Martin - pick a GUI for Karplus synth?

[k brown]

Hey Martin -

I was setting out to finish up a synth I started years ago based on the Radikal Accelerator. It includes something they call a 'String Filter', which is of course, Karplus-Strong. I hadn't a clue back then how do it, so instead put in a simple comb filter. Searching the forum I found your Karplus-based synth. You'd expressed a desire for someone to do a GUI for it - as far as I can tell, no one ever did. In exchange for using your modules, I'd like to GUI that baby up. If you'd like, go to my website and look through the screenshots and pick a GUI style (or some combination thereof) you'd like. I even thought of a perhaps too-cute-by-half name for it: "Karpal Tunnel".

If you have the time, could you look at the Accelerator manual and see if you can correlate the String Filter's controls with those on your synth? I can't quite tell what the equivalencies would be. I'd like to use the Accelerator's control nomenclature as much as possible in my 'semulation'.

accelerator_manual_us.pdf.zip

(2.03 MiB) Downloaded 1028 times

Thanks so much - using even more of your amazing work now that I'm on FS!

[martinvicanek]

Hey Kevin, that's very kind of you, many thanks!

I had a look at the accelerator manual. There is some loose correspondence between the String Filter in that device and my "resonator" in the Karplus Strong IV schematic:

string filter resonator
-------------------------------
tuning aligned with global tuning
String feedback decay/release includes invert as well
String damping cutoff
Lows dampng none
pitch envelope none
glide none
none (keyboard) track
------------------------------------------------------------

I have a current project that is in a way a folow-up on Karplus Strong Iv, although it has moved away from the original concept. I am posting the schematic below. I'll try to find time for some explanations, meanwhile check out the presets.

[Spogg]

Martin, some great sounding presets there!

I look forward to your explanations about what’s going on inside.

I was surprised to see it all done in Mono4.
I guess there’s a good reason but it’s a shame for the piano-type sounds to limit polyphony to 4 notes. I see the CPU is low, so the icing on this yummy cake would be true polyphony!

Cheers

Spogg

[martinvicanek]

Oh yes, of course, to post a synth in 2019 with max 4 concurrent notes was a bit naiv. Thanks Spogg, you cast this flaw in very diplomatic words! I guess at this stage it is merely a proof of concept. I will add more voices at some point, but let me outline the idea.

From my experience randomness is an important ingredient to sound synthesis. I get tired of a synth or drum machine where every note soundt like the other. Real instruments or singers sound different on each note. For this reason "RandomOsc4" creates an ad hoc individual wavetable at each struck note, with some randomness added.

The other thing I have found out is the importance of beating (slow changes of sound or volume for two notes slightly out of tune). When you beat two sawtooths, there is an instant where the phases of all partials are aligned, resulting in a flangy sound. This happens pretty much with any two classical waveforms because they usually have partials with aligned phases. "RandomOsc4" uses four voices with random phases for each note, which results in a smooth rolling, vivid sound without these flangy beats. Check out the strings otr the horns presets.

Because a wavetable (well, four wavetables actually) is generated at each struch note I have taken the whole synthesis and voice management parte out of the poly section, but that is really only an implementation detail. There are a few more tricks in the design which determine the characteristics of the synth. Feedback is appreciated.

[k brown]

Haven't tried the 'random osc' yet - looking forward to it.

Martin - have you had a chance to look at my website to see if there's a GUI style (or combination thereof) you'd like for KS IV?

Back to the subject of the original post. I was so looking forward to including the Karplus in my emulation of the Radikal Accelerator, but ran into a complete brick wall when trying to complete this very old SM project with FS. It opens fine, and can work on it to some degree, but if I copy and paste anything, the program freezes; if I drag anything in from the toolbox, same thing. I finally gave up and am finishing it out with SM. Anyone care to try and see what may be the issue with this? Is it possible it's specific to my computer and/or install? Every other old SM project I've opened so far with FS has been no problem!

https://ln.sync.com/dl/f87583110/fkhzep ... g-ep7uyedb

Here's what this is looking like; almost done, but would love to include the Karplus.

Throttle copy.JPG (197.8 KiB) Viewed 19411 times

The color scheme of the knobs is based on the slider colors on the Yamaha CS80; like tula, I have an aversion to over-flashy GUIs, but the Accelerator itself has the most boring-looking panel I've seen on a hardware synth! I sure wasn't gonna emulate that!

[Spogg]

I can confirm it works fine on my PC (core i7, Windows 7 32 bit, FS 3.06, Sapphire Scarlett 6i6).
I tried several transfers from the toolbox, and copy-paste of internal modules, and no crashes or unusual behaviour.
I tried with DirectSound and ASIO prims.
The response to these changes was laggy, but that’s normal in my experience when a project gets big like this one.

I’ve occasionally found that it helps to turn off the ASIO/DirectSound, do your changes, Save As something, and then turn the audio back on. But I bet you tried that already.
You could also disable anything not required running in the background. I once had an issue where an antivirus update caused problems with ASIO.

Other than that I can’t think of anything else at the moment, sorry.

Good luck!

Spogg

[Spogg]

@Martin:
I realised straight away that there was something “special” about the sounds of your synth, hence my comment. But I looked at the ASM and thought “no chance to understand this”.

When I was making my Wavemaker projects I quickly came to realise what you say about beating and phase alignment of partials. This is why I include the Random phases button. However, once you’ve made a waveform with Wavemaker 4, that’s it; it’s baked in, with no chance to change it. I was fascinated by the fact that two waveforms can look SO different yet sound almost identical, since the ear is not sensitive to phase of harmonics (except maybe for spacial location).

The only way I could see to get round the issue is to uses a random or round-robin selection of several different phase-scrambled fixed waveforms, but your design, amazingly, scrambles the harmonic phases in real time for every note, and that’s a HUGE step forward. AFAIK nobody else has ever done this. You are a true wizard!

Cheers

Spogg

[k brown]

Thanks for checking it out; good news / bad news. Glad there isn't anything inherent in the schematic. I'll try your suggestions (I hadn't tried turning off the DS).

[k brown]

Well, your suggestion worked - after a fashion. I could do some work with it, but very, very laggy - funny, because I can zoom around in this thing at light speed with SM, no problem. Is FS not completely backward compatible with SM?

[Spogg]

Well, your suggestion worked - after a fashion. I could do some work with it, but very, very laggy - funny, because I can zoom around in this thing at light speed with SM, no problem. Is FS not completely backward compatible with SM?

I think it’s purely down to the amount of stuff in the schematic (especially it seems loads of bitmaps cause lagginess) and the speed of your PC. Also FS is far more capable than SM so probably has a bigger overhead. What’s your PC spec?

When I was building the SynthMaker Greatest Hits topic I found that if a schematic worked then I could do anything to it I wanted, with no crashes etc.
Of course not everything actually did work, so my guess is that it’s not fully compatible for whatever reason. But if it opens and functions it should be ok. It’s probably a good idea to replace prims marked as superseded though, to be on the safe side.

Is the reason you can’t incorporate the K-S system a technical one, or one of design; how to integrate it?

Cheers

Spogg