Why do flamenco guitar players use different tensions (gauges) for the bass and treble strings, "colored" treble strings, and a "special" 3rd string?

Question

Looking close to flamenco strings sets, I've noticed that they use different tensions for the bass and treble strings. The bass strings are higher tension than the treble strings. Bass strings are high tension while treble strings are normal tension, or bass strings are extra-high tension while treble strings are high tension.

Also, the treble strings tend to be colored (black nylon, red nylon), and the 3rd string tends to be different than the other treble strings (flurocarbon 3rd vs normal nylon 1st and 2nd, for example).

Examples:

• Daddario EJ25B flamenco custom tension
• Savarez T50 Tomatito
• La Bella 2001 flamenco and 820 elite

Why this variance in the string set? How does it affect tone and technique? Why is this configuration preferred in a flamenco setting? How do flamenco guitar players take advantage of different tensions, different 3rd string, and colored trebles?

Answer 1

Flamenco requires very crisp response for fast, powerful melodic play even in the bass register (as well as for parts that would in other styles be played on specialised bass instruments). That requires high-tension bass strings: lower tension strings would clatter a lot against the frets, which would obscure the actual notes played.

On the other hand, for the treble strings such clatter is (unlike in classical guitar) not only acceptable but even sought for, it adds to the percussive nature of flamenco playing. So there's no need to go to very high tension on the treble strings, that would just make the fast playing even more exhausting because you need to put more force in.

We can also look at it the other way around: standard classical guitar strings make the treble strings higher tension than the bass strings, so that you can produce thick, sweet melodies in the high register without spending too much work on the accompaniment parts that you simultaneously play on the bass strings. (In a classical string set, the high E has ≈ 80 N tension, the low E only ≈ 60 N.) For flamenco, that logic doesn't make sense; absolutely speaking, a flamenco string set actually has more even tension ≈ 75 N across the whole range.