Tuesday, September 9, 2008 @1:07:56 AM
I just posted a reply on BHO that probably sounds crazy to many people. It was a suggestion to add a simple, easily made part to a banjo that will bring out more low frequencies - make a tinny sounding banjo sound full and rich with especially wonderful low tones. The reason that people may think it's crazy is because it involves sound surface waves - a topic which I'm finding most folks don't even want to think about, much less ask about or even comment about. But, it works. I've made it, tested it and incorporated the concept in all of my products for banjos. You can see pictures of this concept used in my Gibson, Paramount and Gold Tone Irish Tenor on the "Photos" page of my website. -But read this first.
Try to find about four or five inches of thin, flexible wood that is about 1/2-inch wide. I use 2-ply mahogany plywood veneer that is about 3/64-inch thick but any thin, flexible wood should work. - Maybe a popsicle stick (craft stick) thinned down a bit to make it more flexible would work. (I'll have to try that.) It must be able to bend in a slight curve.
You need to get one end of this rectangle to lie firmly flush against the inside of the banjo's wood rim. How you do that will depend on your banjo but one way is to loosen the coordinator rod nut, slide its washer away from the wood rim, position the side edge of the rectangle (about 1/2-inch from the end) under the washer and then retighten the nut. You may also be able to do this under a rim bolt's washer. (Don't worry if the other bolt heads getting in the way because the wood rectangle will be raised over them.)
After one end of the rectangle is held firmly against the wood rim raise the opposite end of the rectangle about 1/2-inch or more (until it clears the bolt heads if any are there) and prop it up with anything so that it stays there. You can tape a little block of wood to the rim under this end (don't tape the rectangle), use cardboard, a nail (with a little hole in the rectangle for the point) or anything else to hold it up.
When you've done this you've created a curved piece of wood flush against the wood rim on one end. The wood rim and the curved piece of wood now have the same sound surface waves on their surfaces because they are in firm contact for an inch or so under the washer. Because the curves of the wood part and the banjo's wood rim are different you have also created diverging air space between their almost identical sound surface waves. This diverging air space with the same sounds on either surface converts the inaudible sound surface waves into audible sound - in effect acting like a sound "speaker" to broadcast this sound into the banjo's sound chamber. (It works the same way as my patented high frequency sound emitter that is the heart of my tone amps). Because this audible sound emitter is large - several inches long - it is most efficient broadcasting low and medium tones but the high tones will probably be improved, too.
Now for the surprise. Play your banjo and see if you don't think it sounds great!