nb_drumcrow

caw caw caw
this is a norns mod
it turns a each output of crow into an oscillator, CV trigger, or CV envelope using nb
nb is a note-playing voice library for norns.
nb_drumcrow is turns each output of a monome crow into a drumcrow oscillator

Installation

1. Download this like you would any other script
2. Turn on the mod: go to system > mods > find nb_drumcrow, turn enc3 to the right until you see a +. this tells norns to load the mod at the next power ON
3. Go to system > restart and then check the mods, it should have a dot . to the left of the name indicating the mod has been loaded
4. Find a script that supports nb
5. Go to your params and select drumcrow from your nb voices
6. Start playing notes using a script with nb support. (...by calling player:note_on() like you would for other nb voices)

nb_drumcrow parameters

See drumcrow on lines for documentation of drumcrow parameters.

ON/OFF turns the engine on or off. It is ON by default. This will remove the output from the updating loop and set the amplitude to 0.
synth_preset selects between init, perc, noise, trigger, envelope, and scale presets. Press load_preset to load the selected preset.

Presets

• init: basic sine wave oscillator with decay envelope. Use for melodic synth stuff or as a starting point.
• perc: fast enveloped pitch sweeps for synth percussion sounds. Use for kicks by sending a midi note of like 30 and using this preset.
• noise: fast enveloped pitch sweeps using white noise synth model. Use for snares or hats.
• trigger: CV trigger output. Use to output triggers to modular synths. Adjust amplitude envelope parameters to shape output voltage level, trigger length, etc.
• envelope: CV envelope output. Triggers voltage envelope. Adjust amplitude envelope parameters to shape output level, curve, rise/fall time, etc.
• scale: Quantized CV output. Uses bit to quantize output voltage to 12 sections per 1V for 1 v/oct inputs. Adjust bit slightly to browse different quantization divisions. Adjust all the modulation sources and amplitude parameters (amp_amp, lfo_amp, note_amp) to combine everything into a quantized voltage sequence. Turns the CV envelope preset into a strange arpeggiator.

Trigger, envelope, and scale presets require the "now" shape and "var_saw" synth model to work as expected, but feel free to experiment.

For explanation of synth_shape, synth_model, and the remaining drumcrow parameters, please refer to drumcrow documentation.

nb_drumcrow scripting example

This section is an example of how to support nb in a norns script.

To support nb in a norns script, refer to nb for the most up to date information. nb_drumcrow creates an nb player for each of the four outputs on crow. Use nb:add_param("nb_1", "nb_1") to create a nb voice selector parameter called "nb_1" or any name you'd like. The following code looks up the player selector parameter "nb_1" and returns the player currently selected. Next, the note_on() function of the player is called and passed the midi note value 60 and velocity 5.

local player = params:lookup_param("nb_1"):get_player()
player:note_on(60, 5)

The above code will trigger a single note for one player. To play nb_drumcrow polyphonically using all 4 outputs of crow, create 4 nb voice selector parameters (for example: nb_1, nb_2, nb_3, nb_4), set each to drumcrow 1, 2, 3, and 4, then get each player, then trigger the note_on() function on each player. Each nb_drumcrow player is monophonic, so it only plays one note at a time on a single output of crow.

nb_drumcrow debugging

Crow should be powered on before loading the norns script. Crow should be connected to norns via USB. If you're not hearing sound, try changing model and shape of the drumcrow oscillator to hopefully wake it up, CAW! If you crash crow and hear a constant tone, you'll have to turn off power to crow and turn it on again. If crow hasn't crashed, but won't stop audio, use the on/off switch to silence an output of crow. If a norns script uses crow for different functionality, the script may overwrite the nb_drumcrow setup of the crow outputs. Currently, nb_drumcrow is set up to use all 4 outputs of crow upon initialization of the mod. I think you may be able to selectively remove an output from nb_drumcrow setup. For example, removing the add_drumcrow_player(3) line from the mod.lua file in the pre_init function would skip that crow output. Then, outputs 1, 2, and 4 could be used for nb_drumcrow, and output 3 is free to use for any purpose. I have not tested this.