7 String Bass Sets?

My only guess would be Kalium.

 

Any specific type of strings you're after? Are we talking F#-B-E-A-D-G-C?

 

Add a single low F sharp to any six string set

 

Yes a 6 set plus a single F# will give you more choice, many manufacturers have F# now (D'Addario, Rotosound, Warwick, Pyramid), and with Kalium you would have to mail order anyway. There's also Conklin Guitars Snakeskins Extended-Range Bass Strings

 

That's what most people do. Add a single, either low or high, to an available 6 set.

 

For the B-C players...

I very rarely change the upper 2 strings.. just sand them.

 

I haven't changed much string sets on my 7. Pretty much like others have said, I use 6 string set and add the 7th. I bought a few .020 high F and .175 low F# strings. So, I pair which ever I want to use.