Quilcom Adder: An additive synth

[Spogg]

Hi
I've been messing around with Flowstone for about 6 months now and I'm totally addicted.
This was my first project; an additive synth using 16 partials each of any ratio as required. There is an internal FM (Phase mod) buss fed by two synth strips and a static oscillator, as well as wheel controlled tremolo and an AM oscillator.
Also 2 basic synth strips for noise or base sounds on which to build with the additive section.
I spent some time getting the CPU usage proportional to the amount of partials, so if you set a ratio of 0 the channel is off and cycles are reduced.
I've created some presets which are intended as starting points. While I was developing the project I realised the huge range of possibilities with this method of synthesis but preset creation (sound design) is very time consuming. If anyone wants to upload any good presets to share that would be fun for me.
I made the VST dll and tested it in Reaper and it worked fine for me.
I do this for fun, for the craic, so it's free to use and abuse.
I will soon upload my other projects and feedback of any type is always welcome.
Have fun
Spogg

UPDATE: Please check later in this thread for newer versions!

[martinvicanek]

Nice one, Spogg! I was surprised by the (human-like) voices program 7, sounds like some vowel filter although I haven't spotted one in your schematic.

BTW, your alias resembles the name of a well-known Star Trek character. I wonder if that is intentional?

[BobF]

Hi Spogg,
Wow, great job. You don' t give yourself enough credit. This is really cool. Only been playing withit for a few minutes and have got some great sounds. Keep up the good work.later then, BobF.....

[tulamide]

Just tried your synth. The sound is very good, but it comes at a price I can't pay. On my pc playing a chord on 8th, mid tempo, raises processor usage to over 70%, at which point asio4all switches off (and back on when processor load is lower). Too much for my poor pc, I'm sorry. Would have been fun to create some nice patches.

[Spogg]

Hi and thanks for comments so far.

@tulamide: I thought the cpu load would be an issue for some. My machine uses a core i7 and Creative X-Fi Platinum sound card (Creative ASIO) and has no issues with the synth. As is often the way with newer and more powerful synths, one needs a powerful PC to run them. You could try reducing the Polyphony and make sure that the most partials that can be are set to Zero ratio. Note that just muting a channel doesn't reduce the CPU; it's only there for auditioning the contribution of the strip to the sound, by switching the mute on/off.

@Martin : I came upon the voice-sounding preset when I was trying for something else; a happy accident that I thought was worth keeping.

Live long and prosper!

Cheers

Spogg

[KG_is_back]

The synth is very cool indeed... and eats CPU for dinner too... it certainly is possible to reduce the CPU via optimization. MartinVicanek had made some cool oscillators, that are much lighter on cpu. Also I see you convert linear ADSR to exponential. It is possible to implement exponential ADSR directly (by using multiplication instead of adding) and avoid need of costly exponential scalling.

[Jay]

sounds nice!

but it really kicks the shit out of my pc as well, cpu 33% across all cores on an i7-4980HQ with 32gbs ram and an Focusrite Scarlett 18i20 interface, it also runs away with 2.93 gbs of ram

surely this is a wee bug? i can play monster synths without any of these problems! hope ya get it fixed

[Spogg]

Hey thanks for your feedback KG and Jay.
This was my first project and I did realise the CPU would be very high due to the sheer amount of processes going on (depending on preset configuration and playing styles).
My aim was to explore what could be achieved with additive synthesis using control for each partial rather than being limited by iFFT etc.
When I was experimenting I found that linear ADSRs were inadequate for good emulation of acoustic instruments and expressive playing styles so I made the exponential converter. I realise that the Attack phase is probably the wrong shape by convention but in practice it actually sounds ok. I guess a mechanical instrument doens't necessarily excite its initial vibration in a linear or log manner, so it seems acceptable to my ears. I spent a long time on the ADSRs to get the sonic behaviour I was looking for but hadn't realised that there would be a big CPU hit because it was 'green' stuff I thought. It's not really green though is it?
So, if anyone can upload a good exponential ADSR (I've tried square law and it wasn't good enough sonically) I will try it and see. The Decay and Release shapes are the most critical I would say.
Also if there is a better Sine oscillator CPU-wise I would welcome that too, but it must be a pure sine to keep in with the concept of the Adder.
I did try the Adder as a VST in Reaper and was able to record successfully without drop-out. In practice one would have to render the track, once composed, then freeze the Adder if more VSTs were needed. This worked fine for me.

Thanks again for your input.

Cheers

Spogg

[martinvicanek]

Spogg, try these for lower CPU hit.
Live long and prosper!

[Spogg]

Martin! Once again you did it my friend.
I tested your ADSR against mine and the linear one and yours was the best. I had made a simple cubing converter in ASM and it worked much better than the power-based one I was using in the old exp converter. But, yours won.
I also tested your Polynomial Sine (Cos) oscillator and could hear no difference to the stock pure(?) one.
So, I incorporated both into the Quilcom Adder, tested all the presets and am delighted with the result:
Using the Flowstone CPU meter on preset 7 (Voice--Basic) and holding a 24 note chord on the old version I got 94.9% CPU. With your lovely modules the same procedure gave 51.5% CPU; obviously almost half the cycles. The VST it created gave Reaper no trouble at all. Typical playing seems to benefit even more than the test process above, even with copious use of the sustain pedal.
So, I am SO pleased now and many many thanks for your input.

Cheers

Spogg