flat top

[kencierp]

A little contour is good insurance to prevent the optical illusion of a concave soundboard -- this is why the old time classic builders put in a bit of contour. Beyond that unless you have a sound board baking system such as Bob Taylor uses in his factory for controlling moisture in the materials -- its best to dome/contour for the following reason: Which I recently posted elsewhere

To understand the function of a domed top just take a piece of cloth or paper and push it down in a pie tin so its relatively flat against the tin. Now take a marker and draw around the circumference. Cut out that circle. Now lay that cut out on a table and place the pie tin face down. Of course you will see that the cut out piece is somewhat larger then the flat surface under the tin ----- this is the key function/reason for doming the sound-board and back for that matter. The dome has much more surface area Now if a perfectly flat plate is glued to the perimeter of the guitar and the low humidity causes the plate to dry and shrink (yes get smaller) the plate begins to pull itself apart since it is too small to fit the area defined by the perimeter -- then bingo a crack develops. On the other hand (think about the example above) when a domed top begins to shrink there is extra area (material) so even though the perimeter is restricting the plate the extra area allows the plate to contract (flatten out) without developing cracks -This is not to say the humidity change does not play havoc on the set-up -- it does. So the dome top works as a preventative measure -- working with, rather then controlling the forces of nature.

[Darryl Young]

You can do it and other luthiers do this........but you need to understand what is going on and treat the completed instrument appropriately.