PolyGranuSyn XL

[Tim Kleinert]

UPDATE September 15 2012: This design is obsolete as it has been superseded. Please go here:
http://www.electro-music.com/forum/topic-55004.html

I honestly thought the previous version (PolyGranuSyn X) would be the end of the road. Well...

That previous version had the major advantage over all it's predecessors, as everything relevant (especially the readout pointers) was clocking at audiorate, vastly improving the sound quality and making it really usable in a recording situation. However, getting the required tracking precision meant using a klutzy affair which eat alot of DSP and reduced the grain count to only two grains. And not enough, I discovered when analyzing the older versions that I had made a thought mistake with the crossfading, so even those,although calculating 4 grains, actually still only produced two audible ones simultaneously. I am sorry.

The problem with precision pitch tracking is that the base frequency of the moving readouts is ~0.27 Hz. Doing this the DIY way was very tiresome and DSP-costly. In the old versions, I used sawtooth LFOs for this, as they have perfect keyboard tracking at these low rates. However, they clock at control rate and degrade the sound quality.

My new idea was that since these sawtooth LFOs have a continuous linear rise (or fall), one can upsample them to audiorate via 4-point averaging linear interpolation. So LFOs can do the job again, making everything so much easier and freeing up considerable amount of DSP. Which gets us: FOUR grains. For the first time. So this patch has the same audio quality as PolyGranuSyn X, but with a far fatter and denser sound. Four grains make a huge difference. This is the first polyphonic granular patch to have this.

The only thing that doesn't clock at audiorate anymore is the grain engine. However, I found that this doesn't affect the quality at all (except perhaps if you crank up the grain rate way above 400Hz, and even then it depends on the source audio and patch settings). And also, this new grain engine tracks 100% perfect. Also, this means that the 4-sample discontinuity glitch when resetting the readout LFOs neatly falls under the table.

The controls:
Page A1:
INPUT Source: Select one of the 4 audio inputs.
INPUT Monitor: Pre-listen the signal (compressed and EQed, see below)
SAMPLE Capture: Capture 2.7 seconds of audio.
Page A2:
INPUT LIMITER (parameters): Compress/limit the incoming audio.
Page A3:
INPUT EQ (parameters): 3-band EQ for the incoming signal.

Page B1:
SAMPLE Speed: Playback speed of the audio sample (independent of sample pitch). Assigned to the pitch stick. +64 is precisely original speed, 0 is freeze, -64 is precise original speed reversed.
SAMPLE Pos: Starting point and manually scrubbable sample playback position. Assigned to the mod wheel.
SPEED KBT: Toggles keyboard tracking on the sample playback speed.
POS jitter: Amount of grain playback position jitter.
SAMPLE KBTrig: Toggle on/off starting point retriggering when playing a key.
Page B2:
PITCH Coarse, Fine: Adjust sample pitch (independent of speed).
PITCH KBT: Toggles keyboard tracking of sample pitch.
PITCH Jitter: Amount of grain pitch jitter.
TUNING TOOL: A tuning tool to tune the patch to standard pitch. When activated, the FX are overridden.
Page B3:
GRAINS Rate: Base grain frequency.
GRAINS Fine: Fine-tune the rate (eg. when grain rate is in the audio spectrum)
GRAINS KBT:Toggle keyboard tracking of grain rate (eg. when grain rate is in the audio spectrum)
Overlap: Adjust amount of grain overlap. (a morph group is used for this)
DOUBLE: Toggles between 2-grain and 4-grain operation.

Page C1:
VOLUME envelope

Page E1:
VA Out: Pad settings for voice output level. (In case of overloads)
FX In: Pad settings for FX area input level. (ditto)
FX INPUT EQ (parameters): Pre-FX equalization.
Page E2:
DELAY Time, FB
DELAY Damping: Morph between allpass and lowpass filtering.
DAMPING Freq: Damping cutoff frequency.
MOD Rate, Amount: Delay line modulation. (for chorusing effect)
STEREO Spread: Morph between pingpong and mono operation.
DELAY Dry/Wet
Page E3:
Reverb + output section.

Playback speed is assigned to the pitch stick, so you can conveniently cruise through the sample (which is a lot of fun). Therefore, the various KBT functionalities to not respond to pitch stick movements. If you want this, simply assign pitch stick morph to the desired parameter.
Playback position is assigned to the modwheel, for scrubbing over it.
There are different flavors possible. Eg. by deactivating double mode and setting overlap to zero, you get that glitchy electronic sound. (Variation 5 shows this). Larger grain size with max overlap, four grains, and subtle pitch jitter give a wonderful thick chorusy sound. Lot's of room for experimentation.

As usual, 7 voices from expanded G2s.

This patch uses all interslot busses.

I'm not at home so I can't make a demo mp3. However, all variations are populated. Just capture some audio and step through them to get an idea of what this patch can do. Fool around with the pitch stick and modwheel. Twist the knobs. In short: Have fun.

cheers,
tim

UPDATE September 15 2012: This design is obsolete as it has been superseded. Please go here:
http://www.electro-music.com/forum/topic-55004.html

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PolyGranSynXL_TK.pch2
Description:	Yet another improvement. Perfect keyboard-tracking and FOUR grains.	Download (listen)
Filename:	PolyGranSynXL_TK.pch2
Filesize:	8.63 KB
Downloaded:	2324 Time(s)

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[iPassenger]

Nice one Tim, sounds fab or at least I assume it will based on your description.

[drapdap]

way cool!

btw. Tim, you mentioned maybe you'll write a "book" on low level patching,
i'm totally eager to hear anything about it, i love to read your adventures, and i love these patches, but sometimes i'd love to understand them too, as most of it is totally above my head. ok, i can use them, so thanks a million, but i'd love to read you and learn.


róbert

[grimley]

The most amazing sounds I have heard in ages are coming out of my monitors right now and I can't believe the G2 is producing them. VSynth might be officially retired.
Playing some random old 70's vinyl into this patch and the results are stunning. Single guitar notes transformed into monstrous soundscapes, female whispers turned into beautiful shimmering pads ... possibilities seem endless.
Tim you are a genius. Thanks!!
-grimley

[Tim Kleinert]

Great to hear you guys are enjoying this.

Re: the "low level" tutorial: Yes, it's true that I started working on it some time ago. I only have 2 chapters semi-finished (accumulators and DIY oscillators) up to now. I vastly underestimated the work it takes.

I'd love to share my tricks with all of you and see what crazy stuff you come up with. Also because I probably won't stay with the G2 platform for that much longer and I'd like to leave this as a sort of goodbye present to the wonderful community I have been part of for so long. But I can't promise anything.

Other idea would be to finalize at least these 2 first chapters and put them up here, to see if it makes any sense at all. And then add along as time permits. I've been thinking about this just before. But even these two chapters still need some work -patch graphics and further tweaks.

The problem is also that this low-level field has become quite vast and I still discover new ways of doing weird things all the time. It would probably be an endless journey...

cheers,
tim

[jksuperstar]

A Wiki format is a perfect form for continuous updating

[modulator_esp]

I finally got this patch today and have to say it is extremely fine

many thanks for sharing