Saturday, November 17, 2018

An Acoustic Guitar Experiment

acoustic guitarOne of many irritants about getting old has been circulation issues. I sleep with at least one half of my body tingling from lack of circulation regardless of which side I sleep on, bed softness or hardness (although, hard is better), sleep position (although after being married for 51 years I am “trained” not to sleep on my back), pills, or anything else I’ve tried. Playing guitar is one more place where my poor technique has turned into a minor medical issue. Like many non-classical guitarists, I “rest” my right arm on the edge of the lower bout. For 50-some years, that hasn’t been a problem for anything but the limitations in speed and technique it causes (which are substantial, I know, Scott). This last couple of years, it has begun to cause another problem. After a few minutes of playing or practice, my wrist, hand, and fingers begin to tingle and will eventually get numb feeling from the lack of circulation caused by that pressure on the edge on the blood vessels of my inner arm.

A few months back, I saw Brian Stewart—music store owner and guitar builder/technician extraordinaire—working on an arm rest for one of his customers. I wondered if that device might help with my circulation problem? So, I built one.

Saturday morning at the TreeStrings morning jam, I tried it out. For the most part, it worked pretty well. Brian and I talked about his design verses mine and we had some other ideas as to how this might become an actual product (which he really doesn’t want to build) and I thought about some of those changes while I played this morning. I wish I’d taken a picture of my original design, if for no other reason than to show the evolution of the idea and because I thought the original piece was really pretty. It did cover more of the top than necessary and was heavier than necessary, too. To keep from having to split another piece of walnut to start from scratch, I decided to hack away at my original piece. Might have been a mistake.  

When I got back home, I took that first attempt down to my basement shop and started carving it down to about half of the original width. I smoothed out the bandsaw cuts, sanded the piece back to a beautiful gunstock satin, and tried it again. This time it wasn’t nearly as comfortable as my original design and that was a huge disappointment. So, I reshaped the top side, losing about 1/3 of the total thickness and creating a little more of a flat spot on top while keeping the soft edge I’d originally designed. I refinished that work and reattached the piece. For the initial experiments, I’m using fairly weak double-sided tape to hold the piece in place, but when I decide I’m happy with it I’ll use something more aggressive.

One of the things I did not expect to happen was for the guitar’s tone and output to change for the better. If you look at that guitar-playing picture (at the top of this essay), you’ll notice that the arm damps a fair portion of the guitar top (especially true when the player is wearing long sleeve anything). I play a very small Composite Acoustics Cargo travel guitar and I’d never really thought much about how much of the guitar’s top I was sacrificing with my playing technique (I know, Scott). After listening the “with and not-with” sound of the guitar, I was interested in the concept on a whole different level. I would guess the overall volume is close to 3dBSPL louder with the arm rest in place and it is substantially more full and brighter, too. In retrospect, all of that makes perfect sense, but I hadn’t thought about it until the evidence was right there in my arms.

I will be playing with this concept a lot more in the future. For now, I’m enjoying being able to practice guitar for several hours without numbness and that irritating feeling (or lack of) that comes with circulation problems.

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Wirebender Audio Rants

Over the dozen years I taught audio engineering at Musictech College and McNally Smith College of Music, I accumulated a lot of material that might be useful to all sorts of budding audio techs and musicians. This site will include comments and questions about professional audio standards, practices, and equipment. I will add occasional product reviews with as many objective and irrational opinions as possible.