Trying to understand here.. turning the saw into a spiral... Do you mean the user interface, the visual part of the oscialltor must look like a spiral... Or you want to actually change the saw wave into a spiral? If this is the case, how would you go about that?
But from the description you gave, I chime in with @Sputnki and say that it sounds like a wavetable oscillator of some sort.
Take the grooves of a record, completely unwind it, and put it in a straight line. If you then run a stylus along that groove at a constant speed, the recording will get faster and faster even though the stylus is moving at a constant speed. This is because the record had it's grooves cut in a 'spiral'. meaning the outer grooves are larger in circumference than the inner grooves.
This proves that the geometry of the groove can effect the pitch. If proves that if the groove were in one streight line it would behave differently if it were then wound into a spiral. And that's the idea behind it, to take what is generated at a constant rate, wrap it into a spiral, and rotate it. This has the opposite effect, because rather than recording in a spiral then unwinding it, you're recording in a streight line then winding it into a spiral. It's this spiral that causes one aspect of the oscillators behaviour.
The other aspect is that there's a stylus for every groove in the spiral. So if the density of the spiral is low, say only six turns, then you get 6x stylus to output the sound simulatneously. If the spiral is super-dense having something like 120 turns, then you get 120x stylus outputting the sound simultaneously, cause like I said, the oscillator has a stylus outputting sound from each groove simultanously.
Now you take those two aspects, add them together and you get the Rotating Oscillator. Because due to the time-shifting caused by it being a spiral, it means you can change the characteristics of the harmonics by altering how close together and far apart the grooves are as they rotate. For example, if you modulated the groove spacing across it's surface by using a sinewave, the density of the grooves would get progressively closer and far apart across the surface. Remember, you have to draw a virtual line from the outside of the circle to the center of the spiral, and no matter how many stylus you generate due to groove density, they all sit on that same line.
If you were to do this with a real record, the sound would be a mess, but the sound from each groove would sound as if it was playing at the same speed. That is not the case with the Rotating Oscillator, simply because the sound was not made in a spiral formation, but rather a streight line that was then wound into a spiral. This means that the pitch will differ from each stylus that is outputting sound, therefore giving you control over the sound, over the harmonics, over the phasing etc.
This is what makes me think that such an oscillator would totally rock at string instruments when modulating the groove density across the width of the virtual playhead line. I can imagine it would also work well for air/breath in vocal synthesis, stuff like that.
Not related to the previous post, but has anyone ever considered making a sort of PMCK Physical Model Construction Kit of Axoloti objects?
Would really love to be able to use a complete orchestra of physical instruments, and even sound effects. All the usual stuff like brass and strings are essential, obviously, but as well as all that, I've always wanted to hear a convincing 'old church bells' type of sound. The sort you hear in the distance from really old village churches where they go in and out of tune as they continue to sound - you know that really old, quaint sound those types of bells make.
Would love to be able to do that in Axoloti convincingly, and the same goes for those really huge Gongs, like the one they strike at the beginning of those old movies.
Pianos as well. Can't remember the name of it but I came across a demo of a really impressive modeled piano once, it was even available for Linux. I was tempted to buy it but the licence agreement didn't allow using the sounds generated in it to be used as samples in a commercial product, so I never bought it.
Would be awesome to have Open Source physical models of that quality so that we could generate various pianos that can then be baked to samples for use as a rompler or whatever. So yup, would be cool to see a PMCK project go on around here, where basically, the only objects allowed to be part of the PMCK are strictly physical models of complete objects and instruments, or parts of the models of instruments so that we can mix'n'match and build our own by linking-up the patch cables.
PMCK = Physical Model Construction Kit
pianoteq probably. no point in sampling it imho, because the point of modelling a piano is that voicings actually sound different every time when you play them on pianoteq, depending on dynamics of each note. since every string is calculated, that's possible. if you sample it, you loose that "natural" part of piano playing. that's exactly why most sample based pianos are hard to play for professional pianists.
That's the one, very nice, and very true what you said about losing the modeled aspect of it all when they become samples.
That's all the more reason why the EULA is so amateur and unprofessional. It should be illegal to put such restrictions into the licence of such a product. When you convert to samples you're removing the live modeled aspect of the instrument in exactly the same way you do when you sample a real piano or an FM synth. Native Instruments are another bunch who think it's fine to place such restrictions on products that are sold to sound designers. I have their FM7 synth from way back, love it, and it has a perfectly acceptable EULA. I don't see any restriction on converting any instrument I synthesize with it, into a set of samples for use in a sampled product. So I thought I'd upgrade to FM8, but that was until I saw the EULA for it - which doesn't allow it.
I have names for companies that place such restrictions on products, but it's best not repeated on this forum.
I can understand such restrictions designed to prevent direct copies of samples being reused, but putting these restrictions on actual synthesis is disgusting and completely immoral. It should be illegal because it's no different to a pencil manufacturer saying you cannot digitize the drawings you make with their brand of pencil, and sell them in a book. It's every bit as ridiculous and unacceptable.
My way of dealing with such companies is to simply avoid purchasing their products, and to tell others about the restriction. I basically give them the big finger (which is what they deserve).
But anyway, that's a whole other subject and the thread would only go off on a tangent again talking about that stuff. But it's a perfect example of why Open Source physical models and synthesis is a big deal. It means we don't have to deal with that sort of crap. I'd love to see a piano as good as that in Axoloti.
There's a guy on YouTube, I don't know him personally, but it would be great to have him using Axoloti, and for all I know he might not even be aware it exists.
Here's a couple of his models, but check out his channel for a whole bunch of them:
Hi Guys
Sorry for beign out of touch for so long but I am very busy with other stuff.
A few short thoughts about the rotating oscillator.
A - Ever heard of organs with optically scanned disks? They are actually quite old and basically where the first samplers. For soem time they where more or less competition for the Hammond organ. One of the last incarnations of the principle was the Matell Optigan, which was sold as a toy!
B - In Russia there was a lot of research into optical sound. Google the ANS synthesizer for a great example.
C- 2 previous remarks do not make too much sense to me:
1) The groove on an LP is scanned at a steady pitch, otherwise your music would end quiker then it began. The only thing that really changes is that the length of the groove within a sinlge rotation deminishes the closer th eneedle comes to the centre of the record. That is also why the needle starts to move quiker towards the centre of the record.
2) Endless layering of different waveshapes in the end only leads to noise.
D - Talking about mechnical solutions for electronic instruments: https://www.youtube.com/watch?v=GGDT9yHDTDss
This is an idea I had myself some years ago. It is close to wave table scanning and granular but takes the idea one step further.
What would happen if one could assign a set of waveforms to a program that would play them one after another in a preselected order but only for the length of one waveshape cycle before the next waveform is played? One would then get a rather complex endresult in which the waveshape changes every time the sound crosses the 0 line from the negative part of the cycle. So if for instance 4 waveforms would be assigned the resulting "loop" would last only 4 cycles
The big question then is: What would the audible result be? One would obviously not hear the individual waveforms because the scanning would be too quick for the ear. But what would one then hear in stead? Would one hear different morphed sounds depending on the "waveshpes slected for the cycle or would everything always blur into very similar sounding endresults or even noise when the waveshapes with many overtones are used?
It should actually be possible to program such an instrument in Axoloti, shouldn't it?
This is this sort of stuff I'd like to diccuss here. Things that might be as esoteric as we can up with but can still be programmed on our favorite platform. Anybody else?
It is also possible to use a 2D terrain as a source of grains.
http://stash.reaper.fm/24735/GranularTerrainSynthesizerEngine.pdf
The grain/window loop is a slice of terrain.
You can change the center position of the slice, its orientation and its extent for real time sound control.
Depending on the content of the terrain, the results are quite different (from synched FM to more conventional results).
I've done that in a jsfx synth plugin and it is quite fun.
I'll implement that on the axoloti some day.
Dear Thierry,
Sounds interesting and the way you describe it it reminds me of the way granular sampling is handled in Madona Labs Kaivo.
I do however not fully get how this would actually be a new synthesis form in itself. Is it not more a control solution? Or am I not getting the full picture here?
It's not really a "new" synthesis scheme.
It is rather the combination of waveterrain synthesis and granular synthesis. Both promising techniques have been first descibed in the late 80s and early 90s (i.e. before almost all research efforts focused to VABS).
A wave terrain, as opposed to a usual 1D wave form (as seen in Kaivo), is a 2D function, hence the word terrain.
It is usually scanned with orbits. These orbits can be more or less elaborate (from circles to semi stochastic trajectories).
Granular wave terrain synthesis - as i describe it - does not use orbits.
It uses slices of the 2D terrain as grains.
It can be seen as a simplification compared to complicated orbits, but it provides lots of control and can easily be band limited.
@Marc
I'm sorry also for the late reply, I've been trying to get my computer setup sorted out (see the Nightmare thread).
That idea of yours sounds a bit like Korg's Wavestation but on a more granular level. Regards the Optigan and stuff, sure I know about those things, I love that stuff, my favourite being the Mellotron. I'm a sucker for mechanical, analogue, and tape, so the Mellotron being all three, well, I gotta love that 
So how are you getting on with your Axo now you finally have it?
Is it a Pandora's Box of Physical modeling bliss for you?
Yep, my idea is a sort of utlrashort wavetabeling but on a single cycle basis. I still wonder how it will soudn though.
Maybe the best solution for one not as softwaresavy as me would be to edit some audio tests togheter. It would however be a hell of a lot of work before one get anything resembling a steady tone, wouldn't it?
Still, With my audio workstation it could be done because they can cut and paste 99 copies at a a time. So I can first build an example of 4 different individual waveforms, copy that complete section for 99 times, again copy those 100 x 4 = 400 waves times 99 agian whic is almost 4.000 cycles. Hey, that could already lead to a few seconds of audio, providing the oringal pitch was not that high, say A 440 Hz. Ergo: Testing the concept myself should actually not be difficult at all!
About the Axoloti: I msut confess that I have done diddely squad with it until now. It's summemrtime and I am buzy with loads of other stuff. Heavily customizing motorcycles for one (No, not cliché Custom Harleys! Pulleeze! see: http://www.brassee.com/motorcycles.html ).
It's hwoever just a matter of time before I start. Sooner or later the compas wil automatically turn towards it again. At the latest when Winter draws in again.
Until that time I am of course still game for more Axoloti banter anyway.
Nice bikes, Marc, I especially like the styling on that ZÜNDAPP, but then I'm a real sucker for 80s styling!
Never heared of any of those bikes to be honest, but to be fair, I've never been in a position to get too excited about them cause every time I did, I'd see some clown on the road put me off getting one. Would definitely love to own one though.
Totally love your logo as well. I was thinking of something elongated like that for my own logo if/when I manage to get a business up and running. It will definitely have that sort of stylish and futuristic 80s vibe to it whatever I come up with, there is no doubt about that.
Bring back the 80s I say!!!
A time when telephones were telephones and looked stylish. A time when TV's were something substantial, used analogue "ray-gun" technology, had a real-glass screen, and totally dominated your living room. A time when the hardware you bought was built like a tank and looked futuristic, and didn't spy on you. A time when the design of vehicles actually had the design imprint of the individual designer rather than boring samey-samey Bezier-curved crap we have nowadays. A time when women looked like women, had feminine looking hair, and looked hot and classy at the same time with their red lipstick and blue eye-shadow!
A time when I bought one of these for less than three hundred quid (and see, even that looks futuristic) 
OK, so how many of you still have yours?
I'm not selling mine!
I have actaully been watching the first Max Headroom movie a few weeks ago.
Yeah the 80ties where alright in many repects. To me they where also the period of exiting new technology. Alas they where also the beginning of the end becaue of Raeganomics and stuff, when pure greed began to outphase neccesity (again). But let's not go there.
That you do not recognize these bikes is not strange, Axoman, Google their names and you'll get pictures of machines that look totally diffently. You are however spot on when it comes to describing 80ties styling. S lot of ugly stuff has been dreamed up in tha tperiod as well but at least it still had character. Basically the principle of styling goods to give them an edge over other stuff with similar specs became important, especially for goods that where oriented towards defining ones individuality and for having fun, as motorcycles had become by then and musical instruments of course have always more or less been.
It is also the last period in which rock and pop really where innovative. Even if oen does not like hiphop much, it still was the last really new style as far as I am concerned. On the other hand the same sort of sample maniupualtion led to the first succesfull integration of the Musique Concrete idea in popular msuic. Enter stuff like the Art Of Noise. which nicely brings us back to Max Headroom ("Is that a spoon"?).
Hey, I in term never heard of that Amstrad set. Neat. It probabaly never hit the Eureopan market. We where all into the Tascam Portastudio, which probably was the first incarnation of the concept anyway. My first setup was a Fostex A8 1/4 ich 8 channel multitracker. A little bit more proffesional but still a sort of advanced comapct cassette recorder specwise.
Those where the days, eh? When we all thought we would go in a flash. And then the wall fell and everything would become much better but in reality got even worse. Oops, I just went there again.
Max Headroom, Max Headroom. Must focus on him!
The Amstrad studio could be found in France too...
The 80s were also the terrifying 80s of "Spitting Image".
Ok, guys ... please settle down....
This forum is primarily for support of Axoloti...it is expected to be a friendly, open and welcoming place for everyone.
We love the fact that many users enjoy the supportive nature felt here.
In the lounge we all things to wander a little further away from Axoloti, to allow discussion things like DSP to be discussed more generally, however if this starts causing friction between users we will close it down.
please also remember the written word is easy to misunderstand, especially for non native english speakers, so be particularly careful with things like 'humour' ... if its possible it might be misinterpreted, simply do not say it.
If you have a problem with a post or a user, report it , either via the report icon on the post or my PMing @thetechnobear and/or @johannes ... do not start commenting on it.
this was all covered by the guidelines you were given when you signed up to Axoloti, so if anyone abuses this, we will give you a 'timeout' from the axoloti forum to reflect.
I personally did not take it that seriously. It was more meant as a bit of drole jousting, Sir! So if any offence was indeed taken I hereby appologize.