Single vs 2 Piece back

[mugbucket]

So, after registering for the free mandolin Weber is going to build (it could happen), I went and designed my dream oval hole 2 pointer with a one piece back.

Then I started to wonder if there were any pro's/con's with that decision - meaning, are the tonal qualities impacted? More susceptible to cracks/splits/humidity etc.?

Just curious...

Ski

[Brett Byers]

All things being equal, ie- wood density, age, proper glue joint on a two piece, etc... there is essentially no difference between a one piece back and a two piece back, other than cosmetics.

[mugbucket]

Thanks Brett!

Ski

[Ed Goist]

I have been told that the two piece back may add some complexity to the tone of the instrument because of the slight variation of the plate. This sounded reasonable to me.

[Steve-o]

Perhaps Spruce or Dave Cohen will weigh in here, but from my experience, some one piece backs are slab cut, while two piece backs are often quarter sawn. There is some difference in dimensional stability between the two as I recall, the latter being more stable.

[Paul Busman]

I don't know about tonal differences, but a book matched two piece back sure is pretty.

[mugbucket]

Can't argue with ya Paul - but there's something about a big hunk of quilted maple that makes me drool just a little more. To each his own...

Ski

[sunburst]

Two piece backs can be (and often are) flat sawn, and one piece backs can be quarter sawn. Either type can be either flat or quartered, and the stiffness of maple is about the same either way, so flat vs quartered doesn't make much difference in sound. Likewise, one piece and two piece backs sound the same, so it comes down to cosmetics. If there is any advantage it is perhaps the fact that a mandolin with a one piece back has one less glue joint to fail.
Quartered wood is more stable, as Steve-o pointed out, but that is more important to longevity and structural integrity than to sound. Even so, there are quite a few 80 to 100 year old Gibsons around with intact flat sawn backs.

A quilted maple back that really shows prominent quilted figure will be flat sawn big leaf maple.

[hank]

Seems like I remember someone telling me that quilted maple(big leaf,etc.) is often a tad softer than the maple used for flaming grain patterns. If so can the harder wood be cut slightly thinner for more responsiveness?

[mugbucket]

At the risk of exposing my ignorance I had to research what quarter sawn meant – and thought I’d share…

http://en.wikipedia.org/wiki/Quartersawn
http://www.wisegeek.com/what-is-quartersawn-wood.htm

The stability issue is addressed in the Wiki article, and a good visual aid is presented in the second link. And I’m sure it’s all true ‘cause I found it on the internet. ;-)

Ski

[hank]

Thanks Ski, I think I was confusing riftsawn with quarter sawn before the illustration on the second link. I had it in my mind that quarter sawn was sort of like the way we cut a pizza.

[Tonear]

I've been told that a one piece back sounds different. What I was told is, a two piece back refects more and is therefore brighter. A one piece back vibrates more and is therefore warmer.
I do not have the enough experience to form an opinion. But I have noticed some very expensive and superlative sounding mandolins have one piece backs. Whether or not this is the effect of the back I could not say.
Maybe someone else here has played a bunch of one piece and can weigh in.
T

[almeriastrings]

There are too many variables to generalise... in my opinion, though, tonally, it makes no discernible, consistent difference whatsoever. As mentioned there are some differences in terms of how the wood might distort/warp under certain conditions.. but even then... most of the time, no practical difference. One-piece backs have been around on instruments for hundreds of years. I've seen quite a lot of 16th C. violins with both slab and quarter-sawn one-piece backs. One area where there is a difference is in the species used. Those instruments built using "European Maple", which is actually Sycamore, Acer pseudoplatanus, and has a different density from the American maples. The 'great' violins of the Golden Era were built using this European material. It has a particularly spectacular 'flame', with almost 3D depth... a lot of mandolin family makers also make use of it. It gets a bit confusing as all of these different species (there are well over a hundred of them) just get collectively called "maple" in general use. Even a single species varies a lot depending on where grown, due to climatic influences, etc.