Hi,
I’ve read in another thread that all is needed for a sub bassline is a sine wave and that’s ok. But is it really true that the sine.xrni instrument present in Renoise is ok for the purpose? Aren’t there looping problems? I mean: if a note is triggered when the sine wave has not completed its cycle there might be some click. Am I wrong? Not that I have really experienced this, I’m just asking.
And generally at what octave should be played a note for a sub bass?
If you are making sub bass separate from bass line - play it around g1, in minor scale 
To avoid clicks you can set some attack on volume - in instrument prefs…
lollllllzz…it indeed it veryyyyyyyy true…u read that info from me. I think if u listen to my tracks u will notice no clicks!
I only use renoise .xrni for sub bass…sub portions of bass are only sine waves no matter where u get them from, be it a saw, sq, organic sample etc.
If for whatever reason u end up using another source for a sub, ie a vst synth…the octaves aren’t always listed correctly.
In this case, use a frequency analyser and make sure the note is peaking between 35-100hz, this is the basic sub-bass range.
Mh, why g? And why minor?
Good, thanks.
It doesn’t need to be a G note, and it doesn’t need to be in Minor scale. I think bluszcz is simply saying that something around a G-1 note will be a good place to start.
This frequency chart should help you:
http://www.independentrecording.net/irn/resources/freqchart/main_display.htm
“G” is always good place to start… G-spot - Wikipedia
But sub bass notes should somehow fit your melody, right? 
So don’t take “g1” so direct
And minor - to make it dark 
I think he was being sarcastic.
Generally one or two octaves below you bassline melody note would be a good starting point. Maybe some other musical interval but simple octave work well for sub bass.
watch the kick drum frequency space and headroom