains a range of 8 bass drums, while SD contains a range 8 of snare drums. The drum sounds are 10 bit encodings of some of our favourite electronic kits from yesteryear (see chart below). It is not possible for the user to load their own sounds onto Seismograf PICs, but there is a chance that we may release alternative drum sets as the years roll (!) by.
| BD | SD | |
| Sound 1 | 808 | 808 |
| Sound 2 | 808 | 808 |
| Sound 3 | 909 | 909 |
| Sound 4 | SDSV | SDSV |
| Sound 5 | LM1 | LM1 |
| Sound 6 | DMX | DMX |
| Sound 7 | CR78 | CR78 |
| Sound 8 | DRUMTRAKS | DR55 |
Select
This knob is used to select one of the 8 sounds to be triggered. It has a CV input associated with it, and when a jack is inserted into the CV input, the knob is used to attenuate the incoming control voltage. This CV input responds to 0V to 5V signals.
Tune
This knob may be used to detune the drum sound either upwards or downwards. It has a CV input associated with it, and when a jack is inserted into the CV input, the knob is used to attenuate the incoming control voltage. This CV input responds to 0V to 5V signals.
Distort
This knob may be used to introduce either one of two different types of distortion to your chosen drum sound. When set to the mid position (12 o’clock) no distortion is present. Turning the knob anti-clockwise will cause the sound to be progressively clipped harder, while turning the knob clockwise will cause the sound to be progressively more bitcrushed. This knob has a CV input associated with it, and when a jack is inserted into the CV input, the knob is used to attenuate the incoming control voltage. This CV input responds to 0V to 5V signals.
Secret Sauce
Try running the sawtooth output of an audio rate VCO into Seismograf’s trigger input, then wiggle the Tune knob manually, or apply a control voltage to the Tune input. Wow! What’s happening here then? When I first demo’ed this feature to Jetroid he buffered for a few minutes before performing a cold shutdown, unable to process what was happening to his code. Seismograf is acting kinda like a fliter, right? Well maybe! Probably more akin to oscillator sync really. As the incoming trigger is so fast, Seismograf only gets to play the initial part of it’s waveform, less on high notes, more on low notes. Additionally, there is naturally higher frequency content the higher the note and so forth. Whatever’s going on, we’re sure that you’ll agree that it sounds freaking awesome. More than just a drum module, right?
