Oscillator Devices Minerva

The Oscillator Devices Minerva is a compact, MIDI controlled, stereo sample player built for the pedalboard¹. Instead of processing your guitar, it plays back audio files you load onto a microSD card, triggered and shaped entirely over MIDI: program change messages pick the file, CC messages control play modes, pitch, volume and fades, and MIDI clock can restart a sample in time with your sequence. The input signal stays analog throughout, so the unit is analog dry-through with no A/D or D/A conversion of your instrument².

Oscillator Devices is a German maker, founded by Uwe Halmich in Oberderdingen in March 2021, whose range also includes MIDI switching and volume products such as the Siren, HYDRA4X and ABY.

Loading samples on the microSD card

Samples live on a microSD or microSDHC card, easily accessible from the top of the unit². The Minerva plays .wav and .aiff files, and there are two ways to organize them, each with its own trigger method³:

• Root folder, triggered by program change: Copy files to the root folder of the SD card and play them back with the MIDI PC command. Files are assigned alphabetically, up to 127 files.
• CC folders, triggered by CC: Create a folder named CC followed by a number, for example CC31. The files in that folder are played back with that CC command, assigned alphabetically to the CC argument.

The unit ships with a preformatted 32GB microSDHC card that fits and works, plus an adapter for full size SD card slots, so no separate card purchase is needed to get started².

MIDI commands and play modes

The Minerva has some fixed CC commands, but these can be changed through the configuration file on the SD card³. The default MIDI channel is 6, and you change it in the minerva.cfg file on the card³.

CC 102 is the play mode control, and its values cover transport, direction and looping behavior³:

The same control handles MIDI clock sync. Values 10 through 17 restart the file in the beat of the incoming MIDI clock, which lets a sample sit in time with a sequencer or drum machine rather than free-running³:

Volume and fades are also under CC control, with left and right channels addressable separately since the Minerva is a stereo player with independent left and right track controls³:

Pitch, sample rate and reverse playback

Pitch shifting on the Minerva works by varying the sampling rate, the classic sampler trick: playing a file faster or slower raises or lowers its pitch. CC 111 sets the sampling rate in steps of 409Hz starting at 20kHz, so value 0 gives 20kHz and value 127 gives 72kHz³. CC 110 works in musical terms instead, as an interval sampling rate where 49 is -15 semitones, 64 is 0 semitones and 71 is 7 semitones³.

Two further controls act as master overrides³:

• CC 112 (49 to 71): Master Interval Sampling Rate. Like CC 110, but stays at this rate and ignores the sampling rate stored in the files.
• CC 113 (0 to 127): Master Sampling Rate. Like CC 111, but stays at this rate and ignores the sampling rate stored in the files.

The difference matters if your files carry their own rate information: CC 110 and CC 111 apply per playback, while CC 112 and CC 113 lock the rate globally across everything on the card³.

Reverse playback is handled from the play mode control: CC 102 value 7 sets reverse playback, value 6 returns to forward, and value 8 reverses temporarily, flipping back to forward the next time the file starts³. Combined with the clock-synced play modes, this gives you reversed, pitched, tempo-locked sample playback all over MIDI, while your dry instrument signal passes through the box untouched²³.

Videos

Click to load

Questions