Of Mutants, Tacos, and Mariachi

How Dren McDonald created the unique score for Gunman Taco Truck
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A scientist accidentally puts his coffee cup on a nuclear detonator button, triggering a series of blasts that turns the Earth into a mutant-filled wasteland. You’re a survivor who owns a taco truck, and you must make your way from San Diego to Winnipeg. You stop at cities along the way to sell tacos, which you fill with road kill, mutants you shoot, and other ingredients that you scavenge along the way.

Composer Dren McDonald
Credit: Lorrie Murray

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That’s the basic plot of the new video game Gunman Taco Truck (Steam for PC, Mac, and iOS/Android), which was scored by the busy Bay Area-based game-music composer/sound designer Dren McDonald, whose credits include Restaurant Dash with Gordon Ramsay, Diner Dash 2015, Gathering Sky, and Transformers: Age of Extinction - The Official Game among many others.

The Gunman Taco Truck score is Mariachi-based and the instruments were all played by live musicians. To make it fit the post-apocalyptic mood of the game, McDonald—who tracked some of the music at New, Improved Recording in Oakland, California and the rest in his basement studio—employed some unorthodox recording methods. But before getting into that, let’s start with a little background on the game itself.


Gunman Taco Truck takes place in a post-apocalyptic setting where your job is to sell tacos and kill mutants while crossing the country.

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Gunman Taco Truck is among the many “indie” games that have hit the market over the past several years. “There’s been a real explosion in indie games, because the tools for making games—like Unity 3D and Unreal Engine—have become, basically free to use for independent game makers,” McDonald explains. “And then on platforms like iOS and Android, anyone can publish their game: You don’t need a game publisher. There are places like Steam, which is a huge game marketplace. With the support of the Steam community, anyone can post a game there.”

This influx of independent game developers has opened up the game world to a lot of fresh ideas. “Indie games have become a really important part of game development now, because you see so many different ideas emerging from them,” McDonald says. “There’s quite a bit more artistic expression in the games, as compared to five years ago.”


Gunman Taco Truck was developed by game designers John and Brenda Romero, working under the company name, Romero Games. John made his reputation early in his career with his work on the iconic first-person shooters Doom and Quake. Brenda’s credits include Dungeons & Dragons, Ghost Recon Commander, and Jagged Alliance.

Fig. 1. Donovan Romero, 10, provided design concepts for the game, which were then rendered by an artist.

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The story of how Gunman Taco Truck came into being is about as indie as you can get, as the idea for it and a lot of its design was done by Brenda’s son Donovan, who was 10 years old at the time (see Figure 1). “Having parents that are game developers worked out pretty well for him,” McDonald says. “He had this great idea for a game, and they liked the idea so much they thought, ‘We should try and make this.’ So, we’d get these sketches from Donovan, and we had an artist working on the game who would basically do renders of Donovan’s ideas.”


Fig. 2. Because of the game’s 8-bit-style graphics, McDonald initially experimented with music influenced by chip-tunes.

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At the time McDonald started writing cues, there was an early build of Gunman Taco Truck available for him to work with, so he was able to see how his ideas worked with the various scenes in the game. Because the game’s art has a retro, 8-bit look, the first idea for the music was to combine elements of chip-tune and music in the style of Ennio Morricone, the Italian composer famous for scoring spaghetti westerns (see Figure 2). “We tried some experiments with that,” recalls McDonald, “but the chip-tune thing wasn’t quite working in that style.

“I tried a few different variations of how much of it would sound chippy and how much would sound like Morricone. He had this intense, Italian-Spanish kind of style that he would use sometimes. And that was one of the references the Romeros gave me, in addition to Mariachi. But then we decided to go straight Mariachi, and kind of foul it up a little bit, and make it a little less than traditional.

“Both of the Romeros were big fans of Mariachi. They would have Mariachi groups play at their birthday parties when they were here in California. So, I knew that they wanted to have that, but kind of determining which direction the music should be—whether it should be this chip-tune/Morriconi, or straight Mariachi, or messed up Mariachi—that was probably the biggest challenge.”


Once they’d decided on the “messed up Mariachi,” direction, McDonald got down to writing. “I’ve never done a score with Mariachi music. In certain games, I had done a small bit of related music,” he says, referring to two restaurant-associated games that he scored in the past for the developer Glu Mobile. “Because they’re restaurant-based, there are new restaurants that always need new music. So, in Diner Dash we had a Mexican restaurant, and we actually had some Mariachi musicians that show up in the game and play little stabs and stuff while the music is playing in the background. We had Mexican music in the Cooking Dash game, as well. So, I’ve done it in a couple of titles before.”

Despite the Mariachi theme, McDonald chose not to go with a totally authentic lineup. No guitarrón, for instance. “I didn’t use one of those. The thought behind Gunman Taco Truck is that it’s taking place in the apocalypse. So, the idea is that a lot of the instruments aren’t traditional, because they just can’t find them anymore. They didn’t have any tubas or anything.”

He decided to use real drums, trumpets, violins, guitars, and basses as the main instruments. Using the game-build he’d received, McDonald sussed out what the musical needs would be. “I could see the two different areas of the game. The main game play would be the first area, where you’re making tacos and you’re selling them. And the second area is where you’re traveling from one city to the next. While you’re traveling, you have to shoot the mutants and the cows and the chickens and collect all the ingredients for your tacos. Because when you stop at the next town, you’re going to have to sell tacos so you can buy some more gas, weapons, and ingredients. So, you can literally die if you don’t have enough salsa or cheese. [Laughs.] You have to keep your supplies together.”

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He ended up writing five main cues for each of the two sections. Once they were recorded and mixed, he would chop them up into a variety of loops that would be triggered by various game actions of the player. “I had a rough idea of how long each of the sections would be for the player, and approximately how long each loop would be. We had the taco-making sections and the battle sections. And we figured out approximately how long those loops should be and then how many different ones we should have, depending on how many cities you go to.”

By cutting the main cues into multiple loops, it made it possible to offer a lot of musical variety. “The game kind of randomizes a lot of this stuff, so it’s not like when you go from Fresno to Phoenix you always hear the same music. It can change.”


The recording was done one instrument at a time, starting with the drums. “We recorded the drums all first, with some backing tracks I had laid down in MIDI, so that the drummer had a sense of things—and maybe my guitar and bass. He played along with that stuff. I didn’t want to record drums and trumpets and violin all in one room.

“So, we did the drums and then recorded the trumpets separately and the violins separately. We didn’t have a whole trumpet section. I would have liked to have had one, but we didn’t have the budget to bring in three or four musicians.”


McDonald employed some unusual recording techniques—both for the other musicians and for his own guitar and bass parts—in order to create the sonic feel he was looking for. “Mariachi music is generally very happy and celebratory. So, I wanted it to be that way, but also to have the sense that everything’s not hunky-dory, that everything’s a little bit messed up. You’re shooting mutants, after all. [Laughs.] So, it’s kind of a messed-up world.

“Some of my favorite records are the things that Tchad Blake has recorded, things like Latin Playboys, and Los Lobos. And I know they use those kinds of techniques where they’re recording things in a really unusual way to get some kind of different emotional feeling; a different approach to an instrument that you don’t usually get. I was going for the same thing, trying to get a kind of ‘junkyard sheen’ over the whole recording.”

To accomplish this, McDonald decided to use physical filters on the microphones “I had a couple of these [metal] air ducts I’d gotten from a store called Urban Ore in Berkeley. We tried them on different instruments to see which positions seemed to work. When we were recording over in Oakland, we used a Schoeps 221B, a small condenser mic that we’d stick in there. And when I was recording here, I would use an Oktava MK-012-01—I have a set of those that were modified by Michael Joly—and I would stick those into trumpet mutes or trombone mutes or the air ducts.”

Fig. 3. McDonald shows one of the miking setups he used—an Oktava MK-012-01 pointed into a metal air duct to capture unusual guitar tones.
Credit: Lorrie Murray

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McDonald used the mic-in-the-duct technique when recording his own electric guitar parts at his studio. While he used a Fender Deluxe reverb amp for some of the parts, he also recorded through several small, battery-powered amps including a Smokie and a battery powered Orange PiX CR3, a 3W micro amp. These amps were small enough to fit inside the air ducts, which were about 6 to 8 inches in diameter (see Figure 3).

“It gave it a unique quality that you don’t get by using plug-ins. Especially if I would place the mic a little bit further away from the source. I wanted the guitars to sound distant, and not terribly up front, and give it a little sense of atmosphere, like you were hearing this in a room that was maybe somebody’s repair garage and was kind of messed up, with bits of metal lying about. You get kind of a weird, odd metal-kind of resonance, sometimes. Or sometimes it would just sound different—just kind of sound wrong.”


The workflow between McDonald and the Gunman Taco Truck game designers was also unusual. He submitted his work to them by sending in WAV files. On most projects, he uses some sort of middleware, a type of software that allows game composers and sound designers to insert their finished music right into the game, with the correct code generated. (Check out “Masterclass: Using Game Audio Middleware” at emusician.com for more info.)

One that he uses a lot is FMOD Studio. “What it basically does is it helps the audio creator make interactive audio so that they don’t have to get a lot of code support from an engineer. If you want to say, ‘Hey, I want to take this one sound of this bullet, and I want to randomize every WAV file that gets played for it. And I also want to pitch randomize it and volume randomize it.’ I can do that all in FMOD and just tell the engineer, ‘Play this one sound event; I’ve done all the stuff on my end so you don’t have to worry about it.’”

DAW-wise, McDonald works in Apple Logic Pro for the bulk of his composing and recording, although he also has Pro Tools on his Mac. “I only use Pro Tools if I have to. For instance, this project I had to, because we recorded the drums and the trumpets and the violins all at New, Improved Recording, and they only had Pro Tools. Otherwise, I’m all in Logic all the time. I also mixed it in Logic.”

But mixing a video game that’s going to multiple platforms can be challenging because of the sonic differences between, say, an iPhone and a PC connected to large external speakers. A bass line that is clearly heard on the latter might virtually disappear on the tiny speaker of a mobile phone. McDonald says that influences the arrangements he comes up with. “You basically can’t rely on anything under 120 Hz.”

He also makes sure to check his mixes on earbuds. “I joke with my friends that the Apple Ear Buds are the new NS-10s: You’ve got to make it sound good on them, because everyone will be listening on them. With this particular game, I knew it was going to PC, Mac, and mobile. So, I just mixed to make sure it sounded good on mobile. I didn’t do a separate mix for Mac or PC because you never know what people are listening to on those platforms. Knowing it would sound good on mobile, I figured I’d be fine.”


Fig. 4. McDonald’s Gunman Taco Truck score is also available in album form.

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Despite being delayed a year in the middle of production to accommodate the Romero family moving from California to Ireland, Gunman Taco Truck was released in late January of this year and has been quite favorably received. McDonald’s creativity in both the composition and production of the score is a huge part of the game experience.

Gunman Taco Truck is a free game on both the iOS and Android platforms, so you can experience it yourself and hear McDonald’s imaginative scoring work (see Figure 4). The soundtrack is also available in album form on McDonald’s BandCamp site: drenmcdonald.bandcamp.com. Learn more about McDonald’s work at his website, nerdtracks.com