There’s nothing quite like playing an acoustic guitar that’s been perfectly set up. The action is comfortable, the intonation is spot-on, and every note rings out clear and true. For many players, however, the process of achieving that perfect setup can seem like a mystery. To pull back the curtain, Sweetwater’s Don Carr joined Ben Armour from the Sweetwater Guitar Shop as he performed a complete, professional setup on a gorgeous Martin 000-28 Modern Deluxe. Follow along as we break down his expert process step by step.
The First Step: Inspection and Humidity
Before any tools come out, the first step is always a careful evaluation. As Ben explains, “The first thing any qualified repair tech is going to do is inspect for physical damage.” This means a thorough visual check of the entire instrument, paying close attention to high-stress areas like the bridge and headstock. Documenting any issues ensures you have a clear picture of the guitar’s health before you begin.
Next up is one of the most critical factors for an acoustic guitar’s well-being: humidity. “Humidity on an acoustic guitar is what swells the top and shrinks the top,” Ben notes. “That’s affecting your action, it’s affecting how a guitar sounds, it’s how a guitar plays.”
- Too Dry: When a guitar dries out (common in heated homes during winter), the wood shrinks. This lowers the top, causing the action to drop and often resulting in fret buzz. Other symptoms include sharp fret ends and, in severe cases, cracks in the fretboard or top.
- Too Wet: Excessive humidity causes the wood to swell. The top will belly up, raising the action and making the guitar feel difficult to play. The sound can also become muffled and lose definition.
The target is a stable relative humidity of around 45%. Using a simple hygrometer is the best way to monitor the environment where you store your guitar.
Checking and Adjusting Neck Relief
With the initial inspection complete, the next step is to assess the neck. Sighting down the neck from the headstock, you’re looking for neck relief—the slight concave curve that allows the strings to vibrate freely. On the guitar Ben is working on, he spots an issue immediately: “Absolutely no relief in this guitar.” In fact, it has a back bow, which is contributing to a buzz on the open G string.
The solution is a truss rod adjustment. Ben’s approach is methodical and cautious:
- Small Adjustments: “You really want to do about a quarter turn at a time.” Drastic changes can damage the neck, so slow and steady wins the race.
- Tune and Re-check: Every adjustment affects string tension and tuning. After each small turn, it’s important to bring the guitar back to pitch with a reliable tuner like the Snark SN-1X to get an accurate reading of the new neck relief.
- Finish by Tightening: Ben shares a pro tip: always make your final adjustment by tightening the truss rod. “It’s the same concept as when you put strings on. You tune up to the note, you don’t tune down to a note.” This ensures the rod is fully seated and won’t shift later.
Setting the String Action: Nut and Saddle
Once the neck relief is correct, it’s time to move to the nut. Using a combination of a “tap test” and precise gauges, Ben measures the height of each string over the first fret. On this guitar, he discovers the slots are too high, which can make fretting notes feel stiff and pull them sharp. He also solves the mystery of the buzzing G string: a small chip on the front edge of the nut slot. Using a set of gauged nut slotting files, Ben carefully lowers each slot with “a bit of a roll” to create a clean takeoff point, eliminating the buzz.
With the nut dialed in, the final action adjustment happens at the saddle. Ben measures the string height at the 12th fret while holding the guitar in the playing position to account for gravity’s effect on the neck. To lower the action, the saddle is removed and material is carefully sanded from its bottom. A tool like the Pro-Winder makes quick work of removing the strings. Ben notes that for a guitar with an under-saddle pickup, the bottom of the saddle must be perfectly flat to ensure even pressure and optimal sound transfer.
Fretboard and Fret Maintenance
With the strings off, it’s the perfect opportunity for some cleaning and maintenance. “It’s time to get all the sweat and grime and gunk off the fretboard,” Ben says. He uses Scotch-Brite, advising that you should “almost try to polish the fretboard, and then you’ll take care of the frets.” This restores the shine and removes buildup from the wood.
After cleaning, he applies a small amount of F-ONE Oil to condition the fretboard. He offers a crucial piece of advice: use it sparingly. “Too much oil will go down into your fret slots… you’re going to actually start to affect the glue bond between the fretboard and the neck.” A little goes a long way. This is also a great time to check that all tuning machine hardware is snug and secure.
A professional setup can completely transform the feel and sound of your acoustic guitar, making it more inspiring to pick up and play. After restringing and tuning up, the results speak for themselves: the buzz is gone, the action is low and comfortable, and the guitar is playing better than ever. By addressing neck relief, nut and saddle height, and overall maintenance, you ensure your instrument is performing at its absolute best.
If you have any questions about the setup process, the gear used here, or finding the perfect instrument for you, don’t hesitate to reach out to your Sweetwater Sales Engineer. They have the expertise to help you with all your musical needs!