(First published in Guitarist magazine, issue #466)
After finishing three years studying guitar making, in 2011 I moved into my first workshop in Deptford, London. With only a handful of guitar builds under my belt and a slew of more experienced luthiers already in business in the big city, I decided I would need to do something a little different to make an impact. So, I had a go at figuring out some of the intriguing new ideas I’d seen coming from the workshops of my favourite acoustic luthiers, and top of the list was the side soundport.
Soundports are one or more holes cut into the sides of the guitar, typically on the bass side of the upper bout, facing the player. The front soundhole of a guitar is so iconic and intrinsic that many people at first find the idea of another hole in the side unnecessary, or just plain odd. Some luthiers find the removal of precious tonewood to be questionable. There is, however, a strong logical argument in favour of this ancillary opening.
First, a little refresher on how a guitar functions. When we strike a guitar string it vibrates, and this energy is transferred into the rest of the instrument via the bridge. Much like a beater striking a drum skin, the soundboard will vibrate in a corresponding manner and its surface moves the air to produce the tone and volume that we desire. If we imagine there was no soundhole and that the guitar was a perfectly sealed box, the movement of the soundboard would get restricted by what is in effect a vacuum within the box. As long as the box is ported in some way, the air can freely flow in and out, allowing the soundboard to flex fully and provide the best possible tone.
So what happens to the tone when a second port is added? Well, initially I would argue not a lot. In effect, we can consider that we are simply making the soundhole bigger. By how much depends on the size of the new soundport. Without plunging too deep into the technical stuff, this has an effect on the resonant frequency, essentially shunting particularly prominent frequencies in one direction or other. This might sound like it could have a big effect on the character of a guitar, but in my experience a modestly sized soundport doesn’t translate to a huge difference in overall tone.
What the big deal then? Well, the side porting gives players a completely different perspective. Rather than hearing most of the guitar’s tone as second-hand reflections from the walls of the room you’re playing in, it’s more like sitting in front of the guitar. I would actually describe the experience as hearing what’s going on inside the instrument. There is more detail in the perceived tone and a pronounced natural reverb. It’s akin to having a monitor in front of you on stage, instead of relying on hearing yourself and the band from what’s coming out of the front-of-house PA system.
Some astute skeptics do make the point that the side soundport must be siphoning a certain amount of projection from the front of the instrument, after all you can’t have something for free. Whilst I reluctantly agree this must be the case, I do think the effect is negligible. At any rate, I think an audience benefits more from a performance where the player can indulge in hearing themselves with added clarity.
You’ll not likely find many of the big factories producing guitars with side soundports, so it does mean that these guitars tend to be luthier-built instruments with bigger price tags. However, the extra hole does at least also reveal the beauty of the craftsmanship on the inside. So, next time you are in an acoustic jam session and struggling to hear yourself over the shriek of an adjacent clarinettist, consider giving one a go. It’s not often that us guitarists will admit this but, less is actually more, for a change.
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