Monitor Engineer Josh Cruz Creates an Immersive Binaural Monitor Mix for Charlie Puth with Lectrosonics

“Charlie has literally told me and the production manager, ‘I don’t want to do a show without it.’”

Charlie Puth is living the dream of viral video maker turned mega music star. From TikToks in which he writes songs on the spot to his third studio album Charlie, his combination of humor, big feels, and raw talent has earned him a mantel-breaking number of accolades including five Grammy® nominations. Suffice to say that when Charlie sings, people listen. When he tours for his huge and devoted fanbase, he listens to himself in a monitor mix that factors in his exact position onstage, how his head is turned, and the resulting changes in what he hears. Monitor engineer Josh Cruz deploys an ingenious method of providing this, using the Lectrosonics DCHT dual-channel digital transmitter and companion DCR822 receiver along with in-ear transducers that incorporate embedded ambient mics. In this interview, Josh reveals the secrets behind this singular application, not to mention Puth’s enthusiasm for how it has changed the way he performs.

Tell us about the background that drove you towards audio engineering.

I started like a lot of engineers. as a musician. I grew up playing instruments and my dad was a musician as well. I started with acoustic guitar, and piano even before that. My dad insisted my brother and I take piano lessons from a young age, but I hated practicing! My brother started playing guitar, which to me meant I had to play guitar. One day my dad brought home a djembe drum and a bass guitar he had found in a church he was working for. He said, “Each of you, pick one.” I started on the drum and my brother on the bass. We quickly realized that I couldn’t keep a rhythm very well and his hands were too small for the bass, so we switched. Things fell into place immediately!

Did you study music or engineering formally?

When I got to my senior year of high school, I faced what every young person does, which was figuring out what to do with my life. I found audio engineering as a degree program at my University in upstate South Carolina. The program was split between studio recording and live sound, and the live stuff was heavily theater-based. They had off-Broadway tours coming through and I learned a lot from mixing musicals. Their front-of-house engineers have a lot to manage while also having great ears.

I wanted to be more in the touring band world, so I moved to Atlanta and got connected with a church there. They had a great production team and I networked with a lot of people. From there, I’ve been fortunate to be in the right place at the right time.

What artists did you work with before Charlie Puth?

Charlie has really been my first foray into the larger pop world though I have previously had the opportunity to work with the Nashville pop band COIN and a singer-songwriter named Mat Kearney. I have done a lot more with contemporary Christian artists including Chris Tomlin, Passion Music, and Elevation Worship; most of my audio experience has been in the worship space.

Tell us about the application for the DCHT with Charlie Puth. Is it to send him a stereo in-ear mix?

Not exactly. In fact, it’s the opposite. First, let me say that as far as I know, the DCHT is the only stereo RF transmitter in the form factor of a battery-powered belt pack. Charlie wears it along with his IEM receiver, and it transmits a stereo signal back to the console of his personal binaural room sound.

How does it do this?

It works in conjunction with the recently released Ambient Pro system from the in-ear manufacturer JH Audio. These are high-end in-ear transducers with omnidirectional mic capsules made by the well-known microphone company DPA embedded in the outer shell of each earpiece. (The Ambient Pro IEM system is meant to be paired with the Lectrosonics DCHT transmitter and DCR822 digital receiver.) The cable fantails into two connectors at the end. One is an eighth-inch stereo plug that connects to any in-ear receiver pack. That delivers a monitor mix to the earpieces from my console. The other is a TA6F connector that feeds the capsules’ output into the DCHT.

The mics pick up what’s effectively a binaural soundstage from the point of view of Charlie’s head. I then fold them into the monitor mix as I would with any room mics. This setup gives me what Charlie is hearing at any given moment. I don’t think any other system does this, letting me experience exactly what the lead artist experiences when he’s downstage center or wherever — while I’m hidden behind a curtain at offstage left.

So, you fold back the signal from Charlie’s “on-ear” mics into the monitor mix. Just for Charlie or anyone else in the band as well?

Just Charlie. This is a very personal system. From the perspective of a monitor engineer, the best way to describe it is that you’re vicariously experiencing someone else's hearing outside of their mix.

From Charlie’s point of view, what are the advantages of this over traditional room mics?

Room mics provide a fixed and usually broad stereo picture, which doesn't realistically reflect what a lead singer hears when they’re moving around the stage. With this system, if Charlie looks towards the drums, he hears more of them. It’s not something he has to be constantly conscious of, but it helps him give the best performance Also, for a performer, there’s a lot of energy you get from the audience singing back at you. With in-ears, it can make you feel isolated as a performer. This is why a lot of bands still use floor wedges and side-fills despite there being such great sounding in-ears. Charlie wants to keep that audience energy, but still have a quieter stage because no wedges or side-fills makes the mix so much cleaner for the audience and band alike. He used to pull out his left earpiece halfway to “feel the room”, then I’d do the same to approximate what he was hearing so I could make mix decisions. Now, there’s no guesswork because I hear what he hears.

Has latency between that and the signal from the on-ear mics, which has gone out via the DCHT, ever been an issue?

Not with this system. I’ve had this happen in the past when I went too far down the rabbit hole of plug-ins and got some latency between a performer’s “head voice” and their voice in their monitor mix. One said to me, “Everyone else’s vocal sounds great but mine sounds terrible.” Then of course, everyone else in the band would be like, “No, yours sounds fantastic” because they didn’t have that phase offset relative to the head voice. That taught me to keep my signal chain as minimal as possible. I don’t use any processing or plug-ins external to the console itself.

The on-ear mic signal is transmitted by the DCHT, which Charlie wears. What kind of receiver picks it up?

The Lectrosonics DCR822, but we’re in the process of migrating to the DSQD, which has four channels in half a rack space. The reason is that we want to have hot receiver channels ready to go in the unlikely event we have a problem and need to swap to a backup pack.

Is the DCR in your rack next to the console?

No. It lives with me all the time in the same Pelican case with Charlie’s in-ears and the DCHT. We travel all the time, and if he is going to use in-ears, I will implement this setup.

Did the Lectrosonics setup ever help you survive a gig nightmare?

The fact that the DCR can output both AES and analog [audio] saved me once. On the very last show of 2022, we had a cable get damaged. This was the TA3F to XLR-M cable. The DCR822 has two such outputs on the back — each one sends either a mono analog signal or stereo AES signal. It’s not proprietary but it’s specialized enough that not a lot of audio vendors are going to have them when you’re on the road.

I was testing the in-ears during line check right before the show and didn’t get signal in one side. Someone had stepped on one of the cables and ripped it out of the connector barrel. I was thinking, “I’m gonna have to go mono” and was about to let Charlie know, then I realized I could run AES and get the stereo signal through my remaining good cable! That really speaks to the quality and flexibility of Lectrosonics gear. I know they’re mainly in the film production world, but for concert sound I’ve never used anything that does what they do this well.

What is Charlie’s overall opinion of this system?

He has literally told me and the production manager, “I don’t want to do a show without it.” It’s a unique system that really allows him to connect with the audience. There are some artists that just put on their show, deliver their product, and that’s it, but that sense of connection is very important to Charlie. He wants it to experience that he’s right there with them. In-ears usually make you feel isolated, so it’s cool to have this technology that lets us do what no one has really done before. I’m looking forward to seeing how people take advantage of it in the future.