Oscillators
Oscillators are continuously varying patterns. Unless otherwise stated, oscillators give minimum values of 0 and maximum values of 1, and repeat once per cycle.
What is an oscillator?
Oscillators are continuous patterns, which means they don't have any structure, and must be used with a pattern that does. For example d1 $ sound "bd*8" >| pan sine won't work well, because the >| operator instructs Tidal to take structure from the right, and sine doesn't have any structure, so Tidal will simply trigger events at a fixed rate (depending on your configuration, this might be very fast). d1 $ sound "bd*8" |> pan sine is better, because |> takes structure from the left, so eight kick drums will play, with pan values sampled from the sine wave for each of the eight events. Where a pattern has the type Fractional a => Pattern a, that means that they can be used both as floating point numbers or (rational) time values.
Using oscillators
Periodic oscillators
Sine
Type: sine :: Fractional a => Pattern a
sine is a sinusoidal wave. Playing this example, you should hear the sound slowly moving from your left to your right speaker:
d1 $ sound "bd*8" # pan sine
Cosine
Type: cosine :: Fractional a => Pattern a
A cosine wave, is a sine shifted in time by a quarter of a cycle. It sounds similar to the sine above:
d1 $ sound "bd*8" # pan cosine # speed (sine + 0.5)
Square
Type: square :: Fractional a => Pattern a
A Square wave, starting at 0, then going up to 1 halfway through a cycle.
d1 $ sound "bd*8" # pan (cat [square, sine])
Tri
Type: tri :: Fractional a => Pattern a
A triangle wave, starting at 0, then linearly rising to 1 halfway through a cycle, then down again:
d1 $ sound "bd*16" # speed (slow 2 $ range 0.5 2 tri)
Saw
Type: saw :: Fractional a => Pattern a
A sawtooth wave starting at 0, then linearly rising to 1 over one cycle, then jumping back to 0:
d1 $ sound "bd*8" # pan (slow 2 saw)
Isaw
Type: isaw :: Fractional a => Pattern a
An inverted sawtooth, starting at 1, then linearly falling to 0 over one cycle, then jumping back to 1:
d1 $ sound "bd*8" # pan (slow 2 isaw)
Smooth
Type: smooth :: Fractional a => Pattern a -> Pattern a
Smooth receives a pattern of numbers and linearly goes from one to the next, passing through all of them. As time is cycle-based, after reaching the last number in the pattern, it will smoothly go to the first one again.
d1 $ sound "bd*4" # pan (slow 4 $ smooth "0 1 0.5 1")
Note how the sound goes gradually from left to right, then to the center, then to the right again, and finally comes back to the left.
Non-periodic oscillators
Rand
Type: rand :: Fractional a => Pattern a
An infinitely detailed stream of (pseudo-)random numbers. See the rand reference page for more details.
d1 $ sound "bd*8" # pan rand
Irand
Type: irand :: Num a => Pattern Int -> Pattern a
A function from an integer (giving the maximum) to a stream of (pseudo-)random integer numbers. For more details, head to the rand reference page:
d1 $ sound "drum*8" # n (irand 8)
Scaling oscillators
By default, the oscillators will output values scaled between 0 and 1. You might want to use bigger or smaller values. You might want, for instance, to modulate the frequency of a filter or select a random midi note between 0 and 127. To do so, you can use the range function:
d1 $ s "bass:5*8" # lpf (range 200 5000 $ sine)
Speeding up/down oscillators
Oscillators are patterns! It means that you can speed them up or down using the same function as usual (fast, slow, etc..):
d1 $ s "bass:5*8" # lpf (slow 4 $ range 200 5000 $ sine)
Notice that most of the time, the speed up/down will be in sync with your pattern. How convenient!