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Sampler

Overview

The Sampler (sample player) allows playing 16-bit WAV files directly off the SD card.

Patches are contained within sub-directories underneath the samples directory on the SD card. Their name is the directory name. Much like Wave-mode, each patch contains 16 (0xF in hexadecimal) samples which can be flipped through via the CV input. Each sample is an 16-bit mono WAV.

While the WAV files are 16-bit, the maximum resolution of the Sampler is limited by the DAC which is 12-bit. Smaller resolutions, down to even 1-bit, can be specified per sample. To simulate the GameBoy/LSDJ wave output, one would use 4-bit coupled with a low sampling rate of the WAV itself.

Version of the firmware prior to 0.58 has a 64k limit to WAV samples. This has since been lifted as the samples are now directly streamed off the SD card.

Sampler UI

The Sampler is available via the Main Menu. Once selected, the list of available patches comes up and can be scrolled through using the left encoder. The highlighted patch is loaded automatically and can be immediately used.

Pressing the right encoder opens up the sampler edit menu.

Sampler Inputs

The Sampler just needs a single input, the Gate. All the other inputs are optional, but potentially useful. This is one reason for the Rate Multiplier option for the sampler as it doesn't need a V/Oct input to function.

The gate triggers the sample and it will remain on until the end of the sample; or if a looping mode is selected will loop at the specified loop points until the gate turns off.

At present there is no ring-out when the gate goes low and looping, but that is a planned feature.

The CV input selects a sample which can be useful for, say, drums, where you want to switch between a kick, hi-hats, snare, etc.

Sampler Edit Menu

The edit menu shows a number of details about the current selected sample of the patch. Not that while in the menu, CV is not evaluated and you must instead pick which sample you want to work on. This is also convenient when just sending a single trigger to the module as you can pick which sample you want to play when the trigger fires.

Patch Name

<Sample Number>:<Sample Name>
Bitrate: <X-Bits>
Rate Mult: <#>
Skips: <#>
Loop Mode: <O|F|P>
Start: <#>
End: <#>

The left knob selects the settings which the right knob can change:

  • Selecting the Sample Number / Name and rotating the right knob changes the current selected sample
  • Bittrate selects the bitrate from 12 to 1.
  • Rate Mult (Multiplier) is a sort of coarse tune on the sample. The value is multiplied together with the pitch
  • Skips is a simple sample-rate downsampler. Every 1/nth sample is skipped. So 1/1 means no skips, 1/2 means every other, 1/3 means every third, etc.
  • Loop Mode currently is O (One-Shot) or F (Forward) but Ping-Pong is planned for the future.
  • (Loop) Start: The position within the sample to start the loop. The faster you turn the knob, the faster the value goes.
  • (Loop) End: The position within the sample to end the loop. The faster you turn the knob, the faster the value goes.

For the loop start/end, turning the right knob faster increases the values faster as a means to do coarse vs fine adjustments.

Pressing the right knob saves the sample settings to the SD card.

Patch Details

Each patch lives in a sub-directory under the samples directory on the SD card. The name of the patch is the name of the directory. Within the patch directory there are two sets of 16-files:

  • [0-9,a-f].txt: Contains metadata for each sample within the patch
  • [0-9,a-f].wav: A 16-bit mono WAV file

As of firmware 0.58, the wave files are streamed off the SD card meaning they can be very long. Waves of 4 minutes have been tested, but longer ones may work as well. Prior to 0.58, only the first 64k of the wave would be loaded.

Patch metadata file (x.txt)

This is a simple text file which contains additional information for each sample. Each sample block is as follows:

Name:Sample Name (Up to 16 characters)
Bits:Number of bits between 12 and 1
Multiplier:Sample Rate Multiplier
Loop Mode:(One of O, F)
Loop Start:#
Loop End: #
Skips: #

For example:

Strings
8
128
F
4471
27474
1

At present all the values, except the name of the sample, can be changed via the UI and saved.

Future Plans

These are not guaranteed but some ideas being considered

  • Ping-Pong Loop Mode
  • Release / Ring-Out mode for looped samples
  • Option to use internal VCA or set the sample volume (digitally)
  • Option to view the waveform for setting loop points