Keith wrote: ↑
Wed May 29, 2019 12:10 pm
Just curious how the sound changed--for each step and the end result?
The ports will do a few things if done correctly....
First, they act a bit like a breather hole on a gas can, the change the air resonance and slightly improve the sound out front, and send waves to the player so they can more accurately hear what's coming from out front.
In the case of classicals, they can smooth out boomy bass response which makes it hard to mic or record. Every classical I've ported it got much easier in regard to mic placement.
The dual ports in the positions shown above also create an ambiance to the sound that is hard to describe. I first experienced it about 10 years ago with a Josh House steel string. The ports on Josh's guitar were too large for the body, but it still gave this effect. There's just a wonderful surround effect present if you are really listening!
They also typically increase the treble "fatness" (especially on steel strings)
In regard to the slight modifications of the bracing and top - the goal is just a much "rounder" tone - more full in every frequency and an instrument that is more responsive to a lighter touch. There's a lot of intuition involved in this process and you have to be very careful. As noted above, factory built instruments are typically quite overbuilt because, as one of my builder buddies says "they don't want them returning to the mothership!". Many players don't properly humidify and end up with problems anyway, but as most of us here know, lightly built instruments are more susceptible to changes in temps and humidity.