How do you guys chose the BPM and speed to work at when making a song?
If you want kinda slow-romantic song you choose 80. If you want fast uptempo then you go for 180. If you want midtempo radiohit you choose 120. If you want speedcore you go to 220. If you want funeral Doom you go for 40. This is when you are at speed 6.
Speed 3 is twice faster. 40@6 == 80@3. Speed 12 is twice slower 80@12 = 40@6. But adding more speed gives you more granularity for effects. If you are a beginner don’t touch the speed and set the tempo whatever sounds good for you. 
As Suva explained:when you just getting started, you don’t need to adjust the speed setting perse.
Basically said:
If you want to affect certain triggers on notes at moments that fall in between two rows (for instance row 01 and 02) you set the speed to the amount of points that you want to have a triggerpoint (e.g. stopping or starting a note at that moment instead of starting at the row or ending at the next row)). So if you would like to slice the time between row 01 and row 02 into 6 equal offset points, you set speed to 6.
If you want to have 12 equal points, you set the speed to 12.
And if you play around with these settings you will also notice the scrollspeed of the pattern will be affected as well.
Cheers for the replys, guys!
This is the main thing that bothers me! If I’m composing at a slower BPM, I find I don’t have enough lines for all the notes I wanna be sticking in there – ie if I want an offbeat 16th or a 32nd etc. So I tried changing the speed and then I got odd divisions and I got a bit scared 
When I compose stuff normally, I’m around 96-120bpm. Depends on who I’m playing with/what we’re playing.
Do you guys just choose a roughly correctly tempo/speed then work to it, changing it later when it gets in the way? Or are you all so experienced that you know exactly what you want? (Much in the same way that when I’m tabbing something out in guitar pro I pretty much nail the bpm on my first go. I’m a good guess for these sorts of things!)
If you set the speed to 1, each row is the same as one tick. You could call this a sort of pattern-zoom to the lowest level and the pattern will scroll at godspeed to say so
You have the advantage to see every note and control every note on each beat. You also don’t need to use delay or cut commands as they won’t affect at that speed. Disadvantage is the retrigger effect won’t be doing things for you as you are on the highest speed and if you for instance would like to emulate a guitar strum, you have to put each other string “stroke” on new row which makes it cumbersome to stroke a chord on the same line.
A guitar stroke with speed 6 could be emulated by adding five or 6 notes on the same row and using delay effects to have each snare hit a moment later. I usually play with delay values of 1 and 2 and have two strings being hit at the “same” time.
This method allows you to copy the whole line to the clipboard and paste it to other places allowing you only to change a few notes here and there to change the chord.
If your speed is 1 your overview regarding chords is less obvious and you have to use the cursor-keys more often to change the cursor position whereas on the same line is just a matter of tabbing from one column to the other and making the change.
Just a few examples to give you an idea of how speed works and how you can use it to your advantage.
as well, don’t forget that the tempo/speed can be automated with F0/1 in the effect column so it doesn’t have to be set to one thing the whole time.
wow kaneel… you are soooo 2007…
4 000 bpm, speed 1. that’s the spirit!
No, that’s just plain impossible in Renoise, unless an external master gets Renoise that mad to change this bpm rate.
(i’ve seen one report so far regarding that)