Bajo sexto string tension
The D'Addario EJ86 is the reference bajo sexto set: twelve phosphor bronze wound strings with loop ends, from .026 to .092, tuned E A D G C F. On a 25.5″ (648 mm) scale the calculator puts 312.5 lb (141.7 kg) on the neck; D'Addario's own chart adds up to 306.5 lb (139.0 kg), and no string differs by more than 4.1 %.
Tension of the D'Addario EJ86 set, string by string
Standard E A D G C F tuning on a 648 mm scale, calculated with the unit weights from D'Addario's tension chart. D'Addario's own EJ86 figures differ by up to 4.1 % (306.5 lb for the set against 312.3 lb here).
| String | Note | Gauge | kg | lb |
|---|---|---|---|---|
| 1 | F3 | .026w | 12.7 | 28.0 |
| 2 | F3 | .026w | 12.7 | 28.0 |
| 3 | C3 | .036w | 14.0 | 30.9 |
| 4 | C3 | .036w | 14.0 | 30.9 |
| 5 | G2 | .046w | 12.8 | 28.1 |
| 6 | G2 | .046w | 12.8 | 28.1 |
| 7 | D3 | .030w | 12.3 | 27.1 |
| 8 | D2 | .062w | 12.8 | 28.2 |
| 9 | A2 | .036w | 9.9 | 21.9 |
| 10 | A1 | .078w | 10.7 | 23.7 |
| 11 | E2 | .046w | 9.0 | 19.9 |
| 12 | E1 | .092w | 8.0 | 17.5 |
How to use it
- The calculator opens with the Bajo sexto, the EJ86 set and standard E A D G C F tuning.
- Change the scale if your bajo isn't 25.5″: tension grows with the square of the vibrating length.
- Edit a gauge to compare: the set total and the difference on each string update as you type.
Help and explanations
Pick a tuning, change any gauge and the table recalculates each string in kg, lb or N. It's the quickest way to see what a heavier bass course or a different scale does before you buy strings.
The EJ86 set, string by string
In D'Addario's chart, the treble courses are unison pairs: two .026 on F3 at 27.9 lb each, two .036 on C3 at 30.2 lb and two .046 on G2 at 27.2 lb. The bass courses are octave pairs: a .030 on D3 with a .062 on D2, a .036 on A2 with a .078 on A1, and a .046 on E2 with the .092 on E1, which carries only 18.1 lb because it's tuned so low.
That's why a bajo sexto feels firm on the treble side and looser on the bass. The C3 pair is the stiffest, at about 13.7 kg per string by D'Addario's chart (14.0 kg in the calculator), and the low E1 the slackest, at 8.2 kg (8.0 kg here).
How the calculation works
Tension is T = UW × (2 × L × F)² ÷ 386.4, where UW is the unit weight from D'Addario's String Tension Specifications, L the scale in inches and F the frequency in Hz. Three of the gauges are not in the chart: the .046 is interpolated between its neighbors, and the .078 and .092 lie beyond the heaviest phosphor bronze string listed (.070), so they are extrapolated. The page marks all three as estimates.
The largest gap against the package is the .062 on D2: 27.1 lb for D'Addario and 28.2 lb here. Almost all the difference comes from the scale: the two sets of numbers line up at about 642 mm, which suggests D'Addario calculated on a slightly shorter bajo.
Tips
- If the neck feels too stiff, tuning the whole set down a half step cuts tension by about 11 % without changing strings.
- Loop-end strings fit the bajo sexto bridge; the steps are in how to restring a bajo sexto.
- Tune each course with the bajo sexto tuner; octave pairs are easier to hear one string at a time.
Frequently asked questions
What gauge strings does a bajo sexto use?
The D'Addario EJ86 runs .026, .036 and .046 in unison pairs on the F, C and G courses, then .030 with .062 on D, .036 with .078 on A and .046 with .092 on E. All twelve are phosphor bronze wound with loop ends.
How many strings does a bajo sexto have?
Twelve, in six double courses. The three treble courses are tuned in unison and the three bass courses in octaves. The bajo quinto has ten strings in five courses.
What is the standard bajo sexto tuning?
E A D G C F from the 6th course to the 1st: E1 + E2 (41.20 + 82.41 Hz), A1 + A2, D2 + D3, G2 (98.00 Hz), C3 (130.81 Hz) and F3 (174.61 Hz), at A 440 Hz.
What is the total tension of a bajo sexto set?
About 306 lb (139 kg) by D'Addario's figures for the EJ86 at standard tuning; the calculator gives 312 lb (141.7 kg) on a 648 mm scale. That's nearly double a steel-string acoustic guitar strung with an EJ16 (.012–.053), which carries about 163 lb.
Can I use 12-string guitar strings on a bajo sexto?
Not as a set. A 12-string guitar set is made for E A D G B E, about an octave higher. On a bajo sexto its bass strings would be far too slack, and there are no gauges for the C and F courses.