Six strings, three courses, and one honest disagreement
A Cuban tres has three courses of two strings — six strings in total — tuned to a G major triad: G, C, E. Strum the open courses and you are already playing a chord, which is why the instrument can carry the harmonic and rhythmic weight of a son without help.
Where sources stop agreeing is which courses are octave pairs and which are unisons, and that is worth stating plainly rather than papering over:
- Third course (G): an octave pair, always. G4 with G3 underneath it. Every source agrees, and it is what gives the tres its bottom end.
- Second course (C): a unison, always. C4 with C4. No disagreement here either.
- First course (E): this is the one. Modern practice is largely unison, E4 with E4. The older tradition strings it in octaves, E4 with E3.
Both readings are documented and both are played, so no chart is wrong for showing one of them. What matters is knowing which one is on the instrument in front of you — and that is a thirty-second check: pluck the two strings of the first course separately and see whether the dial names the same octave twice.
Three readings of the same instrument. Compare the first two tabs to hear what the traditional octaved first course adds — and note where the lowest pitch moves to when it is used.
The consequence: where the lowest note lives
That first-course question is not cosmetic. It moves the bottom of the instrument’s range from one end of the neck to the other.
| First course strung as | Lowest note | Which course it is in |
|---|---|---|
| Unison E4 + E4 (modern) | G3 · 196.00 Hz | Third — where you would expect it |
| Octaves E4 + E3 (traditional) | E3 · 164.81 Hz | First — the course nearest the floor |
With the traditional stringing the deepest note on a tres is not in the bass course at all — it is hiding in the treble one, a whole tone below the low G most players think of as the bottom. That is worth knowing before you decide a string “sounds too low to be right” and tighten it.
C major or D major — establish that first
Before any of the above matters, settle which key the instrument is in. The tuning described so far is the C major one. A great many treseros now tune the whole instrument a whole tone higher, in D major: A4+A3 on the third course, D4+D4 on the second, F♯4+F♯4 (or F♯4+F♯3) on the first.
Nothing about the technique changes — the intervals are identical, so every shape transposes and a piece fingered in C sounds in D. But it is a different set of target pitches, and a tuner cannot infer which one you meant. Decide, then tune.
Tuning routine
- Establish the key and the first-course stringing before touching a peg. Two questions: C or D, and is the first course unison or octaves? Pluck each string of the first course separately to answer the second.
- Mute one string of the course you are tuning. Rest a finger on its partner. Two strings a few cents apart make a wavering tone that a pitch detector will chase rather than name — and on an octave course, two different pitches sounding at once is worse still.
- Start with the second course, C4. It is a plain unison and the easiest reading on the instrument, so it makes a good anchor.
- Then the third course, one string at a time.G4 and G3. Watch the octave digit — this is the pair where an octave slip is easiest, because both strings answer to “G”.
- Then the first course. E4 and E4, or E4 and E3, according to what you established in step one.
- Finish each course by ear. Unisons must stop beating: play the pair and adjust until the wavering flattens out. Octave pairs need the same treatment, and steel strings being what they are, the upper one often wants to sit a cent or two sharp before the octave sounds locked.
What the needle can and cannot tell you
The dial handles the pitches. What it cannot judge is the pair, and on this instrument the pair is most of the sound.
Two strings can each read dead centre and still beat audibly against one another, because a few cents of difference disappears inside the needle’s tolerance and does not disappear in the air. The octave courses add a wrinkle of their own: steel is not a perfect harmonic oscillator, and its upper partials drift a little sharp of where the arithmetic puts them, so an octave dialled in to mathematical perfection can sound faintly pinched. Trust the beating over the needle for the last couple of cents. Our guide to cents explains why the two answers differ by a small, predictable amount.
If you are tuning around the tres, the cuatro venezolano has the other famous pitch-order surprise in the region, and the charango shares the octave-pair problem in a course of its own.
Frequently asked questions
Which courses on a tres are octave pairs?
The third course, the G, is an octave pair in every source there is: G4 paired with G3. The middle course, C, is a unison in all of them. The first course is where the disagreement lives — modern practice is largely E4 with E4 in unison, while the older tradition pairs E4 with E3. Both are documented and both are played, so a chart is not wrong for showing one or the other. Check what is actually on your instrument by plucking the two strings of the first course separately: if they name the same note at the same octave, you have unisons.
What is the lowest note on a Cuban tres?
It depends on that same first course, which is what makes the question interesting. With a unison first course the lowest note is G3 at 196 Hz, in the third course, exactly where you would expect the bass to be. With the traditional octaved first course the lowest note is E3 at 164.81 Hz — and that puts the lowest string on the instrument in the FIRST course, the one nearest the floor, rather than the third. Same instrument, same three courses, and the bottom of its range moves depending on a stringing choice.
My tres is tuned to A–D–F♯ rather than G–C–E. Is it wrong?
No, that is the D-major tuning and a great many treseros use it. It is the same instrument moved up a whole tone: A4+A3 for the third course, D4+D4 for the second, and F♯4+F♯4 or F♯4+F♯3 for the first, keeping whatever octave arrangement the player prefers. The shapes and the relationships are identical to the C-major tuning, so everything transposes — a piece fingered in C sounds in D. Decide which one you are in before you tune, because the dial cannot guess.
Does it matter which string of an octave pair is on top?
It matters to your right hand rather than to the tuner. When both outer courses are strung in octaves, the high and low strings are ordered the opposite way round in the first course from the third — so a downstroke meets the low string first in one and the high string first in the other. That is a deliberate part of how the instrument articulates, and it is worth matching your existing stringing when you change strings rather than reversing it by accident.
Can I tune a tres with an ordinary guitar tuner?
A chromatic one, yes, and that is the right tool. What you must not do is use a guitar preset, because a preset expects six different pitches ascending and a tres has three or four pitches spread across six strings — the preset will keep pulling your reading toward whichever guitar string is nearest. A chromatic dial names whatever it hears with its octave, which is exactly what an instrument with octave courses needs. Mute one string of each course with a finger and tune them one at a time.