Is the auxiliary side sound port in acoustic guitars just a newfangled gimmick, or does it really work? Quick answer: Look in the back pages of Acoustic Guitar magazine, where the luthiers advertise, and count how many pictures you see that show sound ports.

   This idea is being enthusiastically embraced and put to use by an increasingly large number of custom builders. A lot of debate about the sound port has been published in the Journal of the Guild of American Luthiers (GAL), and by the Association of Stringed Instrument Artisans (ASIA). Sound ports are showing up like mushrooms after a drenching rain. I’m beginning to think that the only people who don’t believe in the sound port are those who haven’t yet given it an honest try, out of obedience to tradition or whatever.

    Ironically, it was two preeminent Classical guitar luthiers, Robert Ruck, and then his friend Kenny Hill, who were among the first to stand up and proclaim the sound port breakthrough. It was mostly classical guitar makers who lit the beacon on the sound port.

    What is the sound port supposed to accomplish? The first idea was that having a small sound hole on the upper bout, driver’s side of an acoustic guitar would port some of the guitar’s sound toward the player’s ears, allowing him/her to hear the music better. What a boon that would be for private practice, unamplified performance situations, and also the recording studio!

   The second supposition was that porting the upper bout sides would give the whole guitar more lungs to breathe with. It would have more air, more voice, more efficient excursion of sound waves. Same idea as porting a speaker cabinet.

   A consensus quickly formed up among builders and players that the sound port was very effective as a personal monitor for the player. But there was more to it than that.

   A good few forward-thinking luthiers got on board and started experimenting with sound port design. Many subjective experiments were conducted with ported guitars. The idea grew. Then, some canny individuals got out the testing equipment and microphones, to objectively measure what was actually happening.

   Many very surprising things came out of the sound ports in these new, modern guitars. There were numerous reports that the guitar was louder with an open port than when it was covered. People started noticing a rounder, or more spherical sound projection in ported guitars. The words, “organic reverb” and “stereo-acoustic” were bandied around.

   Some builders started getting radical with the sound port idea, trying all sorts of ports, large and small, in odd locations, while others experimented with Helmholtz tubes, periscopes, cattle chute baffles, sex toys, and carved wooden speaker horns. More conservative builders usually opted for a small open port somewhere on the upper bout side. That seemed to make the most sense, once the results were in. As the port continued to gain traction, it became one of the significant evolutionary leaps in the 21st century acoustic guitar.

   As always seems to happen around the turn of a century, true innovation comes in great surges, every hundred years or so. And here we are. It’s happening again.

   The sound port is not a gimmick. It’s an advance whose time has come.

  

I built the first sound-ported Edwinson in early 2006.  The sound port idea  was too good to resist, I had to try it. The sound port made total sense to me.

   My guts told me that the port’s optimal placement would be in the middle of the upper bout curve, on the driver’s side. That’s primarily a reflective area in an acoustic sound box. My first guinea pig was an ECC Consort model.

   For my own skeptical satisfaction, I decided to build that first one with a slider hatch that would enable both open and closed port listening. When I got that first ported soundbox built, I would tap and drum on it with the slider in various positions. That’s when I became convinced that the sound port was for real, a legitimate sound shaper.

   The acoustic guitar soundbox should be built to respond like a well-tuned drum. With the sound port in various positions, I could make it sound like several species of drums, just by thumping on the box and working the slider.

   When the first ported Edwinson was done and strung up, the results were thrilling. With the port closed, the guitar had a very balanced, even response from high to low, and a healthy amount of volume and sustain. It sounded like a brand new guitar with a lot of potential. When I played with the port open, the voice of the guitar took on an effusion of floral essence. It was like sitting in the middle of a rose garden. I’m not sure how else to describe it. It just became more open, and present. The sound became more fragrant. And I could hear every detail, good or bad, in my playing technique. It was a humbling experience at first. Over time, that guitar kind of forced me to become a better player.

   I’m not saying that the difference between open-port as opposed to closed-port sound is dramatically mind-blowing. The essential character of the guitar doesn’t change. It is what it is, only more so.

  

I kept that guitar in the house for about a year, so I could play it in a bit, and let the voice develop. As the guitar settled into itself, the effects of the sound port became more pronounced. The default position of the slider was open; I became addicted to that sound. I asked other people to play the guitar so I could get the audience perspective. With the port open, I could hear the guitar just as well, standing behind the player, as I could standing in front. With the port closed, the guitar has tremendous forward projection. Other players responded with unanimous praise for the guitar. When I finally put it on the market, it sold very quickly. That ECC Consort also won me some commissions for other ported guitars.

   Since then, I’ve built every Consort model except one with either an open port, or with the port and slider. The open port comes standard on my new EFC Falcon model. I’ve included open ports in a few EP Performance guitars as well, but with them it’s almost overkill. In my experience, the sound port works best in smaller-bodied guitars.

  Making a sound port with the slider requires some very careful fitting. No wiggle room is allowed. I intend for the slider to be trouble-free for the full natural lifespan of the guitar. With reliable longevity in mind, I now build the internal slider tracks with a high density fiber material. (The first two were rosewood and maple.) The tracks are lined with felt, bedded in epoxy, for a smooth action. The slider itself is a two-piece laminate of ebony or rosewood, which is very stiff and dimensionally stable. The slider button is held in place with two small screws. (See photo above.) If the slider ever needs service, it’s a simple matter of removing those two screws to remove the button, and slipping the slider out of the tracks. If the action needs to be tightened up, some years down the road, all that needs to be done is to glue a couple of thin strips of veneer to the outside edges of the slider, sand them smooth, apply a bit of paste wax, and reinstall for a silky, precise action.

   All sound ports are reinforced inside with a high density fiber laminate. For additional stability and style, each sound port is bound in wood.

   For some fascinating further reading on sound ports, may I refer you to Tim McKnight’s excellent website. Tim is a luthier of great talent, and his guitars are brilliant and highly innovative. Check out his very well informed take on sound ports, if you need any more convincing. And then have a look at his gorgeous McKnight guitars.