Sampoly V2 and V2 loop — a polyphonic “sampler” synth

V2 is a total rebuild, although it shares the same basic idea as Sampoly V1: “sample” a sound with a looper, and then play it as a chromatic instrument (up to four voices), using the samples as oscillators and applying synthesis techniques to them.

In the intervening two years since I originally made the patch, I’ve… learned a lot, hence the rebuild. Keyboard samplers have become a kind of obsession of mine, and while this patch is not quite my ASR-10, it employs some similar techniques to push “sample synthesis” into someplace very interesting.

Along the lines of the synthesis approach, each sample oscillator has a dedicated amp and filter. There is a global LFO to modulate pitch, filter frequency, and amplitude.

Along the sampling side, there is a dedicated attack/sustain/release envelope that can be looped and may be applied to the start position, length, or pitch/speed of the loops (or all three). There is also a “reverse chance” control, which allows you to set a probability that a given sample will play back forward or in reverse.

The patch comes in two forks: V2 and V2 loop. The former uses “play once” loopers; it is excellent at taking a sampled sound and creating a new chromatic instrument from it. The latter — V2 loop — uses “looping” loopers. Here, the patch becomes a playground for sound design that touches on polyrhthms, granular elements, and shifting, modulated compositions.

I may produce further forking to devote some of the computational power to each patch’s strength: sample synthesis for V2, and sound design for V2 loop.

The patch passes audio in stereo, but it only records from the left input. A stereo image is produced at the output via a stereo spread.


Recording a sample (top left corner and left stompswitch):

There are two methods of recording a sample. When “Threshold record” is off, the left stompswitch serves as a simple start/stop control for recording. A UI button in the top left corner will turn bright red when recording is occurring.

When “Threshold record” is selected, you gain access to a threshold, which can be set however you like (I generally keep it low, so that recording begins as audio reaches the input). When the threshold is exceeded, a pixel beside the threshold control will flash.

Now, pressing the left stompswitch will arm or cue threshold recording, and recording will begin as soon as the threshold is crossed. Recording ends when the left stompswitch is pressed again.

Because the patch needs a reference for what to consider a “neutral” pitch position, there is a “Note reference” control, set to C4 by default. Since many sources may not be a C4, you can reorient the keyboard so that it uses a more appropriate reference point, if you want.

Sample playback (amp controls):

There is an ADSR that can be directed to the sample. This is useful for reshaping the sampled audio (particularly the attack). The envelope can be set to linear or exponential.

When you press the “Gate amp” button, a keyboard gate will override the ADSR. Now, a sample will play as long as a key is held and stop immediately when the key is released.

When you press the “Trigger amp” button, loops will be triggered and the amp will be held open. This condition overrides the ADSR -and- the gate options. In V2, this will cause the sample to play to its natural end. In V2 loop, this will cause all four voices to be heard as loops.

Velocity can be applied to gates and triggers; you can also bypass velocity for all amp settings by using the “Amp velocity bypass” button.


The ADSR can also be directed to the filter, positively or negative, regardless of the Amp condition (it will be applied even if the amp is gated or triggered).

There is a filter frequency control. This sets the frequency of the filter; subsequent controls add or subtract from this frequency.

Resonance is… resonance. A little goes a long way. At more extreme settings, it can add quite a lot of gain; you are warned.

Keytracking tracks the filter to the pitch of the key played. This can be a bit misleading, as the sample may not correspond to the keyboard note. Uh.. you are warned again.

“Tape” effects:

Tape Age is noise modulation of the looper speed. At low levels it adds harmonics, distortion, a bit of vibrato; as it is increased it becomes more destructive.

Warble rate and depth control a dedicated pitch modulation, modeled on tape warble. I set the controls to have extreme settings, but very moderate ones produce the best results (if the result you want is tape warble).

Modulation ASR envelope:

There is an attack-sustain-release envelope that can be used to modulate the loop start position, length, and pitch.

This envelope can be looped, or the looping can be bypassed with the “Loop bypass” button.

This envelope can be retriggered, or the retriggering can be bypassed with the “Retrigger bypass” button (this essentially turns the envelope into a free-running LFO).


There is an LFO located on the front page, so you can adjust its rate, shape, and range as you please.

It can be directed — positively or negatively — to the pitch, filter, and amp.

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  • Category: Sampler Synthesizer
  • Revision: V2
  • License: Creative Commons Attribution Share Alike 4.0
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  • Modified: 1 month ago
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