bass guitar tuning D A D G vs D G C F

i see some songs use one and some others

when would you use each one?

 

The first tuning is what many people call a drop D tuning.
The second tuning is one many bassists use when they have Hipshot tuners on a standard E,A,D,G tuning.
There are a similar two sets of 5-string tunings:
A,D,G,C,F and D,G,C,F,Bb for a soloist oriented player... generally both too with Hipshot tuners.

You can tune it any way you like. The notes remain the same, only where they lay on the fretboard changes.
Check out some of Michael Manring's tunings.

 

So the "traditional" tuning is EADG.

DADG is so called "drop" tuning. Guitarists sometimes use drop tunings to make playing fast powerchords on the lower strings really easy. You can just use one finger. Sometimes for other reasons. If you are playing "guitar music" and this is the tuning the guitarists use, it may make sense for the bass player to use this tuning too.

I'm not really a bass player, but I sometimes play bass guitar. I'm not really into drop tunings either, especially on bass guitar, but if a song happens to be in D I often use this tuning so I can reach the low D note. Takes few seconds to tune just one string.

DGCF is just tuning a bass guitar to "D". Use it if you want to tune your bass guitar to D.

 

Check out the Hipshot tuners. They mean that on each string you can with the newer ones, have two different tuning drops for each string.
So you can theoretically tune your E,A,D,G strings to drop to a D, or a ,C or a B or an A etc etc... read up on it.

https://hipshotproducts.com/collections/bass-xtenders

 

There is no hard and fast rule here, either is fine, just use what is most comfortable for you.
Technically you could play any song in DGCF tuning with DADG, as you're just dropping the low E down a full step to a D so you could cover any of the possible notes within DGCF. You could also play 99.99% of songs in a DADG tuning in DGCF - the only notes you'd be missing would be the highest F# and G (assuming your fretboard has 24 frets and the bass part goes that high).
Upside to DADG is you only have to adjust one string so it's quicker to get to from standard tuning. Downside is there is a small learning curve i.e. learning the new relationships between strings, adjust scales, etc, as with most alternate tunings. If you were reading from a transcription in DGCF and playing in DADG tuning you'd have to mentally transpose the notes on the GCF strings down a whole step (assuming that you're reading something static and not from something like GuitarPro that could transpose it for you).
Tuning everthing down the whole step would mean all your licks, riffs and runs would fall under you fingers in the same way as standard tuning, they'd just be a whole step lower than standard tuning.

 

I like the way my fretless sounds with fine gauge strings for ADGC, but tuned EADG.
Naturally the attack slows down and the sustain increases.

 

I use DADA, tuning up the 1st string to A.

 

If I need to tune down, I go with drop-D (DADG) in a pinch. It's ok for occasional use, whereas tuning all strings down a step needs different gauge strings and it's a more long term setup.