Laser (Tungara) Frog Synth

Before the sun had even set on my first day in Gamboa I had already heard excited chattering about the sound of the “Laser Frogs”. Once it got dark there was a seemingly ubiquitous chorus of these laser sounds, an asynchronous melange of descending glissandi. One might mistake this biophony for a retro video-game arcade, but it is in fact the revelry of an amphibious Bacchanalia.

Túngara Frog in a puddle, photo courtesy of Mangtronix
Chorus of Tungara frogs at night in Gamboa
Spectrogram of the frog chorus

First Attempt

I had other plans and project ideas before arriving at DINACON, but I found myself continuously drawn to the sound of these frogs. I was completely ignorant of them at first, having no idea what their actual name was or anything about their behavior or even what they looked like. I just really liked the way they sounded and kept listening. Indeed these frogs sound like a laser beam from a video game, and since I have worked as a sound designer and synthesized laser beam sounds for video games, I thought “I bet I can synthesize these frogs!”.

My first attempt was a very quick patch using the ES2 synthesizer in Logic Pro. I did this based entirely on listening to the frogs before analyzing the spectrogram in detail. It captured the general gesture of the descending tone, but didn’t capture the timbre or slope of the glissando very well.

ES2 Logic Pro Patch for Laser Frog Synthesis
Lazer Frog Synth attempt #1

Making the Whine

Although the first attempt was not convincing enough, it was close enough to encourage me to continue on my quest to synthesize the frogs call. I began by inspecting an isolated call from one frog via the spectrogram in Audacity.

Túngara frog recording with whine and three chucks
Spectrogram of Túngara frog recording with whine and three chucks

There are many noticeable things from this spectrogram that further inform what we hear. The first being that the frogs make not only this “laser” sound, but also have a percussive sound that follows it. At first I referred to these components as the “chirp” and “beep”, but after being clued in by some STRI researchers (thanks Amanda Savage!) I learned to use the terms “whine” and “chuck”. These are much better descriptions in my opinion.

I decided to use the SuperCollider programming language so that I had absolute control over the synthesis of this sound. The first area of focus was on creating a convincing “whine” using a bank of sine wave oscillators.

Looking at the spectrogram above we can see the “whine” portion of the call is a descending tone, starting around 1kHz and ending about an octave below. It also appears to have some harmonic overtones that decrease in intensity (up to about the 5th harmonic) Here is a recording and spectrogram of the first attempt in SuperCollider.

Túngara “whine” synthesized, first attempt in SuperCollider
Spectrogram of synthesized Túngara whine in SuperCollider

This was already sounding better, but by looking at the spectrogram of the synthetic whine some things are obviously still lacking. First, the slope of the glissando is still too linear, it needs to have more on a exponential (perhaps cubic?) curve to it. Additionally the upper harmonics are too strong and need to be attenuated relative to their ordinality. (The higher the harmonic, the less loud it is)

Making the Chuck

After a few more iterations of refining the whine, I moved onto the chuck.

Spectrogram of Túngara frog chucks.

Looking at the chucks in the above spectrogram we can see partials at relatively even spacing. We could perhaps model this by using a harmonic tone with a fundamental frequency of ~200 Hz or ~250 Hz, with the fundamental and first few overtones missing. The chucks seem to have their highest peak around 2.75 kHz. Is this sound produced via some sort of formant resonance? What mechanism makes it seemingly harmonic but with a missing fundamental? This is unclear to me, but I can recreate the sound nonetheless!

This group of three chucks have different durations, and the last one seems to have a downward pitch contour but not nearly as pronounced as the whine. The first two beeps are approximately 50 milliseconds long, and the third is 40ms.

Using the same approach as the whine, I used a bank of sine wave oscillators to recreate the chuck. Below is a recording and spectrogram along with the synthetic whine.

Synthetic whine and chuck of Túngara frog
Recording of synthetic whine and chuck of Túngara frog

While the timing of the chucks is accurate, the tone is not convincing. I continued to iterate on the implementation until settling on the one below.

SuperCollider GUI Application

For presentation at Dinalab I put together a simple GUI application which allows the user to playback a recording of an isolated Túngara call and compare it to the synthetic whine and chuck. Additionally there are knobs to alter the pitch of both the whine and chuck to hear what GIANT or tiny Túngara frog might sound like.

Video of Tungara Frog Synth SuperCollider GUI Application

Here is the audio of the final form the synthesizer took, there is still room for improvement of course.

Version 6 of Túngara frog synthesizer

Playback in the Field

In order to see if my synthesizer was effective at blending in with Túngara frogs in the field, I did some simple, not very well controlled tests on the streets of Gamboa.

Basically, I walked up to a pond where I heard Túngara frogs calling and they would usually stop calling as I approached. Then with my field recorder running I would play the synthesized call from my cell phone and wait to hear a response.

Here is the first trial (that loud percussive sound in the background is a Gladiator frog, I think) The synth is mostly in the left channel while the other frogs are mostly in the right.

Field test 1 of Túngara frog synthesizer

After shuffling around a bit, the frogs got quiet and I tried again.

Field test 2 of Túngara frog synthesizer

Now, can I conclusively say that the frogs responded to my call? I do not know, I am not a field biologist or experienced with phonotaxis studies, but the results of these simple tests seem promising. I think the frogs are buying my synthetic call.

Future Work

I really enjoyed working on this project and am very interested in improving the audio synthesis and application interface so that it is useful to researchers both in the field and the laboratory. If you study frogs, bioacoustics, phonotaxis or have interest in this project please get in touch with me, I would love more feedback.

From my perspective, the synthesis could still use some refinement. First, it could use better filtering of the whine, perhaps via a resonant filter based on accurate resonances of the frogs vocal apparatus? Additionally, more variability in chuck production would be useful. With more analysis of recordings and a bit more reading on the physiology of the chuck production I think I could better refine the synthesis.

Some final questions:

Perhaps I should port this synthesizer for use in a web/mobile app?

Maybe I could synthesize Gladiator (or other) frog calls?

What additional features would be useful?

Do you have comments, criticisms or any feedback?

Acknowledgments

First I would like to thank all the participants I met at Dinacon, and Dr. Andrew Quitmeyer for organizing the event.

Amanda Savage was very generous in talking with me about my project and in introducing me to the vast literature and research available on Túngara frogs.

References and Further Reading

Quick Guide – Túngara Frogs, Rachel A. Page and Ximena E. Bernal

The Túngara Frog: A Study in Sexual Selection and Communication, Michael J. Ryan

Complex Call Production in the Túngara Frog, M. Gridi-Papp

Unlucky túngaras

There are many, many more papers written about these frogs. They are certainly one of the most studied frogs in documented human history.

Agouti Duties

So, Gamboa, home of Dinacon, is also home to these wonderful, adorable little rodents called agoutis – which bear some similarities to capybaras, but have been deemed infinitely superior for reasons I do not 100% understand. (Maybe because capybaras get all the press?)

I am here to document Dinacon but also am not very good at photos. Go figure.

Agoutis have pretty much become the mascot of Dinalab – Andy is always posting insta stories of their antics, the Dinatruck has an agouti decal, etc. – so of course they needed to have a pretty substantial presence here at Dinacon.

And they do – in the form of a series of Agouti-Do and Agouti-Don’t posters hung about the lab, reminding Dinasaurs of a few simple guidelines for being cool like an agouti (and not smug jerks like those capybaras).

Anyway, they are rad – great job, Andy! – so I thought I’d post a few of them:

So, to recap, just remember: At Dinacon or otherwise, it’s your duty to be cool like an agouti. Good luck out there!

P.S. This Dinalab poster doesn’t have anything to do with agoutis, but I still feel like it captures a lot of that Dinalab spirit.

Kris Casey – Beginning Endless Forms

August 12-19th. Kris Casey is a visual artist and creative researcher from Chicago, IL. Her work draws heavily from various fields of philosophical and scientific inquiry, including evolutionary developmental biology, bio-aesthetics, evolutionary aesthetics, and genetics. Her research and practice examines relationships between biology and technology, natural and artificial, material and immaterial, subject and object. Her paintings can be seen as assemblages or accumulations of natural and technological elements whereby the biological concepts of mutation, contamination, decay, generation, emergence and metamorphosis become modes of inquiry into the production of novel forms.

Jonathan Hefter

August 1st – 16th

Project: I’ll be creating 3D digital models of local flora using photogrammetry that others can then use in their own works. With any luck, I’ll have the Dinalab OpenScan device humming away, if it isn’t already.

Bio: I’m a New Yorker with a taste for going far off the beaten path. I’m also the founder of the edtech company, Neverware, and a former firefighter. I will be travelling the world to learn more about how technology is created, used, and disseminated in different communities. Dinacon will be my first destination, followed by Berlin, and then parts unknown. Collaborators and co-travelers welcome.

Grace Grothaus

Dates: Aug 25-31

Project: Future Seeding, a sculpture series inspired by Karel Capek: “the future is not in front of us, for it is here already in the shape of a germ (seed); already it is with us; and what is not with us will not be even in the future.” Onsite I will be continuing fieldwork in which I find, photograph, and create 3D models of seeds via photogrammetry. The lowland rainforests of Panama form a critical junction of North and South America and are so biodiverse they contain many tree species they even today are not yet part of the taxonomic system. Due to climate change, sea level rise, and anthropogenic habitat disturbances, many may even go extinct before they are scientifically known. Future seeding is an ongoing sculpture series created from the 3D models made in the field; attempted sculptural catalysts of discussion. Upon completion, each 3D printed seed sculpture will also contain a simple electronic circuit that activates an audio recording when touched. Audio artist and composer Felipe Rossi will be traveling to Dinacon with me, assisting in the field audio recording.

Bio: I am a visual artist working in physical computing and other forms to create immersive installations and performances as well as interactive paintings and sculptures. Engaging with themes of environment and technology, I produce my artworks towards the creation of moments of reflection about human agency and balance with the built and natural environment. Right now I am a MFA candidate at the University of California, San Diego where I reside with my dog and many plants.

Dr Betty Sargeant from PluginHUMAN

Whilst at DiNaCon (August 14-20) I will collect unique fauna and water samples and take images of their microscopic biological structures. I will also record bio data, including audio, and the movement of gases and moisture, from inside trees and waterways. This data will be used to create PUL$E, a new digital art installation by PluginHUMAN (Betty Sargeant and Justin Dwyer).

PUL$E places audiences in the centre of a multi-sensory experience that’s controlled by the life force of trees. Through this project we aim to forge deep connections between people and our natural environment, raising questions around ecological conservation in the age of economic rationalism. The development of PUL$E is being fed by a wide range of field trips (to the Amazon, Panama, Taiwan, remote Australia etc) where PluginHUMAN are collecting data from significant local trees and waterways.

The PUL$E installation will feature the internal microscopic structure of significant international trees. This data will be enlarged and printed onto acrylic sculptural forms. The printed acrylic sculptures will be lit by full-colour programmable LED lights. The light show will be controlled by bio data collected from the significant international trees. This bio data will reflect the gas, movement, moisture and sounds from inside the trees. Audiences will be surrounded by environment-controlled audio, visuals and aromas in an immersive art encounter.

More info at: www.pluginhuman.com

Connect via Instagram: @PluginHUMAN

Connect on Facebook: @PluginHUMAN

Tully Arnot

23-31 August

I’m an Australian visual artist, working with kinetic sculpture (cheap servos, Arduino, pretty low tech) , video, performance, photography etc. My practice deals with how people interact with both the environment and technology, especially at the intersections of these. I work a lot with simulations of nature.

Recent work has been documentary based, I hope to explore the jungle and speak with a lot of researchers, and build some kind of speculative narrative about interactions with the environment. Also keen on some en plain air electronics tinkering 🙂

Stuff online at www.vimeo.com/tullyarnot

Susan Booher

Dates: 04/8-10/8

Project: Susan will be recording her travels to and around Gamboa, Panama as well as the local flora and fauna (on land, in the air, and along the river) with a 360-degree camera to deliver an immersive experience in virtual reality to aging and/or disabled people through technology and digital recordings.

Bio: I’m a graduate student in Design Research and Development with a specialization in Aging at the Ohio State University. I practiced commercial interior design for 13 years before returning to academia to pursue an MFA. I’d like to continue with a career that supports the aging population and dementia. It’d be a dream to create an experience that can benefit the cognitive and emotional health of older adults who can no longer travel.

Jason Bond

Attending August 2nd—16th 2019

I’m a digital interactive media (“videogame”) artist with a special interest in our relationship with nature. I’ll be at Dinacon for 2 weeks and will probably make a videogame or something!

Attaching some of my past work below:

A wee prototype game I made where you roam the city of Toronto (re-created via map data) as the local wildlife! Animal models from MalberS Animation, city built using Wrld3D, music by Everloop. I assembled the pieces into a 4-player sandbox game.
A cute all-ages game I co-created with Colin Sanders, wherein one nurtures planets back to health by growing and maintaining a space garden. Features ecosystem simulation and code-generated plants (each unique). I co-designed, did most of the code base, and created the visuals.

Joel Murphy

Hi, I’m Joel. I will be at Dinacon from the 3rd to the 18th.

These are the things/ideas that I want to explore

  • How technology can survive in the jungle
  • Sounds from the canal V Sounds from the jungle
  • Parasitism
  • Symbiosis
  • Cybernetics
  • Zip lines

I know a lot of things, and I don’t know a lot of things. I look forward to helping and learning with all the Dinasaurs!