From the March/April 2022 issue of Acoustic Guitar | By Martin Keith
In this installment of our Ask the Expert series, we dive into the question of bridge pins. There are so many different materials for acoustic guitar bridge pins, but how much difference do they make in your guitar tone?
Q: I’ve seen many advertisements for Tusq, ivory, and even brass bridge pins, and how they can enhance the tone of your guitar. Is there any substance to this? —Brian Beymer
A: On a responsively built instrument, bridge mass is an important variable, and the bridge pins can vary that mass by a meaningful amount. The bridge is the first point of excitation from string energy, and how it responds to that excitation can help determine the instrument’s character. A lightweight bridge will react quickly, yielding a very lively transient response with high sensitivity to touch and technique. The downside is that lighter bridges also tend to give a little less sustain, as the energy is dissipated into the top more quickly. A higher-mass bridge system will reflect some of the string’s energy back into the vibrating length, prolonging the sustain a little. Heavier bridges offer a little less dynamic range to the instrument, as they raise the threshold of energy required to excite the top. However, some makers feel that slightly heavier bridges favor bass frequencies, either by slowing down the top’s vibrational modes or by acting as a filter of sorts, reducing the relative balance of the mids and highs.
On most factory guitars, these differences will be relatively minor, as the tops on those guitars are most often built a bit heavier than is absolutely necessary. Changes from one extreme to the other—going from plastic to brass bridge pins, for example—will probably have the most audible effect, and each player’s ear may prefer something different. If you have a guitar that feels sluggish or uninspiring, a set of lighter bridge pins may help give it a tiny bit of extra life. Conversely, brass pins may help an uneven-sounding instrument sound a bit more controlled by smoothing out frequency peaks where the top is overly sensitive.
Another important consideration is the proper fit of the pins. Pins that are too loose can lead to premature wear or damage on the all-important bridge plate inside the guitar, and replacing a bridge plate is pretty unfriendly work to both the hands and the budget. If the pins are not tight enough, the ball ends can pull up into the gap between pin and hole inside the guitar, compressing and crushing the fibers of the plate.
Overly tight pins can also cause problems—the wedging force of a long, shallow taper is considerable—even more so when multiplied by six. When installing new pins, be cautious about forcing them too tightly into the holes. I’ve seen bridges that were split right down the middle by this very thing. The pin should fit snugly with minimal pressure, but not so tightly that it can’t be removed by hand. (It’s also not fun to break a string on a gig and have to go digging for pliers to extract a stubborn pin.)
Finally, when shopping for new pins, take note of whether your bridge needs the slotted or unslotted variety. Some bridges have plain holes for the pins, and in those cases the pins themselves must be slotted to create a channel for the strings to pass through. In other cases, the holes in the bridge have slots cut in, creating a sort of keyhole shape. Bridges with this detail normally use unslotted pins to avoid having excessive clearance around the string path, which can lead to the same issues described above regarding loose pins.
This is a fun way to play with altering the tone of your favorite guitar. Replacement pins are fairly inexpensive and are available in a broad range of materials—from bone to ebony, brass, titanium, and modern composites such as Tusq. They can also add a touch of visual flash to an otherwise plain-looking guitar—I’ve had a few come in with alternating black-and-white pins, and one once with bright red anodized aluminum ones. Along with different brands and compositions of strings, this is one of the few easy places to experiment with shaping the sound of your acoustic—alongside practicing, of course!
This article originally appeared in the March/April 2022 issue of Acoustic Guitar magazine.