Before making any guitar purchase, you want to be sure that the guitar you are looking at is in good playing condition.  I think it’s easiest to look at the guitar from the top down, in a systematic way.  It helps prevent me from ever missing an item.  We are going to check the following things from the top to the bottom of the guitar: The tuners or ‘tuning machines’, the neck, the frets and fretboard, the soundboard, the body.  The article below is a complete checklist, but we recommend watching the video, too, so that you can see how to perform each of these tests. Thanks to Gary at Chagar Music for lending us one of his Larrivee Guitars for this demonstration.

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The Tuning Machines

Tuning machines vary considerably in price and quality. They range from around $30 for a set up to $700 or more for a high quality hand made set.  Good tuning machines make tuning easier and will save you some time and trouble when you are tuning your guitar.  To check the guitar’s tuning machines, simply turn each tuning knob one at a time.  You should watch the roller, which is the part of the machine that the string is tied to.  If when you turn the knob, the roller turns without delay, then your tuning machine is probably in good shape.  Be sure to turn it in both directions, and to turn the knob at least one full rotation up, and one full rotation down.  You want to be sure that you have turned the knob enough to check all of the gears within the machine.

You might notice some slack in the tuning machine, where the knob turns, before the roller moves, or that wiggles around without feeling like it is catching anything. If this is the case, you have damaged tuners.  The good news is that tuning machines are relatively easy to replace, and should not be considered a deal-breaker, especially when looking at a used or vintage guitar.   If the machines are damaged, be prepared to have a qualified luthier replace them.  It would also be a good reason to ask the seller of the guitar to give you a discount, or to pay for the replacement tuners.

The Guitar Neck

Next, inspect the guitar neck.  Look down the length of the guitar neck from the headstock to the bridge on both sides. The neck should be straight without any bowing, warping, or twisting.  There may be some forward or backward arch in the neck if the truss rod is incorrectly set.  The truss rod can be easily fixed, but warping or twisting cannot.  If there is damage to the neck, especially if it is bowed, warped, or twisted, that cannot be fixed by a truss rod adjustment don’t buy the guitar.  It will affect your playability and tuning.  This one’s a deal-breaker.  If you aren’t sure if the arch in the neck is from the truss rod, or from damage ask the seller or store to correctly set the truss rod.  Don’t be afraid to ask!  If the neck still does not look straight after the rod has been set then stay away.

If the neck is straight and set up properly, move on to the fretboard.  The fretboard should be smooth, flat, free of dents, and should not be worn away.  The frets should be flush with the side of the fretboard, and should not be protruding beyond the sides. Run your fingers along the sides of the fretboard to feel for protruding frets.  The frets should also be firmly seated in the fretboard and should be smooth without any significant wear from the strings. Frets can be replaced or ground down if they protrude or are too worn. Having poor frets is not necessarily a deal-breaker, but consider the cost and time of doing the repairs before making any purchase decision.

The Action

The action of the guitar simply describes how close the strings are to the fretboard, and the angle they are set to the fretboard.  I can’t prescribe a string height or angle for you, because different players desire different action heights.  A lower action means that the guitar will be easier to play, but will be more likely to buzz when playing at louder volumes.  A higher action means that the guitar will be harder to play, but that you can play louder before buzzing occurs.  To test the action you should play every fret on every string of the guitar. Make sure there is no buzzing on any fret at low to moderate volume levels.  If all of the frets produce clean sounds at low volumes, then the action is acceptable as long as it is not too hard or too tiring to press. Then try to play the guitar at louder volumes, being aware of the volume level at which buzzing starts to occur.  You will have to decide upon an action height that suits your needs.   As long as the neck is in good shape, then the action can be adjusted to your needs.  Therefore, action that is too high or too low is not a deal-breaker.

My basic recommendations for setting the action are the following:

Guitar Beginners should choose the lowest action possible that does not buzz at quiet or moderate volume levels. This will allow them to play with more ease as they develop their technique. As hand strength and technique improve, the action can be raised.

Gigging Guitarists who play concerts or gigs without amplification may choose a higher actions that will give them a louder volume before buzzing occurs, and thus a wider dynamic range. There is nothing worse that trying to dig into your guitar to create a big musical moment, only to have your guitar respond with buzzing and grunting!

Gigging Guitarists who play long gigs, or concerts with amplification might choose a medium action that will give them some dynamic range for musical reasons without sacrificing playability. The volume in this case if primarily achieved by the sound amplifier or PA system, and this will allow the player to perform for longer periods of time before experiencing fatigue.  If you’ve ever been on a 5 hour wedding gig, you know exactly what I mean.

The Intonation

While it is impossible to have a guitar that is perfectly in tune, the frets should be at least set to produce clean octaves on the guitar.  To check this, simply compare the sound of the note that is fretted on the 12th fret of each string with the harmonic produced on each string at the 12th fret. Those two pitches should be the same.  If they are audibly different, then the guitar has poor intonation.  This intonation might be easily remedied on an electric guitar with a movable bridge, but is not such an easy fix on an acoustic guitar.  I would not recommend buying a guitar with poor intonation.

The Soundboard

The soundboard should be free of cracks.  Visually inspect the guitar to make sure there are none. Cracks can also be repaired, so its not a complete deal-breaker.  I bought my concert guitar even though it had a small humidity crack in it that had already been repaired.

The Body 

Check the rest of the guitar body, back and sides for cracks.  You should also check every seam (every place where two pieces of wood are joined together) to make sure they have not separated.  The most common places for cracks are in the soundboard, and the most common places where joints have come apart are where the bridge is glued to the soundboard, the neck where it is glued to the body, and the headstock where it is glued to the neck.

Unfortunately, you can’t see inside the guitar. Sometimes braces or other structural components might come loose inside the guitar. To check for loose items, simply tap all around the body of the guitar on the top, sides, and back.  If you hear any buzzing or rattling as you tap, it’s an indication that something is loose.  Loose braces can also be repaired, but at an additional cost.

In Summary

Most problems with a guitar can be repaired. If your guitar has any problems listed above that can be repaired, you should consider the time and expense of those repairs in your purchasing decision.  If the guitar has any problems with warping or twisting of the neck, intonation, major cracks or structural damage, or a total number of repairs that exceeds the value of the guitar, you might want to keep on shopping. Whether you are gigging or taking guitar lessons, having a playable guitar is extremely important!

Now that you know what to look for structurally, let’s take a look at how body shape affects the sound of a guitar.