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Feature: LFO Pre-delay + LFO Attack

Started by rio, August 27, 2021, 11:25:13 AM

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If someone is interested, I have implemented these two new parameters for the two first potentiometer of the 2nd bank (instead of duplicated filter and Q params). This feature is inspired by what also exists with the NES Chiptune Synthesizer as vibrato attack and vibrato pre-delay to create more a NES sound and is a nice addition to the beloved Atmegatron. Midi support is also included (CC50 LFODLY, CC51 LFOATT) and as an addition a "LFO Sync" option can be set in the configuration using 3rd slot of VALUE dial - so that both parameters are not reset when played notes are not released (default off).

If someone would like to try it out, the modified library is needed and then the SsAtmAtmegatron has to be compiled and uploaded or you take the precompiled binary. The source is based on the last libraries-master branch:

Please note:
A. I also fixed the PWM offset, which is used for the "Pulse Width LFO" and fits much better than half a square wave (offset is now HIGH 127 instead MIDDLE 0).

B. You will be amazed that all (or most) of your patches sound strange at first - don't panic. The reason is: The LFO pre-delay and LFO attack values ​​must first be set to 0 for each patch, as the original firmware stores the two filter and Q parameters as duplicates in both banks (green and red). So make sure to take a backup of your patches first before you experiment with this modded firmware ;)

C. I am not sure, maybe all the fun doesn't work properly with arpeggios yet. I'm still looking.

have a nice day & greetings, rio

Edit: Uploaded the final binary here - AtmegatronV2-5.lfo-attack-dly.hex  [2021-08-31]

i have attached a few audio examples (1..7). The pause and/or the transition through the attack to the full LFO portion can be clearly heard. Some examples are also combined with an envelope. Note: The examples are not pure, there is still a tape delay fx in the audio path.


C. the feature is now fixed for arpeggios. :)

there is unfortunately one last little issue if no filter (FILT=OFF) is selected. Then the delay/attack time is quite short. I look again.
Edit: I have to take the CycleTicks into account, i.e. determine the correct timing. that shouldn't be too difficult either.



The mod is now adjusted to the correct timing.

You can find the last/final binary in the first post.

Have fun  8)