It’s such a nice day out, it seems a shame to ruin it by offending as many readers as possible. But here goes anyways …
On a solid body electric, I don’t think a good nitrocellulose finish sounds any better than a good poly one.
Many guitarists, particularly those who love vintage instruments, believe everything affects the sound of those great old guitars we love so much. One longstanding claim in particular is that the finish affects the tone, with nitro finishes being at the top of the tone heap and poly finishes at the bottom because of their supposed blanketing effect.
But the real problem for tone on a solid body is not whether it’s nitro or poly, but how well it’s applied. The incredibly thick poly coatings from the Sixties and Seventies that are still used on many budget guitars is heavy enough to affect resonance and have given these finishes a bad reputation. But quality modern poly finishes can be applied much more thinly, like traditional nitro.
At that point, the differences between finishes are more about cost, environmental safety, durability, feel and aesthetics, not sound.
A lot of our preferences have to do with tradition. “Nitro” lacquer finishes come to us via the world of classical stringed instruments. There, the low mass, thinness and hardness of a nitro finish matches well with the light, thin, stiff spruce tops of violins and cellos.
Because they are built so delicately, on classical stringed instruments and acoustic guitars, the finish represents a substantial proportion of the soundboard’s mass and stiffness. So historically it makes sense that nitro was (literally) applied to acoustic guitars as well, since they share a lot of physical similarities to violins.
But finishes don’t do nearly as much to the vibration of a roughly 2-inch thick Strat or Les Paul as they do to the 1/10” thick soundboard of spruce on a Martin. There just isn’t enough in a thin finish for it to matter whether it is poly or nitro when it comes to the way the electric’s body vibrates.
Besides which, the sound of a solid body electric is created by the pickups sensing the strings’ motion, which is then passed to the amplifier—not by the vibrating top acting like a speaker cone as on an acoustic guitar. So again, the finish is a less critical aspect of the sound.
“Aha!,” you say, “But the body vibrates and this vibrates the pickups, adding to the tone!”
It’s true enough that the pickups themselves vibrate. But it’s miniscule compared to the vibration of the strings—as you can see for yourself when you play a chord. The strings flap all over the place, but (hopefully) not the pickups.
Moreover, the pickups are not exactly held in a sound-enhancing material. In a Strat-style electric, for instance, they’re suspended by rubber tubing or springs screwed into a plastic pickguard.
If the pickup’s vibrations are so important, we should really be arguing about whether vintage bakelite, single-ply or multi-ply plastic pickguards sound best. Or better yet, we should demand hand-carved, tap-tuned spruce pickguards finished in nitro.*
Nitrocellulose lacquer (commonly called “nitro” or simply just “lacquer”) finishes are great, don’t get me wrong. If you think they look beautiful, I agree. If you dig their majestic “mojo” and the way they wear over time, awesome. If you’re restoring a vintage instrument to its original finish, I think you’re doing the right thing. But don’t count on nitro to change, let alone improve the sound of a solid body electric in any way you can hear compared to a well-applied poly finish.
Still not convinced? Determined that you can hear the difference between these two well-applied but different finishes on a solid body?
Then let me share a little thought experiment with you. Imagine yourself playing the guitar. Which do you think has the biggest effect on the sound:
A. A millimeter-thick coating of nitro.
B. A millimeter-thick coating of poly.
C. Sandwiching your electric guitar between eight pounds of sweaty forearm and 200 pounds of flannel-covered beer belly.
If you believe the type of thin finish on a thick guitar makes a noticeable difference to the sound, then the same reasoning says that holding the guitar against your body as you play makes hundreds or even thousands of times more difference. Contact with your body is going to substantially muffle and alter a solid body electric’s sound orders of magnitude more than any sonic benefit you might get from coating the guitar in nitro, poly or waffle syrup.
There's more point in debating what material your shirt is made of.
And no, that’s not an argument for wearing polyester.
* Patent pending. Just in case.