I recently ordered a new guitar from Marcus Dominelli and had to decide on whether to get an armrest. It seemed silly at first because the rest further extends the guitar outward (only millimeters but still) so at first I didn’t want one. However, after trying one out I found it quite comfortable on the arm, my arm could more smoothly move up or down without as much friction due the curved edge of the armrest. Also, the idea of the arm muting the soundboard does make sense, although I do wonder if it’s significant enough to be noticed.
Here’s a few words about armrests I found across the web :
Some guitar makers, like Greg Smallman propose an armrest integrated to the guitar. An armrest provides three primary benefits: it lessens damping of the top caused by the right forearm; it is potentially more comfortable for the player; and it absorbs the wear to the finish that would otherwise happen on the top, the binding, and the side. These benefits are of particular importance for ultra-thin-topped instruments, such as Smallman’s, but will subtly improve any guitar, including double-tops. The Rasgueo-Rest armrest additionally helps large and tall players avoid hunching-over the Guitar, since the Guitar’s surface area is in effect, “expanded” using the arm-rest, giving the arm-height support needed for good playing posture. – via wikipedia
Maybe not high on the priority list for a lot of players, but an armrest has a couple of advantages. First, it helps keep the right arm from muting soundboard vibrations. Second, it protects the french polish from slowly getting worn away by the right arm. Touching up this area of the finish is less likely needed in the future.
I’ve been making my armrests out of African Blackwood (dalbergia melanoxylon) a true rosewood that looks black like ebony. Other woods could be used as well. The guitar pictured here is a cedar fan braced guitar with claro walnut back and sides. – Luthier, Marcus Dominelli.
Quote and Photo via dominelliguitars.com
They’re mainly for comfort, but some makers claim that there is some advantage to keeping the player’s arm off the soundboard. I don’t really think it makes much difference in this respect – I find on my guitars I have to very deliberately press my arm into the top to hear any change – playing normally there’s no difference. – Luthier, James Lister via delcamp
I have mixed feelings about them, I’ve run into some resistance when it comes to older more traditional guitarists, the younger players seem to like them more than traditional guys. As far as the volume goes, I’ve read by some that they boost the volume by 20%. I don’t know how that figure was arrived at, I will say however, it does increase the volume, but mostly in the bass, because your arm without the arm rest, tends to dampen the bass side of the guitar, this may or not be desirable for some. If your guitar has tight basses an arm rest might help, if there too open it might not. – Luthier, Michael Thames via classicalguitarforum.com