Which strings should I use and why there are so many kinds and tensions ranges?
Every guitar differs in its tension. Even from basses to trebles sometimes these differences may be there in the very same guitar.
It also depends on the players personal taste. For example, if a specific guitar is a high tension one by nature and the player has not much strength playing (pulsación), or, if he prefers a softer touch, then it may be a good idea to have -on that specific guitar- some low tension strings. This depends on the season and on humidity factors of the environment as well.
This applies from simple principles to “picky” ones like the following one:
If one plays with a female guitar that has not much high action (I mean distance from the 12 fret to the string itself ) and if you are supposed to play for a recording in a recording studio in full summer here in Malaga, and that room where you will play has the cold air conditioning system on, then you can use high tension basses for that particular female guitar provided you will use the capo –say- at 4th fret for the recording of a particular track.
As you see there is a lot of fancy stuff on this strings topic. I learned all this personally from Paco as well as from my own experience (after being “The Best Client Ever” to each and every brand of strings for 30 years so far).
Those different tensions, brands and materials *(Nylgut, Titanium, Carbon,Nylon, Silk, Pure Silver etc) are there for different guitars, different needs and seasons of the year. They exist to compensate or create diverse dynamics and sounds types besides the touch factor (pulsation) in such a way that there are many possibilities. Sometimes seasons also affects the guitars touch or pulsación; for example for some male guitars I high tension strings in summer and mid tension in the winter.
To be continued…