Webinar Video
Q&A
Q: What would be required to make it a polyphonic synthesizer? What are the limitations (bottlenecks) in the current design for making this possible?
A: A polyphonic design would probably require a much more optimized sound engine. The limitations are as always the MCU speed and available memory.
Q: I never have heard the term "bitcrusher" could please say a little bit more about it?
A: A bit crusher is an effect that reduces the number of bits used to encode samples. For instance it can reduce 16-bit samples to 10-bit samples. This reduces the quality the sound.
Q: Is there a possibility to analogue connect an existing sound generator or regular keyboard sound to the filter section?
A: No, there is no sound input.
Q: Hi, for learning harmony I'd like to have *frequency* intermodulation between 2 notes, as with real string instruments. Would it be possible to write code for 2 connected synths or should I go analog (multipliers)?
A: Of course you can do this in software, this is an ideal platform for experimenting with all kinds of sound algorithms.
Q: I remember a project from Elektor where a certain signal level was used to trigger the ADSR function.
A: OK. But that would require an external sound input which is not available.
Q: Will a PCB board will be available or perhaps a kit offering?
A: Yes, as usual. A kit including the assembled PCB will be available from our shop: www.elektor-magazine.com/140182.
Q: Is Bit Crusher and Wave Crusher standing for the same?
A: Almost. The wave crusher also reduces the sample rate.
Q: What is the name of the software?
A: J2B-synthesizer (based on Atmegatron)
Q: Can you write me how to install eclipse & C on my desktop? I am not familiar.
A: For this project you need LPCXpresso which is a customized version of Eclipse. All the details are here: http://www.lpcware.com/lpcxpresso
Q: Mash-up with GestIC for a modern take on the Theremin? Or maybe a separate GestIC MIDI controller?
A: Sure. Have a look at the 3D-Pad (http://www.elektor-labs.com/node/3850) project too, they were planning to build something similar.
Q: Can all these parameters be preset so that a new sound is created by a single key press either on a lap top computer or the midi keyboard?
A: Not really. But you can upload new sounds over MIDI sysex.
Q: Looks like the ADSR is repeating. Is it the case?
A: No. You probably refer to the LFO’s strange modulation waveforms that can produce similar effects. There is also the arpeggiator that can produce repeating notes.
Q: It is possible to control the synthesizer through CV. The main objective is to add this synth to one modular system.
A: Not without a software modification. Analogue control inputs are available through the six performance rotary encoders. Have a look at the schematics to see how.
Q: Will there be any chance for a Eurorack module (like a wavetable generator) based in the near future? So that can be a part of bigger modular system.
A: We do not have plans for such a module.
Q: What about stereo - you have this in the circuit design, so does it just need to be added to the software?
A: The current software is "stereo". There is a fixed phase shift between the two channels which creates a stereo effect.
Q: Can the controls be "played back" at a later time?
A: The synthesizer does not send MIDI performance data. However, it accepts MIDI CC performance data so it can be controlled from a sequencer or computer.
Q: Does it require other libraries besides the HAL library?
A: The project is divided in three parts: the board abstraction library, the MCU abstraction library and the sound engine. Everything is included in the download.
Q: how much does a kit cost?
A: See our shop: www.elektor-magazine.com/140182.
Q: If so much power is left in the processor, the AD converter on the chip could add another input from the outside?
A: Yes, this is possible. However, the ADC on the MCU is only 12-bits.
Q: Do you need a keyboard to generate the sounds or can the synthesizer be used alone?
A: It is possible to create sounds by pressing the Value rotary encoder. This is useful for programming a sound, but not for playing music.
Q: Is there a software simulated version for PC?
A: No.
Q: Analog filtering would add character, is there any performance left for adding analog voltage control? (LFO/EG out)
A: Analog voltage control is not the same thing as analog filtering. Analog filtering requires the addition of extra electronics. This synthesizer is purely digital.
Q: And, can audio path be interrupted? (so analog filter can be 'inserted')
A: No, there is no audio input.
Q: Once you reach the sound you want by trial how is easy to save it and recall another day.
A: Easy. Just select the patch memory and press the Parameter control for two seconds to save. To recall a sound it is enough to briefly press the Parameter control.
Q: Block diagram showed OSC -> PWM, isn't this the other way around?
A: No, because PWM is an effect that modifies the waveform. You probably think of an LFO that modulates an oscillator with PWM output. Usually PWM is created by processing a saw or triangle waveform.