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I'm interested in pursuing the idea of a sound port in one of my classicals, not for the usual reasons but because I happen to be mostly deaf in my right ear. Like most players I turn my head to the left while playing, which puts my bad ear into the prime listening spot. Would a sound port closer to my good ear help me to differentiate a cardboard box from a Hauser? How would I safely accomplish this retro fit? Thanks for any input.

It should help. The port puts out sound in the high frequency range that is normally mostly projected out to the front of the guitar. Since most hearing loss cuts down on your high frequency acuity this should help. Several people with hearing loss have reported that this works for them.

I usually locate the port just below the wide part of the upper bout on the right side, where you can see into in as you're playing. This gives it output in a useful frequency range and doen't alter the timbre of the guitar too much. It need not bee very big to be reasonably effective: 1" or so in diameter works pretty well. I tend to dislike the tone of guitars with ports larger than about 3": this tends to raise the 'main air' pitch too much unless you reduce the size of the main sound hole to compensate.

I like to reinforce the sides when I put in a port. On the first guitar I experimented on with ports I just glued cloth tape across the sides on the inside before I drilled the (20) holes. So far it has no cracks. Cross grain veneer works well, or you could get some thin ply (1/32" is available, believe it or not) from a hobby shop that sells model airplane supplies. To use a wood reinforcement on an existing guitar I'd start by drilling a 1/4" hole where the center of the port will be. Make a shaped caul that will fit inside and drill that to match. You could wax the caul or put plastic over it to keep glue from sticking. Thread the reinforcement over the bolt in the caul, making sure the grain in the reinforcement runs across the side grain. Butter it up with glue, stick the (well waxed) bolt through the hole in the side, and use a nut to pull it in tight. When the glue is dry you can remove the caul easily (we hope), and the 1/4 " hole provides a pilot for the hole saw that you use to make the port.

Thanks Alan. I appreciate the good info.

You might want to try a compromise between a hearing aid and a sound port that I stumbled upon. Get a piece of rubber/plastic tubing that will fit comfortably into your ear. Plug one end into your ear and drop the other end into the sound hole. I was surprised not at the loudness, but the ability to hear all kinds of overtones that I do not otherwise hear.

Which overtones you hear the most will depend on just where the tube winds up.

My violin making teacher built a fiddle to explore the effects of 'air' resonances that had about 63 holes in the ribs that could be plugged with small corks. With all the corks in it sounded pretty good, but as you removed them the tone got worse and worse. One of the other students got a pair of head phones on a flight that worked like a stethoscope: you plugged them into the the sound source in order to hear the movie. The two plugs just fit into the cork holes in the fiddle, and we had a lot of fun trying different locations as we played the thing.