Synthesizer oscillator intervals

[Dark Fiber]

First off I want to say that I'm still learning about scales, chords and such. At this moment I can make songs that all have a certain scale, so my melodies, bass, strings etc. don't play any notes that are not part of the song scale. While doing this I noticed that some synth presets have an oscillator interval set. for instance: osc1 set at zero, so a c is a c, and osc2 set at +5 or +7 semitones, so when playing note c an E and F# is added to the sound.

How can one play a melody in a chosen scale when oscillators have intervals like this? Playing different notes will result in quickly being out of scale.

Also, some arpeggiators are programmed with semitones. Is it supposed to only be played with a single note the whole song?

Dune 2 ARP.PNG

There surely must be a reason for these intervals, I just don't understand it yet

[askoan]

This is an interesting point. Indeed none of the integrated arpeggiators and osc tuners that i tried allow to express their parameters into a scale (which is different than constraining the input to a scale), but i think i saw Vital adressing that regarding the osc tuning. Not common though.
Not wanting to be too philosophical, but here's what i think : osc tuning is a part of the synth sound itself. Arp is a part of the playability of the synth itself.
Neither are composing tools or assistants ; this is more the role of offline tools like Orb Producer or even maybe Cubase various harmonic tools.
But i know no "live" tool for this, and i would love to hear from this, as i'd like to read other thoughts on this (other than "wot?" obviously )

Another point is it's common at least in some electronic music fields not to work on a piece in terms of one or two scales, nor having a clear melody/harmony separation (take arps for example !), but instead to focus on chord progressions, whatever the scale it fits in during some chords. Of course this can be theorized as "modulation", but when you modulate every few chords i don't know if it's relevant. I'm not talking about "experimental" music here, but entertaining, quite popular music.
I'm talking about all this because it explains how a single arp pattern can be useful in multiple roots into a same piece (by modulation)
Sorry i don't know the names of those concepts... Let the real musicians answer

[Cro-magnon]

OP,are not you satisfied with all the replies you got from Gearslutz?All the guys there summed everything about oscillator tuning pretty well...
I would note that your picture is a screenshot of a sequencer,not an arpeggiator.Given all these specific intervals,I would play it with one note or with 2 notes,one octave up/down.Or in case you want to play some chords,take care to set intervals that fit your scale,in the sequencer.