Scale length and sound

[MusicalWood]

Hi there, new member so its stupid questions time

I make my own guitars, from scratch, 12 of them so far - all different styles. My next project is going to be an offset - heavily Jaguarish

The challenge is I have load of pre slotted fretboards all 25.5 or 25" scale lengths. I don't see me getting on well with a 24" scale length.

How much of the Jaguar sound comes from the scale length? Would a 25" be a good halfway house between a JM and a Jag if it is using Jag pickups and the classic trem setup?

[copacetic]

I dont think the scale length affects the sound as much as it affects the way i play. Perhaps there is some measurable difference in sound between identical models with two different scale lengths, but in my estimation, the pickups, general body/neck construction (set neck vs bolt on, hollow bodies, etc), bridge/tailpiece type, even types of strings will have a much more noticeable effect on tone than simple scale length alone.

If you build a jaguar that is identical to a standard jag in every way with exception of being 25.5" scale or 25", it will more than likely still sound like a jag in every measureable way, but will be a little more comfortable for you personally to play.

But will it feel or play like a jag? I'd probably argue no, or at least not 100%. But it sounds like thats what youre after anyways. The shorter scale on jags definitely is noticeable and makes me play a little differently from other guitars. Mustangs have a 24" scale just like jags, but something about the mustang vibrato/bridge makes me play a little more delicately than i would on a jag. Jags seem to just pull out a certain type of surfy, plucky, percussive, slightly more aggressive playing from me due to the unique relationship between scale length, bridge/vibrato, and pickups. Mustangs tend to make me want to fingerpick more and play with a softer touch. Jazzmasters seem to inspire some combination of the two. No real idea why other than different bridges/vibrato systems or scale lengths leading to a different feel.. its just what happens to me when i pick one up.

Not sure if any of that makes much sense but its my personal experience/opinion as a builder.

[epizootics]

Just decide for yourself - tune all of the strings down a half-step on one of your 25.5" scale guitars and put a capo on the first fret. Voilà - you are now playing a 24" scale! Granted, one with the fret dot markers in the wrong places.

I do that all the time on my pickup mule to see how a pickup will sound on a short scale guitar. It does affect the sound, more so than people think. When playing chords, especially. But, as pointed above, a change in feel will also make you play differently, which will in turn make you sound different.

[interceptör]

For me, the scale length makes a world of difference; not necessarily in the way the guitar sounds, though, but in the way it acts. 24" is much more percussive, aggressive and immediate.

[timtam]

I'm always surprised when someone on a guitar forum says that scale length is one of the main contributors to the sound of common guitars, like Les Pauls and strats (commonly heard over at TGP). Invariably, they offer no proof of that. And when you ask them why they believe that, the answer is usually along the lines of "well obviously a Les Paul sounds very different to a strat, and they're different scale lengths, so it makes sense that scale length is a big part of that". No it doesn't.

There is of course a difference in string tension when using the same string gauge and tuning across different scale lengths - string tension being entirely due to scale length, tuned frequency, and string mass per unit length (~= gauge squared). Which is why many people use a higher gauge on a 24" jag than a 25.5" jazzmaster - such that the string tension is then similar. As such, the guitars have closer playing feel (string tension is a major influence on that) than if the same gauge were used.

There is surprisingly little published science investigating any sonic differences between common guitar scale lengths (ie where scale length differences are quite small), with or without adjusting to the same string tension. Luthier Ralph Novak presented some very limited data in the mid-1990s asserting that there were frequency differences between common scale lengths. But it was far from convincing, limited by the frequency analysis software available then.

With larger differences in scale length, eg between short-scale and regular-scale bass guitars, there is more reason to suspect a sonic difference. For example, bass guitars are also more subject to inharmonicity (sharpening) of upper partials, which is a product of the physics of their particular strings (especially so for shorter, thicker, lower tension, stiffer strings). So there is a string physics reason to expect different scales on bass guitars to sound different. That reason does not really apply to common 6-string guitars.

Jim Lill in one of his 'citizen science' videos compared scale lengths, including both the actual string tension differences and also with attempts to equate string tension (by changing string gauge). He also adjusted for pickup position along the scale, so that the pickup was at the same relative location. At the beginning of the video, he did do the capo/retune test to simulate different scale lengths; but that of course that does not adjust the relative pickup position within the scale length. Towards the end he does the simple comparison of 25.5" scale (Fender) to 24.75" (Gibson) on the same guitar (he cut a new nut slot on his tele to allow him to test 24.75"). He does the test both with the same strings (10-46) - so, different strings tensions - and also with the same string tension (10-46 and 10.5-48 strings). Can you hear clear differences in one or both comparisons ?
https://web.archive.org/web/20230329134 ... uqBDIaZ0BE

The overall conclusion would seem to be that any assertions of significant sonic differences due to scale length differences of common 6-string guitars are on rather shaky ground.

Regarding fret position spacing differences between a 25.5" jazzmaster and as 24" jag (ie dictated by equal temperament), the difference is basically one fret. That is, the distance between the 2nd and 3rd fret at 25.5" is the same as the distance between the 1st and 2nd fret at 24" scale. You can easily verify that with Stewmac's fret position calculator (below). That knowledge helps one not to over-emphasize the cramped feeling on the upper frets of a jag - just move back by only one fret and you're at the fret spacing you would be at the original fret on a jazzmaster.
https://www.stewmac.com/fret-calculator/

[JSett]

Shorter scale = more dominant fundamental and lower harmonic overtones

A great way to notice this is with a SS bass vs regular scale. A SS bass has more of the root note 'thump' and tone and less of the bite and clang of the overtones. The same happens on a shorter scale guitar. That's all based on physics of the vibration within a string's length.

Short scale is warmer and more focused as a rule - all other things being equal.

[epizootics]

Can you hear clear differences in one or both comparisons ?
https://web.archive.org/web/20230329134 ... uqBDIaZ0BE

I'm afraid I can
I like Jim Lill's videos, anything that goes towards demystifying, erm, 'tone', for lack of a better word, is a healthy endeavor in my book. He really goes for it and his tests are as un-biased as possible.

However, this particular test is limited to open strings played through a clean amp, which is fair enough because the alternative would be using two different necks, which would alter two factors at once. But to really assess a difference in tone, one has to play the whole neck on a few different rigs. I spend a lot of time prototyping and testing pickups and my what I see is that a small change in the clean tone can turn into something a whole lot more drastic with distortion. When you listen to the raw signal coming from a guitar, ie. direct sound into an interface, it can be hard to tell a P90 from a Jazzmaster pickup from a Strat pickup (the difference with a humbucker with 8000 turns of wire per bobbin is of course more obvious). Once they go through signal chain, the subtle differences in the raw sound are amplified and it become *fairly* easy to tell them apart.

The other thing is that not all pickups react the same with different scale lengths and signal chains. In my experience, pickups with a lesser relative inductance tend to keep their 'tonal character' (which, I'll be the first one to admit, is not a very clear term at all) better than those with higher relative inductance across different rigs. A low-wind strat pickup vs. a P90 is a good example of that. One of my designs uses a ceramic bar magnet inside a coil and has even less inductance than a strat pickup (under 2 Henries); it does a pretty good job at sounding the same with different amps and scale lengths.

I am in no way trying to diss Jim Lill's work here - my post is backed by data from way less rigorous testing than his video - but as always with guitars and sound, there are almost too many factors to take into consideration.

edit: I'll add that the difference between 25.5" and and 24" is more significant than between 25.5" and 24.75". This is stating the obvious - 1.5" vs 0.75" - but it is something to keep in mind with regard to that video.

[timtam]

Can you hear clear differences in one or both comparisons ?
https://web.archive.org/web/20230329134 ... uqBDIaZ0BE

I'm afraid I can
I like Jim Lill's videos, anything that goes towards demystifying, erm, 'tone', for lack of a better word, is a healthy endeavor in my book. He really goes for it and his tests are as un-biased as possible.

I wasn't implying that I couldn't hear any differences. But I think they're much less when tension is equated across scales - in the second test. Which suggests that the difference between scale lengths is mostly down to the difference in string tension. Which is not exactly an earth shattering notion. And if like me, you use a higher gauge on a jag, to give you a similar playing feel to a jazzmaster, then you've taken out perhaps most of what would be the reason for sonic differences.

I agree that Lill's tests were a limited set of scenarios. But well controlled under those scenarios (with the exception that he didn't adjust picking location to the same relative position on each scale as he did pickup location - they have analogous comb filter effects on the predominant harmonics). Other scenarios might or might not show more differences. But just like Lill's "tonewood" video that sent tonewood proponents into conniptions (yet they've failed to explain how such vast differences in the amount of wood produced rather similar tones), it's now up to those arguing that scale is a bigger sonic influence to provide some direct evidence to support that. More than just TGP's "a Les Paul sounds different to a strat". I'm not sure what that experiment would look like though - because it's almost impossible to produce fretted necks at two different scales (so that notes could fretted) that are themselves sonically equivalent (that would require complex measurements to verify - resonant model frequencies, admittances, etc). And as a counter point to the distortion argument, Glen Fricker's "experiments" (not as cleverly devised as Lill's) tend to suggest that distortion reduces sonic differences. And might reduce them even more when conditions are properly equated according to Manfred Zoller's recent criteria for valid guitar comparisons, his response to what he saw as limitations in Fricker's tests. Parenthetically I think Zollner would argue that the sort of pickup differences you describe are often due to simple output differences, which then mean that a higher output pickup starts to break up at the amp earlier (and thus also has implications for apparent sustain differences, with that signal now being clipped and others not).

[MusicalWood]

So given it will have an AVRI trem, Jag wiring (Johnny Marr style) and Jaguar pickups (Mojo) - it will still jangle then ?

[epizootics]

I wasn't implying that I couldn't hear any differences. But I think they're much less when tension is equated across scales - in the second test. Which suggests that the difference between scale lengths is mostly down to the difference in string tension. Which is not exactly an earth shattering notion. And if like me, you use a higher gauge on a jag, to give you a similar playing feel to a jazzmaster, then you've taken out perhaps most of what would be the reason for sonic differences.

I agree that Lill's tests were a limited set of scenarios. But well controlled under those scenarios (with the exception that he didn't adjust picking location to the same relative position on each scale as he did pickup location - they have analogous comb filter effects on the predominant harmonics). Other scenarios might or might not show more differences. But just like Lill's "tonewood" video that sent tonewood proponents into conniptions (yet they've failed to explain how such vast differences in the amount of wood produced rather similar tones), it's now up to those arguing that scale is a bigger sonic influence to provide some direct evidence to support that. More than just TGP's "a Les Paul sounds different to a strat". I'm not sure what that experiment would look like though - because it's almost impossible to produce fretted necks at two different scales (so that notes could fretted) that are themselves sonically equivalent (that would require complex measurements to verify - resonant model frequencies, admittances, etc). And as a counter point to the distortion argument, Glen Fricker's "experiments" (not as cleverly devised as Lill's) tend to suggest that distortion reduces sonic differences. And might reduce them even more when conditions are properly equated according to Manfred Zoller's recent criteria for valid guitar comparisons, his response to what he saw as limitations in Fricker's tests. Parenthetically I think Zollner would argue that the sort of pickup differences you describe are often due to simple output differences, which then mean that a higher output pickup starts to break up at the amp earlier (and thus also has implications for apparent sustain differences, with that signal now being clipped and others not).

I know you didn't


Regarding the difference in output, you are absolutely right, since it is correlated to the inductance.

Regarding distortion, it is obviously a very vague / subjective term since there are so many ways to distort a signal. But I was thinking more about how some high-output pickups only start to sound lively with large amounts of distortion.

The problem in all of this is that guitarists do not control factors when they are playing. Even if it does turn out that string tension is the only relevant variable here, the simple fact that their left hand interacts with frets that are closer together, thus altering their whole posture, will make them play differently than they would on a longer scale, and they'll end up sounding different.

This got me thinking. It would be possible to have two scale lengths cohabitating on the same fretboard and sharing the same bridge point. The nut would obviously be out of tune when playing the 24.75" scale but other than that the fret locations are actually far enough apart that you wouldn't end up with two frets closer than 0.211" to each other. I just did a quick and dirty CAD check on this -



It WOULD get confusing as hell since using different fret materials wouldn't be an option (something like EVO gold vs. regular nickel silver) but a color system under each fret would help. A swimming pool route like the one I use on my pickup mule would make it easier to move the pickups around -





If I ever get the spare time I might build something like that