Appendix II - Why is there no such thing as Random?¶
There’s a philosophical viewpoint that "there are only patterns too complex to understand".
However, in the scientific sense and in the context of music, there are two potential issues with a random approach.
1) You are not in control. You are leaving the decision-making up to the algorithm.
2) It's not possible to repeat a truly random sequence.
Can it be called a "musical" melody if it's just an ever-changing stream of notes with no repeat?
Instead, ARP allows you to mix and match the many parameter values to create complexity and, yet, always in a repeatable pattern. Automate, Repeat, Play. That's where the name came from.
Even the FX parameter uses a repeatable, pseudo-random sequence. This was added to satisfy the demands of early customers who asked for some random for their generative compositions. ARP obliged this request with something that provided a generative feel but also met ARP's non-random rule.
But the concept goes deeper…
ARP’s Deterministic System¶
Have you ever uncovered a lovely little melody (sequence) and then pressed stop, then play, and it is doing something completely different?
This is the problem ARP solves.
ARP is fundamentally a deterministic system. One in which no randomness is involved in the development of future states of the system. It will always produce the same output from a given set of inputs.
Most sequencers do not take into account their current position in time. They simply count upwards.
Example:
Imagine 2 sequences, each with 4 steps and the following patterns: (A,B,A,B) & (C,C,D,D). If you change from sequence 1 to sequence 2, after the 3rd step, the sequence would be: -
A,B,A,C|C,D,D,C|C,D,D,C|C,D,D,C|...
(See how it plays the 1st step of sequence 2 at step 4?)
Press Stop and Play and you get
C,C,D,D|C,C,D,D|C,C,D,D|C,C,D,D|...
The pattern has changed from |C,D,D,C| to |C,C,D,D|. (Though you might only notice it if it was played in sync with something else, a metronome, kick drum, or another sequence, for example).
This is the problem that ARP resolves. ARP calculates the step (pitch, gate, timing, etc.) based on the current time (i.e. the number of clock ticks since you pressed play).
ARP ignores everything that came before, meaning it always plays the step as if the parameters had never changed since you pressed play.
So, given the same example as before, the 2nd sequence would play as if it had been playing from the start: -
A,B,A,D|C,C,D,D|C,C,D,D|C,C,D,D|...
(See how it plays the 4th step of the 2nd sequence, not the first step!! )
This is key to how ARP operates.
ARP has many, many parameters that impact the length of the sequence and the order in which notes play... if it wasn't deterministic, every time you changed a parameter you'd be moving the start point of the sequence; and constantly be finding and losing those lovely melodies.
That’s why there is No Such Thing As Random.