The short version: A capo does three things at once. It changes the key. It changes which open strings ring underneath your chords. And it moves the whole guitar up in register, which costs you low end and shortens your sustain. Most players only think about the first one. The other two are what decide whether the part sits right in a song.
Ask a guitar player why the capo is on the second fret and you will usually hear the key. The singer needs B. G shapes with a capo at 2 gets you there. Done.
That answer is correct. It is also about a third of the story.
The capo is the only thing on the instrument that changes your open strings. Not your pickups. Not your amp. Not any pedal you own. Move the capo and a different set of notes rings underneath every chord you play, the guitar loses low end, and the notes stop sooner. Those are tone decisions. You are making them either way.
Three Things the Capo Changes
Which open strings ring. In standard tuning the open strings are E, A, D, G, B, E. A capo at the second fret makes them F sharp, B, E, A, C sharp, F sharp. At the fifth fret they are A, D, G, C, E, A. Every drone under every chord is a different note.
Where the voicing sits. A capo raises the lowest note the guitar can make by one semitone per fret. Capo 5 and your bottom string is an A. Capo 7 and it is a B. You have given away the bottom of the instrument in exchange for the top.
How long the note lasts. Shorter string, shorter decay. This one is quiet enough that most players never name it, and it changes more about how a part feels than either of the other two.
The Position-by-Position Guide
This assumes standard tuning and the five open shape keys. Pick the row by what the part needs, not by what gets you to the singer's key fastest. There is usually more than one way to get to the key.
| Capo | Open strings ring as | Character | Good for |
|---|---|---|---|
| 0 | E A D G B E | Full range, longest decay | Anything that carries the song alone |
| 1 | F A# D# G# C F | Almost unchanged from open | Key access, nothing else |
| 2 | F# B E A C# F# | Still full, slightly tighter | The default second choice. Very safe. |
| 3 | G C F A# D G | Low end starting to thin | Rhythm parts under a vocal |
| 4 | G# C# F# B D# G# | Noticeably brighter, less bottom | Second guitar under an open-position player |
| 5 | A D G C E A | The crossover. Sounds like a different guitar. | Parts that need to sit above the bass |
| 7 | B E A D F# B | Small, tight, fast decay | Mandolin-adjacent parts. High counterlines. |
| 9 and up | Very high | Almost a different instrument | Specialty. Slide-adjacent. Albert Collins territory. |
Capo 5 is the line worth remembering. Below it you are transposing a guitar. At and above it you are playing something that behaves differently.
The Open Strings Are the Whole Argument
Here is the test. Play a D chord in open position. Then capo 2 and play a C shape. Both are D. They are not the same sound.
In the open D chord the only string you are not fretting is the D itself. The drone is the root. In the capo 2 C shape you are not fretting the third string or the first string, which now ring as A and F sharp. The drone is the fifth and the third.
Same chord name. One of them is anchored to its own root and the other one floats above it. That is not a small difference and it is not a matter of taste. It decides whether the guitar props the vocal up from underneath or hangs in the air around it, and which one you want depends entirely on the song.
This is why "just capo up to the right key" is bad advice for a part that matters. You do not get to pick the key and ignore the drone. The drone comes with the position.
The practical version. Find the note the melody keeps landing on. Then pick a capo position where that note is one of your open strings. The guitar will ring underneath the singer instead of fighting them.
Higher Capo, Shorter Decay
I expected a high capo to be mostly a brightness change. Capo up, the guitar gets thinner and jinglier, that is the whole thing.
That is not the whole thing. The bigger change is that the notes stop sooner.
A shorter piece of string carries less energy at the same picking force, so it gives that energy back faster. Play a chord open and it hangs. Play the same pitch with a capo at 7 and it is gone before you expected it. Nobody tells you this and it changes how you have to play.
Which is useful, once you know it. A high capo part in a full band sounds tight and clean and stays out of the way, because the decay is doing your muting for you. The same part played alone in a room sounds thin, because there is nothing filling the gap the short decay leaves. If a capo 7 part sounded great at rehearsal and hollow at the solo gig, that is what happened. Nothing is wrong with your amp.
The fix when you need a high capo part to carry on its own is not more reverb. It is to play more notes, closer together. Let the part be busier and let the short decay be the reason it does not turn to mud.
The Intonation Cost
A capo makes the guitar sharp. The question is how much.
Clamping a string down to the fret stretches it. More clamp, more stretch, more sharp. Most spring capos clamp harder than they need to, because they are built to work on any neck without adjustment.
Three things fix nearly all of it.
Use the least tension that stops the buzz. If your capo has an adjustment, this is what it is for. If it does not, a capo with one costs about twenty dollars and is the cheapest intonation fix available.
Place it just behind the fret. Not on top of the fret. Not back in the middle of the space. Just behind.
Check the plain G and B first. Not the low E. The plain G is the thickest unwound string on the guitar and the stiffest for its pitch, which makes it the first one to go sharp under a clamp, the same way it is the first one to go sharp everywhere else on the neck. If G and B are in tune the rest almost certainly are.
There is a second version of this problem that catches people out. If the chords sound fine right above the capo and sour by the seventh fret above it, the clamp is too tight and the error is compounding as you go up. Back the tension off. Do not touch the saddles.
Partial Capos
A partial capo covers some strings and leaves the rest open. This gets you the behavior of an alternate tuning without retuning, which matters if the next song needs standard.
The common one covers the A, D, and G strings at the second fret. In standard tuning that gives you E, B, E, A, B, E. An E suspended drone with a full open low E under it. Every simple shape you play over it rings against those two E strings and it sounds much bigger than the work involved.
A third-hand capo lets you pick any combination of strings, which is more control than most players need and exactly the right tool for the few who do.
The honest limit. Partial capos are for parts built around a drone. If the song moves through four chords that have nothing in common, the drone stops being a feature and starts being a wrong note. Test the whole progression before you commit to one on stage.
Two Guitars, Two Capos
This is the part that pays for the whole article.
Two guitarists playing the same shapes in the same position are one loud guitar with a phasing problem. Put one of them at capo 5 and the same progression suddenly covers two octaves, with two different sets of open strings ringing underneath and two different decay lengths.
Neither player has to learn anything. The chords are the same chords. Only the position moved.
The usual split. The player with the better bottom end and the fuller strumming stays in open position. The other one goes to 4 or 5 and plays fewer strings, higher up, more sparsely. If you are reading numbers off a chart rather than chord names, this gets easier still, since the Nashville Number System is written in concert key and both players read the same page from different capo positions.
For country and Bakersfield playing the capo is not an accessory. Albert Collins built an entire voice out of a Telecaster, a minor tuning, and a capo parked high on the neck, played with fingers and no pick. That sound is not available at the first fret.
Picking a Position on Purpose
Four questions, in order. It takes about a minute.
- What key does the singer need? This narrows you to a handful of positions, not one.
- What is the melody sitting on? Pick the position where that note is one of your open strings.
- Is another guitar already covering the low end? If yes, go higher than you were going to. If no, stay at 3 or below.
- Does the part need to ring or does it need to stop? Ring means low capo. Stop means high capo. The decay is doing work either way.
If two positions both pass, play the progression at each one and listen to the second chord rather than the first. The first chord always sounds fine. It is the move to the second chord where a wrong drone shows itself.
What This Does Not Fix
A capo is not an EQ. If your rig sounds thin, moving the capo up will make it thinner and moving it down will not repair it. Fix the rig first. The pickup position and the amp EQ are the tools for that job.
And a capo does not fix a guitar that will not stay in tune. It makes an out-of-tune guitar out of tune in a new place. If it sounds sour capoed, tune it capoed and see if it sounds sour open too. Usually it does, and the capo was just the messenger.
Put it where the song needs it. Then leave it alone and play the part.
