Multiscale basses - how to plan string spacing at the nut & bridge?

[ZachM]

I am planning out a multi-scale bass build which I hope to do in the future (hopefully later this year, finances permitting!). The idea is to do a Peavey T-40(ish) design, with a 36.25-to-34" fan, parallel seventh fret, nut width of 1.65" and bridge width of 2.125". Basically, it just closely follows Dingwall four string dimensions.

Here's the fretboard planned out in FretFind2d

I'm having trouble understanding something though - how does the string spacing difference between the nut and bridge affect intonation on a fanned fret instrument?

In order for a string to be perfectly intonated on a normal fretboard, you would need to have the string cross the frets at exactly a 90deg angle, which doesn't happen exactly due to the difference in nut vs bridge string spacing. On a normal bass I know this issue exists, but isn't much of a problem functionally and unless I understand this wrong, you're essentially compensating for the issue with your bridge saddle intonation, correct?

On a multi-scale bass though, I don't know how problematic this becomes (if indeed it does at all). Do you need to compensate for this somehow during the build? I saw some posts talking about this problem elsewhere on Talkbass, but sadly cannot find them now. It seems like an issue that would be exacerbated but I'm not sure.

Thanks for reading!

 

[Gary_M]

I am planning out a multi-scale bass build which I hope to do in the future (hopefully later this year, finances permitting!). The idea is to do a Peavey T-40(ish) design, with a 36"-36.25", parallel seventh fret, nut width of 1.65" and bridge width of 2.125". Basically, it just closely follows Dingwall four string dimensions.

Here's the fretboard planned out in FretFind2d

I'm having trouble understanding something though - how does the string spacing difference between the nut and bridge affect intonation on a fanned fret instrument?

In order for a string to be perfectly intonated on a normal fretboard, you would need to have the string cross the frets at exactly a 90deg angle, which doesn't happen exactly due to the difference in nut vs bridge string spacing. On a normal bass I know this issue exists, but isn't much of a problem functionally and unless I understand this wrong, you're essentially compensating for the issue with your bridge saddle intonation, correct?

On a multi-scale bass though, I don't know how problematic this becomes (if indeed it does at all). Do you need to compensate for this somehow during the build? I saw some posts talking about this problem elsewhere on Talkbass, but sadly cannot find them now. It seems like an issue that would be exacerbated but I'm not sure.

Thanks for reading!

You had me at T-40.

 

[Bruce Johnson]

Quick answer:

The scale length doesn't really affect the compensation very much. The amount of compensation you'll need to get the correct intonation is mostly dependent on the action height and the diameter of the string. So, it doesn't matter much if it's multi-scale. Position your bridges so that you have about 0.100" on the G, ranging up to about 0.450" on a B.

The angle for the fret also doesn't matter here. It's a round string sitting on a rounded fret crown. Basically a point to point contact between them.

 

[ZachM]

Quick answer:

The scale length doesn't really affect the compensation very much. The amount of compensation you'll need to get the correct intonation is mostly dependent on the action height and the diameter of the string. So, it doesn't matter much if it's multi-scale. Position your bridges so that you have about 0.100" on the G, ranging up to about 0.450" on a B.

The angle for the fret also doesn't matter here. It's a round string sitting on a rounded fret crown. Basically a point to point contact between them.

Thanks for taking the time to answer, Bruce, much appreciated!

So basically, as long as I've got adequate bridge saddle movement to compensate, it doesn't much matter that the string spacing changes from nut to bridge? I was concerned that skewing off a parallel line would be extra problematic on a multi-scale bass, but the same skew happens on a normal bass and it doesn't seem to be an issue so I guess it must work out

 

[ZachM]

You had me at T-40.

Yeah I love these basses! I'd like my bass to have a T-40 body but with a paddle headstock instead. Similar to this guitar, with a Gibson-esque headstock, but fanned frets obviously in my case.

Not really sure what I'd need to do for pickups either, it may need to be a custom job.

 

[Gary_M]

Yeah I love these basses! I'd like my bass to have a T-40 body but with a paddle headstock instead. Similar to this guitar, with a Gibson-esque headstock, but fanned frets obviously in my case.

Not really sure what I'd need to do for pickups either, it may need to be a custom job.

I started playing on a cheapo Aspen, Japanese Jazz bass copy. My first decent bass was a sunburst T-40 with a rosewood fretboard. I didn't appreciate how great that bass sounded at the time. I ended up pawning it to pay a phone bill in the early 90s and lost the bass. I'm still kicking myself over that and I regret it to this day. I've been keeping an eye out for one, but it's rare to find one with a rosewood board.

Good luck with your build!

 

[ZachM]

I started playing on a cheapo Aspen, Japanese Jazz bass copy. My first decent bass was a sunburst T-40 with a rosewood fretboard. I didn't appreciate how great that bass sounded at the time. I ended up pawning it to pay a phone bill in the early 90s and lost the bass. I'm still kicking myself over that and I regret it to this day. I've been keeping an eye out for one, but it's rare to find one with a rosewood board.

Good luck with your build!

The Sunburst ones are definitely a bit harder to find than the natural and black basses for sure. But if you want one, they seem to only be growing in price so I'd jump on it soon!

 

[ctmullins]

Not really sure what I'd need to do for pickups either, it may need to be a custom job.

Why? Normal pickups will work just fine, although you may want to angle them a bit to match the fan.

 

[Rôckhewer]

Fretfind 2D.
Wow, do I feel silly... how did I not know about this amazing & time saving site?!?
Several times I have needed a digital fret layout & have drawn it myself in CAD using only the numbers from the StewMac fret calculator.
Oofaah!... so much time wasted.
It saves directly to an SVG or DXF...etc. !!
The only thing I can see that would make it better would be the ability to input string thickness ga. values... to get width compensated nut slot spacing layout at the same. Or is that something else I missed?

 

[ZachM]

Fretfind 2D.
Wow, do I feel silly... how did I not know about this amazing & time saving site?!?
Several times I have needed a digital fret layout & have drawn it myself in CAD using only the numbers from the StewMac fret calculator.
Oofaah!... so much time wasted.
It saves directly to an SVG or DXF...etc. !!
The only thing I can see that would make it better would be the ability to input string thickness ga. values... to get width compensated nut slot spacing layout at the same. Or is that something else I missed?

It doesn’t do compensated nut slot spacing afaik. But it is amazingly handy!

On that subject - how common is compensated spacing on production instruments? Is it common enough that basses built without compensated spacing feel unnatural, or is that more of a traditional feeling instrument?

 

[ZachM]

Why? Normal pickups will work just fine, although you may want to angle them a bit to match the fan.

Yeah since this is a four string I could probably get away with a five string pickup placed at an angle, so long as it wasn’t a pickup where polepiece alignment is crucial

 

[Rôckhewer]

It doesn’t do compensated nut slot spacing afaik. But it is amazingly handy!

On that subject - how common is compensated spacing on production instruments? Is it common enough that basses built without compensated spacing feel unnatural, or is that more of a traditional feeling instrument?

The bass I currently need it for, is a 4 string, but is strung BEAD.
I wouldn't even consider equal/on center string spacing. The .130" & .105" would look way too crammed together.
It may not even "feel" unplayable...IDK. I just can't abide the way it would look.

Of course... it's not hard to reposition the lines on the DXF file... but it would be a nice additional feature.

Honestly... I personally haven't paid much attention to what the "production" basses are doing with regards to nut spacing.

 

[Beej]

Honestly... I personally haven't paid much attention to what the "production" basses are doing with regards to nut spacing.

I think with a few exceptions, neither have they!

 

[Bruce Johnson]

I think with a few exceptions, neither have they!

Yeah, most production and lower priced basses have the nut slots cut on Equal Centers (equal distance center-to-center). The easy route. Only on some skinny neck basses will you see the slot spacing shifted. Not necessarily to actual Equal Gap (equal distance between the outsides of the strings), but just shifted somewhat to look better.

True Equal Gap spacing is done by some of us "boutique" builders. It's a fine little detail that most players don't notice or care about. I do it on all my basses because I'm an engineer. I can't help myself.