# 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!