Wonder if you all remember me saying that instruments come to me in twos or threes. Either two or three of the same brand, or, two or three with the same problem.
After I finished working on two instruments with a belly bulge and lifting bridge, I thought it was time to talk about the whys and wherefores, guitar anatomy, strings and all that good stuff.
In the last two posts, I have touched upon the issue, causes and remedies but a detailed post was in order. So, here goes!
The second photo shows you a bridgeplate and where it is situated in the guitar, while the first photograph is a diagrammatic representation. There is no one design of the bridgeplate, but it usually fits into the ‘X’ brace.
As you can make out, a bridgeplate is placed on the underside of the top of the guitar, right below the bridge, and its job is to buttress this area where there is most tension – due to the strings.
The two photographs above show the bridge area with the strings and bridgepins, and the underside with the ball ends of the strings sitting resting on the bridgeplate.
Now, imagine the strings tuned up to pitch. They are pulling up with a force equivalent to almost 80kg. Their effort is to rip the strings right out of the top. The only thing preventing that from happening is the bridgeplate. If any of the following – size, thickness and material – is not up to the mark, the bridgeplate will surely give in, resulting in a belly bulge, high action, and the bridge lifting under stress – much like this
NOTE: A little bit of belly is normal EVEN in the best guitars (the Martins, the Guilds, the Taylors and the Gibsons), but the difference from budget guitars is that the belly will appear after a decade or so of playing.
In extreme cases, the tension of the strings even breaks the bridgeplate.
I find it strange that guitar ‘pundits’ and so called experts speak about everything under the sun but seldom refer to the bridgeplate as one of the first things to check when you’re buying a guitar – new or used!
The bridgeplates that I have seen are light-coloured woods, which tells me that these are not hard woods, and thus, susceptible to buckling under the tension of the strings.
Even a maple bridgeplate (as seen above) – the wood is considered a hard wood – is incapable of bearing the strain of the strings.
Instead what you want to see inside your acoustic guitar is a piece of a dark wood
SIZE, THICKNESS & MATERIAL
A piece of hardwood – rosewood, mahogany, ebony, walnut and paduk – no lesser than 1.4 mm thick and no thicker than 1.8 mm is said to be of the appropriate thickness.
The length and breath of the plate should be such that the ‘X’-brace pocket is relatively filled. Look at the first two photographs. That is the general ‘popular’ shape of the bridgeplate. However, I would prefer to see the area right from the point where the arms of the ‘X’-brace cross to at least some portion in line with the tone brace being covered by the bridgeplate.
Make it too large, or too thick and it will not let the top vibrate, resulting in a dull, muffled tone!
Why the emphasis on a hard wood for a bridgeplate? Because the top itself is made of soft wood which can vibrate much easier as compared to a hard wood. Basically, the hard wood compensates the vibrating top and lends a lot of structural integrity.
STRINGS PLAY A HUGE ROLE
The gauge of strings that you usually string your instrument with plays a huge part in how quickly the neck starts creeping up (warranting a neck reset), whether the neck-to-heel joint starts separating, how quickly a belly develops and how much damage is caused to your fingers.
The lighter the gauge, the smaller the effect and vice versa. To think that by putting on the lightest gauge there is you can delay the inevitable, is true to quite an extent. HOWEVER, what about the sound? Can you really appreciate and enjoy the tone of your guitar?
Thinner strings will always give you an amplified treble response while thicker strings will accentuate the bass response.
If you are a purely rhythm player and own a dreadnought guitar, the thicker the strings used, the bigger is the bang for your buck! But then you know string tension is playing havoc with your guitar.
The path to take is the middle road. Not too thick strings and not too thin.
Here’s to the health of your acoustic guitar!