I have an old nylon strung resonator banjo probably about 80/90 years old which I play clawhammer The resonater is just a piece of plywood pinned onto the rim. I have it tuned in double C tuning and to me the mellow sound is great. I thought it would be good to have the steel strung Ozark 2109 I have with the same sort of mellow sound. It was in standard tuning D B G D G so I tuned it a whole tone lower across all of the strings so it is now tuned C A F C F and sounds novel. As I have no plans to play in a band anytime soon as I am 83 I understand that the tuning would not work however I guess there must be other people who have played around. Any comments or information regarding lowering the tone would be appreciated. I notice it is easier for me to sing (?) along
I have recently been keeping one of my banjos tuned to Open F like John Hartford liked to do. Sure like the low end for a different sound, although I play it 3 finger Scruggs style. Like you, it would match my efforts at singing. I just grab it once in awhile when practicing for a different tone. Often think of getting a long neck and tuning down to open D but really don't want to drag two banjos around.
When I play with others jamming and as a small group at nursing homes, etc. I just stay in standard G tuning. The people I play with would not have a problem playing in F tuning, but don't really sing in F much.
If you go much lower strings get a bit floppy sometimes. I tune low for singing reasons too. So I'll go down by 1.5 tones max, so down to open e (equivalent to standard gDGBD) and will sometimes tune double c equivalent down at B flat or even A. With double c the 4th string is lower, so in A my 4th string get a bit floppy, but double B flat is fine. I use medium heavy steel strings. And have nylgut red series tuned low on my antique banjos. Playing alone means do whatever you feel like!
Because I'm currently taking some online classes, my banjo is tuned up to "standard" pitch (gDGBD) - its just easier to follow along, but normally, its down to open E (eBEG#B). I like to sing the old tunes. I've only once played with someone else, so it doesn't really matter where its tuned when you're alone.
If you are learning songs off pre-recorded music, e.g. CD's or Youtube, or downloaded BHO tunes, you can adjust the song's key (and thus the tuning you use) with computer programs such as free (donation accepted) Audacity. I used it all the time; I can slow tunes w/o changing the pitch, change pitch w/o changing the speed (tempo) or do both at the same time (which is my usual method for learning).
I keep my kit-built mountain banjo tuned down 5 semitones from standard pitch. This is to keep from bending the neck, which has no adjustable (or in fact any) neck rod. Noah Cline down-tunes some of his gourd banjos 5 semitones, and if he does it, then that's good enuf for me :-) I built the banjo from a kit by Brian Carver - easy build, and banjo sounds very nice.
There are a bunch of good reasons for tuning someplace other than normal. Some instruments just sound better at a lower (or higher) pitch than "normal." Also, when playing with others, playing out of a different tuning, but in the same key, with a capo, can add a lot to the mix.
I have a banjo that I tune three frets low--rather than double C, it is in double A. I buy individual string from Elderly Instruments for it. They are one notch thicker than GHS medium strings. Any thinner strings don't give good tone.