Max Normal Posted February 19, 2012 Share Posted February 19, 2012 (edited) [size=4]I was reading a forum by a guy who designed the optical pickup and the physics of how it works. One of the questions was whether it would not work if it was placed on a node (part of a string that vibrates at a different frequency to the fundamental), and he replied that it worked anywhere due to the movement of the fundamental and of the harmonics along the string. I’m a bit too hungover to go out and do something useful, so I spent the afternoon researching the science of why our guitars sound the way they do, and why they all seem to sound different, and why wood matters when the pickup is basically just sensing the vibration of the string. This is what I came up with, and I think it raises some interesting questions.[/size] [size=4]Every now and then the same question pops up. We know that different tonewoods and bass guitar construction materials affect tone but some of us (including me until recently) do not know exactly how. Frustratingly, somebody just usually pipes up with a list of the tonal qualities of various tonewoods, and does not actually answer the question.[/size] [size=4]For those that don’t know, the answer is fairly simple if you think about it. Once plucked, the string vibrates in a wave pattern dependent on its length. The frequency of this wave pattern determines the pitch of the note and the fundamental note is released (the “main” note that you expect to hear).[/size] [size=4]This is not necessarily however a “standing wave”. The waves of vibration retain their frequency, but travel along the length of the string. This is illustrated brilliantly here:[/size] [url="http://www.youtube.com/watch?v=0AWTUN6RD1c&feature=related"]http://www.youtube.com/watch?v=0AWTUN6RD1c&feature=related[/url] [size=4]and here:[/size] [url="http://www.youtube.com/watch?v=_X72on6CSL0"]http://www.youtube.com/watch?v=_X72on6CSL0[/url] [size=4]When the string rebounds, the various partials called harmonics and overtones are released. Partials are vibrations that are integer multiples of the fundamental (i.e. higher pitched notes), and these also travel as waves along the string. When you hear the note, you are not just hearing the fundamental, you are also hearing all of the harmonics and overtones layered on top of it and adding to its tonal character (you might notice that some of the string waves being produced by the hairy guy with the acoustic bass are quite asymmetrical, showing the pattern of overtones on the string).[/size] [size=4]Naturally the sting is anchored at each end to the instrument, so when these vibrational waves reach the ends of the strings they continue to travel through the body and neck of the instrument. A vibrating string is a fairly pure and simple system, however a bass guitar is not. The body (including the neck) of a guitar can be thought of a filter for specific frequencies.[/size] [size=4]When the string vibrations return from the body material (in the case of wood, principally via the biopolymer lignin), certain harmonic frequencies will have been lost, while some will have been retained and are transferred back into the string to be collected by the pickup.[/size] [size=4]In its simplest form, this explains why a softer, less lignin-dense wood such as basswood gives a softer mellower tone than a wood with a tight lignin structure like maple, as the higher frequency partials have been absorbed by the wood (the individual fibres in the wood are less well connected can move more freely, and convert the vibration into heat rather than transferring it along between the fibres), and only the lower frequency partials are transferred back into the string. Conversely, more of the original partials are returned to the string in the case of maple, giving the appearance of a “brighter” tone.[/size] [size=4]But lignin itself has a different structure as well as density in different woods. There is not a simple sequential dampening of partials from high to low frequencies as the lignin density within the wood decreases, more that a range of specific partials are “selected” for transmittance back into the harmonic characteristics of the vibrating string, while the rest are absorbed by the body of the instrument and lost. Moreover, it’s not just the lignin density. Seasoned wood also contains cellulose and the lignin: cellulose ratios will vary between different types of wood, or even different cuts of the same wood.[/size] [size=4]Undoubtedly the grain of the wood also has an effect. Rosewood is a fairly dense and hard wood (which is why we can use it for fretboards), but has a far more open grain structure than maple or ebony. The open grain structure of rosewood can be thought of as a series of dampening chambers that filter out certain partials from the specific resonance of the string, again giving the tone a warmer, softer character. Wood sawing angles change the grain structure, and neck joints and joinery between multiple body pieces also act as dampeners of specific frequencies. [/size] [size=4]This is far from the end of the story though. After the body of the instrument has decided which partials it will transmit back to the string, certain remaining partials may cancel each other out as they travel along the string, or combine and create new, amplified partials, and this will all add to the overtone spectrum of each specific instrument.[/size] [size=4]Obviously the method in which the strings are anchored to the body of the guitar also makes a difference, a dense metal bridge and a metal nut transferring more high-frequency partials than softer materials, and perhaps selecting others, Dead skin particles stuck between the windings of your string, the type of winding, and overstretched un-elastic old strings will select for particular partials, all contributing towards the overall tone of the instrument.[/size] [size=4]I’m wondering how easy it would be to measure the relative partial/overtone profile of a really great sounding bass, and try and replicate it by predicting what the partial profile of a new bass would be. Also, it would be interesting to use this to see exactly relatively how much each component (bodywood, fingerboard material, badass bridge etc) contributes towards the tonal characteristics of a bass so we know which component to spend more of our lucre on. Also, is there a consensus partial profile for each instrument (i.e. is there one for “the perfect Jazz bass” or “the perfect Stingray”) that we can aspire to and maybe modify our instruments to achieve?[/size] Edited February 19, 2012 by Max Normal Quote Link to comment Share on other sites More sharing options...
thepurpleblob Posted February 19, 2012 Share Posted February 19, 2012 You could be overthinking it Quote Link to comment Share on other sites More sharing options...
Max Normal Posted February 19, 2012 Author Share Posted February 19, 2012 [quote name='thepurpleblob' timestamp='1329670207' post='1545602'] You could be overthinking it [/quote] Lol! wondered if it might be a dry subject for some. It's all well researched stuff, but I had always wondered about it. I'm a science geek so I found it interesting. Quote Link to comment Share on other sites More sharing options...
GreeneKing Posted February 19, 2012 Share Posted February 19, 2012 (edited) Sure, the woods used and the contruction of the instrument do affect tone. If the string vibrates with altered overtones then the pickup will respond differently. But in my opinion and experience this influence is minimal. The overwhelming influence is the pickup and electrics. Witness people who've made a bass out of a lump of aluminium and guess what, it sounded just like a bass, perhaps even a little 'woody'. Peter. Edited February 19, 2012 by GreeneKing Quote Link to comment Share on other sites More sharing options...
Muzz Posted February 19, 2012 Share Posted February 19, 2012 Yeah, but once the guitard cranks up, it's all pretty academic... While the factors of wood density and internal construction (which will vary from tree to tree and slice to slice) might in theory have an effect on the sound, in practice it's so subtle as to be undetectable by most people who aren't looking for it. And even then... The 'strap a couple of pickups and a neck onto some plywood and compare to a Fender Jazz' thread on TB pretty much demonstrated that. I've found pickup type and placement to be the biggest influence on tone (after your fingers) by a long, long, long way. These days I like to think of 'tone woods' as nice to look at... Quote Link to comment Share on other sites More sharing options...
discreet Posted February 19, 2012 Share Posted February 19, 2012 [quote name='GreeneKing' timestamp='1329670699' post='1545608'] The overwhelming influence is the pickup and electrics. [/quote] This. Note to self - buy more plywood. Quote Link to comment Share on other sites More sharing options...
Muzz Posted February 19, 2012 Share Posted February 19, 2012 [quote name='discreet' timestamp='1329670996' post='1545613'] This. Note to self - buy more plywood. [/quote] Could be a plan, but as I'm sure Fender's marketing department* know, people won't pay a grand for a bass made from plywood, no matter how it sounds... * And all the others, too... Quote Link to comment Share on other sites More sharing options...
discreet Posted February 19, 2012 Share Posted February 19, 2012 [quote name='Muzz' timestamp='1329671217' post='1545615'] ...people won't pay a grand for a bass made from plywood, no matter how it sounds... [/quote] Don't tell 'em! Call it 'Nordic Birch' or some such. Quote Link to comment Share on other sites More sharing options...
Muzz Posted February 19, 2012 Share Posted February 19, 2012 There's got to be a Latin name we could come up with which would be factually correct and yet sound...expensive. How's about Lignum Misceremus? Quote Link to comment Share on other sites More sharing options...
discreet Posted February 19, 2012 Share Posted February 19, 2012 [quote name='Muzz' timestamp='1329671622' post='1545624'] How's about Lignum Misceremus? [/quote] Wood Mix... not bad. What about 'Lignum Strata'? Quote Link to comment Share on other sites More sharing options...
LawrenceH Posted February 19, 2012 Share Posted February 19, 2012 Great post IMO, I've been boring people to tears about this for a while now but a lot of people seem resistant to the idea that an electric instrument is still reliant on mechanical propagation of vibration, instead seeing the wood as an 'ideal' rigid structure whose resonant properties are negligible. Understanding the role of pickup placement and type seems a lot easier for some reason. One of the confounding variables is the overlap between wood varieties and heterogeneity within a single variety - ash for example can be hugely different weight from one piece to the next which will have a significant impact on resonant frequency (weight and stiffness). If you knew what you were doing you could probably build a plywood instrument with excellent acoustic properties, and I guess a fair few custom builds with fancy laminate tops etc already qualify. Quote Link to comment Share on other sites More sharing options...
discreet Posted February 19, 2012 Share Posted February 19, 2012 [quote name='LawrenceH' timestamp='1329672176' post='1545635'] ...you could probably build a plywood instrument with excellent acoustic properties... [/quote] AFAIK good plywood (Baltic Birch et al) is uniformly dense and predictably stable... what other parameters need to be taken into account to make a decent plywood bass, do you think? Quote Link to comment Share on other sites More sharing options...
Mr. Foxen Posted February 19, 2012 Share Posted February 19, 2012 The wibbly effect from the video is a shutter effect and not directly reflecting of the way the string oscillates, it is to do with the relationship between the strings position in each frame, like when in video of propellers it seems that they change direction. Quote Link to comment Share on other sites More sharing options...
Happy Jack Posted February 19, 2012 Share Posted February 19, 2012 Plywood? Naaaah - this is what you need: [IMG]http://i1128.photobucket.com/albums/m496/h4ppyjack/4a03923a.jpg[/IMG] Quote Link to comment Share on other sites More sharing options...
discreet Posted February 19, 2012 Share Posted February 19, 2012 [quote name='Happy Jack' timestamp='1329673094' post='1545654'] Plywood? Naaaah - this is what you need... [/quote] Horses? Quote Link to comment Share on other sites More sharing options...
soopercrip Posted February 19, 2012 Share Posted February 19, 2012 You could also argue that the body shape and size will dictate the amount of tone filtered and returned to the string? Quote Link to comment Share on other sites More sharing options...
EssentialTension Posted February 19, 2012 Share Posted February 19, 2012 I wonder how long this thread will last before the big argument. Just for the record I'm on the 'wood doesn't matter much' side of things; fingers, strings, pickup, electronics, amp, speakers, all play a much bigger role in how I sound. I'm certainly unconvinced by the concept of 'tonewoods'. Anyway, just in case, IBTL. Quote Link to comment Share on other sites More sharing options...
leftybassman392 Posted February 19, 2012 Share Posted February 19, 2012 (edited) I don't really know where to begin with this, but would like to make the following observations:- 1. Whatever it is that the videos show, it is not an accurate, scientific representation of how a bass string (or any other string for that matter) vibrates. Please tell me that you're not attempting to pass off vid 1 as remotely scientific: there isn't enough paper on my page to describe how many ways that drivel is not scientific. As for vid 2, whilst it can at least make some claim to be scientific, it doesn't come close to replicating the way the aforementioned bass string works in practice (not least because it doesn't show any of the overtones). 2. I am alarmed at your liberal use of words like 'undoubtedly' and 'naturally' and 'obviously', as if a failure to 'understand' the following text is somehow the reader's failure to grasp the blindingly obvious. The one thing that proper scientists don't do is sprinkle words like these around when the subject matter is, well let's be kind and call it contentious. The last thing any of this is is undoubted. Nor natural. Nor obvious. This topic has been covered at great, great length in the following thread: [url="http://basschat.co.uk/topic/73234-tonewoods/"]http://basschat.co.u...3234-tonewoods/[/url] And before you come up with some 'oh poor benighted soul that only sees darkness when light is all around us' gibberish, you should know that I have a Mathematics degree, (with a good understanding of how the harmonic series actually works), not to mention an 'A' level qualification in Physics and Electronics. Whatever the relationship between the various elements that make up the sound of a bass guitar, it is most certainly neither obvious nor undoubted. Ooops! Have I started an argument? Edit: I notice you have included the word 'aspergers' (referring, I assume, to medical condition that falls within the Autism spectrum) in your keywords list. Care to enlighten us? Edited February 19, 2012 by leftybassman392 Quote Link to comment Share on other sites More sharing options...
EssentialTension Posted February 19, 2012 Share Posted February 19, 2012 [quote name='Max Normal' timestamp='1329669305' post='1545574'] [size=4]... We know that different tonewoods and bass guitar construction materials affect tone[/size] ... [/quote] My guess is that you'll find this claim is going to be heavily disputed. Quote Link to comment Share on other sites More sharing options...
discreet Posted February 19, 2012 Share Posted February 19, 2012 [quote name='leftybassman392' timestamp='1329673217' post='1545660'] ...know that I have a Mathematics degree, not to mention an 'A' level qualification in Physics and Electronics... [/quote] Wow! I've got a certificate for swimming a width and the Mrs Joyful prize for rafia work. Quote Link to comment Share on other sites More sharing options...
EssentialTension Posted February 19, 2012 Share Posted February 19, 2012 [quote name='discreet' timestamp='1329673724' post='1545672'] Wow! I've got a certificate for swimming a width and the Mrs Joyful prize for rafia work. [/quote] Best you keep out of this discussion then, you're not qualified. Quote Link to comment Share on other sites More sharing options...
leftybassman392 Posted February 19, 2012 Share Posted February 19, 2012 (edited) [quote name='discreet' timestamp='1329673724' post='1545672'] Wow! I've got a certificate for swimming a width and the Mrs Joyful prize for rafia work. [/quote] ...which probably makes you as well qualified to talk about this stuff as anyone else hereabouts - myself included. Edited February 19, 2012 by leftybassman392 Quote Link to comment Share on other sites More sharing options...
discreet Posted February 19, 2012 Share Posted February 19, 2012 [quote name='EssentialTension' timestamp='1329673830' post='1545674'] Best you keep out of this discussion then, you're not qualified. [/quote] What discussion? What a bass is made out of makes little or no difference to its tone. We decided that ages ago. I'm just here for the lulz. Quote Link to comment Share on other sites More sharing options...
risingson Posted February 19, 2012 Share Posted February 19, 2012 I appreciate the thought that some people put into this sort thing, but I am so indifferent to being aware of this kind of stuff. I love bass guitars, and I love playing bass guitars, but its not up to me to be thinking how they're made etc. that's for the companies that make my instrument to be thinking of. I just want to plug in and play safe in the knowledge that a.) the tone of my instrument meets my needs, b.) that the instrument is stable and well set up and c.) that it looks good. I have preferences on woods that I like and that I don't, but these are only faint impressions of what my ears have told me, e.g. I think rosewood sounds less bright than maple fretboards. I've found this to be true on all the basses I have played and owned, but I have no idea why or even whether there's a science behind this assertion. Maybe I'm totally wrong! What I do know is that this subject has a habit of dividing people. I just know that I love the instrument that I play Quote Link to comment Share on other sites More sharing options...
EssentialTension Posted February 19, 2012 Share Posted February 19, 2012 [quote name='discreet' timestamp='1329674108' post='1545682'] What discussion? What a bass is made out of makes little or no difference to its tone. We decided that ages ago. I'm just here for the lulz. [/quote] I knew that. Quote Link to comment Share on other sites More sharing options...
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