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I fancy building an OM size multiscale guitar, just for fun. I only build instruments for fun, for me, or for one or two family members or friends. I've built a couple of multiscale (electric) bass guitars but no acoustics.
From what I've seen, people who do build them rotate the bridge more or less, depending on where the 'perpendicular' fret is, as shown in drawing No1. This means that the top bracing has to be rotated also, or moved off-centre, particularly in the case of X-bracing so that the ends of the bridge are supported by the X.
But what if I rotated the saddle and pin holes (as in No1 but left the body of the bridge perpendicular to the centre line, as in No2? That way I could leave the bracing symetrical, in its usual position. The bridge would be more or less like the one in the photo. What do you think?

Just by looks I'd go for number 1. And it says multiscale. Number 2 looks bulky.

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Why be normal?

I would rotate the bracing to land bridge wings on X brace legs. No change in sound, I have done this many times and the results are great.

Video of my 24-25 scale https://www.youtube.com/watch?v=94SdQCVRLwo several others on my youtube chanel

Fred

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Fred Tellier
http://www.fetellierguitars.com
Facebook page http://www.facebook.com/pages/FE-Tellier-Guitars/163451547003866

13-fret OOO. Regular bridge in the standard position, nut rotated. Works good if scale difference is not too big. Scale is 25.4 and 25.15, copied, with permission, from Bruce Sexaur.

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Steve Smith
"Music is what feelings sound like"

More than one way to keep the bracing symmetrical.

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

It's strange, the bridge does look a little more bulky in No2, but it's exactly the same profile as No1, rotated round the centre of the radius on the treble end of the saddle.

Are you sure the bracing is symmetrical in those two guitars Colin? I'd say that a symmetrical X-brace that goes just under the treble end of the bridges is going to miss the bass end.

As I recall Bruce likes to keep the bridge "straight" and all the small difference difference in scales is at the 1st fret.

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

And I would agree with your statement, but also say that a symmetrical X-brace that goes just under the bass end of the bridges is going to go under the treble end, no?

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

Either way is fine with such a small saddle angle. Personally I prefer 7th fret perpendicular, which gives more angle to deal with. I use a combination of bridge twist and bracing modification.

I don't like the Somogyi style bridge in Colin's post above. The square wings draw too much attention, like it's a regular bridge which has been twisted. I prefer shapes that have an S curve to them, but look like they're meant to be that way to begin with. These two also have asymmetrical body shapes, which I think looks more natural with fan frets. And it makes the armrest bevel look elegant (if you notice it at all), whereas they look awful to my eye when cutting into an otherwise symmetrical body shape.

Of course Colin. I'd just got it into my head that the X-brace is supposed to go under the ends of the bridge. So if the bridge is revolved, the X-brace has to be revolved or moved south to keep it under the bass end, which might not be desirable. After all, people make 13-fret guitars in order to move the bridge (and X-brace) north, looking for the 'sweet spot'.

Yes. If I recall correctly, his reasoning is that since players control tone by moving the picking position between the bridge and the neck then a straight bridge makes it easier for the player. And it does work well, this one is easy to play and the 1/4" difference seems to make it quite balanced from bass to treble. This is my only multiscale guitar so far so I can't compare to others.

Having said all of that I do like the looks of #1 and if it was my project I wouldn't be worried about shifting the bracing to make it work since it wouldn't move much.

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Steve Smith
"Music is what feelings sound like"

That's true of classical players, and the difference in tone between the bridge and the fingerboard is even more remarkable on a classic guitar than a steel strung one (IMHO).
But it's something I've very rarely seen or heard steel string players do and I've often wondered why.
(Derailing my own thread now. )

P.S. The Master demonstrating.
https://youtu.be/okeDOYlFXb0

Sorry about the derail but at least it's related to multiscale design. As an acoustic steel string player I move between the bridge and the neck while playing quite often, I picked it up based on something Tony Rice once wrote about picking position and technique. There is enough of a difference to be significant. Admittedly, I have little experience with classical guitars so no argument that the difference there may be even greater. I just started a hybrid nylon guitar so I will have something to use when we perform songs that call for a nylon string guitar. Guess I'll learn

Back to multiscale.

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Steve Smith
"Music is what feelings sound like"

The major change in tone of the string when plucked depends on where the pluck happens as a proportion of the string length. If you pluck the string at 1/5 of it's length from the bridge then it produces a 'square wave' signal at the bridge with a 'duty cycle' that's 'up' 1/5 of the time and 'down' for the other 4/5. There will be little or no energy in the 5th, 10th and 15th partials, and so on. Plucking in the center of the vibrating length give a sound with only the fundamental and the odd partials; 3-5-7-9 etc. Note that when you fret a string, that moves one end of it up, and changes the proportion for that string. At any rate, on a multi-scale you would need to move the picking spot to a diagonal line to get the same effect as on a regular scale, no matter what the bridge looks like.

Classicals are much more sensitive to right hand position because the strings themselves produce so much less power in the high frequency range. If you pluck a steel string and a nylon one in the same place the initial wave looks exactly the same, and has the same proportions of all the partials to a fairly high pitch. But nylon strings have high damping, and 'eat' those high frequencies, so that a second or so later there is only energy in a few of the lower partials, where the steel string will have energy all the way out to 8000 Hz or higher. As one classical player said to me, playing his repertoire on steel strings is like listening to Julie Andrews in 'The Sound of Music': "There's no darkness!" Classical players exploit this to bring out a range of timbres that more or less disappear under the high-end jangle of steel strings. It also helps to have a pretty good steel string guitar to bring out these differences.

I've always just angled the bridge enough to make the saddle angle work. With harp guitars you often end up with a boomerang.

By the way, talk about bulky, this is bulky!

Yes, always thought the Lowden fan fret bridge design was a poor design choice.

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

To derail things a little further, but still related, harp guitars by their nature are somewhat "multiscale" because of compromises made to keep the strings a reasonable length. On the travel Harpguitar (contraguitar) I built I used two bridges rather than "boomeranging" one so I could keep all the strings on a single peghead. The second bridge was moved down and angled to provide the additional string length similar to multiscale instruments, and lastly nylon cored sub basses were used to both lessen string tension and avoid the high upper partial "chime" of steel strings. As with my other travel guitars the neck unbolts and slips inside the body.
I don't recall making any big changes to the typical X brace design, and the guitar works fine.