[plectron]

Hello :-) i‘m new here and my question is regarding writing a classic disco song. So I for now I got real old school disco drums, percussions and a 4 Chord Keys progression, but I always struggle with how to arrange a good bassline and strings, so here my questions: should I generally stick to the songs key for these? Even if in my 4 chords I do not use ththe 1st chord of th songs key? Cheers guys

[dasntn]

Hi and welcome!
For classic disco baselines you want to aim for funky riffs around the root note of the chords. Check out isolated Bernard Edwards riffs on YouTube for a master class.

And the strings tended to play variations in ascending and descending lines from the scale, rather than held chords
Cheers
Dave

[tboswell]

I’ve just done a disco song recently, at least the chorus is disco
http://www.songwriterforum.co.uk/index.php?topic=15744.0

Things I would recommend
1. Octave notes in the bass, they are quite iconic for disco. Rising or falling lines, alternating notes an octave apart.
2. Strings, active ascending and descending lines. No boring chords. Quite often a single line doubled in 2 octaves by violins. I would skip violas and cellos altogether and just have treble string stuff.

Go back and listen to chic, sister sledge etc to see how it is done.

[Boydie]

I definitely agree with what has been said

All of the answers you need are "hidden in plain sight" within the disco hits - and now we have access to isolated parts and multi-tracks via t'internet you should be able to see exactly what they did