THE MODERN SCIENCE OF SOLID BODY GUITAR TONE
(originally written Jan 2023; Update April 2023)
The credit for most of this goes to YouTubers like Jim Lill, Glenn at Spectre Sound Studios, and Josh of JHS. These guys did the work, I just tried to put it together in one place.
How important are the components of a rig to your overall solid body electric guitar or bass tone? I was one of those guys that believed in the voodoo and the marketing myths of guitars until Josh Scott started opening my eyes about digital pedals. Now, are there people out there who insist they can hear the subtle differences between a vintage Fender and a properly setup Fender Squier with the same specs? Of course - there's always at least one. But I would wager the rest of us honest folk can't, especially in a mix.
Clean or Distortion
Playing on the same amp's clean channel, the unique tone of different instruments might be heard. But Glenn of Spectre Sound, a metal musician and engineer, demonstrated that once you start applying distortion, all the unique variables of a guitar become less prominent. It seems the compression, clipping, and volume mask the subtleties that cleaner players might find. In a nutshell, if you play ten different solid body guitars unplugged, you may get ten different tones (or actually timbres). Plugged into the same clean amp and speaker cabinet, and the tonal differences between them begin to decrease or start to be filtered out. But play them through the same distortion effect and rig, those guitars will start to sound very similar. As you increase distortion, differences in tone become less noticeable.
Increasing the distortion reduces tonal differences between instrument components.
The Wood & Finish
I used to believe that wood was the base of the tone pyramid and that without an expensive foundation, the tone was going to be of lesser quality. Evidence shows this is not the case. I also believed that too thick of a paint job would dull the tone and kill the sustain. Oddly, I have a Japanese Squier that I repainted with really thick Home Depot spray paint, but I love how it sounded clean - I used to think, "that's strange how this cheap EMG Select pickup doesn't care about this awful finish." Burls Art has made plenty of nice-sounding electric guitars* without traditional finishes, or even using wood - go check out his video of the guitar he made out of a shovel if you doubt anything on this page.
Here is a short video of a luthier describing the results of building five different guitars with identical pickup locations and using the same humbuckers, then installing different humbuckers."Are we guitar players or are we amp players?"
Material and finish make very little difference.
* Burl is certainly using some after effects to refine the shovel tone, but isn't that the case of every professionally produced album? It is an excellent demonstation that wood choice is not integral to good tone.
The Pickup & Electronics
The pickup can play a role in tone. It seems the most significant difference between pickups is that they are either single coil or they are humbucker. Different brands and designs may have more-than-subtle differences when played clean. But when you add distortion, most single coils will start to sound similar and most humbuckers will start to sound similar. The heavier the distortion, the more similar two different humbuckers will sound. Do understand that the position of a pickup along the length of the string and the pickup's height play a larger role than the pickup itself. What about pickup quality? Well, it seems that as long as a pickup isn't microphonic, pickups of varying quality will sound more similar as distortion increases. Properly functioning trim pots and orange drops from different manufactures will all sound similar, although their values can roll off higher frequencies differently.
Ultimately, a pickup is a "magnetic sensor" - it cannot hear the acoustic properties of wood or measure the movement of air since it is only able to recognzie the magnetic field between iteslf and the steel strings moving above it.
When playing clean, different pickups can make a difference.
Positioning of that same pickup can make a difference the further you move it.
As you add distortion, any difference between pickups will start to disappear.
Pickup height will affect sustain (high output pickups have a greater magnetic pull to slow vibrating strings).
Note: some pickups are hotter, which increases output volume. As Josh has explained, "loud is more good" to our ears. Higher output pickups are similar to using a TubeScreamer or other booster.
The Hardware & Body-Neck Interface
This has more to do with sustain than the tone of the instrument. There seems to be little to no difference between the mass of the hardware or the materials they are made of. As an example, the barely subtle tone difference between a brass and an aluminum bridge. For the best sustain and tuning stability, high quality hardware with tight tolerances, a stiff neck, and a proper setup are ideal, though these might even be questionable: Jim bolted a neck to a body with bubble wrap sandwiched between them and found no discernable difference to tone.*
Different hardware designs and hardware materials make very little difference.
Neck-through versus bolt-on makes very little, if any, difference.
String-through bridges? Given the other results in this category, this likely makes no difference.
* So much for me preferring those cooler-looking neck-through designs that may get damaged but can't be fixed with an off-the-shelf neck.
This plays a role in how well the guitar will stay in tune, by allowing the strings to slide over it easily without getting hung up. A graphit nut will provide a smoother surface than a plastic nut. Also, an incorrectly filed nut or poorly adjusted Floyd Rose can adversely affect tuning, intonation, and sustain. However, that is more of an issue with set-up rather than a contributor to tone.
Scale Length & Tension
Jim found that outside the pickup and the quality of the hardware, the one factor that dictates an instrument's intrinsic tone most is the scale length. This is likely attributed to string tension, though. Longer scales have a "brighter" tone due the increased tension on the strings. I began thinking of the scale as defining the timbre of a solid body instrument. Jim proved, by building a guitar out of a 2x4 and one with no body at all, that he could get a similar tone to a conventional guitar of the same scale. So, if you use the same pickup, pickup placement, hardware, and scale, then you will get a very similar tone.
Scale length can make a difference, but this is likely due to string tension. However...
Matching string tension (by changing string gauges) can make different scale lengths sound similar.
Still, difference due to tension will become less noticeable as you increase distortion.
The Strings, in Regards to Metal
I've not seen or done a lot of research on this, yet. The differences in tone tend to be subtle between string models, but even more subtle as you increase distortion. For playing through distortion, strings and string gauges might be better chosen based on feel, resistance to your sweat, and price. Very few will ever argue that old strings sound better than new strings, though. Also, some strings are designed to work better for different applications, such as being wound long enough for longer-scaled bass guitars - this affects set-up rather than tone. However, matching string design and tension on different scale lengths can sound similar through a clean amp.
The Amplifier & Effects
Glenn found that when you plug in and start adding distortion, the subtleties of an instrument start to get drowned out. The more distortion you add, the less unique a specific guitar will sound. When you add enough distortion, different guitars will start to sound identical on that same amp - the tiny subtleties just aren't worth the argument, especially in a live mix. Different amp circuits do influence the tone differently, though. The differences between amps has to do with how the signal routes through the circuit board (aka topology). For example, where in the chain does the EQ effect the signal and where in the chain are the amp's gain stages? Think about how a modulation pedal changes the end result compared to it being placed first or last in a chain. This all applies to distortion pedal circuit designs as well.
The circuits and the way the signal is routed through an amplifier can make a difference.
Tube versus Solid State or Analog vs Digital
Josh fooled everyone with a Kemper and his love of DigiTech effects. Differences are extremely subtle when you mimic a circuit's topology. Changing tube manufacturers does not make a difference - think of them as lightbulbs to better wrap your brain around this.
Speakers essentially have an EQ curve built into them. Equalizers manipulate tone, and speakers will do the same thing. Some speakers are of inferior quality or made of different materials, which make them respond faster or slower to input. A damaged speaker will fail to produce certain frequencies and/or produce undesirable frequencies.
Glenn has a video analyzing the audible differences of Celestion V30 speakers over the past 20yrs - it was the dust cap!
Speakers make THE BIGGEST difference because their design dictates how they reproduce frequencies.
Speakers seem to mostly impact frequencies above 1k, while cabinets seem to mostly impact frequencies below 1k.
The Speaker Cabinet
Jim built various cabinets while using the same speakers. He found that the dimensions and layout of the cabinets plays a bigger role than the material the cabinets are made of.* His theory is that a different cabinet geometry can cause the same speaker to reproduce frequencies differently. For example, an open back cabinet will allow the speaker to move more freely, while a sealed cabinet may interfere with the same speaker's movement. This may not always be a bad thing as these differences can cause the frequencies to bounce differently, thus impede or facilitate the speaker's movement ...in other words, reduce or amplify certain frequencies.
Speaker cabinet layout/geometry make a big difference.
Cabinets seem to mostly impact frequencies below 1k, while speakers seem to mostly impact frequencies above 1k.
* as long as the material affects sound similarly. For instance, wood and styrofoam both reflect/deflect sound waves (albiet, to different degrees), while acoustic foam will absorb sound waves.
The Player's Hands (Heavy Metal)
When it comes to playing with distortion, the tone becomes indistinguishable between different players using the same techniques.