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Trouble with Additive synth CONFUSED

January 10, 2012 | 2:04 pm

I am making an additive synth for a uni project and have run into a bit of trouble. As far as I know this patch should work but it isn’t lol any suggestions?…

January 10, 2012 | 3:49 pm

You don’t need that line~. Go straight from adsr~ to *~.

Also, there’s nothing additive here. Your use of segmented patch cords makes it hard to follow the signal flow. And, I’m not sure that note-off logic is necessary since the patch is monophonic. When/if you go for polyphony, be sure to look at the Borax object.


January 10, 2012 | 4:31 pm

Now it’s additive. It’s a work in progress lol. Thanks for the help! What other note off logic would you suggest to use with midi? I tried [midiin]>[cycle~] before but the note doesn’t stop when I let go of the key. Could it be done more simply with [select] objects?
Also the next bit I am trying to add with the [noise] object is confusing me. I would like to automate the signal. For example press a button which would trigger the noise object to send noise for a specified time before stopping.

January 10, 2012 | 4:31 pm

p.s. apologies if the text doesn’t work. I used a custom font…

January 10, 2012 | 8:13 pm

The midi note stuff was more complicated than it needed to be, I think. I replaced it with some simpler code, then complicated it again with some velocity scaling stuff. I also added a noise blip on the beginning of notes.

– Pasted Max Patch, click to expand. –

It’s still not an additive synth, BTW.

January 10, 2012 | 11:07 pm

your sustain should be a floating point value between 0. and 1.

how come you scale the float on the velocity and not /127.?

isn’t this a subtractive synth?

January 11, 2012 | 1:27 am

Thanks for the help! I really appreciate it. I don’t understand how it isn’t an additive synth though. I’m adding different waveform together to create a new one… surely that is additive

January 11, 2012 | 2:04 am

Or is it all about the partials?

January 11, 2012 | 2:56 am

Here we go. Pretty much completed =) I decided to stick with the original midi note stuff because for some reason it was more responsive. The new one that you created for me Chris, was great but if i overlapped two notes slightly there were some issues with notes cutting off when i didn’t want them too.
Also, now I’ve added the option of changing the 2nd 3rd 4th and 5th oscillators to be partials of the fundamental it should be a fully fledged additive synth right?
Thanks for all the help guys! Let me know what you think XD

– Pasted Max Patch, click to expand. –

January 11, 2012 | 3:39 am

I missed the sustain thing.

The reason that this is not additive is that in a traditional additive synth there are sine wave oscillators arranged in the harmonic series.

January 11, 2012 | 5:42 am

I just noticed that a comment snuck in before my last comment. I didn’t notice a problem with my note parsing code, but if you end up putting this into a poly~ so that it can be played polyphonically the note input code will change anyway.

As far as this being an additive synth, I don’t really think it is yet. True, you have a few oscillators that can be set to harmonic ratios to the fundamental, but there would need to be individual envelopes for each partial, and there would need to be significantly more partials before I would call it an additive synth. It’s not just mixing oscillators, it’s how those oscillators change in relation to each other.

This is closer to a Hammond organ in spirit, so far. You have slider to create a mix of harmonics, a Hammond has drawbars, but the concept is similar.

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