BassBoy monophonic digital MIDI controlled bass synthesizer (MIKROE-684)

BassBoy is a 16-bit monophonic digital MIDI controlled bass synthesizer. Device receives all information via MIDI input.

The Idea

The author of this device, Aleksandar Krstic, had a childhood dream of bulding his own version of one brand of then famous MIDI synthesizer. As he learned more and more about sound processing, he also developed interest in programming. When the worlds of music and programming met, he started building great signal processing algorithms. And soon after, idea for BassBoy was born. In order to utilize each and every single CPU cycle, Aleksandar wrote the firmware in plain assembly. This is why BassBoy runs smoothly even on 8-bit ATXMega32D4 microcontroller.

Signal processing

Sampling frequency is 31.25KHz which generates audio range up to 15.625Khz. Although it's based on 8-bit processor, the signal processing inside the unit is 16-bit.

Signal characteristics

The unit is mono, and 6.35mm jack is also used as carrier for the circuit board itself.

How it works?

The unit consists of oscillator which generates SAW & SQUARE WAVE using 16-bit band-limited wavetables, thus making the number of harmonics limited. The signal then goes through a simple MOOG filter, whose frequency range is chosen by MIDI commands and which is affected by the level of the envelope. The filtered signal then comes to the controlled amplifier, which creates the signal shape, and in the end through DAC and pre-amp circuit goes to the audio jack.

 

Download Data Sheet