Understanding String Tension....

[donslow]

Apologies if this is posted in the wrong section, mods please feel free to move if so

 

So I’m preparing to hide under the table for asking such a noob question, buuuuutt.....Can someone explain to me what is meant by string tension?!

i read things about high tension this and low tension that And I’m struggling to work out what it all means

If I may share with you a little understanding (or misunderstanding) of mine

I use the same gauge strings (105 85 65 45) on all of my basses and all are set up to my personal preferences, on one bass for example, an sr300 the strings feel tight with little give in them when their plucked, which is something I like, where as the flats on my p bass feel a little looser when plucked.

 my understanding is this is the difference in tension but then I assumed, setting up a bass differently, higher bridge saddles for example will tighten the strings or would buying “high tension” strings make them feel tighter, I don’t really understand how this works if that’s the case as surely their always strung up the same way?!

or is string tension referring to how the strings are made or strung up on the body?!

really want to understand this a bit better than I apparently do (or don’t) at the minute so any guidance is much appreciated

Edited August 20, 2019 by donslow

[Andyjr1515]

It's a perfectly reasonable question.  My layman's answer is this.

For each given musical note, a string has to vibrate at a specific frequency. 

Regardless of what the string is made of, the tighter it is, the faster those vibrations are and the slacker it is, the more the string flaps about at a lower frequency.  So you can get a rubber band to vibrate at the same frequency (and therefore musical pitch) as a piece of string, or as a piece of wire.

The material used, and the size within each material will affect how much you need to stretch them to get the same note.  So you will have to stretch a thick rubber band differently to a thin rubber band to get the same note.  And - for the same size - you will need to stretch a silicone rubber band differently to an india rubber rubber band for the same note.

Guitar and bass strings are just the same.  It's not just the size that is different, but the metals they use, and the windings they have around them and event the shape of the windings.  And everyone of those differences will affect how much you have to stretch (tension) the string to vibrate at the desired frequency.

So if a maker has a combination of metals and windings they are happy with for strength and durability and feel and corrosion resistance and wear resistance and makes ALL of their strings with the same materials, then the only thing that will affect how much you need to stretch the string is going to be thickness.  Hence the grades of strings.  And - to have compatibility of nut slots, playing feel, etc, most makers have dropped into a convention of the broad size ranges they offer.

But if, say, D'Addario, want to make their strings at the same thicknesses as Ernie Ball...but they want to use different metals, with different windings, etc., then the amount they will need to be stretched to produce each frequency, will be different to the Ernie Balls.

Somewhere around there is a database of all of the strings from all of the manufacturers with the string tension for a fixed note - they vary CONSIDERABLY across manufacturers and across types of strings from the same manufacturer.

 

Final point.  For a given string, how you set up the bass (with one exception) WILL NOT affect the tension at all.  You will still have to stretch the string the same amount whether you fit the string on a bass or between two vices!  (The exception is an extreme - if your bridge lets you wind back your saddles to the extent where you actually change the scale length, then yes, technically, it will affect the tension).

But the opposite is certainly true - the tension of the strings WILL affect the setup.  The tension higher or lower will pull on the neck more or less meaning that the trussrod will need loosening or tightening to compensate. 

 

Hope the above makes some sort of sense.  I'm sure there are more accurate scientific factors I've missed or misunderstood...

[ikay]

This article provides a useful summary of factors affecting human perception of tension and compliance/stiffness, but it's a recurring topic with many differing viewpoints so be prepared for an animated debate!

https://www.liutaiomottola.com/myth/perception.htm

[itu]

I actually do repeat most of the stuff that these gentlemen before me wrote already. Hope that my angle gives some light to the topic.

Basically the tension is related to the string thickness + string length (= mass) and tuning. There are details in the strings that affect the tension, like materials and how thick the string core is. If you buy a set strings that are 30 - 90, they are very light. On the other hand a 55 - 110 set would be heavy/hard, compared to so called basic 45 - 100 set. But as said, there are differences depending on manufacturers' designs.

Usually the feel between different basses with similar strings is related to the height of the strings from the fretboard and the neck dimensions (like 30" - 36") and if the neck is convex or concave. So setting up a neck and bridge are important.

Remember that the tension is the same, no matter which way you string your bass. If the string posts are certain or the bridge has different holes, like through-body, these do not affect tension. If you think that the string is between two bricks (or vices, as @Andyjr1515 already wrote), there is no effect, whether the string is doing some curves after that brick or not, if the string behind that anchor point does not stretch. There are constructions that minimize that stretch like a double ball end headless bass.

Check this chart, it may give you ideas and lit that lamp above your head:

www.daddario.com/upload/tension_chart_13934.pdf

This was my key to different tunings with the same tension as with basic string set and tuning.

Edited August 21, 2019 by itu
typos

[donslow]

@Andyjr1515 that’s a fantastic explanation, a massive help! Thank you for taking the time!

@itu & @ikay thank you also, the help and links you posted were also quite insightful!

 

So, if I have this right, the string tension really only relates to how/of what the strings are made of, so generally speaking, the harder/stronger/thicker the materials used, the more tension will be required to tighten that string to get it to pitch?!

on that note assuming the strings on one of my basses being a bit flappy when tuned up, one would assume that, for example, the center core for example isn’t so thick as the ones in my flats (la Bella deep talkin’) on my precision bass?!

In my head, I’m kind of comparing it to two lengths of metal studding, for example, one at say, 2mm diameter and one at 6mm, if they were strings on an instrument, tuned to pitch, the 6mm would be the high tension string due to having a lot less flex in it?!

would that very long winded analogy sound about right?!

 

[Andyjr1515]

Yes - but the size of the core is only one of many factors. 

The cross section shape of the core (some are round, some hexagonal); the metal they are made of; the thickness and cross section of the windings; the metal they, too, are made of.  All of those factors (and more) will affect the tension you need to apply for it to vibrate at a particular frequency and, therefore, at a specific musical pitch.

[itu]

The core can be thick and the winding round it thin - or vice versa, and still you have two strings with equal thickness. But the mass may differ, and the force to tune it to certain frequency is different = different tension.

Remember, as an example there are flatwounds with nylon wound. Again the cross section may be the same as some other set, but the ratio of mass / length is not.

http://www.rotosound.com/tru-bass-88/

[itu]

1 hour ago, donslow said:

...so generally speaking, the harder/stronger/thicker the materials used, the more tension will be required to tighten that string to get it to pitch?!

You are on a right track. You could try to tune your D-string to the same pitch as your G. Maybe you lost that D, as it might break, and at least the neck gets substantially more tension to it. It has to put equally much tension against the strings to keep itself straight. Here truss rod adjustment helps. It is there for different gauges and tunings, i.e. tensions.

[donslow]

Thanks again fellas, you’ve been most insightful