In pursuit of an electric cristal (2023)
In early 2023 with the generous support of Arts SA, I was able to refine the design of the Electric Cristals I first made in 2020. I was again developing the instrument for my colleague Gabriella Smart, and the brief around what was required was long and detailed. The main requirement was that the glass rods could be detached with ease, and without hand tools. The stand needed to be collapsible, more beautiful and functional than the stand for the 2020 cristals, and the whole instrument needed to be able to fit into a standard check-in suitcase, in order to avoid excess luggage fees on flights. Although I wasn't quite certain I'd be able to achieve all aspects of the brief initially, the almost finished instrument is certainly a vast improvement on the 2020 prototype. The new instrument is shown below:
The first task was to work on figuring out how to make the glass rods easily detachable from the instrument without the performer having any need for the use of hand tools. My colleague Sebastian Collen solved this problem by devising a small cylindrical 3D printed sleeve which contained in one half - the glass rod, and in the other half - a small brass screw. I later experimented with aluminium instread of 3D printed plastic, and both designs seem to be feasible options. The 3D printed sleeves are much more practical and easy to produce, while the aluminium is stronger, more beautiful when polished, but requires much more time to produce. The aluminium sleeves attached to the rods are shown below:
The inside of the aluminium sleeves requires two type of adhesive - epoxy resin, and silicon. The epoxy resin is needed to hold the brass screws firmly in place, while the silicon is needed to attach the glass rods. Through experimentation, I discovered that only using silicon causes the screws to turn freely inside the mechanism (which is not desirable!).
Something worth discussing at this point is the length of the glass rods. A question I often got about the 2020 cristals was if the length of the glass rod affected the tuning of the instrument, to which I would always need to give an uncertain answer as all the glass rods on the 2020 ECs are the same length (within around 0.5 - 1mm or so). I would usually guide to conversation to discussing the glass rod as a kind of bow - similar to a violin bow - all it does it transfer enegery, and while I didn't think it affected tuning, what I was certain it did affect was the possible duration of any note. Longer bows = longer amount of time before you need to change bow direction and start a new note, just as with any stringed instrument.
When I began ordering materials for the new 2023 ECs I initially ordered a large amount of 300mm rods, thinking that we would have longer bows on the new instrument than the 20mm bows on the 2020 ECs. Realising I could have any length I wanted some time later, I contacted the glass maker I order from and asked for a variety of lengths, as well as some different coloured rods (to help orient the player visually with the instrument's glass board).
Once I finished the instrument, I was able to test the effect of glass rods of different length, and low and behold, the glass length did indeed have some bearing over the tuning that was produced. One of my colleagues who knows much more about physics than I do (I know pretty much nothing) did attempt to explain why this is the case at which point I glazed over, unable to process. Essentially, a longer and therefore heavier rod will produce a lower pitch than a shorter and therefore lighter rod, but not by much more than a tone or semitone in my experience so far.
One task I spent many hours on when refining the Electric Cristal was polishing aluminium. The 2020 ECs were quite rough in their craftsmanship with saw cuts still being visible in the tuning weights. With the 2023 ECs I set myself the challenge of achieving the kind of flawless perfection that musicians tend to expect from their instruments - this is still a work in progress, but I think I have now mastered the art of polishing aluminium. Below is one of the polished sleeves:
The polishing process requires many grades of sandpaper, and a bench top grinder. First I sanded the aluminium with relatively rough grit sandpaper (80grit), then 120, then 240, then 360, then 420, then 800, then 1200, then 2000. Using a range of devices here helped, these included a large bench top orbital sander, a small handheld orbital sander. Polishing the cylindrical sleeves for the glass rods was done by attaching them to a handheld drill. This made the sanding process very quick, but drained the battery of the drill rather quickly too.
Once the cylinders were sanded through the various grades of paper, they were then polished on a bench top grinder using a little bit of polishing compound, on three different wheels.
For other components I made up a sanding board with some of the finer grades of sandpaper, as orbital sanding paper only goes up to around 360 grit or thereabouts. The sanding board I made up is shown below, clamped to the bench.
The best advice I can give anyone who sets out to sand aluminium to a polished mirror finish is to allow plenty of time, and be as patient as possible. Patience it appears is not my greatest virtue, and I paid the price for this, having to re-sand a number of pieces of the instrument due to rushing through the grades. For each grade you need to be patient and ensure that you have removed all the scratches from the previous grade, otherwise you will waste much time - as I did.
Above are the nuts and bolts that I used to create the detachable glass rods. The bolts needed to be not too long otherwise they would not be entirely enclosed in the cable lug which is attached to the instrument. The material of the nuts is important as the nuts needed to be soldered into the cable lug. The material that was chosen, by my colleague Sebastian Collen, as being the most suitable was brass. The nuts were ever so slightly too large to fit inside the cable lugs, so the edges of the nuts were painstakingly individually filed down to size. The bench top grinder may have been an option, but one that I didn't quite work out how to make work safely and efficiently. Nut successfully soldered into a cable lug is shown below:
To complete this project quite a lot of drilling was involved, so I managed to justify purchasing a freestanding drill press, as trying to drill straight holes with a handheld drill is a futile and fruitless undertaking. The drill press was particularly important as the thickness of the base plate of the instrument was around 12mm thick, meaning that quite a lot of drilling - with a sufficiently powerful tool - was necessary. The new drill is shown below.
The drill might have been slightly bigger and more powerful than what was needed for this project, but will hopefully last for a few more projects and decades to come. Following the advice of my skilled instrument making mentor Michael Snowden, I set the drill to its slowest speed for the task of drilling aluminium and used a small amount of oil to keep the drill bits cool to prevent snapping. Similarly important was the drill vice which I often clamped to the bench when drilling to secure the work piece and ensure the best accuracy possible. Below is one of the polished base plates.
The finished base plate, although seemingly simple took quite a long time to get right, and I did waste a couple of pieces of aluminium in the process. Particularly difficult is getting the holes perfectly on both axes - a task that I'm sure I will continue to perfect with future instruments.
To start I needed to determine what distance from the edge of the plate the holes would sit. I then applied some masking tape, and scored two lines from end to end, one for the M6 holes, and one for the M8 holes. Then figure out how many holes you're planning to put on the piece, determine distance between holes and set up a carpenters compass at the distance you wish to space the holes. Create a slight impression on the aluminium using the compass, and then go back along the piece with a centre punch and punch larger impressions.
Next remove the tape and start drilling. The main purpose of the tape is to avoid deep scratches in the piece which you might find yourself sanding for hours if you don't have a light touch.
Even once the holes had been carefully and painstakingly measured out, slow, careful, staggered, and precise drilling was still important to get the holes as close as possible to being straight. Drilling small holes initially (around 2mm) then working my way up to a final thickness of 6.5 then 8.5 was important in achieving the straightest rows I possibly could. Trying to skip straight to drilling 6mm and 8mm holes will likely result in failure to get the lines as straight as possible. I wasted some aluminium learning this.
Once the base plate was drilled, and all of the tuning weights were drilled and polished, came the task of re-designing the stand. For this task there were a number of options. I discussed with Sebastian, Gabriella, and Michael how we might best approach this. In the end, I decided that as I had studied a proper Baschet-made instrument over the summer (polytonal percussion instrument in Portugal - courtesy of the Winston Churchill Memorial Trust) that I would base the design of the stand on the Baschet design. Picture of the Baschet designed polytonal percussion instrument is shown below, I think the year of production is 2020:
The general design of the stand is very stable, and the instrument quite heavy. The only problem that I faced was that the Baschet designed stand was very much designed to be - as far as I could tell - permanently assembled, or at least assembled and disassembled by someone who is reasonably technically minded and has the properly sized wrenches.
Each of the legs is made up of two parts - one solid bar, and one hollow tube. The solid bar slots into the tube and then is fastened with a bolt. I'm not a metal expert but I think that the solid bar is aluminium while the hollow tube is steel - but I could be wrong. The solid bar is bent at a slight angle to achieve the wide base where the legs meet the ground.
The other point to note about the Baschet designed and made stand is that the aluminium bar and tube are both square. I initially attempted to make the legs on my instrument from the same square materials, but eventually abandoned this design, opting for round bar and tube instead. I abandoned the square design, when I discovered a product at my local Bunnings (Australian hardware store) that would allow me to join the solid round bar with the hollow tube. I didn't know the name of this product, or what it's regular 'day to day application' outside instrument making would be, so it took some hours of online and in person scouring to find it. Now with a little more experience I know that this product is called "round threaded tube insert" - pictured below:
This off-the-shelf product just happened to fit perfectly inside the 16mm aluminium tubes I sourced from my local aluminium supplier. At this point in time I haven't even glued these inserts inside the tubes (and it's been many months). It is on the list of things to do, but they serve their purpose reasonably well even without being securely fastened.
On the round bar, I drilled out a hole, and tapped a thread allowing me to glue in an 8mm threaded rod that would screw into the threaded tube insert and voila, the stand was suddenly collapsible - without the need for hand tools, or even hand nuts.
Next I needed to be able to fasten the legs onto the main bar of the stand. The legs of the Baschet's polytonal percussion stand simple bolt directly into the main bar. In hindsight I might have made my stand in exactly the same way, but I had come across some components online on a website called Makerstore.com.au which I planned to use on the stand. The components are called "Linear Rail Shaft Guides". To fit the aluminium bars into the shaft guides simply required trimming a little bit of material off the end of the bars - this is most effectively done on a lathe - not the way I choose to do it, but in hindsight this would definitely be the best approach.
Fastening and loosening the shaft guides is the only part of the instrument that currently requires any hand tool (a single 3mm hex key), and I am considering replacing the hex screw with a small hand nut.
The next step was bending the aluminium bars at roughly a 120 - 150 degree angle. For this task I needed to enlist the help of a master blacksmith - Geoff Barnes. I couldn't have tackled the task myself, it requires not only skill and knowledge, but also specialised and expensive machinery. If I had attempted this myself, it no doubt would have wasted time and materials. Geoff helped complete the task for me in a matter of minutes.
The semi-finished, and completely finished stage of the stand are both shown below:
Attaching the instruments to the stand I used a couple of "off-the-shelf" products. One product was a cylindrical rubber isolator, designed for mounting machinery onto work benches and eliminate the amount of vibrations that transfer into the bench. The other product I used between instrument and stand were firm suspension bushings.
Both products have essentially already been engineered to significantly reduce vibration and while I they may not be the perfect items for the job, they are a considerable improvement on what I was previously using to eliminate vibrations in my 2020 stand.
In the new and refined 2023 design I decided I wanted two instruments, a tenor cristal and a subcontrabass cristal. The subcontrabass cristal has turned out to be an absolutely wonderful addition. Everyone who plays the instrument is excited by the subcontrabass range, and my colleague Grayson Rotumah recently composed a piece for the Adelaide Symphony Orchestra which featured - in the opening passage - the subcontrabass range of the instrument. Thanks to great sound engineers and the orchestra investing in 'the best PA system that money can buy' the world premiere of the instrument's subcontrabass range was indeed sublime.
The way that the subcontrabass range and tenor range were incorporated into the same design - which fits inside a suitcase - is due to the modular configuration of the instrument. After studying the Baschet's stand design, I saw no reason that a second instrument could not be mounted in the empty space below the main instrument. So far I can't see any reason why the subcontrabass instrument as a lower manual shouldn't be incorporated into any new build of a cristal instrument. Below is a photo of the first time I attached the threaded rods to the new instrument.
The happy side effect of this new design - with two instruments mounted to the single stand - is that one instrument can be rotated by 180 degrees and one glass bowboard can face in each direction, meaning that a duet on the same instrument is possible. Since making the instrument I've had a couple of jam sessions with my colleague Gabriella Smart in our rehearsal studio at the Centre for Aboriginal Studies in Music, but we're yet to publicly premiere this feature of the new instrument. The premiere of the duet feature is planned for November this year at the 30th birthday celebration of Gabriella's new music organisation "Soundstream New Music". The duet configuration is shown in the photographs below:
Depending on what the performer and composer are aiming for in their work, it's also possible that only one of the instruments is used. This is of course a pragmatic solution to weight limits when airlines are involved in musical affairs. The photo below shows only the subcontrabass cristal mounted above, and no tenor instrument (excuse the messy desk!):
The next challenge to solve was tuning related.
(To be honest, there are many many many challenges to confront when it comes to tuning these instruments. I'm quite looking forward to some literature on this front, and hoping that the literature comes from someone very well informed that is not me!)
I had initially planned for three successive octaves (non-octave repeating) of ten notes in each octave for this instrument. I wrongly assumed that with all other variables constant, then half the threaded rod length would result in double the frequency, or one octave higher. This was not the case and if any well informed reader happens to be reading this, I would welcome an email from you explaining in simple terms why this didn't work. I ended up having to re-cut the upper most ten rods. Below shows the initially planned threaded rod lengths:
The next challenge lay in the amplification of the instrument. Since making the 2020 version of the instrument, I have made some adjustments to the new instrument in pursuit of improving consistency and quality of tone colour.
On the 2020 instrument, I left a small section of the base plate for attaching a single contact microphone. Extensive conversations with my good friend and colleague Grayson Rotumah helped me to realise that the approach I needed to take with the 2023 instrument could be informed by that of the electric guitar. Most modern electric guitars have a tone control switch or dial which changes that nature of what is being amplified. My basic understanding of guitar pick-up systems is that the tone control switch changes between vibrations coming from the body of the instrument and vibrations coming directly from the string (through the air). The result is two very different tone qualities.
The way that this translates to the cristal is through many contact mics (around 4 - 6) running to a minxing desk. Some of the contact mics are attached directly to the body of the instrument, while others are attached to the flat resonator plates. The contact mics attached to the flat resonator plates have lost much information from the original tone of the vibrating threaded rod and so the tone quality is quite mellow and warm. The contact mics attached directly to the body of the instrument on the other hand retain much more information and have a rather different tone quality.
The tone quality that one is aiming for in their music is a very personal and subjective matter. My current preference is to achieve a moderate blend of resonator and direct body signal, but I know that others have different desires and approaches. So it seems that in pursuit of an electric cristal for the masses this system of allowing some control over tone quality should most definitely be considered. The picture below shows the system of multiple contact microphones attached at various points:
The next factor in tone-quality control is the use of a DI box (pictured in the photo above, on the ground on the left). This is not something I had considered until my colleague Daniel Pitman mentioned them to me, and set them up for me. The short and simple answer about why DI boxes are needed is something to do with impedance - whatever that is. All I know is that tone quality is significantly different with and without these technological devices. The other thing to note in the photograph above is the use of double sided mounting tape between instrument and contact microphones. Very expensive contact microphones come with some kind of intergalactic space goo that eliminates vibrations, which I'm sure works brilliantly due the amount of research that goes into space exploration. Not being inclined to invest in space microphones, mounting tape and blue tac seem to do on a budget, what the space goo would do at much higher cost.
There is still some research and development and building and so forth to continue with the 2023 electric cristals, but I hope that this post is of use to other cristal makers around the world. As always, if you've gotten this far and have some questions that I can be of assistance with, please don't hesitate to drop me a line. Contact details available on my site.