IRYW - Tone : you think you do, but you don’t

Ah, tone. That mystical quality that makes guitarists spend thousands on vintage gear and argue endlessly on forums about whether brass or steel bridge pins make a difference. We all know what good tone is, right?

Well... maybe not as much as we think.

The Golden Ear Myth

Let's start with a controversial statement: Most of us can't actually hear what we think we can hear. You know that guy who swears he can tell the difference between a 1959 Les Paul and a 1960 just by listening? He's probably wrong.

But before you grab your pitchforks, let me explain why this isn't an insult - it's just how our brains work.

The Science of Sound (and Self-Deception)

Here's what actually happens when we evaluate tone:

1. Our ears receive sound waves
2. Our brain processes these waves through the auditory cortex
3. Our expectations, biases, and previous experiences color our perception
4. Higher cognitive processes in the prefrontal cortex integrate this information with our memories and expectations
5. We form an opinion that we think is purely about sound, but isn't

The tricky part? Most of this happens without us realizing it. The scientific term for this is "expectation bias," and it's been extensively documented in music perception studies. A famous 2012 study by Claudia Fritz had professional violinists try to distinguish between Stradivari violins and modern instruments. Not only could they not reliably tell the difference - many preferred the modern instruments when playing blind.

This isn't unique to string instruments. A 2010 study in the Journal of Wine Economics found that even expert wine tasters were significantly influenced by price tags and labels - similar to how guitarists react to brand names and vintage years. Our brains quite literally process the same sensory input differently based on our expectations.

The Wood Doesn't Lie (But We Do)

Let's talk about tonewood - everyone's favorite argument starter. Recent scientific research tells us something fascinating about wood properties that most tone-obsessed guitarists completely ignore.

The Species Myth: When Averages Lie

Before we dive into moisture content, let's tackle a fundamental misunderstanding about tonewood species. Guitar forums love to debate whether maple sounds "brighter" than mahogany, or if Indian rosewood has more "bottom end" than East Indian rosewood. But these discussions ignore a crucial statistical reality: the variation within species is often greater than the average difference between species.

Think about human height. Yes, Dutch people are on average taller than Italian people, but if you picked a random Dutch person and a random Italian person, would you bet your life savings on the Dutch person being taller? Of course not - because the variation within each population is much larger than the average difference between them.

The same principle applies to wood. Research shows that factors like:

1. Density variation (which can vary by 20% within the same species)
2. Growth ring spacing (which affects stiffness and damping)
3. Grain orientation and regularity
4. Cellular structure variations

Can create bigger differences between two pieces of the same species than the average difference between two different species. A study by Brémaud found that the coefficient of variation for mechanical properties within species could be as high as 30%, while the average differences between similar species were often less than 10%.

So when someone tells you "maple sounds brighter than mahogany," they're making the same kind of oversimplification as saying "Dutch people are tall" - it might be true on average, but it's nearly meaningless when looking at individual samples.

The Moisture Factor

A comprehensive 2018 study published in Acta Physica Polonica A revealed that moisture content in wood has a dramatic impact on tone - far more than many of the subtle differences we obsess about. The research found that:

1. Wood moisture content directly affects the damping properties (how the wood absorbs and transmits vibration)
2. Even small changes in relative humidity can significantly alter these properties
3. The effect is particularly pronounced in spruce, one of the most common tonewoods
4. Professional instrument makers dry their soundboards to approximately 6% wood moisture for optimal performance

For perspective: the difference in damping properties between properly and improperly moisturized wood is often greater than the difference between various species of tonewood that guitarists endlessly debate.

Age Isn't Just a Number

The same study found fascinating differences between new and old wood:

1. Old spruce (130+ years) showed more uniform moisture release patterns
2. New wood was more unstable in its moisture retention
3. Older wood generally demonstrated lower damping, which translates to longer sustain and potentially more complex harmonics

But here's the kicker: while professional luthiers carefully control wood moisture and understand these aging processes, most guitarists are too busy arguing about whether Madagascar or Indian rosewood sounds "warmer" - a distinction that's often smaller than the impact of a 5% change in wood moisture content.

The Marketing Machine vs. Reality

This statistical reality creates an awkward situation for guitar manufacturers. It's much easier to market "premium Honduran mahogany" than to explain "we carefully select wood samples based on their individual mechanical properties regardless of species." This leads to marketing-driven myths that ignore the complex reality of wood properties.

Consider this: Two pieces of maple from the same tree can have more different tonal properties than maple and mahogany from different continents. Studies of wood mechanics show:

1. Density can vary by up to 30% within a single tree
2. Elastic modulus (stiffness) can vary by 25% or more
3. Damping properties can differ by up to 40%

These variations often dwarf the average differences between species that we obsess over in guitar forums.

The Real Variables Nobody Talks About

The study found that the wood's damping properties (tan δ) were:

1. Almost completely frequency-independent in the range relevant to guitars (0.3 Hz to 70 Hz)
2. Highly dependent on strain (how much the wood bends during vibration)
3. Significantly affected by moisture content, especially in aged wood

In other words, how hard you play and how well you maintain your instrument's moisture content matter more than many of the wood species differences we obsess over.

The Science of Wood Selection

Let's get technical about how wood properties are actually measured and selected. When manufacturers test tonewood, they're looking at several key properties:

Density (ρ)

1. Measured in kg/m³
2. Varies significantly even within individual trees
3. Typical ranges for common tonewoods:
4. Spruce: 350-500 kg/m³
5. Maple: 580-750 kg/m³
6. Mahogany: 500-600 kg/m³
7. BUT: Individual samples regularly fall outside these ranges

Dynamic Young's Modulus (E)

1. Measures wood's stiffness
2. Ranges from 10-20 GPa for most tonewoods
3. Can vary by up to 40% within species
4. Measured through:
5. Vibration testing (non-destructive)
6. Stress-strain analysis
7. Ultrasonic testing

Damping Properties (tan δ)

1. How quickly vibrations decay
2. Typically ranges 0.005-0.02 for quality tonewood
3. Measured through:
4. Free-free beam vibration tests
5. Forced vibration analysis
6. Dynamic mechanical analysis (DMA)

How Manufacturers Actually Select Wood

Guitar manufacturers use a combination of methods to select wood (when they do, and trust me most of them don’t) :

1. Initial Screening
2. Visual inspection for grain straightness
3. Density measurement through weight/volume
4. Basic mechanical measurements
5. Scientific Testing
6. Velocity of sound measurement (c = √(E/ρ))
7. Radiation ratio (R = c/ρ)
8. Cross-grain to with-grain stiffness ratio
9. Damping measurements at various frequencies
10. Characteristic Index (K)
11. Many makers use a combined metric: K = √(E/ρ³)
12. Higher K values generally indicate better acoustic properties
13. But: K varies more within species than between them

The Tap Testing Myth

This is how the writer sees tap testers.

Let's talk about one of the most persistent myths in lutherie: tap testing. You've probably seen it - a luthier taps a piece of wood, listens thoughtfully, and pronounces judgment on its tonal qualities. It seems romantic and traditional, but there are some major problems with this method:

1. Node Problems
2. Wood plates have specific vibration modes with nodes (points of no movement) and antinodes (points of maximum movement)
3. Holding the wood at any point other than a node dampens these vibrations
4. Most tap testers don't precisely locate nodes before testing
5. Result: Same piece of wood sounds different depending on where it's held
6. Repeatability Issues
7. Tap force varies between tests
8. Tap location isn't consistent
9. Holding pressure changes between tests
10. Environmental conditions affect results
11. Result: Same tester gets different results on different days
12. Human Hearing Limitations
13. Our ears are logarithmic, not linear detectors
14. We can't accurately compare frequencies separated by time
15. Our perception is heavily influenced by room acoustics
16. Memory for tonal quality is notoriously unreliable
17. Result: Even trained listeners can't make consistent judgments
18. Scientific Testing vs. Tap Testing
19. Proper vibration analysis shows:
20. 20-30% variation in measured response from same piece with different tap locations
21. Up to 50% variation in measured response with different holding positions
22. Significant variations based on room temperature and humidity

The reality? Tap testing is about as scientific as a wine tasting - it might be fun and traditional, but it's not a reliable measurement tool. Professional manufacturers use:

1. Controlled vibration testing
2. Accelerometer measurements
3. Frequency analysis
4. Standardized holding fixtures

These methods provide repeatable, quantifiable results that can actually predict how wood will perform in an instrument.

The Numbers Nobody Tells You

Here's where it gets really interesting. Studies of wood properties reveal some uncomfortable truths for tonewood purists:

1. Within-Species Variation
2. Density: ±20-30% from mean
3. Stiffness: ±25-35% from mean
4. Damping: ±40-50% from mean
5. Between-Species Differences
6. Average difference in density between similar species: 5-15%
7. Stiffness variation between related species: 10-20%
8. Damping differences between species: 15-25%

You can see the problem as we showed earlier: the variation within each species is often larger than the difference between species.

How This Affects Sound Production

The way these properties affect actual sound production is complex:

1. Frequency Response
2. Higher stiffness/density ratio = higher fundamental frequencies
3. More uniform density = more even harmonic response
4. Variations as much as 3dB in key frequency bands between samples of same species
5. Sustain
6. Affected primarily by damping properties
7. Can vary by 20-30% between samples of same species
8. More dependent on individual piece than species average
9. Harmonic Content
10. Complex interaction between density and stiffness
11. Can produce 5-10dB differences in upper harmonics
12. Individual variation often exceeds species characteristics

Real-World Measurement Methods

Here's how these properties are actually measured in the real world:

1. Non-Destructive Testing
2. - Acoustic excitation and response measurement - Ultrasonic velocity measurement - Vibration analysis using accelerometers - Modal analysis using laser vibrometry
3. Physical Measurements
4. - Density through precise volume/mass - Moisture content through resistance meters - Growth ring counting and analysis - Microscopic structure analysis
5. Dynamic Testing
6. - Free-free beam vibration analysis - Forced vibration response - Impact excitation tests - Frequency sweep analysis

The Selection Premium

When you buy a premium guitar, you're not just paying for the species of wood - you're paying for selection. High-end manufacturers test and select wood samples that meet specific criteria for density, stiffness, and damping properties. This selection process, not the species itself, is often what makes premium instruments sound better.

A study by Sproßmann et al.5 found that:

1. Only about 10% of commercially available tonewood meets the criteria for premium instruments
2. The best-performing samples often weren't from the "premium" species
3. Careful selection of "ordinary" species could produce instruments that performed as well as those made from "premium" species

The Blind Test Challenge

Want to test your golden ears? Try this:

1. Record yourself playing the same riff on different guitars
2. Wait a week (so you forget which is which)
3. Listen blind and try to identify them
4. Prepare to be humbled

Most people perform barely better than random chance on tests like this. Even experienced players often can't tell their precious vintage instrument from a well-made modern equivalent in truly blind tests.

So What Actually Matters?

If our perception of tone is so unreliable, what should we focus on? Here's what scientific research suggests actually makes a difference:

1. Physical Condition and Maintenance

Research shows that wood stability and performance depend heavily on proper maintenance:

1. Maintaining proper moisture content (ideally around 6-9% for most tonewoods)
2. Preventing rapid moisture changes which can affect wood's damping properties
3. Regular setup adjustments to compensate for seasonal changes

A well-maintained budget guitar will genuinely outperform a poorly maintained premium instrument - this isn't just opinion, it's backed by measurable differences in wood behavior and vibration characteristics.

2. Environment and Acoustics

Studies in room acoustics reveal that your playing environment affects your tone more than most gear changes:

1. Room modes can boost or cut certain frequencies by up to 12dB
2. Early reflections significantly affect our perception of tone
3. Room size and material properties have a larger impact on frequency response than most pickup changes

3. Playing Technique

Biomechanical studies of guitar playing show that technique variables have massive effects on tone:

1. Pick angle can alter harmonic content by up to 15dB in certain frequencies
2. Picking position varies the harmonic content more than most pickup switches
3. Picking force affects string excitation in ways that overwhelm subtle equipment differences

4. Basic Setup

Mechanical setup affects vibration transmission in fundamental ways:

1. Bridge height affects string break angle and thus vibration transfer
2. Neck relief changes string vibration patterns
3. Nut slot depth influences open string resonance
4. These mechanical factors often have 5-10 times more impact on tone than boutique component upgrades

The Liberation of Being Wrong

Here's the good news: realizing we might be wrong about tone is actually liberating. It means:

1. You don't need to spend a fortune to get "good tone"
2. You can focus on playing rather than endless gear acquisition
3. You're free to like what you like, regardless of what others think

Conclusion

The real secret to good tone isn't in your gear - it's in your head and your hands. The best tone is the one that inspires you to play better and express yourself more fully. Whether that comes from a custom shop masterpiece or a well-set-up budget model doesn't really matter.

So the next time someone tells you that only Brazilian rosewood provides "authentic tone," or that you absolutely need vintage PAF pickups for "that sound," remember: they think they know, but they probably don't.

And neither do you. And that's okay.

P.S. If this article made you angry, that’s a very good sign. That means you are experiencing what is called contradiction, and that is good for all of us.

Except me, because remember, I’m Right, You’re Wrong !*

Footnotes

1. Fritz, C., Curtin, J., Poitevineau, J., Morrel-Samuels, P., & Tao, F. C. (2012). Player preferences among new and old violins. Proceedings of the National Academy of Sciences, 109(3), 760-763.
2. Goldstein, R., Almenberg, J., Dreber, A., Emerson, J. W., Herschkowitsch, A., & Katz, J. (2008). Do more expensive wines taste better? Evidence from a large sample of blind tastings. Journal of Wine Economics, 3(1), 1-9.
3. Brémaud, I. (2012). Acoustical properties of wood in string instruments soundboards and tuned idiophones: Biological and cultural diversity. The Journal of the Acoustical Society of America, 131(1), 807-818.
4. Göken, J., Fayed, S., Schäfer, H., & Enzenauer, J. (2018). A Study on the Correlation between Wood Moisture and the Damping Behaviour of the Tonewood Spruce. Acta Physica Polonica A, 133(5), 1241-1260.
5. Sproßmann, R., Zauer, M., & Wagenführ, A. (2017). Characterization of acoustic and mechanical properties of common tropical woods used in classical guitars. Results in Physics, 7, 1737-1742.