Pick up a mandolin for the first time and count the strings. You get to eight before you expect to. For most players coming from guitar or violin, those extra strings feel like a puzzle. The mandolin only plays four notes at a time...so why eight strings?
The answer is courses. Understanding what a course is explains not just how the mandolin is set up, but why it sounds the way it does, and why that design has held for hundreds of years.
What a Course Actually Is
A course is a group of strings tuned to the same pitch and played together as a single unit. On the mandolin, each course contains two strings. When you pick a note, you're not striking one string. You're actually striking both strings in the course at the same time, and the pick treats them as one.
The standard mandolin has four courses, each with two strings, for a total of eight strings. The four courses are tuned G, D, A, and E from lowest to highest. This is identical to violin tuning. Written out as individual strings, that's GG-DD-AA-EE, with each pair sharing a pitch.
This is why talking about mandolin strings can get confusing quickly. When a player says "I broke my A string," they mean one string from the A course. When they say "I'm playing the A course," they mean both strings together. The two ways of describing the same instrument coexist, and which one is meant usually comes from context.
Why Four Courses of Two?
The mandolin developed this way before electrical amplification existed. A compact instrument without any way to plug into a speaker has a natural limitation: it doesn't produce much volume on its own. Doubling the strings was one of the solutions instrument builders landed on centuries ago, and it works by concentrating vibrational energy.
Two strings vibrating together produce more energy than one string vibrating alone. The body resonates more, more air moves, and the result is a louder instrument. For a body the size of a mandolin's, that volume boost is meaningful.
That fast note decay is part of the instrument's physics. Shorter strings on a compact body lose energy quickly, and notes fade out within seconds after the pick strikes. Doubled strings help compensate by sustaining slightly longer and producing enough initial volume that the note has room to breathe before it fades.
This design was so effective that the mandolin kept it long after amplification became available. Today, the course system is simply how the instrument works, and the acoustic properties it produces are considered fundamental to the mandolin's character.
What Doubled Strings Actually Do to the Sound
Two strings vibrating together add volume, but the course design does something more interesting. The two strings in a course are never tuned to exactly the same frequency. They're close; you tune both to the same note, but no two strings vibrate at precisely the same rate. The tiny gap between them creates a natural beating effect, a slight shimmer or chorus quality in the sound.
This is the shimmer players describe when they talk about the mandolin's tone. The two strings interact slightly out of phase, and that interaction produces a layered, ringing quality that a single string at the same pitch couldn't replicate. You hear it most clearly when the instrument is well in tune and both strings in a course ring together cleanly.
Carbon fiber mandolins, like the KLŌS A-Style and KLŌS F-Style, produce this shimmer with more sustain than a comparable wood instrument. They are also louder overall, which means the full character of the course system comes through more clearly in ensemble settings where you need the instrument to carry.
Courses and Tuning: The Practical Side
Because each course has two strings, every note on the mandolin requires two strings to be in tune. Standard tuning is G-D-A-E, and each course needs both strings matched to the same pitch before the instrument is ready to play.
Tuning eight strings to four notes sounds manageable, but it's the first real challenge most beginners encounter. The paired strings have to be in tune with each other before they're in tune with the instrument as a whole. A slightly mismatched pair produces a wavering, pulsing sound rather than the clean shimmer the instrument is capable of. The pulse grows faster as the two strings drift further apart in pitch.
With a wood mandolin, string movement and seasonal shifts in the body mean the instrument needs frequent tuning checks. Retuning every time you pick it up is standard advice for wood instruments, especially in the first few months when new strings are still settling.
Carbon fiber mandolins hold pitch significantly better. On a KLŌS instrument, the neck and body don't shift with humidity or temperature, which keeps the strings closer to pitch between sessions. Keeping eight strings in tune is still the same job it always was, but it's a more stable foundation to work from.
You're Not the Only Instrument Built This Way
This course system is not unique to the mandolin. It belongs to a family of instruments that solved the same volume problem the same way.
The 12-string guitar uses six courses of two strings each. The Greek bouzouki uses three or four courses. The lute family, from which the mandolin descends, was built almost entirely on the course system across its many regional variations. What makes the mandolin specific is the combination of four courses, violin tuning, and the short scale length that produces its bright, fast-decaying tone.
If you've played a 12-string guitar, the course concept is already familiar — you just didn't call it that. A 12-string guitar applies the same doubling idea to six pitches instead of four, across a much longer neck. The principle is identical.
Getting Comfortable with Eight Strings
The first weeks on the mandolin are largely about pressing two strings cleanly at the same fret. Your fingertip needs to cover both strings in the course and press firmly enough that neither buzzes. It takes a bit more left-hand pressure than single-string fretting, and it takes time for your fingertips to build the calluses the doubled strings demand.
Most players find that the course system becomes natural faster than they expected. The picking motion is the same as on any fretted instrument. The eight strings stop feeling like a problem and start feeling like the instrument.
Worth knowing as you get started: the mandolin community is small and notably welcoming. Jams, online forums, and local sessions tend to include experienced players who remember the early adjustment period and are happy to help. The shared love of an underappreciated instrument makes it an easy community to enter.
Curious what the course system sounds like in action? Explore the KLŌS A-Style Mandolin and hear what a well-built carbon fiber instrument does with eight strings.
