How will changing scale length affect the sound

[Quinny]

Hi there,

I have plans for a tenor uke with 14 frets over the 240mm from nut-to-body. The scale length at the 12th fret is 216mm. As i have big hands and are a beginner to playing, I want to make it 12 frets from nut to body - making the scale length 240mm. There is room in the plans to shift the bridge back.

Any ideas of whether this will affect the sound dramatically. Will the pitch be that much deeper? Will it take away that traditional ukulele twang sound?? What do ya think?

Thanks

Andrew

[Allen]

I think you have some confusion with what a body join, and scale length is Andrew.

Your scale length stays the same no matter where you join the neck to the body. What does change is where the bridge (or actually the saddle) is located on the body. Your 12th fret is 1/2 of the scale length. So not taking in compensation into account, on a 17" scale tenor, the 12th fret will be 8 1/2 inches from the nut, and another 8 1/2" to the saddle.

If you move from a 12 to a 14 fret to body join, then the bridge moves towards the sound hole the same distance.

A couple of really common Tenor uke plans available are the ones drawn by Scott Antes or Hana Lima. Both have these neck join options with the appropriate bridge positions noted. But in either case, if the scale length is 17" as is common on a tenor, then that is what it is, regardless of where you join it to the body.

[Trevor Gore]

I'm reading that a little differently....

It seems that Andrew wants to go from a 14th fret neck joint, 432mm scale length to a 12th fret neck joint, 480mm scale length. The saddle will go from being at 192mm from the top of the upper bout (ignoring compensation for the moment) to 240mm from the upper bout, i.e. will shift down the body 48mm. I don't know anything about ukes, but that seems like a long way for a small instrument. If you go 480mm scale length, 14 fret neck joint, that will move the saddle back up about 26mm, to 214mm from the top of the upper bout, putting the saddle 22mm further back than it was originally. A 432mm 12th fret body joint will have the saddle at 216mm, if that is, in fact, a viable option on the design he's got, so only 2mm difference.

The uke experts will be able to tell you whether 480mm scale and 14 fret neck joint is a good idea or not and what it might do to the sound.

[Allen]

Ok, after reading Andrews question again I may have misunderstood.

I always work in inches for scale lengths, so I do a rough conversion. The 17" scale length for a tenor (432mm) is what you have plans for, but want to stretch it out to 480mm or 18.9".

One of the standard scale lengths for Baritones is 19" so close enough to be what is called a long neck tenor.

As long as your design is still going to put the bridge into middle or very close to the lower bout, you will be fine. You won't have any problem with sting choice. Standard tenor stings will be appropriate. I'd suggest going with the low G sets. You will have plenty of tension from the longer scale length to drive the low G which is sometimes a problem.

The extra tension isn't going to be so great that I'd modify the bracing other than to make sure that you take into account where the bridge is placed.

Ukulele sound is affected by body size first, then soundboard type, bracing and the choice of stings and their tuning in equal measure. You will never get a tenor to sound like a soprano or concert. Which is what most people would equate with the "Ukulele Sound".

If you go with a long neck tenor as mentioned and a low G, especially with a spruce soundboard, you will have far more of a guitar type sound than a ukulele. However if you are coming from a guitar background, this may appeal to you very much.

[Quinny]

Thanks for the clarification Trevor; and Allen your advice was spot-on, very comprehensive and reassuring.
To help my understanding, I have three further queries if I may:

With the longer 12 fret neck and a 480mm scale length, there will still be 45mm between the back of the bridge and the edge of the lower bout, placing it just past the widest section of the bout. The plans originally have the bridge 90mm from the edge placing it just before the widest part of the bout.
1) Is that likely to affect the volume or sound much - like a deeper pitch??

2) Allen, are you suggesting a 'Low G' for the reason of getting a guitar sound or are there other benefits??

I have never played guitar so are after more of a uke sound - i just can't get my fingers around a soprano fretboard. I found it very interesting Allen, that the body size is the number one factor in the sound, followed by soundboard, bracing and strings. I am using Zircote for back and sides, Port Orford Cedar for the soundboard, fan bracing and the D'Addario strings have a wound 'C' string. The body type is also bell-shaped (dreadnought shaped). These factors, along with the longer neck, suggest I will have more of a guitar sound???

3) If i wanted more of a uke sound which of the following factors would be more important:
- having a traditional "figure 8" body shape as opposed to bell/dreadnought shape?
- keeping the scale length at 432mm and therefore the neck a standard length and the bridge better placed?
- not using a spruce/cedar soundboard but, for example, the same wood as the back and sides?
- not having a wound string but have all full nylon strings?
- anything else?

Any ideas are greatly appreciated and greatly add to my learning.

Thanks

Andrew

[Allen]

There are lots of questions and I have several comments. I hope that this isn't too disjointed.

If with your plan you are going to be moving the bridge towards the tail block by 45 mm, with only 45mm from the tail bock, then yes, this is going to be having a very significant affect on the instrument. I wouldn't be building it that way.

I know you were saying you wanted a 12 fret to the body, but with stretching the scale length from a plan that already had a 14 fret to body join, I don't think it's going to work.

As well, you said that a soprano scale is too tight for you (me as well) but that's a 13 3/4" one, but the plans you have are for a 17" tenor (if you don't change them). This is a huge difference. Do you also feel that is too tight? Most people that struggle with the soprano size find that the concert is perfect and that is only jumping up to 15".

When I get a request for something different I always draw the instrument out full size to work out these things before I commit to anything.

So I highly recommend drawing the body out full size and then note were the original plans call for the sound hole and bridge to be placed.

Now measure out from that point for your desired scale length. Were does the body join fall on the fret scale?

If it happens to be very close to the 14th then it's easy enough to move the bridge a little to get the desired fret on the body join. But if it happens to be say the 15th or even the 16th, then you have to ask yourself if that isn't a more appropriate spot, or do you have enough room to move that saddle about.

If you need to move the bridge about, then draw it out on the plan and see what it looks like in relation to the sound hole and the rest of the lower bout. If it gets too close to the sound hole, this will affect the sound, and can look really weird. Same goes if it's move towards the tail block as I am surmising from your last post.

On some body shapes, there is plenty or real-estate in the lower bout, but in others (mine for instance) that don't.

With the tenor body, and that scale length, I haven't heard any ukes with re-entrant tuning (high g) that really work. What you are building is leaning towards the guitar sound, but that's not to say you couldn't go with it. Just really uncommon. But it's easy to give it a go. If you don't fancy the high g you just switch it out.

What people tend to describe as the "Ukulele" or "Hawaiian" sound is from a small bodied instrument. Soprano or concert. Re-entrant tuning, and a hardwood top with all nylon strings. Tenors weren't even considered a ukuleles for a very long time. In some circles they still aren't. The sound and response is totally different. And with that scale length certainly wouldn't be. Same goes for a softwood top.

Now that's not to say this won't look and sound like a uke. Just not a traditional sound to the purist.

Hope that covers some of your questions.

Oh....and draw it out full size. You will be amazed at what you learn even with the plans in your hand. You might find that there are glaring errors in them.....and yes, there are plenty of uke and guitar plans out there that if you built exactly as the plans call for, the instrument wouldn't be playable.

[Quinny]

Thanks Allen - for your time, effort and for being helpful. Your reply was clear, and I will take some time to reflect on these issues. For some reason these issues are bugging me, which usually means there is something important for me to learn and understand. I might get back to you in a day or two with some follow-up points if that's OK.

Thanks

Andrew

[Quinny]

Thanks again for your detailed reply Allen. I have had a couple of days to sort out the facts from my desires of what i planned to build in the first place. Can I check a few things to clarify and then I believe I will be clear - and at peace - on how each of the factors you have outlined relates to the traditional sound versus more of a guitar sound - and as it relates to my build.

1) You noted: "With only 45mm from the tail bock, then yes, this is going to be having a very significant affect on the instrument." Is that effect mainly volume or will it affect the clarity of the tone or something else?

2) You noted: "With the tenor body, and that scale length, I haven't heard any ukes with re-entrant tuning (high g) that really work." Could you clarify what you mean by high g on a tenor not working?

3) Does having a traditional "figure 8" body shape - as opposed to bell/dreadnought shape - add to the traditional sound?? It seems to me some of the traditional shaped bodies have very little size difference between the two bouts. Does that narrow the pitch repose, if that makes sense, as I have heard tenor ukes where all the open strings seem to blend with a homogenised sound and not much clarity or distinction between string sounds.

Thanks

Andrew

[Allen]

Moving the the bridge towards the tail block and only leaving 45mm to the edge is going to really restrict the top from moving. Especially when you consider that the tail block is going to be taking up at least 10mm of that space on the inside of the instrument. Leaving you only 35mm.

I would say that at the very least the volume is going to be restricted. But most likely the entire dynamics of the instrument will be choked.

It's not that tenors with the 17" scale length don't really work with a high g. It's the 19" one that you are suggesting you'd like to build.

I've had a couple of clients wanting double course strings at longer scale lengths, and I've felt that at that length, it that "in between" range of scale length and sting choice from a standard set that somehow doesn't do it for me. You might find a set that works, or building a custom set from single strings. Dirk at South Coast Ukes may be able to help you with a set of strings for that scale length to do what you want. However you might find that he suggest a different tuning. Perhaps dropping a semi tone.

Couldn't say about the body shape without building quite a few instruments in that style and trying out different options. As mine is quite different from that, and I'm not likely to change, I can't see that happening. However I doubt it's going to make that huge of a difference, as a pineapple shape doesn't have a waist at all and they can sound great.

And remember, that bridge, and bridge patch are the two most important braces in a uke. Try and envision what happens when you pluck a string and get that bridge / top moving. You really want it moving as much as you can but controlling it with your bracing. I'm suggesting you don't want to restrict it by being too close to either the lower transverse brace or the tail block

[Quinny]

Thanks so much Allen. I think I have imposed enough on your time and luthier wisdom!!
I feel our discussion has opened my mind to a greater awareness of how the build and the desired sound are related. It all makes so much more sense now. so off to the shed to start work!!

Thanks again

Andrew

[lucpet]

Hi Quinny, I'm a lefty, getting into building slowly and the uke is now my instrument of choice.
I play a tenor and own a soprano and baritone, and find the tenor to be the closest to what feels comfortable
but I'm going to make my next build at 18'' rather than 17" the 19" Baritone is a little large and soprano a little small
so if this porridge is the scale length I'm happy with then I'll be making left handed acoustic versions of this.

I always design from scratch http://lukethier.blogspot.com.au/2015/0 ... build.html
and this is my plan for my solid body electric uke at 18"

I'm building this as another practice before getting onto an 18" acoustic and finishing up getting some of the
gear I'll need to do it. ie making a bending iron, plate joiner etc

Luke