Bat Utility Belt: SparkFun Tsunami Super WAV Trigger

I didn’t set out to build my own MIDI sample player, but SparkFun made it so easy I couldn’t resist.

The SparkFun Tsunami is a 3 x 3-inch circuit board that streams WAV files from a microSD memory card. Solder on some MIDI and audio jacks, pop in a card, connect USB power, and you can play and loop thousands of sounds in unique ways. The Tsunami is impressively expandable, too. It offers 16 additional trigger inputs, a serial interface for Arduino control, and eight audio outputs. You can configure the outputs as four stereo channels or eight mono channels, even triggering sample-locked 5.1 or 7.1 surround sound from a single note.

All this (minus jacks and SD card) is just $79.95, which makes the Tsunami another perfect fit for the Bat Utility Belt series, where I cover surprisingly useful synth gadgets that cost less than a hundred bucks.

From WAV to Tsunami

Lots of inexpensive circuit boards play sound files. One reason the Tsunami is superior for musicians is that it’s polyphonic. You can simultaneously play as many as 18 stereo or 32 mono voices. Unlike on lesser boards I’ve tried, loops play back seamlessly. A voice-lock option lets you prevent new events from cutting off important grooves or ambiences. You can access a maximum 4,096 WAV files per card; the Tsunami supports 16-bit, 44.1kHz WAVs and cards up to 32GB. That capacity has endeared it to the modular synth community. One popular application is to record the output of a complex, evolving Eurorack patch and then load the recording into the Tsunami to loop as a background ambience, freeing up your modules for other sounds.

So, what else makes it super? The Tsunami is the second generation of the popular SparkFun WAV Trigger, a $50 circuit board that’s sonified everything from Halloween costumes to model trains. YouTube madman Look Mum No Computer featured WAV Triggers in his Synth Bike and Circuit-Bent Bible.

The extra 30 bucks for the Tsunami get you the four stereo outputs (up from one on the WAV Trigger), seamless looping, more polyphony, the audio input, and simple MIDI hookup. (The WAV Trigger requires extra circuitry for MIDI control.) The Tsunami also supports firmware updates from its SD card. You can change the four stereo outputs to eight mono outputs and back with a quick firmware swap.

The Super WAV Show

To me, what really makes the Tsunami special is the perspective of its designer, Jamie Robertson of Robertsonics. Robertson contributed to groundbreaking instruments from the Synclavier to the Linn 9000 and has decades of experience building interactive audio systems as a Disney Imagineer. (Here’s a cheerful interview in which he describes how he embedded samplers in theme park rides.) 

That creative thinking shines in the Tsunami’s numerous trigger modes, which are quick to configure with the companion WTConfig software (Mac/Win/Linux; see the screenshot). The program generates a text file you copy to the SD card, which then gives the Tsunami its marching orders on bootup. 

It’s crucial to choose the right card. Robertson explains, “In order to play and mix low-latency, polyphonic audio, the [hardware] must perform ‘just-in-time’ reads all over the card.” The first microSD card I tried wasn’t optimal, which led to clicks at the beginning of notes and a weird issue where the Tsunami crashed on the third iteration of a loop (see the video below). Since I added a compatible card, my Tsunami has performed perfectly.

You also have to remove any metadata from your WAV files, or they won’t play. This tutorial explains how to clean WAVs with Audacity. I found it was faster to nuke the metadata with Mark-V Tag Stripper, a free drag-and-drop Mac app.

Surf MIDI

The Tsunami is more like a Mellotron than a conventional MIDI sampler. Each MIDI note is mapped to a single WAV file on the card; to play a chord, you need a sample of every note in the chord. To create the mapping, you add the corresponding MIDI note number to the beginning of the filename. You can also add a code to tell the Tsunami whether to loop the file and which output to send it to. For example, 060_S3 You a Farm Boy.wav plays a single time through output 3 (S3) when MIDI Note Number 60 (middle C) arrives. I use another Mac app called NameChanger to wrangle file names.

So that maps all 128 MIDI notes to the first 128 WAVs. How do you access the other thousands of files? One way is by sending a MIDI Program Change command. Program Change 2 maps MIDI notes 1–128 to WAVs 129–256, and so on. You can also use the triggers or serial input to play any of the 4,096 files directly. The manual has the details.

Additional MIDI controls include attack time (CC73), release time (CC1), Velocity, Pitch-Bend, and Sustain. At its heart, the Tsunami is a sample player; it has no filter, no envelopes, no LFOs, and no effects. However, Robertsonics does offer alternative firmware that turns the board into an experimental performance looper.

You a Farm Boy?

All of which brings us to my ongoing Tsunami project, SwineWAV. Often my DIY instruments start with the case. This one was originally a novelty radio shaped like a pig and immortalized in an internet list called something like “5 Gadgets NEVER to Buy Your Valentine.” 

Indeed, the radio sounded awful, so I pulled it out and popped in a Tsunami. Originally, the pig’s ears were buttons to choose the radio station. Now the left ear triggers sequential sound bites about pigs and pork products, and the right ear triggers random swine and barnyard sounds. Next, I added buttons for the eyes. The left eye plays music loops from Pink Floyd’s “Pigs (Three Different Ones).” The right eye decrements the volume. A MIDI jack on the rear lets me play other loops and Mellotron samples from a keyboard. 

My proudest hack was running a microSD extension cable into the battery hatch on the pig’s belly so I can swap out the card without unscrewing everything. In fact, it’s so easy to add new features by updating the config file that I added three more buttons. These buttons play, pause, or stop recordings of spam emails (continuing with the pork theme). And I still have nine triggers left, so I plan to add more buttons and a tilt switch. I’ll also hook up the second stereo output so I can run loops dry while feeding sound bites and melodies through external effects. With the SparkFun Tsunami, it’s amazing what you can build for under a hundred bucks.

What’s in Your Utility Belt?

Tell us about your go-to music gadgets. Post a tip on Facebook, Instagram, or Twitter, and tag your nomination #BatUtilityBelt. You can also reach me through Batmosphere.com. If I feature your submission in an upcoming column, you’ll win a free subscription to Synth and Software. Oh, wait—that’s free already. Pig out!

Websites: SparkFun | Amazon (As an Amazon Associate, the author earns from qualifying purchases.)

Price: $79.95