Review: Casio on steroids

March 3, 2016 | 15:00
Review: Casio on steroids
Review: Casio on steroids
Around a month ago, in his review , my colleague Thijs Beckers was extolling the virtues of the assembled J²B synthesiser module, but he didn’t tell you everything. From my point of view, he even forgot the essentials, to know what comes out of the synthesiser and enters in our ears! We need to revisit this subject, especially because in the description of the synthesiser already published by Elektor (Jan 2015), it was only a question of…
This software bias is logical, because it was about illustrating the portability of an open software from one microcontroller to another of a totally different family.

Now, when you talk portability, you can talk possible improvements! Thus a display has appeared on the J²B synthesiser, useful to check its parameters. In its initial form, the Soulsby Atmegatron synthesiser had only buttons (10) almost all potentiometers, but no display. In the Elektor J²B version there are not only buttons – which are in fact rotary encoders without end stops like potentiomenters – but also a 2-line LCD display. We’ll come back to that.

The sound of this monophonic synthesiser reminds one of that of the “Chiptunes” from the ‘80s and ‘90s. Combining well with the sounds and algorithms of today, it is interesting that these sounds are coming back into fashion. Go past the appearance, show some curiosity, there are some sonic pearls between the controls of this digital synthesiser. The synthesis is done by the LPC1347 with waveform tables associated with Pulse Width Modulation (PWM). The calculating power of the ARM Cortex-M3 at 32 bits allows 16-bit PWM (against 8 in the Atmegatron).

The J²B is in fact a 9-bit synthesiser. It offers 32 pre-programmed waveforms, plus some user-defined ones, 15 types of filters (Digital, with steep rolloff), 2 envelope shapers with the 4 ADSR parameters individually variable – and invertible, to obtain unheard-of sounds – and finally two LFOs with 16 waveforms. In addition, a “bit crusher” and distortion effects are just asking for you to get off the “beaten track”. All this gives a total number of combinations which, while not infinite, are certainly worth exploring. .

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