I tried Savarez high tension strings on my guitar a while ago, and was rather pleased with them. However, I feel like strings are something I know nothing about, and so thought I might try out a couple of others on my guitar. I've put some D'Addario normal tension on it last night. Now, I know that it doesn't sound as good to me - but I'm not quite sure why. The strings feel chunkier somehow, and looser to the touch.

What is the difference between high and normal tension strings?

Also, the Savarez ones I had were 'cristal strings' and the 'alliance' type (blue card), as opposed to the traditional ones - does anyone know what the difference is between those?

High tension strings are put under a greater force to acheive the same note, for example with the low E string made by D'Addario;

EJ44 Extra hard tension
the string guage is 0.029" at a tension of 16.4 lbs

EJ46 Hard tension
the string guage is 0.0285" at a tension of 15.8 lbs

The idea is meant to be that the harder tension strings produce more resonant notes. I have found that putting good strings and a bone bridge on a mid range student instrument will improve it and make it sound like it should be twice it's actual value.

I did some pseudo-scientific testing of D'Addario Normal (E45) vs High Tension (E46) strings. I normally used high tension strings but restrung with normal tension on the principle that they should be a little easier to play. After a couple of days of playing in, I convinced myself they sounded "flabby" (whatever that may mean). So I changed three of the strings so that I had two from each set i.e. 2 bottom Es, 2 Ds, and 2 Bs. It made for some interesting chords.

Then I enlisted my wife (a pianist) and compared the sound. Neither of us could hear any difference whatsoever. Maybe the E45s were a little easier to play but who can tell with that combination of strings.

Prejudice being what it is, I decided I didn't like normal tension anyway so reverted to HT Ramirez strings.

In theory normal tension should be a bit easier to play (press down) but more liable to buzz (I think that bit may actually have been true). I've heard that very high tension strings can start to warp a classical guitar because the neck isn't reinforced.

Hope this helps.