Thursday, September 14, 2017

Dreams of Cassini's Demise

By the time I’m done with breakfast tomorrow, the joint NASA/ESA mission to Saturn, Cassini, will be over.  I’ve been enthusiastically following its progress from before its arrival at the Kronian System in 2004. I remember clearly my awe at some of the first pictures of this spectacular, pale yellow-green-brown giant, Saturn at crescent, Saturn eclipsing the sun and setting fire to its rings, Saturn from above, alone against what appears as an empty inkiness behind.  Too, I could barely contain myself -- and entirely neglected my job -- as I followed on my work computer the progress of the Huygens probe’s descent to the surface of Titan as a strangely familiar yet utterly alien world unfolded before me.  These early outcomes captured me irretrievably and, across these last 13 years, the Cassini mission has become part of my day-to-day reality.  In a few hours, that will, as all things must, come to an end.

If you’ve followed the mission or any of the recent popular science pieces on it, you know that the probe is being dropped into Saturn’s atmosphere to protect the moons Enceladus and Titan from any potential contamination:  these two worlds, in very different ways, proffer two of the solar system’s best candidates for extraterrestrial life and scientists hoping for future missions to explore them wish to minimize the chance that any life found comes from us.  So, the solution is to crash the probe on Saturn, which shows every indication of being entirely inhospitable to life as we understand it.

In all of the articles I’ve read about this, the story ends with the loss of signal from Cassini and perhaps descriptions of scientists shutting down computers, turning off monitors, rolling chairs under desks, and walking out of Mission Control to drink a solemn toast to a collective job well done.  But Saturn, while unwelcoming to life, is far from dead; it is a rich, complex, and almost unimaginably vast system, a churning, roiling, rapidly rotating ball of gas -- with a (relatively) little bit of rock.  What happens to Cassini after transmission ceases?  This has been a fascinating question to me and a little reading and Googling has yielded some interesting possible answers; here is what I imagine based on what I found.*

Science journalists describe Cassini’s last waking moments:  edging into Saturn’s upper atmosphere at tens of thousands of miles per hour, it begins to be buffeted and tossed about.  Its aerodynamics pull it to begin to tumble, but its stabilizers, at first, keep its antenna pointed at Earth, but this does not last long.  In short order, the crashing of the wisps of gas at horrendous speeds pummel the craft until its ability to direct itself -- designed for near-vacuum -- is overwhelmed and Cassini tumbles and (some light-minutes further/later) Earth loses its signal.

Almost immediately after this, as the drag on Cassini brings it ever more quickly into thicker and thicker air, the probe begins to break up, heat up, and vaporize.  Different parts will presumably respond differently to the atmospheric insults and, as bits break off and apart, some will slow more quickly than others, and what remains of Cassini will, after probably no more than a few dozen seconds, slow and cool enough to become a minor rain of detritus falling into Saturn’s cloudtops.  I imagine some of these as relatively light pieces of framework or housing, unmassive enough to decelerate rapidly enough to avoid completely vaporizing, as well as various chunks of dense, durable stuff -- the most formidable of which might be whatever remains of Cassini’s power core:  66 pounds of plutonium.

As these bits variously plummet, tumble, or float their way into Saturn’s depths, they will pass first through its upper layers with clouds of ammonia and water ice and bands of ammonium hydroxide.  As pressure in these upper layers increases, water can form droplets and mix with ammonia.  Saturn is, however, by far mostly hydrogen and it is through this that Cassini’s remnants will pass for a very long time.  The outer layers are gaseous hydrogen, but, as pressure increases, this becomes liquid and, eventually, metallic hydrogen.  As the scattered bones of Cassini works their way down through the gas and liquid hydrogen, its densest pieces may come to rest somewhere around the transition from liquid to metal, some 18,000 vertical miles from where it sent its last radio pulse.

Think about this:  Earth is about 7,900 miles in diameter; that means that the shards of Cassini could fall through two and a half Earths before stopping.  For how long will they fall?  Years?  Decades?  Centuries?  Millenia?  Just imagine...

One question I didn’t get an answer to (mine was not an exhaustive search) was at what point might different parts float -- particularly the plutonium?  Metallic hydrogen can, in theory (at least as I understand the lay descriptions), exist as a liquid under sufficient pressure:  would plutonium float in this ocean metal if it made it down that far?  Or would it continue falling?  Down, down below inconceivable depths of the most abundant constituent of the universe, there is probably a hunk of iron, nickel, and rock:  Saturn’s core.  might the densest pieces work their way through the metallic hydrogen, all the way down to stone?  Also, what (if anything) happens when radioactive material like Cassini’s heart comes in contact with a highly conductive material like metallic hydrogen?  And is it possible -- even likely -- that Saturn’s core already has at least a few dozen pounds of radioactive elements?  The metallic-rocky core may be larger than the Earth:  what would that look like?

In my dreams tonight, I imagine Cassini’s bones wafting through ammonia clouds and currents of liquid hydrogen.  May they find a well-deserved and worthy rest there.


*NOTES:  This is pure speculation on my part, based on a relatively cursory search of a handful of what I perceive to be relatively reliable sites (e.g., NASA, Wikipedia, etc.).  I’d actually be thrilled if a real planetary scientist did this thought experiment!  Also, I normally hyperlink my essays extensively, but, tonight, I'm sleepy and actually just proud I got this written and posted.  I invite anyone to explore and/or correct any of the facts I list or ideas I have shared.

Thursday, August 24, 2017

Memories of Andrew

I got a text today from my brother, Matthew, reminding me that it was 25 years ago today that Hurricane Andrew made landfall in South Florida.  He and I were there to witness the event and lived in its aftermath.

I first heard about the storm’s threat the Saturday nine days before (Andrew came through on a Monday night) while I was at a seminar in Boca Raton.  Matt had been staying with me for only a few days, having just relocated to Miami, where I had lived for several years.  At that point, the storm’s prediction cone was pretty wide and best guesses took it north of my apartment on South Beach.  By the next Sunday, it had narrowed in on Fort Lauderdale, less than an hour north of us; to escape the destruction, we could either go well north -- we had relatives in Tampa -- or a little south.  We decided on south.

At the time, I was working as a massage therapist at an acupuncture clinic run by the wife of a mentor of mine; they were kind enough to let Matt and me join them in their apartment to ride out the storm.  All day Monday, Matt and I moved furniture, emptying my east-facing living room and placing as many of my possessions as possible on high shelves in closets in my first floor apartment.  In the evening, we headed down to South Miami, where my boss, Marlene, and my mentor, Bob, lived.  I remember putting my two young kittens, Kylie and Ashoka, in an empty office at the clinic around the corner, as the apartment building allowed no pets; I was really anxious to leave them, but I had no better place.

Safe in the apartment -- old Coast Guard housing converted to condos -- we awaited Andrew’s wrath, watching the green, computer-animated avatar of its wind and rain bear down on us via the local news until we lost power.  At one point, a large picture window in the living room bowed back and forth frighteningly while we put cardboard over it (being an upper story apartment, the usual prophylactic of putting plywood over the outside had been prohibited), but mostly, for us, the storm passed with little more than -- at times unnerving -- noise from wind and rain.  We remained awake until the small hours of the morning, eventually heading to sleep around three or four.

Probably due to nervous energy, we were up again by eight; the wind and rain had largely died down, the sky was cloudy but light, so we ventured out.  As relatively underwhelming as our experience of the storm from inside the apartment had been, the impact on the world outside was overwhelming:  we emerged into what felt like an entirely different world.  We could only be awestruck.  The lush, subtropical paradise of South Miami had been razed such that almost nothing stood more than about a dozen feet high.  Woody deciduous trees were snapped in mid-trunk, their crowns tossed aside like incompleted model train landscape decorations.  A neighbor’s ancient and expansive banyan tree had, over the years prior to the storm, entangled his favorite chair in its aerial roots; Andrew had stripped the tree of its leaves, uprooted it and tossed it back in the yard on its side like a great squat barbell, the owner’s chair still comically clinging, otherwise undisturbed, in the roots.  Power lines and poles littered the streets and cars were buried under detritus.  Palm trees stood like great phalluses lining the streets, shorn of their leaves, the only things of any height remaining.

We learned later that Andrew had not gone north of us, along the Dade/Broward county line, as predicted, but instead had turned suddenly south, with the deadly northern eyewall passing perhaps a dozen and a half miles south of us:  instead of moving further from the storm, my brother and I had come closer.  Indeed, only about a mile south of Bob and Marlene’s, the damage became significantly worse.

I don’t recall where I had stored my car, but it was undamaged.  By mid-day, I heard reports that authorities were letting residents back onto Miami Beach, so, expressing our gratitude to Bob and Marlene for their hospitality and the safety it afforded us, Matt and I retrieved my lonely kittens and attempted to make our way back home.  The drive was a post-apocalyptic steeplechase through downed trees, power lines, and billboards, with neighbors walking about, half-stunned, inspecting the damage and other drivers attempting to wend their way through the newly created maze.  As I recall, it took a few hours, but eventually we were able to make it back to Miami Beach via a causeway north of the route we normally took.  Streets were swept with sand shoals and piled with verdant wreckage.  Working our way south, we were forced to take residential and side streets, which were often blocked by fallen trees, but neighbors were already out in force, clearing sidewalks and roads of branches and trunks; we took part in several efforts that required chainsaws and teams of muscle.

When we finally made it home, we were astonished to discover that a single pane of the jalousie windows had worked loose, leaving a narrow opening for Andrew to deposit a small puddle of muddy water on the living room floor; the rest of the apartment was as we had left it.  We quickly went to work restoring the space to its former condition.

Over the next week, we had many experiences that told of how much our corner of the world had been upended.  Matt and I went to help a friend who lived in one of the neighborhoods where the damage had been more severe.  When we arrived, there was more roofing tile on her lawn than remained on her roof.  We found her in her flooded sunken living room, pathetically scooping water into a kitchen trash can with a measuring cup.  We spent the day with her, mostly picking up Spanish tile and emptying her new in-living-room pool.

Another day, a kid in my neighborhood, previously a stranger, invited us to his uncle’s house in Coconut Grove, a very wealthy suburb on the mainland:  having been out of power for three days, the meat in his freezer had thawed and he was cooking it all on his barbecue and serving it to anyone who would come.  We ate well -- and gratefully, as my own, much more modest, larder had been similarly compromised.  While there, I took a walk around the neighborhood and I stumbled upon a 35’ sailboat, still attached to its pier, a good hundred yards inland from the bay.

I was an avid cyclist during the years I lived in Miami and one of my favorite places to go was Key Biscayne; the route was a nice, eclectic 30 mile out-and-back from my apartment.  I had heard that the park at the south end of the island had been particularly badly hit by the storm.  When I finally made it down to see for myself, I felt as devastated as the land looked.  What had been rich, green, breezily swaying acres of Australian pine and palm trees, in which bright yellow and brown, tea-saucer-sized spiders wove glistening four-foot wide orbs, had been mown down to a height of no more than six feet.  I could stand on my bike at the park entrance and see, across an immensity of jagged, graying, desiccated stumps, down to the cape of the island.  I felt shocked as if I were a bug stumbling out of a field of wildflowers into someone’s lawn.

City-sized changes took place overnight:  with thousands of houses suddenly unfit for living, entire communities relocated instantly, many permanently.  This created traffic snarls like I had never seen:  an infrastructure that had grown organically over decades suddenly functioned like it had been imported unmodified from another, entirely different city.  By the time, a week or two later, when enough of the city was functioning that most of the inhabitants were returning to work, long stretches of previously fluid expressway were turned into rush hour parking lots, while others seemed abandoned.  Drivers got pretty good at four-way stops, since nearly all the city’s traffic lights were dead for days, many for weeks.  Postal service was rendered third-world in its reliability.

Most disturbing for me, though, was Homestead, a town and military base at the south end of the county, bordering the entrance to the Keys.  I had heard that that area had been hit the hardest, with families reporting their homes literally collapsing around them and many residents killed.  It wasn’t until months later that I visited it:  the military base had been abandoned completely and, apparently, suddenly, with yards still scattered with toys and playsets, curtains and blinds hanging raggedly in shattered windows, trees lying dead where Andrew had felled them, some with rusting cars beneath them.  It reminded me of films I had seen of atomic test sites.

The non-military parts of the city were worse:  nearly all the homes there were abandoned, too, but most were in partial or complete collapse and spray painted unceremoniously with contact information for the owners’ insurance companies.  Some properties, by that time, had been scraped clean of wreckage, leaving concrete slabs, with odd bits of plumbing or electrical conduit occasionally reaching up from them, as testaments to a family’s life and Andrew’s power to interrupt it.

Post-storm analyses revealed that Andrew had been a Category 5 storm, rather than the 4 it was estimated as when it hit.  Embedded in its inner tempest were scores if not hundreds of tornadoes, which apparently were responsible for the worst destruction, especially around Homestead.  On the other hand, steady, unchecked wind, can snap stiff, woody trunks, which is why the Australian pines of Key Biscayne and the decorative deciduous trees of Bob and Marlene’s neighborhood were killed, while the bendy native palms with their sacrificial heads grow back, after an awkward, Seussian stage.  Being especially strong, the hurricane’s center held exceptionally low atmospheric pressure within its eye, which lifted up the sea into a roiling hill of a storm surge; vertical forces like this, rather than the horizontal ones, were apparently responsible for events like lifting a pier by the boat tied to it and depositing it whole a football field inland.

I left Miami about eleven months after Andrew.  This is largely coincidence:  although my career was going well and I really loved the city and my apartment, an opportunity arose the next spring that took me to New York City.  My brother had come to Miami to live with me and to heal our estrangement of some years; leaving him behind, as well as a city I loved, was difficult, even as accepting the opportunity felt right.  I sometimes wonder what my life might have looked like had I stayed; Miami still inhabits my dreams.

Thursday, July 20, 2017

Galenean Harp

I've spent a lot of time in the three and a half months since my last post messing around with different parts of my musical/audio instrument collection:  whacking bells, banging on the toy piano, hooking up contact mics to random objects and hitting them, learning how difficult good field recording is, patching miscellaneous objects together in Max and M4L, etc.  I've produced a lot of noise, started a lot of projects, and none of it seemed really to want to go very far -- at least until the last week or so, when a couple of disparate ideas came together and formed this new piece.

It's an ambient work, so you can put it on in the background or you can sit and listen meditatively; I wrote it more with the latter in mind, but it works for the former.  As usual, I recommend good headphones and sufficient volume so you can hear all that's going on (it doesn't get much louder than where it is by the first 90 seconds or so).



This post's title is a reference* to aeolian harps, string instruments that are played by the wind; the central instrument in this piece is a kind of electronic version of that which is "played" by the field recording of waves I made recently.  It's called a resonator; I built it in M4L and gen~, based on an instrument built by a Max programmer (who had, in turn, built his instrument based on a Karplus-Strong synthesizer).  It works analogously to an aeolian harp in that it takes random energy -- in the case of the aeolian harp, wind; in the case of the resonator here, white noise in the form of surf -- and allows tiny samples (effectively grains) to loop in on themselves at specific frequencies and, well, resonate.  The frequencies are, in my version, determined by MIDI pitches, which are programmed by me in an adjacent Live track and fed into the resonator on the audio track through a side channel.  The end result is this sound like waves brushing against open strings, which I just love.

The two additional instruments here are a choir sample pack and Valhalla VintageVerb.  I wanted the choir to remain almost hidden, leading the listener to stretch her ear to hear it.  The reverb fades in very slowly, again, being something you tend to notice only after it's been there a while; I really liked the otherworldly effect it has on the familiar sound of the surf.

Last, a bit on the surf itself:  the waves were recorded among rocks on a stony/sandy beach in Westport, MA early this summer.  I placed my field recorder down as close to the waves as I could get; this yielded the wonderful sloppy, smacking, slapping sounds as the water played around the stones.  The high dynamic range was especially well-suited for use with the resonator, producing the strum-like tones; narrower dynamic ranges tend to produce more organ-like or sustained-string sounds from it.  The stones in the pic accompanying the piece were photographed on the beach as I found them.

*The piece's title is a bit of a pun, in case you hadn't already noticed:  resonances are, by definition, waves.

Monday, April 3, 2017

"Hello Polly! This is your nine o'clock alarm call!"

I've been following Marc Weidenbaum's Disquiet Junto Project for some months now.  I originally discovered it on the lines forum and have made a couple of attempts to participate; in all cases, I did not complete my effort before deadline.  This current piece is the most recent attempt and the only one to see actual (if tardy) completion.  That I finished it is in part due to my enthusiasm for the project:  I have for decades struggled to find the perfect wake-up music and decided now was the time to write some for myself.



It's a simple piece, but I'm very happy with it, for some technical as well as musical reasons.  Technically, I'm pleased that, having identified some mixing issues, I figured out how to resolve them, as well as having gotten a little better with making the granular sampling in the Tuvan voice track work smoothly.  Musically, I like that I was able to incorporate my mother's Coniff bells, as well as some native Live bell samples, and I liked how the voices and the bells worked together.  I was also pleased with how nicely the birds surprise in the end.

The challenge that I've found in choosing music to wake up by is that it must fade in ever so gently -- so as not to scare the piss out of me -- and it cannot have a strong beat; ideally, it would have no beat at all.  For many years, I relied on Pat Metheny Group's "The Bat, Part 2," but my new wife feels that Vasconcelos' berimbau at the beginning sounds creepy.  I switched to Phill Niblock's "A Cage of Stars," which works because of its fade-in and simplicity, but I never listen to the entire 28 1/2 minutes (and, anyway, doing so through an iPhone speaker would be even more criminal than doing so with "The Bat, Part 2").  Weidenbaum's Junto #273 gave the the chance to explore what I really want to wake up to and to create that for myself.

This piece was constructed in Ableton Live using native samples, the wonderful Olympus Elements choir sample pack, AAS's Chromaphone 2 and Valhalla Vintage Verb plug-ins, and two recordings from freesound.org, along with my personal bell samples, mentioned above.

Friday, November 25, 2016

Going Live

I've always been fascinated by how the atmosphere stratifies, and that it does so with such sharp boundaries.  Growing up in New Mexico, I was often treated to spectacular views of these layers, by virtue of the common 100-mile visibility and the mile-high -- and higher -- altitudes of the places where I lived.

This piece was inspired by my experiences during two trips I made this fall when I had the opportunity to observe the daytime sky a great deal, both from below on the ground and from within on the plane.  In the Land of Enchantment and southern Massachusetts, I was treated to incredibly varied and rapidly changing sky moods, and the light and the layers and the motion inspired me to express these experiences musically.


I'm very excited about this new piece for several reasons.  On a musical level, it's my first attempt at leaving behind the drone as a unifying structure and I'm very happy with the result.  Some of the people who's music I admire most, even if their work is considered drone music, can vary the structure and timbre of a piece in evolving ways that, if one compared brief samples from different moments in the work, they might not sound related, but as the work unfolds they feel like natural and intuitive developments.  I was pleased with the degree to which I was able to achieve that here.

On a technical level, it's the first piece I've written with Ableton Live, a new DAW that I recently invested in.  I had been growing increasingly frustrated with Logic Pro 9, in terms of the quality of its plugins and its lack of interface with Max.  Too, I had been seeking for some time a good MIDI controller interface, both an alternative to the standard keyboard and a good set of rotors, launch buttons, and sliders -- and, ideally, a nice, multitouch X/Y pad.  In a brief serendipitous conversation with a local musician, I was reminded that Live interfaces seamlessly with Max and decided to give the trial version a chance, taking my idea for Layers of Sky as the guinea pig.

I was thrilled to be able both to import favorite Max patches into Live -- the super-long-delay in the beginning of the piece came from the latest iteration of a patch I built when I could not find a commercial plugin that would let me go more than 10 seconds -- as well as modify native Max for Live (M4L) patches to meet my needs.  In exploring Live, I was also reminded of the Ableton Push, which I had looked at previously in my investigations into hardware interfaces for Logic but had dismissed because it was so intimately tied with Live.  It's not an inexpensive piece of gear, but, as I fell more and more in love with Live, it made increasingly more sense to make the investment.  Before my Live Trial (30 days) was up, I was sold on the whole kit and kaboodle.

A few technical notes about this piece in particular.  I used a range of native Live and third-party plugins, as well as some of my own samples.  These include several tracks running the Chromaphone 2 physical modeling synth, and Robert Henke's M4L granular synth Granulator II, which I set to chewing on a sample of one of my mother's Coniff windbells.  The strings in the final section consist of my own viola playing (which, I think, is the first time that has made it into a final version of anything), plus a solo 'cello from Ableton's sampled orchestral strings.  Finally, I used two delays, the super-long filtered delay I mentioned above and a three-channel native M4L delay I modified, and then fed it all through Sean Costello's Valhalla VintageVerb, which also features a super-long (up to 70 second) reverb.

Right now, I am as excited about the path my music is taking as I have been in years:  I feel like I have the tools I need and can integrate them in efficient, flow-supporting ways.  I have several new works in mind (and new approaches to long-shelved ideas) and have already started what's next...

Sunday, October 2, 2016

The Circle Game

“I’ve been here before.  I feel like I’m going in circles.”  Who has not had that experience?  Sometimes it seems like we’re walking the same path, over and over.  On the other hand, it’s also a truism that “you can’t step in the same river twice.”

I’ve come to see how both of these can be true, that we can feel we are going in circles and yet also never be the same.  We can appear to be going around and around, repeating the same behaviors, having the same experiences, but, if you think about it, we are not, because our hindsight belies a new experience.  Our experience of now as being like the past includes that past, layer upon layer.  Rather than going in circles, a better metaphor might be that we travel in a helix, each trip around looking in some ways the same, yet moving inexorably forward  Sometimes there are big, long patterns in which the helix is high frequency (loops are close together) and high amplitude (loops have a wide diameter), sometimes low frequency, low amplitude, sometimes different combinations.  Life is a series of helices, nested, stacked, winding and unwinding concurrently and in series.

This piece is something I first imagined in the winter of 2013/14; its long gestation has been due both to the technical challenges in realizing it and to an evolution in my musical sensibilities.  It’s not meant to be directly allegorical, as several of my pieces have, but rather I sought to express musically the way the patterns of our lives can play off of each other, creating new patterns and disrupting others.

It’s best listened to with a good set of headphones or between well-separated speakers.



Building the piece started with an attempt to create as literal a helix as can be sonically represented in Max/MSP (indeed, I purchased the software specifically to make this piece); the result of that effort was the patch used to produce the low drone heard throughout the piece.  Apart from the obvious left-to-right panning and the conceit of volume and timbre working in tandem to approximate distance, careful listening will reveal that the pitch of this drone increases slowly throughout the piece, ending about a minor third higher than it started.  A strong reverb (a plate emulation, built by Tom Erbe in Max/MSP) was applied to the drone as well, creating a kind of shimmering in the overtones that I especially enjoy.  Two other voices were created in Max/MSP, beginning about the eight minute mark and again at about 9’ 30”, the first based on the same helix patch that was used to produce the bass drone and the second a sped-up Shepard tone that ended up sounding a bit like an air-raid siren.

In recent years, I’ve become increasingly interested in bells; I am fascinated by the stretched and otherwise inharmonic overtones they typically generate.  I’m especially interested in alternative means of playing them, such as with “singing bowls” and bowed gong.  Using mathematical models of the physical properties of various materials, good physical modeling synths (PMSs) can produce surprisingly natural bell tones and allow them to be played in unconventional ways, including some that would be impossible in the real world.  Logic, the DAW I use, has a native PMS, but I found it to be limited and not very natural sounding (sometimes you don’t want “natural” sounds, but it’s much easier to get a synthetic sound from a good PMS than a natural sound from a poor one).  All of the voices in Helix, other than those mentioned above, were created using a PMS called Chromaphone 2.  It’s not terribly intuitive to use, but I’m very happy with the textures I’ve been able to create with it; for most of them, I started with a metallic bar or plate as their primary “physical” component and then “excited” them using a bow-like function.

I’ve generally found Max/MSP to be much more intuitive (which is still not very) in the Max (control functions) objects, than the MSP (digital sound production) objects.  As a consequence, I have, thus far, used it mostly as a kind of robot-musician, playing virtual instruments, rather than as a means of generating timbres, as I intended when I initially started working in it.  This is reflected in Helix both in the relative paucity of MSP-generated sounds (and the simplicity of the ones there are) and in my use of a Max-created MIDI controller that I used to give the “bouncing bell” Chromophone voice its “bounce.”  Other performance-related aspects of the piece were either controlled from a keyboard or in Logic’s automation.

Finally, I recently was introduced to VintageVerb, a reverb plug-in.  In some of the Chromaphone-generated voices, I used a touch of the program’s native reverb, which is very nice, and I used Erbe’s reverb, mentioned above, for the bass drone, but I wanted an output-level reverb to tie the various voices together and give the piece a sense of expanse.  In my attempts to implement this, I became increasingly dissatisfied with Logic’s native reverbs, which generally sound muddy to me.  I learned about VintageVerb through a Max/MSP newsletter and initially considered it for another project -- among many other wonderful features, it has an outrageously luxurious 70-second reverberation period -- but when I began playing with it, I discovered that it was capable of producing a much clearer, smoother, and more natural sounding reverb than what I’d been able to get with Logic’s reverbs.  The amount of reverb I added using it is small, but it provided what I felt was a necessary final touch.

I’ve learned a great deal putting this piece together, both technically and musically.  It’s hard to separate how much of that was as a result of my work on it and how much was a result of how long it’s taken.  In the end, though, I’m very satisfied with it and excited about the new directions I have been inspired to go as a result.

Tuesday, March 22, 2016

Theme and Experimentation

This is a piece I’ve been working on for several months.  It was initially inspired by a sonification by Milton Mermikides of a video of “pendulum waves.”  I had seen this particular video before and several others like it:  a set of pendula of slightly different but related periodicities are set in motion simultaneously and then viewed longitudinally, so, together, their differing periodicities create a visual wave and other patterns that eventually repeat.  However, Mermikides took it a step further and sonified the visual wave by coordinating the pendula’s periods with a marimba playing a D pentatonic scale.


When I saw Mermikides’ sonification, I thought, “Hey, I’ll bet I could do that in a Max/MSP patch.” It took quite a bit of futzing around, but I figured out how the pendulum waves worked and was able to build an emulation that followed Mermikides’ sonification note-for-note.  In the process, it also occurred to me that the emulator would work as a music controller.  Out of those ideas was born this piece.

The first section is the emulation of Mermikides’ sonification.  Following that are five experimental variations using Max patches based on or inspired by it as synth controllers.  I’ll discuss their structure and, where appropriate, original voices below.



Theme
It took me quite a while and several failed attempts to figure out the math for this.  Initially, I assumed a linear relationship between each pendulum, specifically, p+nx, where p = the period of the shortest period pendulum, n = the pendulum number (1-16, in this case), and x = the difference in length between the shortest and the next shortest pendula.  However, I found that, although my Max patches, effectively collections of virtual pendula, did interesting things, they never “wrapped around,” never repeated the way the real ones in the video did.  After puzzling about this for some days, it occurred to me that the waves manifested by the video’s pendula behaved analogously to the way waves in a vibrating string would, as in this diagram:


Since the ends of the string are bound, the waves are necessarily fractions of the total length of the string, or fundamental, and so have resonant relationships with each other.  In the case of the pendula in the video, I guessed that, if each one were to represent a partial of the same fundamental, it could explain how they wrap around as they do.  In other words, it might work if each pendulum frequency was 1/n, where n = the number of the harmonic of some fundamental.

If you’re familiar with the overtone series, however, you know that the partials in the low end of the series are fairly far apart from each other frequency-wise (being an octave, a seventeenth, two octaves, etc., above the frequency of the fundamental).  You’ll also note that in the video there are no adjacent pendula that swing in ratios of 1:2 or even 4:5, so they had to be pretty high up in the series.  And, indeed they were:  I finally got my 16 virtual pendula to match those in the video swing-for-swing when I calibrated them with the lowest pendulum as the 51st partial of a base periodicity 60.5 seconds long.  In other words, the pendula in the video represented a 16-partial section of the top 66 harmonics in an overtone series with a fundamental of 0.0165 Hz.  Once I had this worked out, it was a relatively simple thing to connect the patch’s MIDI output to a marimba sample.  It is that output that I recorded for the Theme.


Variation 1
The 1/n overtone series structure of the pendula begged the question:  what would it sound like to emulate a pendulum wave for the entire overtone series up to that partial (1/66)?  Building this was relatively simple, once I had worked out the patch for the theme:  I simply took the individual pendulum patches and stacked them, ending up with a 72-pendulum system, just because stacks of 12 were easier than stacks of 16.

A 72-note pentatonic scale would have an auditory range wider than was practical to listen to, so I thought it would be interesting to have the overtones themselves broken out, such that each pendulum might play a harmonic that is analogous to its frequency.  Even this represented a wide range, so I pitched the note for the fundamental pendulum at A at the bottom of a piano’s keyboard (27.5Hz), so that by the time we got to the top pendulum we’d still be well within human auditory range (1980Hz, or 4.5Hz sharp of the B three octaves above middle C).  I kept the fundamental periodicity about where it had been in the theme, at 0.0167Hz, or once every minute, making the periodicity for the top pendulum 1.2Hz.

The MIDI instruments that I have mostly do not allow coding for non-tempered pitches, so, if I wanted to hear how the overtones were actually pitched, I needed to have the pendula output to a synth that could take frequency directly.  So, I added a simple softsynth to each pendulum:  a couple of sawtooth oscillators and a square wave, evenly balanced dynamically, with the duty cycle for the square wave set at about .65 and the whole thing passed through a low-pass filter set to 1760Hz cutoff (2-stage, so a shallow slope) and a resonance around .5.  This was run through an ADSR with a sharp attack and about two seconds of decay (0% S and 0ms R) — not much more than a “ping!”  My intention here was to make distinguishing the cycles and pitches of each pendulum as clear as possible, especially the highest notes.  Finally, just to make it a bit more kind to the ear, I added a bit of virtual plate reverb.  I then recorded this through a single cycle (1/1 of the fundamental).

The result was not terribly musical, although I did find it interesting in other ways, especially as it reveals structures of the overtone series.  For example, you may notice that it appears to play more than one cycle.  What is actually happening is that what plays up through about 30 seconds is performed in reverse in the second 30 seconds; these two sections are separated by the sounding of the second harmonic/first partial (second lowest pendulum) — in other words, the 1/2 period frequency.  So, in terms of the sequence of pitches, it’s a palindrome; the first half “winds up” a sequence which is then “unwound” in the second half.  If you look back at the visualization of the vibrating string above, this makes sense:  imagine tracking center-crossings from left to right and you’d get the same pattern.  If you listen closely, you can hear other parts of this pattern in the sequence, for example, the 1/4 pendulum also punctuates the ~15-second and ~45-second marks, and the top end pendula play in little runs together off and on.  Too, I found it interesting to hear how close together the partials in the upper range are, so much so that they almost make a glissando when played in order.


Variation 2
I felt that, although I was very proud of having “unlocked” the math behind the pendula in the video and thought that the result was interesting from a theory-of-sound point of view, the 1/n model was musically limited.  The most I saw that could be done with it was to sample sections of it, e.g., pendula 1/12-1/24 or 1/72-1/88 or 1/1-1/6, and possibly vary the speed, but they would always make essentially the same pattern.

My initial incorrect model, p+nx, I thought, ironically, had more potential for creativity:  by varying the periodicity of a target pendulum (p) and the size of the difference between it and the next pendulum (x), I could produce a wide range of patterns.  This model would be the basis for the remaining variations.

For #2, along with the periodicity and difference ratios, I had also been playing around with key-center changes.  One configuration, with a fairly high periodicity for the highest-frequency pendulum (quarter note equals 250bpm, or a pulse every 100ms) and the same difference between pendula (i.e., the fastest pendulum pulses every 100ms, second every 200ms, third every 300ms, etc.) produced something that, rhythmically, reminded me very much of Steve Reich.  This is not surprising, as you could argue that each pendulum represents a polymetric pattern relative to the other pendula.  I also played with different key centers and programmed in a sequence that felt pleasing, even if it is not especially sophisticated.  This output was sent to a Yamaha piano sample I have, resulting in the above recording.


Variation 3
This piece used essentially the same controller (actually it’s an earlier, simpler version than Variation 2), but with two critical differences:  First, the primary pendulum periodicity was shorter than the differences between pendula (2:3 ratio), setting up a syncopated feel to the rhythm.  Second, by toggling the top (fastest) pendulum on and off separately from the rest and repeatedly starting and restarting the controller, I could “play” the emulator in an instrument-like way.  The result, to my sensibilities, has a more intentional, and therefore more musical, feel to it.  The voice was something I had originally created in Logic Pro 9’s ES2 for another piece some years ago which I never used but really liked.  I recorded myself improvising with the controller and sent Max’s MIDI into Logic to control the ES2 voice.


Variation 4
For this piece, I took the p+nx model and theme from Variation 2 and slowed them down quite a bit to quarter note equals ~40.  However, I did not make them precisely the same; the periodicity was 380ms and the difference between pendula was 375ms, which meant that the pendula would initially sound like they were playing together, but eventually drift apart.  Additionally, I took this variation as a chance to use a bell voice I had developed in Max/MSP and especially like.  The result, to me, sounds more aleatoric than the previous variations, especially as the 5ms difference between p and x progressively de-coordinates the pendula.


Variation 5
For this final experiment, I wanted to play with more scales than just the pentatonic or the overtone series and to arrange the pendula in something other than highest-to-lowest order.  I reconfigured the pendula such that the fastest pendulum (#1) would be the center pitch and the increasingly longer periods would alternate to either side, i.e., #2 would be next up from #1, #3 would be next down from #1, #4 would be next up from #2, #5 next down from #3, etc.  I then set up a mechanism to change scales periodically, beginning with a chromatic scale, then octatonic, major, minor, septatonic blues, whole step, hexatonic blues, pentatonic, minor thirds, major thirds, fourths, and, finally, fifths, which the controller then cycled back through palindromically.  The velocity was allowed to vary increasingly from beginning to middle and then decreasingly from middle to end.  Middle C was retained as the tonal center through all of these changes.  For the voice, I chose a physical model marimba, rather than the sampled instrument from the theme; along with feeling like it was just a good instrument for the music, I liked the symmetry of using a marimba again for the final variation, with the twist of it being an entirely synthetic sound.  This piece also has a kind of aleatoric feel to it for me, although at times a flavor of intentionality seems to chime in, which I construe simply as artifacts of the tonal scales.


Overall, I am proud of this piece primarily because of the total hours invested in it, which are far more than for any other musical work I’ve done so far.  This is not important in a gratuitous sense of more hours = better, but rather as a reflection of my growing ability -- and confidence in my ability -- to see larger, more complex projects through.  Aesthetically, I think Variation 3 is the most interesting (indeed, I have some thoughts about building a more “performable” controller from it).  Timbrally, I’m very pleased with the bell tone synth in Variation 4 and it also is the result of many hours of experimentation.  Too, I’m proud of having figured out the math of the theme; this is not my strong suit and that I was able to work it out at all left me encouraged about future adventures in sound.  Much of the rest of the piece is not terribly musical or, to my ear, very interesting, but the project has from the start been an experiment, and the nature of such efforts is that some things work and some things don’t.  I am happy and grateful to be able to share the successes and the failures here.