Nearly every guitar forum has topics on string tension from time to time. Anytime this topic comes up, the primary focus always seems to be on calculating tension based on scale length, string gauge, and tuning. While those things are very important in determining how strings feel, PERCEIVED string tension is also extremely important...and often completely overlooked. In this thread, the focus will be on BOTH measurable and perceived tensions and how they relate to string feel.
Before diving in, I want to say that I am not anybody special. Just an average Joe guitar player who is very interested in this topic and has studied it for over 10 years.
PLEASE NOTE: whenever an example is given, it is given with the qualifier that ALL ELSE IS CONSTANT.
On to the discussion...
First of all, we'll look at measurable string tension. This will be a quick review because this information has been rehashed over and over in multiple threads on multiple forums.
Three (and only three) things affect measurable string tension:
1. String mass: Notice I didn't say string gauge. While gauge is a factor, what matters is the unit mass of a string because unit mass can vary greatly between different brands/models of strings of the same gauge. The higher the mass, the higher the tension. The lower the mass, the lower the tension. For example, flatwound strings will generally have higher tension than roundwound strings because the flatwound strings have higher unit mass. To further clarify, a .050" flatwound string will have more measurable tension than a .050" roundwound string.
2. Pitch: This is simple: the higher the pitch, the higher the measurable string tension. The lower the pitch, the lower the measurable string tension.
3. Vibrating length (scale length): The longer the vibrating length, the higher the measurable string tension for a given pitch. The shorter the vibrating length, the lower the measurable string tension for the given pitch.
Before moving on, I want to reiterate that NOTHING, I repeat NOTHING aside from those three things affect measurable string tension.