In the previous tutorial we saw how to record simple patterns on the Volca Sample. This tutorial is a rundown of the controls you can use to modify the sound of each of your samples. This text is a more verbose explanation of the video tutorial I published on YouTube in September 2015.
There are four “places” you can use to modify each sample: the Sample Editing Matrix; the [REVERSE] and [REVERB] menus, and the LOOP on/off switch.
The Sample Editing Matrix
The Sample Editing Matrix is the grey area at the centre of the front panel (labelled STEP PROGRAMMABLE PARAMETERS) shown in the Figure bellow. It is composed by a rotary encodes (SAMPLE) and 11 knobs. Each knob has a little notch which is barely useful as an indicator of the parameter’s value. Fortunately, moving each knob shows the codified value (from 0 to 127 or -63 to +63) for that parameter in the display, and recording these values is actually a better way to save a configuration rather than noting the position of each knob.
The Sample Editing Matrix always acts on the selected part, and not as a global setting. In both Live and Step modes, the active part is indicated by a lighten LED on the lower row of LEDs in the keypad.
The first line allows you to edit general settings for each sample:
- SAMPLE when touched, the display will show “S.XXX”, where XXX is the sample number, then moving it will change the sample. The Volca Sample can store up to 100 samples (numbered from 0 to 99) and a total of 4Mb of audio, which can be rather limiting.
- START POINT lets you change the beginning of sample playback. Think of each sample as a line of text. When a sample in triggered, the Volca will start reading that line. With this knob you can choose if this line is going to be read from the first character onward, or from the second character, or start at the middle, or even if only the last character is to be read. This value is stored between 0 (start of the sample) and 127 (end of the sample) and is an approximate percentage of the sample length, where 127 corresponds to 90%.
- LENGTH lets you change how much of the sample is going to be read, as a percentage of the sample time (after discounting any effect from START POINT). Used in combination with START POINT, this can be used to focus your sample on a particular feature, remove transients (or isolate them). Additionally, setting LENGTH very close to zero and using LOOP will transform your Volca into a granular synth, which opens new creative possibilities (see bellow and/or the video).
- HI CUT controls the cutoff frequency of a simple non-resonant low pass filter. The -3dB cutoff frequency appears to be set at 20 kHz or 18 kHz when it’s fully open (127) and at the low end of the audible spectrum (about 100 Hz or less) when it’s fully closed (0). To see more on the characteristics of this filter, head over to this blog post of mine.
The second row is dedicated to controlling the pitch of the sample, this is always accomplished by changing the playback speed, so increasing the pitch decreases playback duration, and vice-versa:
- SPEED allows you to set the pitch of the sample. This is set from -63 to 63, with a notch at 0. There are a number of interesting values you may to take notice: 2 corresponds to a half-tone interval, 18 will increase the pitch to a fifth, 31 corresponds to double speed (it will sound one octave higher), and 49 corresponds to increasing the playback speed 4 times, giving a pitch 2 octaves higher than the original. The same correspondence holds for negative values, lowering the pitch by the same amounts.
- [FUNC]+SPEED also allows you to set the pitch of the sample, but by pressing the [FUNC] button is going to display the pitch shift in notes (semitones). One trick I use is to have 3 or 4 parts with the same sample, but change this setting, so that I can play simple melodic lines.
- EG INT allows you to set the intensity of the pitch envelope. This setting varies from -63 to +63, allowing the use of negative envelopes. This value can be regarded as the maximum amplitude of the pitch envelope. Using this knob with the filter attack set to 0 and decay set to 127 is equivalent to using the SPEED knob (but allows you to add motion to the pitch at a latter stage). When EG INT is set at 0, changing the following two knobs won’t have any effect on the sample’s playback.
- ATTACK controls the attack time of the pitch envelope. When set at 0, the pitch envelope will start at its peak value (set by EG INT). At 127, the pitch envelop will take approximately 0.7 to 0.9 seconds to reach its peak value.
- DECAY controls the decay time of the pitch envelope. At 127 I could not find the envelope’s tail, so it acts essentially as a sustain (the envelope will keep it’s peak value after the attack transient). A value of 80 appears to put the decay transient to somewhat bellow 1 second. At 60, the decay appears to last about 0.4 s, while at 40, it will last about 0.2 s. It gives a very fast decay when set bellow 20, which is difficult to measure.
The third row of the Sample Editing Matrix controls the amplitude of each sample.
- LEVEL controls the output lever for each part. This is useful when your original samples are set at different volumes. It can also be used to make transitions, adding and removing parts in a pattern.
- PAN positions the sample in the stereo horizon. It varies from L63 to R63 with a notch at 0 (centre).
- ATTACK sets the attack time of the amplitude envelope. At its maximum value (127) the amplitude attack lasts for about 0.9 s.
- DECAY sets the decay time of the amplitude. At its maximum value (127) the decay lasts for about 10 s, making it almost a sustain. The decay time decreases rapidly when turning the knob to the left. At a value of 100, the decay time is just bellow 3 s; and lasts about 1 s at 80.
The Reverse Menu
The revers menu can be accessed by pressing [FUNC]+[PART<], you’ll have to keep the [PART <]/[REVERSE] button pressed to be in this menu. You can select which part is going to be played in reverse. when in the Reverse Menu, the parts for which the upper LEDs are on will be reversed (played from end to the beginning).
The START POINT and LENGTH knobs take precedence in the signal path, so the Volca will only reverse the section of the sample that is selected for playing. This means the same sample region selected to play in the original direction will be played when that part is reversed.
The Reverb Menu
The Volca Sample allows you to add a reverb as an insert effect for each part. This is nice, because you usually don’t want to add reverb to every part playing. However, the amount of reverb (the Dry/Wet mix) is set universally for all parts using the REVERB MIX knob.
The reverb menu can be accessed using the [FUNC]+[PART >] combination. As with the Reverse Menu, you have to keep the [PART >]/[REVERB] button pressed. When this menu is active, the parts affected by the reverb processor will show their upper-row LED lit, and you cans select them on or off by hitting their corresponding pad.
Looping Samples and Granular Synthesis
The LOOP ON/OFF switch is found at the 11th pad of the keypad, and can be modified using the [FUNC] button. It affects only the selected part, which can be set to loop (LED lit) or play one one time (LED off).
Granular synthesis is a basic sound synthesis method that operates on very small time scales. By setting LENGTH very close to 0, your sample duration can be in the mili- or micro-second range. Then, by activating LOOP you can generate a new waveshape, which would be equivalent to an oscillator in a subtractive synth. The filter can be used to attenuate some of the high frequencies, and the pitch and amplitude facilities can also be used to shape new sounds, as exemplified at the end of the video.
In the next tutorial, we’ll see how we can add movement using the settings on the Sample Editing Matrix and Volca’s ability to record automation.