
A client wanted her D-12-20 to fret in tune all along the fretboard. Can it be done?
Intonating a flattop’s bridge saddle is tricky, and that’s especially true when it comes to vintage 12-string guitars. Back in the day, it was rare to find an acoustic 12-string with a compensated bridge saddle. In fact for many players, the slightly out-of-tune jangle was a big part of a 12-string’s aural mystique. But times have changed, and as music and recording technology have evolved, most musicians and producers expect a 12-string to play reasonably in tune all along the fretboard.
Intonating a flattop 12-string with a straight bridge saddle involves filing unique break angle and intonation points for each string—an operation that requires skill and patience. Let’s investigate and see exactly what’s involved.
We’ll use a beautiful 1972 Martin D-12-20 as our project guitar. The guitar was in good shape when its owner brought it into the shop, but it didn’t play even remotely in tune and the action was uncomfortably high. Many old 12-strings require a neck reset (an expensive proposition), but I checked the neck angle and it was fine. Fortunately for the guitar’s current owner, the problem was rather simple. Somewhere along the line a previous owner or tech had installed a saddle that was both too high and incorrectly radiused (Photo 1).
My job was twofold: lower the action by reshaping the bridge saddle and then intonate each string. I knew that once I completed these tasks, the D-12-20 would play better than ever and sound more in tune at the higher frets.
Requisite tools. To intonate a 12-string, you need a few specialized luthier tools. These include a string action gauge, radius gauges, and a radius block (the latter must match the fretboard radius). You’ll also need a mechanical pencil, a capo, self-adhesive 80-grit and standard 400-grit sandpaper, and flat, single-cut miniature needle files.
You can estimate where each string should rest on the saddle, but it’s nearly impossible to get it perfect on the first try.
Preliminary check. Before starting this kind of work on a guitar, it’s important to tune to concert pitch and take measurements. These specs provide a baseline to help gauge your progress. You’ll be taking several measurements, so write them down as you go.
First, put a capo on the 1st fret and measure action at the 12th fret with a string action gauge. Take this measurement for both the 1st and 11th strings—the first of the doubled high Es and the low E string. (We’ll assume your 12-string has the standard octave-string configuration, i.e., the octaves in each pair are closer to you than their wound partners. Some electric 12s, notably Rickenbackers, reverse this order.) Measure the distance between the bottom of the string and the top of the 12th fret.
Next measure the relief: With the capo still on the 1st fret, hold the 11th and 12th strings down at the 14th fret and measure the greatest gap between the bottom of the 11th string and the top of the frets. Typically this occurs around the middle of the fretboard, somewhere between the 7th and 9th frets. You can identify this gap by tapping the 11th and 12th strings against the frets while still pressing them down at the 14th fret.
Now remove the capo and check the action at the 1st fret.
Finally, using a strobe tuner, check the intonation for each string. (Naturally, this is tricky on a 12-string because you have to pluck each individual string of the six pairs.) Starting with the 1st string, play the 12th-fret harmonic—make sure it’s in tune—and then fret the same note. If the fretted note is sharp or flat compared to the reference harmonic, write down how many cents it’s off and in which direction. Repeat the process until you’ve documented the intonation at the 12th fret for all 12 strings.
Our 12-string’s preliminary specs. Here’s how the D-12-20 measured up: The action at the 12th fret was 6/64" for the 1st string and 7/64" for the 11th string. Too high to play! The relief was .012"—perfect for my client’s playing style. At the 1st fret, the 1st string was 1/64" and the 11th string was just over 2/64" above the fret. Again, perfect action at the string nut. At this point, I knew my job would simply entail lowering the action at the bridge saddle.
When I checked the intonation with a strobe tuner, and compared the 12th fret harmonics to their corresponding fretted notes, I found most of the fretted notes were from two to six cents sharp, although the G and D pairs were flat by about three cents.
With these measurements in hand, I was ready to get to work.
Photo 2
Sanding the bridge saddle. My next step was to check if the saddle’s radius matched the fretboard radius. My radius gauge revealed what I’d suspected—it wasn’t even close. The fretboard had a 14"radius (Photo 2), but the bridge saddle was around 8". This meant the saddle had a much more pronounced arch than the fretboard. I knew if I didn’t reshape the top of the saddle to match the fretboard, the D and G pairs would be radically higher than the other strings.
Photo 3
Using a 14" radius block and self-adhesive 80-grit sandpaper, I sanded the top of the saddle until it matched the block’s radius. Here’s the most accurate way to reshape the top of the saddle: Place the radius block in a vise with the radius side up and affix the self-adhesive sandpaper to the block. Now remove the saddle from its bridge slot, turn it upside down, and gently sand its top in the block’s concave area. If you shine light behind the saddle, you’ll be able to see how much material you’re removing from the saddle and make sure its radius matches the block (Photo 3).
Since the action was pretty high on our 12-string, I removed about 1/32" from the top of the saddle at both E string pairs. I removed quite a bit more from the middle of the saddle to flatten out the arch.
Once the saddle is correctly radiused, slip it back into the bridge and grab your mechanical pencil.
Photo 4
Marking the saddle. Now it’s time to draw guidelines on the saddle crown for both the individual intonation points and the various angles needed to guide the strings as they emerge from the pin holes (Photo 4). But before you start drawing lines, let’s take a moment to discuss where the strings should sit on the top of the saddle. First we’ll deal with the intonation points, then the string angles.
Fair warning: Setting the intonation entails some trial and error. You can estimate where each string should rest on the saddle, but it’s nearly impossible to get it perfect on the first try.
For this task, it’s helpful to mentally divide the 12 strings into three groups:
• The six E, A, D, G, B, and E strings you’d find on a regular flattop. We know the lowest four are wound, and the top two are plain. So far, so good.
• The plain octave strings (E, A, D, G) that pair with the wound E, A, D, and G strings.
• The doubled unison B and high-E strings. Just like their mates, these are plain.
Okay, think about the first group—our standard 6-string. As a general rule, both the low E and B strings intonate best at the rear edge of the saddle (closest to the bridge pins). The G string’s intonation point is typically at the very front of the saddle (closest to the soundhole).
That leaves the high E, D, and A strings to be accounted for. The high E will typically fall between the B (remember, that’s at the rear of the saddle) and the G (at the front of the saddle). The D and A strings usually create a stair-step pattern between the G and low E strings, with the D closer to the G, and A closer to the low E.
The four plain octave strings are a different story. Both the low E’s octave and the G’s octave points will be at the front of the saddle. The octave strings for A and D will be further back toward the bridge pins.
As you’d expect, the unison B and E strings sit at exactly the same point as their siblings.
Now consider how each string travels from the pin hole in the bridge to the top of the saddle—the intonation point. On this Martin, the six primary strings—those that correspond to a standard flattop—are set back toward the rear of the bridge. The six additional strings, the four octaves and two unisons that make a 12-string such a beautiful beast, emerge through the soundboard and bridge right behind the saddle.
On the rear of the saddle, you need to file individual angles (think of them as ramps) that allow each string to reach its intonation point without encountering a sharp edge. Correctly filed angles minimize string breakage and maximize sustain. The angle for the primary strings will be shallower than the six extra strings.
Photo 5
On the rear of the saddle, you need to file individual angles (think of them as ramps) that allow each string to reach its intonation point without encountering a sharp edge. Correctly filed angles minimize string breakage and maximize sustain. The angle for the primary strings will be shallower than the six extra strings.
Filing the saddle. This is where your inner artist gets a chance to shine. Using a miniature flat file, carve each string’s intonation point and rear angle, based on your markings (Photo 5). Go slowly, and to prevent any sitar-like buzzing, be sure each string leaves the saddle from a crisp, defined peak as it heads toward the soundhole.
Checking intonation. As I mentioned earlier, there’s a lot of trial and error involved with intonating a 12-string. Once you’ve done the first pass of filing, put on a fresh set of strings, tune them to pitch, and check the intonation.
Photo 6
The goal is to have the fretted note at the 12th fret match the corresponding 12-fret harmonic. Use a tuner to keep track of how close the fretted note comes to its reference harmonic. If the string frets sharp, file the intonation point back toward the rear of the saddle. Conversely, if the fretted note is flat, carve the intonation point forward toward the front of the saddle. When you’re done, the saddle should look similar to Photo 6. Don’t be dismayed at how many times you’ll need to slacken and remove the strings, file the saddle, restring, retune, and recheck the intonation.
Wrap it up. When you’ve got the intonation dialed in to your satisfaction, take off the strings one last time, pop out the saddle, and then polish it with 400 grit sandpaper, followed with a polishing cloth. Restring, retune, and you’re good to go.
This process takes a long time to master, but in the end, it’s worth it when your 12-string plays in tune all the way up the neck.
A live editor and browser for customizing Tone Models and presets.
IK Multimedia is pleased to release the TONEX Editor, a free update for TONEX Pedal and TONEX ONE users, available today through the IK Product Manager. This standalone application organizes the hardware library and enables real-time edits to Tone Models and presets with a connected TONEX pedal.
You can access your complete TONEX library, including Tone Models, presets and ToneNET, quickly load favorites to audition, and save to a designated hardware slot on IK hardware pedals. This easy-to-use application simplifies workflow, providing a streamlined experience for preparing TONEX pedals for the stage.
Fine-tune and organize your pedal presets in real time for playing live. Fully compatible with all your previous TONEX library settings and presets. Complete control over all pedal preset parameters, including Global setups. Access all Tone Models/IRs in the hardware memory, computer library, and ToneNET Export/Import entire libraries at once to back up and prepare for gigs Redesigned GUI with adaptive resize saves time and screen space Instantly audition any computer Tone Model or preset through the pedal.
Studio to Stage
Edit any onboard Tone Model or preset while hearing changes instantly through the pedal. Save new settings directly to the pedal, including global setup and performance modes (TONEX ONE), making it easy to fine-tune and customize your sound. The updated editor features a new floating window design for better screen organization and seamless browsing of Tone Models, amps, cabs, custom IRs and VIR. You can directly access Tone Models and IRs stored in the hardware memory and computer library, streamlining workflow.
A straightforward drop-down menu provides quick access to hardware-stored Tone Models conveniently sorted by type and character. Additionally, the editor offers complete control over all key parameters, including FX, Tone Model Amps, Tone Model Cabs/IR/VIR, and tempo and global setup options, delivering comprehensive, real-time control over all settings.
A Seamless Ecosystem of Tones
TONEX Editor automatically syncs with the entire TONEX user library within the Librarian tab. It provides quick access to all Tone Models, presets and ToneNET, with advanced filtering and folder organization for easy navigation. At the same time, a dedicated auto-load button lets you preview any Tone Model or preset in a designated hardware slot before committing changes.This streamlined workflow ensures quick edits, precise adjustments and the ultimate flexibility in sculpting your tone.
Get Started Today
TONEX Editor is included with TONEX 1.9.0, which was released today. Download or update the TONEX Mac/PC software from the IK Product Manager to install it. Then, launch TONEX Editor from your applications folder or Explorer.
For more information and videos about TONEX Editor, TONEX Pedal, TONEX ONE, and TONEX Cab, visit:
www.ikmultimedia.com/tonexeditor
The luthier’s stash.
There is more to a guitar than just the details.
A guitar is not simply a collection of wood, wire, and metal—it is an act of faith. Faith that a slab of lumber can be coaxed to sing, and that magnets and copper wire can capture something as expansive as human emotion. While it’s comforting to think that tone can be calculated like a tax return, the truth is far messier. A guitar is a living argument between its components—an uneasy alliance of materials and craftsmanship. When it works, it’s glorious.
The Uncooperative Nature of Wood
For me it all starts with the wood. Not just the species, but the piece. Despite what spec sheets and tonewood debates would have you believe, no two boards are the same. One piece of ash might have a bright, airy ring, while another from the same tree might sound like it spent a hard winter in a muddy ditch.
Builders know this, which is why you’ll occasionally catch one tapping on a rough blank, head cocked like a bird listening. They’re not crazy. They’re hunting for a lively, responsive quality that makes the wood feel awake in your hands. But wood is less than half the battle. So many guitarists make the mistake of buying the lumber instead of the luthier.
Pickups: Magnetic Hopes and Dreams
The engine of the guitar, pickups are the part that allegedly defines the electric guitar’s voice. Sure, swapping pickups will alter the tonality, to use a color metaphor, but they can only translate what’s already there, and there’s little percentage in trying to wake the dead. Yet, pickups do matter. A PAF-style might offer more harmonic complexity, or an overwound single-coil may bring some extra snarl, but here’s the thing: Two pickups made to the same specs can still sound different. The wire tension, the winding pattern, or even the temperature on the assembly line that day all add tiny variables that the spec sheet doesn’t mention. Don’t even get me started about the unrepeatability of “hand-scatter winding,” unless you’re a compulsive gambler.
“One piece of ash might have a bright, airy ring, while another from the same tree might sound like it spent a hard winter in a muddy ditch.”
Wires, Caps, and Wishful Thinking
Inside the control cavity, the pots and capacitors await, quietly shaping your tone whether you notice them or not. A potentiometer swap can make your volume taper feel like an on/off switch or smooth as an aged Tennessee whiskey. A capacitor change can make or break the tone control’s usefulness. It’s subtle, but noticeable. The kind of detail that sends people down the rabbit hole of swapping $3 capacitors for $50 “vintage-spec” caps, just to see if they can “feel” the mojo of the 1950s.
Hardware: The Unsung Saboteur
Bridges, nuts, tuners, and tailpieces are occasionally credited for their sonic contributions, but they’re quietly running the show. A steel block reflects and resonates differently than a die-cast zinc or aluminum bridge. Sloppy threads on bridge studs can weigh in, just as plate-style bridges can couple firmly to the body. Tuning machines can influence not just tuning stability, but their weight can alter the way the headstock itself vibrates.
It’s All Connected
Then there’s the neck joint—the place where sustain goes to die. A tight neck pocket allows the energy to transfer efficiently. A sloppy fit? Some credit it for creating the infamous cluck and twang of Fender guitars, so pick your poison. One of the most important specs is scale length. A longer scale not only creates more string tension, it also requires the frets to be further apart. This changes the feel and the sound. A shorter scale seems to diminish bright overtones, accentuating the lows and mids. Scale length has a definite effect on where the neck joins the body and the position of the bridge, where compromises must be made in a guitar’s overall design. There are so many choices, and just as many opportunities to miss the mark. It’s like driving without a map unless you’ve been there before.
Alchemy, Not Arithmetic
At the end of the day, a guitar’s greatness doesn’t come from its spec sheet. It’s not about the wood species or the coil-wire gauge. It’s about how it all conspires to either soar or sink. Two guitars, built to identical specs, can feel like long-lost soulmates or total strangers. All of these factors are why mix-and-match mods are a long game that can eventually pay off. But that’s the mystery of it. You can’t build magic from a parts list. You can’t buy mojo by the pound. A guitar is more than the sum of its parts—it’s a sometimes unpredictable collaboration of materials, choices, and human touch. And sometimes, whether in the hands of an experienced builder or a dedicated tinkerer, it just works.
Two Iconic Titans of Rock & Metal Join Forces for a Can’t-Miss North American Trek
Tickets Available Starting Wednesday, April 16 with Artist Presales
General On Sale Begins Friday, April 18 at 10AM Local on LiveNation.com
This fall, shock rock legend Alice Cooper and heavy metal trailblazers Judas Priest will share the stage for an epic co-headlining tour across North America. Produced by Live Nation, the 22-city run kicks off September 16 at Mississippi Coast Coliseum in Biloxi, MS, and stops in Toronto, Phoenix, Los Angeles, and more before wrapping October 26 at The Cynthia Woods Mitchell Pavilion in The Woodlands, TX.
Coming off the second leg of their Invincible Shield Tour and the release of their celebrated 19th studio album, Judas Priest remains a dominant force in metal. Meanwhile, Alice Cooper, the godfather of theatrical rock, wraps up his "Too Close For Comfort" tour this summer, promoting his most recent "Road" album, and will have an as-yet-unnamed all-new show for this tour. Corrosion of Conformity will join as support on select dates.
Tickets will be available starting Wednesday, April 16 at 10AM local time with Artist Presales. Additional presales will run throughout the week ahead of the general onsale beginning Friday, April 18 at 10AM local time at LiveNation.comTOUR DATES:
Tue Sep 16 – Biloxi, MS – Mississippi Coast Coliseum
Thu Sep 18 – Alpharetta, GA – Ameris Bank Amphitheatre*
Sat Sep 20 – Charlotte, NC – PNC Music Pavilion
Sun Sep 21 – Franklin, TN – FirstBank Amphitheater
Wed Sep 24 – Virginia Beach, VA – Veterans United Home Loans Amphitheater
Fri Sep 26 – Holmdel, NJ – PNC Bank Arts Center
Sat Sep 27 – Saratoga Springs, NY – Broadview Stage at SPAC
Mon Sep 29 – Toronto, ON – Budweiser Stage
Wed Oct 01 – Burgettstown, PA – The Pavilion at Star Lake
Thu Oct 02 – Clarkston, MI – Pine Knob Music Theatre
Sat Oct 04 – Cincinnati, OH – Riverbend Music Center
Sun Oct 05 – Tinley Park, IL – Credit Union 1 Amphitheatre
Fri Oct 10 – Colorado Springs, CO – Broadmoor World Arena
Sun Oct 12 – Salt Lake City, UT – Utah First Credit Union Amphitheatre
Tue Oct 14 – Mountain View, CA – Shoreline Amphitheatre
Wed Oct 15 – Wheatland, CA – Toyota Amphitheatre
Sat Oct 18 – Chula Vista, CA – North Island Credit Union Amphitheatre
Sun Oct 19 – Los Angeles, CA – Kia Forum
Wed Oct 22 – Phoenix, AZ – Talking Stick Resort Amphitheatre
Thu Oct 23 – Albuquerque, NM – Isleta Amphitheater
Sat Oct 25 – Austin, TX – Germania Insurance Amphitheater
Sun Oct 26 – Houston, TX – The Cynthia Woods Mitchell Pavilion
*Without support from Corrosion of Conformity
MT 15 and Archon 50 Classic amplifiers offer fresh tones in release alongside a doubled-in-size Archon cabinet
PRS Guitars today released the updated MT 15 and the new Archon Classic amplifiers, along with a larger Archon speaker cabinet. The 15-watt, two-channel Mark Tremonti signature amp MT 15 now features a lead channel overdrive control. An addition to the Archon series, not a replacement, the 50-watt Classic offers a fresh voice by producing retro rock “classic” tones reminiscent of sound permeating the radio four and five decades ago. Now twice the size of the first Archon cabinet, the Archon 4x12 boasts four Celestion V-Type speakers.
MT 15 Amplifier Head
Balancing aggression and articulation, this 15-watt amp supplies both heavy rhythms and clear lead tones. The MT 15 revision builds off the design of the MT 100, bringing the voice of the 100’s overdrive channel into its smaller-format sibling. Updating the model, the lead channel also features a push/pull overdrive control that removes two gain stages to produce vintage, crunchier “mid gain” tones. The clean channel still features a push/pull boost control that adds a touch of overdrive crunch. A half-power switch takes the MT to 7 watts.
“Seven years ago, we released my signature MT 15 amplifier, a compact powerhouse that quickly became a go-to for players seeking both pristine cleans and crushing high-gain tones. In 2023, we took things even further with the MT 100, delivering a full-scale amplifier that carried my signature sound to the next level. That inspired us to find a way to fit the 100's third channel into the 15's lunchbox size,” said Mark Tremonti.
“Today, I’m beyond excited to introduce the next evolution of the MT15, now featuring a push/pull overdrive control on the Lead channel and a half-power switch, giving players even more tonal flexibility to shape their sound with a compact amp. Can’t wait for you all to plug in and experience it!”
Archon Classic Amplifier Head
With a refined gain structure from the original Archon, the Archon Classic’s lead channel offers a wider range of tones colored with gain, especially in the midrange. The clean channel goes from pristine all the way to the edge of breakup. This additional Archon version was developed to be a go-to tool for playing classic rock or pushing the envelope into modern territory. The Archon Classic still features the original’s bright switch, presence and depth controls. PRS continues to stock the Archon in retailers worldwide.
“The Archon Classic is not a re-issue of the original Archon, but a newly voiced circuit with the lead channel excelling in '70s and '80s rock tones and a hotter clean channel able to go into breakup. This is the answer for those wanting an Archon with a hotrod vintage lead channel gain structure without changing preamp tube types, and a juiced- up clean channel without having to use a boost pedal, all wrapped up in a retro-inspired cabinet design,” said PRS Amp Designer Doug Sewell.
Archon 4x12 Cabinet
As in the Archon 1x12 and 2x12, the mega-sized PRS Archon 4x12 speaker cabinet features Celestion V-Type speakers and a closed-back design, delivering power, punch, and tight low end. Also like its smaller brethren, the 4x12 is wrapped in durable black vinyl and adorned with a British-style black knitted-weave grill cloth. The Archon 4x12 is only the second four-speaker cabinet in the PRS lineup, next to the HDRX 4x12.
PRS Guitars continues its schedule of launching new products each month in 2025. Stay tuned to see new gear and 40 th Anniversary limited-edition guitars throughout the year. For all of the latest news, click www.prsguitars.com/40 and follow @prsguitars on Instagram, Tik Tok, Facebook, X, and YouTube.