Post 22: Making the 12 Strings Bass

         After sanding and polishing, the neck blank looks really good:

      I made the bridge out of solid brass. It's not really easy to "machine" an entire brass bridge without machines. I just cut the 10 pieces on the band-saw,  sanded them to size and shape on the belt sander, and assembled with M3 socket screws. 

      Next, I made the tuners using long M3 screws. 

       Last but not least in terms of difficulty, I made a brass anchor block for the strings to attach to the end of the neck. I broke a drill bit deep in the block on one of the first holes. I found a solution to remove it on the internet, which is apparently an old trick of watch and clockmakers. Dropping  the brass block in a very hot saturated solution of alum, and let it bubble until the steel is completely dissolved:

     I put the whole thing together as a mock-up to see how it would work. The two humbucker soap bar pickups will need to be embedded deep into the "neck", and it will have to be extended 6" or so to fit the pots and jack assembly. In order for the bridge to fit and the tuners to do their job pulling the strings down on the bridge at a sufficient angle, it will have to be bent :

    The cut is so deep there will be just an inch or so of aluminum left, so it will need to be re-enforced somehow at the bent. The best solution seems to be if it can be found, to use a foot long section of 1/4"' thick 2 1/2" aluminum pipe that will wrap tightly around the neck and be attached to it with two large bolts on each side of the bent. It would make the "body of the bass 1/2" wider, just about enough to accommodate the bridge, tuner, and pickup full width:

Post 21: Starting to think about the 12 Strings Bass

     I just ordered some black Bass Tuners, some black Guitar Tuners, a set of flat wound bass strings, two sets of flat wound guitar strings, and two soap bar humbucker pickups. I am pretty much out of large aluminum pieces, so I am going to go by the Metal SuperMarket to check prices and see what is available on their scrap pile at a discount. The length of the shortest string will determine the length of the neck. For the guitar to be playable, I need the shape of the neck to be similar to a regular wooden neck, not just be plain square or round aluminum tubing. An option might be two side by side round tubes with a wide flat piece on top for the fingerboard and another narrow one under to place the thumb. I tried different arrangements, then realized I actually had a piece of 2" aluminum pipe with thick 1/4 " thick walls and an outside diameter of about 2 3/8". Now, that's about what the neck is supposed to be at it's widest on most 12 strings basses, narrowing to a tad less than 2" at the nut. If I cut that tubing at a slant, it would be just about perfect. It could be filled with a half-round piece of wood to create the fingerboard.

    So I sliced the pipe lengthwise on the bandsaw, sanded it even, and cut a piece of padouk I am going to carve to fit inside:

     The carving was difficult, and I ended up wasting some wood, but I finally got it to fit well enough, and used plenty of epoxy to attach the wood to the aluminum. I camped it tightly overnight:

     Then, looking at some 12 strings bass on the internet, I ran into the image of a few brass adjustable bridge/tuner set up that doesn't use standard tuners with a knob, but something similar to what I did on that first "homemade guitar" I built when I was a kid using bicycle spokes as tuners.  This is even more basic actually, and I think I could design and make something similar that would look a little slicker...

   I went to the hardware store to look at socket screws and figured out I would need M3 Metric 3 mm screws, some long for the tuners, and some short ones for other adjustments and assembly. So I ordered an assortment of long ones and an assortment of short ones with nuts and wrench:

      

    I worked out the basic dimensions from the photograph above:

Post 20: How about a Single String Stainless Steel Stick Bass(Model #SSSSSB!)

As always looking to use stuff I already had on hand and going for utter simplicity and minimalist design I modified the original design and ended up with something finished and functional before I even had time to post about the process. 

        Detail of the tuner, made of a 1" thick circular piece of solid brass (leftover from outfitting my bobber years ago) that slides over the stainless steel tubing, a stainless steel flange normally used to install a coat hanging rod, a brass disk, and a 1/4-20 x 3" screw with a knurled brass  knob:

    Detail of the brass bridge (a section of a nonfunctioning brass punch) and its support/spacer(a stainless steel gear out of a gearbox):

    The plain black soap bar pickup is attached the long way with the two stainless steel adjusting screws it came with through the tubing. An extra nut raises the side closest to the bridge so it is in line with the string. The angle plug at the end of a black coiled electric guitar cable is simply fitted tight in a 1/4" hole(establishing the ground), and the red wire of the pickup is soldered to the end of the plug. Could not be simpler:

      The ball end of the string is threaded through the end of a copper plug that has been hammered into a cup, comes out through a hole in the stainless steel tube, and goes over a brass nut shaped like a lopsided ring:

      A wooden fingerboard was carved out of cedar, grooved to fit over the tube, and stained black to look like ebony(see image 1).  I may replace it with the real thing.

      A stainless steel lever with a black ball knob (out of an old tile cutter) is used for the pin, and slides in a series of metal tubes forced into the end of the stainless steel main tube.

 

Post 19: I got to build a monochord first to do some testing on scales and tunings

    I was again yesterday reading about scales and intervals,  the seven pitches of the major scale, frequency ratios relative to the tonic,  just intonation with unequal frequency intervals:

                                 1:1 ,  9:8 ,  5:4 ,  4:3 ,  3:2 ,  5:3 ,  15:8 ,  2:1  

the 12-equal intervals of the tempered scale, the key multiplication ratio of 1.05946 from one frequency to the next, and the compromises involved. 

    I was also reading about the other equal temperaments that had frequencies approximating the just intervals, namely 19, 24, 31, and 53. That got me intrigued, and I got into some more research, which led me to the idea of making a monochord to do my own experiments, and to try to find what are the sound combinations I like best. It's a very simple instrument to build, so I looked through my stuff, and found part of a reinforced 3"x 1/4" aluminum rail from long ago video experiments, that could be modified and turned into an Aluminum Monochord. 

      The monochord actually has 2 strings exactly one meter long from one end bridge to the other, with a built-in metric scale so the ratios can be measured easily and accurately. It has a moveable bridge that needs to be exactly the same height as the other two (so there is no stretching of the strings raising the pitch), so it has to both pinch the string and be tied down. 

      It didn't take long to assemble. I stuck 3 piezo pickups to the underside of the soundboard. I didn't even have to use a preamp, it was pretty loud. But the sound is very metallic, so I also tested it with a regular magnetic pickup set at an angle across the two strings, and it sounds better .

         I then tested the unfinished monochord with a little wooden bridge and marked the seven ratios for just intonation, plus other simple ratios to test such as  6:5, 7:5, 7:3, 8:7, 8:5, 8:3, 9:7, 9:5, 9:4, 15:11,  15:5, 16:7, 16:9,  16:11. The bridge raises the strings slightly and causes a  small increase in pitch.

        I want to cut a long slot in the base on which I can slide and clamp down in place a metal pinch bridge made of brass and aluminum along those lines:

Post 18: Well then, let's work on a one string bass, and in parrallel, at the one string bass-gurdy

       The concept is very simple, a stick, a tuner, a tail, a bridge, a string, and a pickup, just like the 2 string stick I am already playing with. Except that this one has to be somehow glorified and perceived as a "work of Art"..., whatever THAT is!

     There are two bass guitar on the market that are really unique, both made of stainless steel but with different looks that I consider also true works of Art. One is the Stash, which is soon going to be available fretless:

     The other is the minimalistic Gittler:

    Both are truly extraordinary designs, unique, and very beautiful functional objects. They definitely are more than guitars, they are true works of Art. They certainly inspire me, probably will influence me, but I need to come up at least with my own interpretation as a One-String Double-Bass, within my means, preferably with what I already have around, and using aluminum and brass.

       Doing some research, collecting info, looking at what is available around the studio, the workshop, the attic, even Rachel's shed, I started putting a few things together, just to see:

     Close up of the first concept at the center, in a short mockup using a brake lever that came out of a motorcycle as the pin, various disks as the body, and a single tuner head I just made out of a 1/4" thick scrap of aluminum, attached at the end of a single one-inch aluminum tube. The bridge is made of a 1" brass ball attached to a 1/2" aluminum rod. The angular tail-piece could be cut either out of 1/8"aluminum, or maybe some 1/4" brass I have, and shaped with a curve.

      I also found some stainless steel rods and tubes left over from building the house, so I polished them up and started playing with them too, coming up with two rough very minimalistic mockups. The first one is for one string "triple bass", the other could be a long stainless steel rods bass guitar with small brass rods for frets:

            Detail of the bridge and tail:

      I am not sure I can weld the stainless steel rods together well, but I will try, because I like the utter simplicity of this design very much. The solid stainless steel rods are 1/2", there is a plain 3/8" thick brass bar at each end acting as nut and hardtail, and the bridge is a stainless rod on top of a piece of 1" brass tubing. The pick up is a plain black rectangle, and the only decorative elements are the 3 black bakelite balls from old machine levers. It's probably too heavy to be hand held, but it could make an interesting lap guitar, fretted with sections of 1/8" brass rod soldered across the stainless rods making the neck. 

      The tuners would be at the tail and look something like this:

     Drawing inspiration from various images and sources, amalgamating them, stirring up the pot, a little brainstorming, and voila! 

Post 17: A Bass Zither of sorts...?

         However, the project might actually temporarily take a different direction. That is because I happened to have a piano hammer nearby, and used it on a whim to hit the strings. The sound was loud and clear, and perfectly on key, not too brash, just beautiful. I could lower the big string all the way to a VERY LOW B.  The smallest cello string is a G, and surely can be tuned to an A, which would give me practically 3 octaves. 

        That is enough to make me think of a giant bass zither of some sort, played both by plucking with one hand and hammering with the other... The strings would be re-tuned to different keys depending on the music being played. I would of course use my favorite minor keys, both natural minor and harmonic minor, and also the "paddy tuning" of my harmonicas.

        Big bass zithers have been made, like the one the Blue Men Group uses:

        But it is flat and would be hard to bow as a psaltery, the tuning pegs being very close.

       Let's at least consider what that instrument could be. Immediately, the Guzheng comes to mind, except that the strings would not all be the same length. The strings would have to be about 3/4" apart. How many should there be? I am not trying to get all 36 notes in the 3 octaves,  just about three minor scales of 7, or 21 notes total, just like the Guzheng! That would take 3 sets of double bass strings and 3 sets of cello strings, about $100 worth or so...

       Retuning by moving individual bridges is easier than with tuners, and tuning pegs are a lot cheaper than tuners. The curve of the soundboard allows bowing too, although probably not much below the low E. I really would love to make one, but between the strings and the pickups, it's an expensive project, and I better shelve it until things get better. 

Post 16: An Electric Amplified Organistrum?

   I received yesterday a little digital amplifier that packs a lot of power for only 13 bucks. On paper, they say 100 watts, but that would be with a 24V power supply. 

       Still, using a weak single coil ANILCO pickup, an acoustic guitar preamp/equalizer, and connected to one of my big 8 ohm stage speakers,  it does a pretty decent job. There is a fairly loud 60hz hum that can be controlled to some extent with the equalizer. 

     Grounding everything and using a humbucker pickup should help get rid of it. A 24 volts power supply would make it louder. And the amp is supposed to be able to handle a 4 ohm speaker, so I will try connecting my two big 8 ohm speakers in parallel.

    I had a little 3D printer that was dropped and broken, so I cannibalized it and used a 6mm rod and flange to mount the thicker wheel on a rough plywood frame sitting in a box to which the long double-bass stick with a single screw on the left-back corner(red arrow). By swinging the stick a little, the strings can be brought in contact with the rotating wheel driven by the little 50 RPM geared electric motor(arrow). This motor is placed at the end of a long shaft using a flexible coupling, so it is far enough from the pickup not to cause hum, and the speed can be lowered with a controller.

      The wheel can easily be raised or lowered, and moved laterally on the shaft to test its attack angle and location in relation to the bridge and the pickup. I have to admit it is hard to get a reliably beautiful sound, and it often sounds awful when the low string stays against the wheel. It also seems to sound a different note that when the string is plucked. The smaller string sounds much better, but I am still not happy with it. The tone is OK when the wheel is brought only very briefly against the strings and they are left to sound free. It will take a lot of trial and error to make it work to my satisfaction. And I don't think I want the strings of the instrument to stay in contact with the wheel. 

        What I am envisioning now is a vertical instrument, with a motor mounted on a round base driving a bigger wheel rotating at about 25 RPM. A dozen of one string sticks would be attached to the base so they stand vertically with the strings close but not touching the wheel. There would be just enough flexibility so any stick could be pushed against the rotating wheel, and naturally spring back to position. It may take a rubber band or a spring to help them. Ideally, I see an aluminum instrument with a heavy aluminum round base, a stronger geared motor driving a 12" aluminum wheel with a fiberboard ring at 30 RPM. The sticks would be aluminum tubing 1" in diameter and 1/8" thick, with tuners mounted near the top end. A brass ring would act as the nut, and a tipped brass screw would serve as a fixed adjustable bridge. Another option might be to use single hardtail bridges with adjustment screws like these:

        The strings would then be close to the tubing, so each stick would have a humbucker pickup mounted on a bridge ABOVE the string on the inside of the instrument. 

         It would also be good if the sticks had some up and down adjustment. There would of course be long 5ft ones with double-bass strings, and shorter ones with cello strings. That would range from a very low C to possibly an A on a cello G string, two and a half octaves or so.