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How and Why Woods Affect Your Bass Sound

Skjold Design Guitars bass bodies

Q: Experience and all instrument makers tell us that the choice of wood affects the sound of a bass. Of course we know and feel the difference of alder vs. ash bodies, ebony vs. rosewood vs. maple fingerboards, and so many other differences. But, do we know why exactly this affects the amplified sound? What we deal with are metal strings vibrating in the magnetic field of pickups (not talking about piezos). The resonances of the body should not be captured by the pickups. I imagine that the construction of a bass affects, for example, the sustain. But this is not about wood. So what exactly happens here? How would a physician explain this? Does the wood affect the overtone structure of the vibrating string? Voodoo? Black magic?

A: As this is not in my area of expertise, I decided to send this week’s question to my favorite luthier, Pete Skjold, the guru behind most of the basses I play these days and well respected within the bass playing community. (You can discover more about Pete and his instruments here.)

Here is what Pete had to say:

These are general terms, so keep that in mind. Different density of wood produces different results, because the woods vibrate at different frequencies. The string receives these frequencies (which we call tone) and then the pickup reproduces these frequencies based on it’s own ability to reproduce the sound into an electrical signal.

Generally, the more resonant the wood, the broader and smoother the tone will be from the lower to higher frequencies. The denser the woods, the more you’ll get a more focused, narrower frequency band.

Knowing which woods generally produce a certain frequency range and tone will allow a builder use the proper combination of resonance and focus to achieve the tonal goal. Leo Fender found a great combination with the classic Jazz bass. He typically used very light and resonant alder for the body, giving it a great amount of range from the bass response to the midrange. The necks, being made of denser maple, gave the midrange more focus. Capping the neck with a dense, but open grained rosewood fingerboard added a nice sweet treble to the top end of the tone, but the open grain was less bright than a fingerboard of maple. This made the bass perfect for the types of tone we hear in classic rock, country and blues.

Later as dense ash bodies were introduced with maple fingerboards, the character of the tone was changed. The denser ash added more focus to the low mids and the maple fingerboard added even more treble range to the bass. This gave way to the basses being particularly good for slapping and popping.

Today, with all the various woods available to builders, there are even more possibilities to choose from.

Well, there you have it!

Does anyone else have any thoughts or insight? Share your thoughts in the comments a comment below!

(And thanks Pete!)

Photo taken from our Custom Shop feature on Skjold Design Guitars.

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    Graham

    Graham

    It’s all very well applying science to this subject but wood is not a scientific substance. It is natural. Every tree grows at a different rate which will affect the density of each piece of wood. You can prove anything you want with a scientific formula. Nature does not conform to formulas.

    Bradlee Thedawg

    Bradlee Thedawg

    This whole topic is fraught with pseudo-science. The only fact out this entire thread is that “variables impact solid-body instrument tone”. The problem is that EVERYTHING is a variable. There is nothing whatsoever consistent about a “species” of wood – so you simply can not say “Maple is this…. Basswood is that…” Also – the body is not vibrating until the player makes the string vibrate. So there is nothing additive here. The string is put into motion… that vibration transfers TO the bridge/nut/frets/body.. NOT the other way around (unless you have some kind of yet-to-be-invented sustainer contraption that makes the body vibrate). So what actually happens is the properties of all those things – string/nut/fret/bridge/ air spaces around the pickups/ neck/body joint… and yes the characteristics of the body/neck wood… all those things are ABSORBING overtones… absorbing the fundamental…..some of the series faster than others.. and therefore altering what the pickup “hears”. That’s really all there is to it – and some of this response can be predicted successfully – other aspects of it can’t be unless you know a ton more about the wood your using than most organic chemists and micro-biologists know. So some wood combinations might absorb midrange fundamentals and their overtone series more than the high and low-end… so that bass is going to sound more “scooped”. Another, with identical hardware and electronics might absorb everything BUT the mid-range… so that bass is going to sound nasal or “quack” or “honk”. Add a thicker or thinner finish… or a different top-to-body glue joint… or a set neck instead of a bolted neck… and you’ve changed it. Now that *exact same* chunk of wood might do something different, thanks to the other variables you’ve just introduced. Bottom line – some instruments sound better than others. Some sustain longer… some have a quicker attack and shorter sustain that’s physics folks… more mass takes more energy to put in motion but will remain in motion longer. Less mass takes less energy to put into motion (i.e.- same energy… faster attack) but then also will decay much more quickly. That’s why a typical Flamenco guitar (low mass) is much ‘faster” and more “crisp” than a typical classical guitar … but the classical guitar can sustain a note easily for 4 beats at 120/min but the flamenco sadly – can not. Anyway – the bottom line here is that we’re not playing a chunk of mahogany or Swamp Ash – we’re playing a SYSTEM – the whole instrument with all of the variable acting together on the vibration of the string = the “sound of your bass”. It’s why if you take 10 otherwise identical instruments – one or two will be horrid…. 6 will be average… and 1 or two will be stellar. It’s also why you should NEVER purchase a “daily player” you can’t play before purchasing and compare to several others. Even the Sweetwater system where you can send it back without much pain doesn’t give you the opportunity to play 6 of the same basses or guitars side-by-side. So if I was going to spend upwards of say… 2 grand .. (below that it’s probably moot) on a new instrument… I’d spend another $3-400 on a plane ticket and spend the day out at Sweetwater (or wherever… Norm’s Rare Guitars … it makes no difference) … and do the side-by-side. Then I’d know all those variables were doing what i wanted. Any discussion of this topic that just talks “tone wood” totally misses the point – which is you CAN NOT predict much of anything based on just the “species” of the wood. So let’s stop the madness and just all agree “variables make basses sound different from one another… and there are 101 variables. Wood being one of them .

    Russ Griesemer

    Although not strictly bass related, it’s interesting to note the comments Peter Frampton made recently in an interview for the re-issue of “Humble Pie Rockin’ The Filmore”. When asked for a rig rundown for himself and Marriot, along with the usual heads & cabs, he made it a point to say that there were no effects used on that album, no pedals, nothing. It was guitar to amp, period. I get a bit of a warm fuzzy when I think about that…

Monsieur

Monsieur

Just play the damn thing

Paul

Paul

Wood has always affected my judgement…

Paul Cartwright

GR888 article .; I love the idea of leaning your bass against the stereo speakers to re align the molecules , in some way it would also absorb the energy of lets say Zeppelin or Jaco , and then we could tap into there vibe and the magic would be endless ;.;. there are things beyond our ability to fathom ;..

virtanen

virtanen

This thread has several good notes that should be combined. I also think that testing these mentioned details would open up a lot of more knowledge. I do admit that I hate “religious” comments about how things should be done without a proper background. Super instruments can be built with real knowledge and lots of testing.

I have been in blind tests to find out actual differences in stead of believing to hear something that does not exist. Ear-opening exercises. But require an open mind and may be bitter for a fanatic.

Probably it was Rick Turner who tried a method of aging the wood by putting it to an industrial vibrating table years back. Actually you can read about the method in more detail from here:
http://www.its.caltech.edu/~gbelford/Acoustic%20Guitar%20Central-Aging%20a%20guitar%20with%20vibrations.html

Cliff Rochester

Cliff Rochester

I bought a 65 J Bass in the early 80’s which unfortunately lost it’s authenticity when someone fitted a P Bass neck before I bought it. It is awesome to play however as I prefer the wider P Bass neck. I have played bass for over 50years professionally and knew nothing about various woods affecting resonance, tone etc until I read this article with great interest. This bass has a brass nut fitted, presumably when the neck was changed and having owned two P Basses since the early 60’S I can honestly say I haven’t heard or played a bass with the resonance and tone this bass has. Is there any substance in my presumption that the brass neck has had this effect on this cherished bass? It has the original electrics.

CLIFF ROCHESTER

CLIFF ROCHESTER

Sorry was meant to read brass nut not brass neck.

casper gomez

casper gomez

Funny my guitar builder and i think that wood has so little to do with whats goin on with steel string and magnetic pickup that its not even worth talking about HOWEVER when it comes to accoustic guitars wood is everything

casper gomez

casper gomez

Funny my guitar builder and i think that wood has so little to do with whats goin on with steel string and magnetic pickup that its not even worth talking about HOWEVER when it comes to accoustic guitars wood is everything

Mike Masuda

Mike Masuda

Nice article! As a physicist and bass player, I have been fascinated at the nuances in the different “tone woods”–part of it is subjective, part hype, and part actual science. The basic premise is that the instrument is basically a bow (as in bow and arrow) and how it reacts in vibration is a factor of geometry, string tension and composition, translation of energy at the nut and bridge, and how the bow flexes and resonates with string vibration.

I would imagine a bow made of a more flexible wood would react adversely different to a less flexible one–with wood density, porosity, and other factors affecting vibrational attenuation for various frequencies.

If we ever learn the “perfect” amounts of all these criteria in a bass, and are able to synthetically manufacture a carbon fiber to match these criteria, it would forever change the way basses are made. Imagine wanting that vintage tone but maximizing the best qualities of it, or the modern tones–you just select the parameters online, the carbon fiber “tone wood” is made, and the bass neck and body from those parameters. “Someday” is pretty close to that now.

But of course, all that science *could* take the mystique away from the search for the perfect bass–the search itself is to some extent an exciting journey in itself. I don’t mind a little of both. I own a lot of basses (most are semihollow, my aesthetic preference)–each with a different personality and voice. Personally, I prefer the diversity. But I also like making each of these basses the best it can be by modding their electronics and swapping out hardware to get the best tones out of them.

Vive Le difference!

mbka

mbka

This is interesting and yet the subject has a strong polarization into believers and non believers. Why should the frame around the string (the body and neck) influence the electronically generated sound? I found some interesting pointers at this luthier’s site: http://www.fruduaguitars.com/ – sadly he seems to have changed it up so I can’t point to the technical pages where I read the information. In a nutshell, the claim is that the neck influences the sound the most, including the trussrod. That is because the neck is thin and long, and flexes. It really works like a bow as one commenter noted. And if this is so, that explains a lot of experiments where listeners couldn’t hear the differences between bodies. Well, the neck matters a lot more than the body. Not to mention the notorious problems with blind tests – most people can’t tell the difference between coke and pepsi either because they lack a specific vocabulary to describe what they sense, and so they get confused in A/B/X tests.

So what are the effects of material and construction? As another commenter noted, resonance is not all of it, damping is also important. For resonance, stiffness (elastic modulus) is important, as well as mass. Resonance will absorb energy at first, then give it back (sustain). For damping, in some ways the opposite of resonance, the oiliness of the wood is important, besides the wood type. Oily wood dampens vibrations better. Damping makes resonance peaks lower in amplitude and broader in frequency. So why would all of this influence the electronically generated sound? I find the answer is quite obvious: Because the string loses energy into the neck and body, but also gets it back (damping, resonance) and the electronics amplify the slightest effects. If you have a hard time to believe this, think of string noise for instance – it’s always more of a problem in electric instruments than in acoustic ones. Small movements are amplified. In acoustic instruments you have a hard time amplifying anything at all.

What’s important here is that all of these effects are frequency dependent. And luckily so – we all want to hear complex colored sounds. No one wants to hear pure sine waves, and no one would want to hear just a single resonance centered around one frequency. That would just be a drone. So how do you get a rich, complex sound? By having many different resonances, clearly separated, none too strong or overpowering. You want some color, but not one-sidedness.

So, a bass made of combinations of materials with different properties should likely produce a more complex sound than a homogeneous construct. And I suspect this is what we hear as differences between basses. For instance to me bolt-on designs often sound more “alive” than set neck ones. I suspect this is because neck and body now represent two vibrational components separated by a clear interface that produce two vibrational modes rather than a single one. There is more – I have read a study that found some strong isolated resonance modes in the horns of a bass, of all places. So physical shape (surprisingly) also matters. I suspect we don’t necessarily want a strong coupling between string and body either. You want some vibration to be kept on the string – if it all transmits to the body you get more mushy body and neck resonance and less “attack”.

Finally, I believe that Leo Fender accidentally hit the holy grail with his instruments. Bolt on necks, different woods, steel strings, bone nuts, brass saddles, steel bridges, car lacquers… all done for efficient production, and this coincidental mix of materials resulted in lots of vibrational modes, and lots of discontinuities in his instruments. At each discontinuity, there is a change in impedance, and part of the vibration is reflected – it’s not dampened either mind you. So the effect should be a multitude of undampened resonances over the instrument. And I believe it is THAT that generates a rich sound, many discontinuities with no clear dominant modes, and with low dampening. And if you don’t believe this, add resonant materials to a guitar, with a none-to-good interface to the guitar and low dampening. Just as the commenter did with glass beads glued to a guitar – I once did it with aluminium plates on a Les Paul. You immediately get an “interesting” sound out of it.

The funny thing is that all these effects can be measured, just as pickup transfer functions can be measured, and pickup locations can be described in frequency response terms. But no manufacturer does this. Instead we get all sorts of vague talk about “warmth” or “snap” that really doesn’t mean anything.

    mbka

    mbka

    That is a thing of beauty – wonder about the technical details though, example, what kind of stiffeners they used (spray with lacquer / glue / epoxy to make it hold up to fraying, inserts for the screws and frets to make them stick to the corrugated cardboard etc).

      JJ

      JJ

      Indeed, but it’s not wood that makes it sound great, whatever it is

      JJ

      JJ

      But it’s still not wood…

        mbka

        mbka

        There’s wood fibers in that cardboard :) . Actually from the video it’s impossible to tell if it sounds “great” (as strats go), or just “close enough” to a strat to raise eyebrows, given what it’s made of. I suspect the latter. Some kind of measurement would have been nice here. I have seen scientific papers where different neck / body combinations were examined and yes you can see a signal in the frequency response.

        But, of course, there’s no reason it has to be wood to sound decent. Plenty of guitars and basses out there are made either of aluminium, composites, have graphite or carbon fiber necks, and what have you. To me, the more homogeneous and “perfect” the materials, the more I tend to find the sound nondescript and boring. The point of my post was this: there is good reason to believe that the imperfections in the behavior of the material, the discontinuities, and various resonance points, make the sound “interesting”. For example, pickups don’t transmit vibration intensity linearly either, and they have resonance peaks which makes their frequency response totally non-flat. So, as long as you create enough interesting deviations from a pure sine wave, any material can work. Even a synthesizer on a DAW. The complexity of a natural material is hard to simulate though.

          JJ

          JJ

          Heh, I think the discussion will go on and on. My Bogart basses were regularly positively commented on by recording engineers (graphite necks, plastic shell body filled with foam). And these days I play Precisions… :)