Gordon's Progress

I know what you mean. It's kind of marmite music. I like marmite, and spread it fairly thick, but I wouldn't want to spoon it straight from the jar. That would be too much... For the real hardcore Jazz I would need to be in a very odd mood indeed to fully appreciate it.

D'accord. My thoughts exactly. (P.S - "Pssst! You're coming on the 1st of August right?")

Glances round furtively to make sure no-one's listening.

Oh, yes, I'll be there. I'm excited and nervous about it in equal amounts. This will be the first time I have played alongside other thereminists - one who I have seen play and is jolly good :-), one I know of by reputation as a very talented musician and songwriter and one whose name was dropped into the email inviting me along as if I really ought to have heard of him. Daunting stuff.

I am so excited!

And I am now actively scared - Just checked my email - 4 thereminists have now become 6, possibly seven, and I have been promoted from "tagging along" to "raison d'être."

Ah well. Hopefully I should have a couple of worthwhile postings to make come Wednesday - here re: my progress and over in the World Thereminisation forum re: Hands Off 2007.

Raison d'etre maybe, but I think you'll find it was little 'ole me who first pestered Bruce and Dr. Alexander via e-mail some months ago . . . .

Heheheh. I actually cannot wait. An RCA!!!! I will actually be pleased to even see one in the flesh (well. wood.) let alone perhaps to get the chance to play it!

I'm also looking forward to witnessing some of the famed inventions of the elusive and ingenious Mr. Charlton!

I shall certainly bring my trusty frothatrill with me.

I'm particularly interested to try Percy Grainger's free music. From a cursory look at some pages about it, this is aerial stroking!

A couple of comments about my recent dalliance with tonality.

I neglected to observe that, while the chart at the top is of a section of a logarithmic scale, for ease of drawing I distorted it a little. In reality the even tempered notes are evenly spaced in the pitch field of a theremin, and my rational notes should be shifted to match.

I think this means that a perfectly linear theremin is naturally even tempered, in that successive notes on an even tempered scale are equidistant. Interesting.

One other thought. What if the foot-switch were held down all the time?

It would, I think, have to be a monophonic instrument.

The centre key would mean - play the same note that was just played. Each other key would mean play a note this much higher (or lower) than the previous note.

A parallel could be drawn between a regular keyboard, that plays absolute pitches, to Cartesian geometry, and my relative keyboard and Turtle Graphics (http://en.wikipedia.org/wiki/Logo_programming_language), which is purely relative, and as intuitive as giving a soldier his marching orders. :-) (And has a very rich geometry underlying it - I recommend the book Turtle Geometry by Hal Abelson and Andrea diSessa (MIT Press) if you are curious.)

I do wonder what my turtle keyboard would be like to play.

I remember turtle! That was the only 'game' availabl;e on our school computers, and it was much better than playing on Microsoft Word 1998.

You could draw squares and circles, and if you got pretty good you could create spirograph-type patterns and designs. Or, you could crash it by giving it over-complex commands that didn't make any sense. ;-)

OK, cool.

For the currently mystified, the "turtle" is, conceptually, a little robot that you move around the screen. As it moves it leaves a trail of, er, "ink" behind it. Commands to the turtle are either "go forward/back a specified distance from your current position on your current heading" or "turn left/right a specified number of degrees from your current heading". These could be likened to "play a note for a specified duration" and "move from the current note to a new note by a specified interval."

The turtle can be taught more complicated commands like "draw a square of a specified size" from the basic commands, and new commands like "draw a square" can be used as part of yet more complicated commands - "draw a picture of a house", "draw a street of so many houses, each a little smaller than the previous one".

An important convention to observe when teaching the turtle new commands is "state transparency" which means that, among other things a new command should make sure the turtle ends up on the same heading as when it started. This could be likened to the musical concept of resolution.

Turtle Geometry, the mathematics behind turtle graphics addresses this with the Total Turtle Turning Theorem (henceforth T4), which states that if the sum of a turtle's turns is 360 degrees or a multiple thereof, this is the same as not having turned at all.

So, to draw a regular pentagon, you need to draw five lines of the same length, with a turn of (360*1)/5=72 degrees at the end of each line, because the turtle turns around full-circle once. To draw a five pointed star on the other hand, the turtle needs to turn around twice, so each turn should be (360*2)/5=144 degrees.

It would not surprise me if a corresponding Total Turtle Interval Theorem that applied to resolution (as T4 applies to state transparency in graphics) was equally straight-forward and as easily applicable to some aspect of melody as T4 is to geometric objects. (Charlie - spirograph pictures are only the start of it. Wait until you find out how easy it is to draw fractals!)

The programming language Logo, which introduced turtle graphics, was designed by Seymour Papert (http://en.wikipedia.org/wiki/Seymour_Papert) for teaching five year olds. It is essentially a variant of Lisp, the original heavy duty computer science language. On of my lecturers at college used it for his PhD.

And as Charlie quite rightly suggests, it's a whole lot of fun. You can't really say that of Cartesian Co-ordinates and Euclidian Geometry, and you'd have a tough time teaching it to five year olds.

From what I understand of aerial fingering technique, mostly courtesy of dear Kevin K's thread of the same name over in the Theremin Technique forum, the focus on playing is often how to move to the next note from the current one, rather than it's distance from the aerial. Again, relative rather than absolute.

Gordon,

You are spot-on about aerial fingering. The position of one's arm is a reference point (albeit a moveable one) and the knuckle extensions towards the antenna are motions relative to the arm position.

The arm position is relative to your torso rather than the rod. In all cases, the arm positions and motions have more to do with muscle memory than the distance to the rod.

Also, I tune the Theremin by checking two things: 1) the interval of a fourth between positions 1 and 4 with a fixed arm position and 2) octave jumps -- ascending and descending.

Once I have the 4th tuned, I then check out my jumps. If I am hitting the jumps consistantly within 50 cents, then I will tweak the tuning a bit so I hit the jumps exactly. If the jumps are farther off from that, I recheck my 4ths... if the 4ths are ok, then I practice my jumps to be sure that I am hitting them correctly (tweaking the muscle memory).