oval hole vs round hole tonality

[epicentre]

I've been looking at The Mandolin Project book by Graham McDonald, and he gives two examples of oval (50x70 mm.) hole, and 60mm. diam. round hole.

I'm thinking in particular of both of these in carved top mandolins, and wonder if anyone has had any experiences to compare, vis a vis, "better" tone. - given the same size of mandolin. The 'search' yielded little.

Any assistance appreciated as usual.

[Matt DeBlass]

It's my understanding that, given the same approximate placement, the overall size of the hole matters more than the shape. I think bigger favors the treble a bit, whereas a smaller hole makes for a more boomy bass sound.
I'm far from an expert, though.

[epicentre]

Thanks Matt; PM sent.

[i-vibe]

I think bigger favors the treble a bit, whereas a smaller hole makes for a more boomy bass sound.

actually i think just the opposite is true....vis a vis Paris Swing mandolins and Selmer style gypsy guitars.....the large hole 'le grande bouche' is supposed to yield better bass and the smaller "le peite bouche" is supposed to yield more treble.


i do agree that overall size and not oval vs round might be much more of a decisive factor.

YMMV

[mandroid]

Oval in an arch top versus round in a flat top?

[Geoff B]

It's been my experience and understanding through talking with other that the shape of the hole(s) makes minimal difference (if any) compared to its(their) size and location. A bigger hole will raise the main body mode and bring emphasis into the treble range, a smaller hole will lower the same mode and put emphasis on the lower range. You need relatively large changes in hole size to get noticeable changes in the mode frequency, so take that anecdote with a grain of salt. The relationship is an inverse square root, if that helps. I haven't read Graham's book, but he is highly regarded and I'd put a lot of stock in what he says about anything with mandolins.

[epicentre]

Thanks all for your comments and advice.

In finality, one does all one can do, carefully, and then rolls the dice.

Suits me. Always has worked before................srto fo.

[Graham McDonald]

I really don't think the shape of the soundhole is going to make any noticeable difference in the sound of the mandolin, especially when compared to all the other variables involved in making a carved top mandolin. These are going to at least include:the individual characteristics of that particular piece of spruce (or other softwood), arching height and shape, graduations, size and placement of the internal bracing, depth of the sides, back and side material, bridge height and string angle over the bridge and probably more.

For a simple flat-top mandolin - a first go at mandolin building - a round soundhole and rosette can be accomplished quite simply with a hand held circle cutter, or a small router on a jig. It is much harder to do that on a carved top, and in many ways easier to trace out an oval shape, cut it out roughly and then refine the shape with sandpaper wrapped around a dowel. I used to think an oval hole was harder to do than a round one until I tried it and found it wasn't all that difficult. In addition there is an aesthetic tradition that carved mandolins have oval holes (if they don't have f-holes), and people expect to see them there.

As a couple of previous posters have mentioned, soundhole size is important as it is a major part of setting the air resonance of the soundbox, which is a basic determinant of the tone of the instrument. The air resonance is that note which booms out when you hum into the soundhole. The soundbox resonance has to be within a fairly narrow range for the instrument to have what is generally considered an optimal tone, and having either a too big or too small soundhole won't allow that resonance to be in the right place. At the same time there is a fair bit of leeway in the size of the soundhole.

Structurally, f-holes (of whatever shape, not necessarily f) are a better idea as they keep the longitudinal arch in one continuous piece, not broken up 2/3 of the way up the body. The soundboard of an f hole mandolin can be made lighter and thinner than an oval hole, as there doesn't need to be the extra mass of the soundboard around the soundhole to resist collapsing. I am a firm believer that lighter is better if the stiffness can stay the same. Exactly how you do that is, of course, ever open to debate.

cheers

graham

[epicentre]

Thank you Graham. Your book has been of great value to me, and will continue to be a reference.

Re: your above post.............what I said about rolling the dice..........!

Cheers back at ya.