Short vs long scale

[Mike Buesseler]

I own an oval-hole A model mandolin and an F hole w/scroll. The neck meets the body at about the 10th fret on the A model, around the 14th on the F model. This seems be about standard for models like these.

Both my mandolins are very well set up and are both a pleasure to play, but I have to say that the longer scale F is noticeably easier to play as you go up the neck.

Now, this seems to be a simple matter of physics: shorter neck, steeper angle between the strings and the fretboard.

I just haven't heard anyone address this issue much around here when people are discussing the differences between A models vs F models (which is a frequent topic).

I have read that part of the 'sweet' or 'tubby' sound of most A models is due to the shorter neck. But, am I correct in my assumption about the ease of play (I guess it's the height of the strings) as you go up the neck? Is this a necessary shortcoming of oval hole mandos (assuming the short scale)??

[Bruce Evans]

Seems to me that the real issue here is the neck angle in its mounting to the body on your A, and not the length of the scale. A half degree can make a huge difference in the action, or the height of the strings above the twelfth fret, which is what I believe you are referrencing here.

Of course you can adjust the action by adjusting the bridge height, but that changes the height of the strings above the sound board and therefore the moment arm that the strings have in transmiting their vibrations to the top. It also changes the break angle at the bridge which changes the amount of downward biasing force that the strings exert on the soundboard.

I am speaking as a mandolin playing engineer. I am not a luthier.

[Mike Buesseler]

Seems to me that the real issue here is the neck angle in its mounting to the body on your A, and not the length of the scale. A half degree can make a huge difference in the action, or the height of the strings above the twelfth fret, which is what I believe you are referrencing here.

That's fine with me. Neck angle, string height, scale length...whatever. I just want to know if this is pretty much always the case with oval-hole mandolins.

[markishandsome]

Whoa dollies, the cart's way out in front of the horse on this one. The position at which the neck joins the body is not the same thing as the scale length, which is the distance from the nut to the bridge. As far as I know, all gibson-style mandos, A or F, oval or f-hole, have the same 13 7/8'' scale.

Even is the scales on your two instruments are different, there is no law of physics saying that the action must be higher for shorter scales. Neck set angle and bridge height (and even nut height) can be adjusted to get any string height you want on any mandolin you want. Try this experiment: "shorten" the scale of any mando by capoing at the 3rd or 4th fret (it doesn't matter really). All the strings between the capo and the bridge are now CLOSER to the fretboard than before.

Furthermore, the string height can't possibly have anything to do with the shape of the soundhole (you'd need to do some cutting on your a-oval to prove this, so trust me). There are oval-holed mandos with long necks and f-hole mandos with short necks. The strings don't care!

[red7flag]

Actually what you are talking about is not the scale, as that could be the same as that is not determined by where it is attached to the body, but by the length from the bridge to the nut. For example, certain brands will have a longer scale on all their models. My F4 is attached at the 12th fret, but the bridge locates closer to the tailpiece and so the scale is the same as my F5s. Where is attaches to the neck just effects the ease of access to the upper registers. One thing I like playing the F4 is that my hand feels more comfortable with the bridge located closer to the tailpiece. I hope this helps. Tony

[Mike Buesseler]

I guess I am confused...no less now than when I posted the original question, except I get that scale lengths are probably the same for Fs or As. (In fact, I just measured 'em. Almost exactly the same.)

So, then...by having the neck join the body at a different point (say 10th fret vs 14th fret), this requires that the bridge be located at a different relative location on the top. Is this right?

I also understand how you get better access to the upper register when there are 13 or more frets clear of the body. A no-brainer, even for me...


But, what is this stuff about getting that 'tubbier' sound from oval-hole mandos? I heard Norman Blake say he likes 12-fret guitars for the same reason...bridge location, I guess?

[Dale Ludewig]

Merry Christmas to you all. I don't know why I felt I needed to come to the cafe on this night, but I had some time and "why not?". Then I saw this thread, so I'll throw in my thoughts.

There should be no difference in action between an oval and an F hole, regardless of where the neck meets the body. There is no reason the angle of neck to body should be any different; normally oval holes join at the 12th fret, F-holes join at the 15th, although that's not necessary. The bridge/saddle is simply in a different position in relation to the body. On an oval hole, the bridge is a little a farther (further?) back on the body. We can get into the physics part of it at some other point, but it's already been dealt with on this forum before. A search should get you lots of input from a lot of different builders. But if you look at historical instruments, there is a trend and there is a reason.

Neck angle and bridge height are intimately related. Break angle (angle of the strings after they leave the bridge and head toward the tailpiece) is also of great importance for many reasons.

Scale length, within reason, shouldn't affect action too much. Of more importance, IMHO, is break angle over the bridge, and setup. A good setup on a well built mandolin will make it a joy to play. A bad setup on any instrument will make it an unpleasant experience. From what I can tell, I'd be looking for a luthier to do a good setup. But, that's just my opinion. I haven't seen your instrument or its setup and there are many very knowledgeable people on this forum. But it's Christmas night- I'm off to supper with my wife.

[Mike Buesseler]

My point--or question--is getting lost here, I think. I'm more than fine with the set up on both my mandolins. No complaints at all. I guess I'm trying to learn something about the difference in sound of As vs Fs. I know there are lots of factors. I guess I'm trying to focus on what difference the neck-joining-body-point makes...or maybe it's the difference that location of the bridge makes in the characteristic sound of each type of mando. Or, how about this: why do most A mando necks join at the 12th, Fs at the 15th?

Dale, thanks, as always, for your valuable input. I should have thought this out better, done a search, I guess. I'm just not sure what to search for....'effect on sound due to bridge location' doesn't yield much.

[Bill Snyder]

A's and F's (built by the same builder with the same materials) with oval holes tend to sound pretty much the same. A's and F's with f holes tend to sound pretty much the same.
Unless I am mistaken the Gibson A-5 joins at the 15th fret just like the F-5's.
It is the hole configuration more than anything else that makes an oval hole and an f hole sound the way they do.

[markishandsome]

Unless I am mistaken the Gibson A-5 joins at the 15th fret just like the F-5's.

And all the Fs before the F5 had oval holes and 12 fret necks. The 12/15 fret thing is historical. Before truss rods were invented it was dicey to make the neck any longer than 12 frets. Once you had truss rods, why not make the neck longer for better access? To do this you need to overhaul the arching, bracing, bridge position etc, which might be why gibson never switched to 15-fret F4s: too much re-tooling. Most oval holed mandos built today (A, F or otherwise) still have 12 fret necks because they deliver the tone tone people expect from an oval.

[Antlurz]

Sitting here chuckling to myself about throwing another brick at the fire. I'm working on an F4 with an F5 neck which will have the bridge positioned in the standard F4 location. Simply used an inch longer scale. It will be interesting to see if retaining the F4 bridge location preserves the F4 sound.

BTW... the join is at the 13 3/4 fret.

Ron

[Mike Buesseler]

Hey, Ron,

I think you're on to something there....Mike Vanden makes an A5 with an elongated scale. I have a good friend who owns one. THE sweetest sounding mandolin I have ever played. I can only imagine what an oval-hole long-scale mando will sound like...keep us posted!

[Dale Ludewig]

Mike, I've reread and will try to do a better job answering your questions from what I know and understand. That leaves a lot of unexplored land.

It seems you're asking 3 or 4 (?) questions:
1. Difference in sound between A and F models (same type hole- oval or f).
2. Why oval hole models join at the 12th fret (they really do from my experience) and f-hole models join at the 15th (they really do). I think, and I'm guessing, that your definition of where they join is different than mine.
3. Why oval hole models sound "tubby" compared to f-hole models.
4. What effect scale length has on action.

My thoughts:
1. The physics of oval hole models are very different than f-hole models. The internal bracing is traditionally very different. Oval holes traditionally have one brace running left to right right behind the oval hole. That's it! And traditionally oval holes have the top carved up to support the fingerboard, effectively rendering that part of the top not a big sound producer. F hole models have tone bars, or more recently, sometimes are x-braced. And the fingerboard is raised above the top, allowing that part of the top to vibrate. I'm sure the bridge location has an effect, but what exactly it is, I don't know. Dave Cohen would know far more than I. But if you imagine moving the bridge way back toward the edge of the mando, you can imagine that it would affect the sound. But I think the location of the hole has the major effect. I wonder what 2 f holes placed crosswise where the oval hole is would do. For what it's worth, I've made two oval holes that are x braced and they still sound extremely different than f holes.
2. Oval hole mando's have their neck joints at the 12th fret as a rule is because if you made the neck longer and joined at the 15th, you'd pull the bridge up much closer to the hole and this would cause structural issues. Not that they couldn't be dealt with, but they'd have to be dealt with.
3. I guess I said in "1" that I don't exactly understand why. Maybe Dave Cohen will weigh in, or someone else who understands this better than I. I also wonder what an oval hole violin would sound like. Someone probably has made one.
4. A shorter scale length will likely feel stiffer, period. Press down on the strings behind the bridge vs. the fingerboard on the same mandolin. The strings are under the same tension.

Lastly, there is no reason to my thinking why an A model with f holes and an F model with f holes should sound any different. At least not that you should notice.

I hope I did better this time.

[hotclub]

[QUOTE]4. " A shorter scale length will likely feel stiffer, period. Press down on the strings behind the bridge vs. the fingerboard on the same mandolin. The strings are under the same tension."
I beg to differ; To achieve the same pitch, with the same diameter strings, a short scale length will use less tension than a long one.

[Mike Buesseler]

Thank you, Dale. Happy New Year! You hit 'em all!

[Dave Cohen]

Seems like so many things being confused here.

I shipped a commission a few weeks ago. It is an A-model with f-holes (well, my "c"-holes, actually), and a short scale. The scale length is 13.125", as opposed to the usual 13.875". On this mandolin, the 13th fret is over the cross-piece. On typical F mandolins with f-holes and a 13.875" scale, the 15th fret is over the cross-piece. The bridge is within 6 mm or so of the usual position (for an f-hole mandolin) on the top plate. The commissioner wanted the sound of one of my c-hole mandolins with the playability of the shorter scale. Her reasoning was that she has "short fingers". Not having done something like that before, I was not exactly sure how it would turn out, but as it turned out, I shouldn't have worried. The sound was pretty much what was asked for, and the playability was too. The mandolin plays easily, with a "soft" feel.

Now, this may still not be exactly what is being discussed, as think that several different factors are being discussed. My point is that easy playability can be achieved with many different configurations, and has to do more with set-up than anything else. As to the physical difference between oval hole mandolins and f-hole mandolins, I have posted several times on that in past threads. The main difference between f-hole and oval hole mandolins has to do with the way they radiate sound in different frequency regions. In ovals, the main body modes don't couple as well with the Helmholtz air mode as is the case for f-hole mandolins. Also in ovals, the body longitudinal rocking mode is positioned pretty well (frequency-wise) to couple with the longitudinal sloshing air mode, and may result in addtional monopole sound radiation in the 700-800 Hz region. Otoh, f-hole mandolins don't do that. Those factors, much more than differences in bracing patterns, seem at the moment to be responsible for the differences in sound between f-hole mandolins and ovals. I may change my mind about that in the future, and when I do, I will let you know.

I don't know why people keep bringing up that stuff about "sounding bouncing off of" this plate or that plate. That is simply not physical. The air in the body cavity vibrates in specific normal modes, just like wood and strings do. One is the Helmholtz mode, at about 290 Hz in f-hole mandolins, 210 Hz in ovals; the 2nd is the longitudinal sloshing mode at 700-800 Hz in both types; the 3rd is the sideways sloshing mode at about 1.0 - 1.3 kHz. That is covered in the Cohen & Rossing papers, and is completely consistent with what has been known for the last 30 yrs for guitars, violins, etc.

[David Houchens]

Sorry about the pictures I posted here the other day. I got my threads mixed up. I've moved them to the other one. Hope no confusion. David

[Geoff B]

I will be sure to check out your papers Dave. That sounds incredible. Regarding this topic, often the "tone" we hear is a result of the structure of the sound producer. Take your voice box, for instance. You get different tones by changing the shape of your mouth, throat (larynx?), tongue and lips. It is these differences in shape that produce the different noises we associate with words and language. An interesting thing to note is that the human vowel recognition is based on the series of harmonics in the sound being produced. "Ah" and "Eh" and "oh" etc. at the same pitch are recognized because they contain a different set of harmonics (or partials, overtones etc.).

Here is where my knowledge goes down. I imagine the modes to which Dave Cohen is referring are in some way related to the series of overtones produced by the instrument. Oval holed instruments, one kind of structure, will produce certain overtones and operate in different modes more than f-holed instruments of a different structure. Maybe Dave's papers discuss what that relationship is. I'd like to know.