Brad Madix with a Radial PZ-DI
Brad Madix signed on for his fifth full tour as front-of-house engineer for Rush this past year, and for the first time, the iconic Canadian progressive-rock power trio would have a string section perform on stage with them.
"I'd worked with strings in the past, but it was always either in a very quiet setting with minimal sound reinforcement or the violins were strictly electric," Madix explains. "On Rush's Clockwork Angels tour, the band definitely meant for the strings to be featured and acoustic. The main challenge was going to be fitting pickups to the instruments without tampering with them too much and getting a great sound with maximum isolation—all in a high-gain environment."
With the strings being placed directly behind Neil Peart's drum kit, Madix had to rule out miking the instruments as a section or even individually. He opted instead to use bridge mounted pickups on most of the instruments: "We wanted to avoid any involved install on the instruments, hoping to find a solution that simply clamped on [as opposed to replacing a bridge or gluing something to the instrument]. There were a few different solutions available, all of which amounted to some version of a piezoelectric pickup mounted to the instrument in one fashion or another.
"That's when things got a little dicey," Madix continues. "All of the piezoelectric pickups are very hi-Z. In fact, our first choice topped the list at 10 million ohms! Obviously we were going to need a DI for these and it was probably going to have to be an active one, and even then not just any was going to do the trick. When I started digging into which would make the best solution I was not surprised to find that input impedance specs on DIs are generally a bit lower than we were going to need. We found preamp solutions, but they offered too many bells and whistles for my taste. We just wanted to get the signal to the consoles in the best possible shape."
Madix had resigned himself to having something custom-made when he sent over a note to Radial President Peter Janis.
Janis explains: "When Brad contacted me, I told him his timing was impeccable! We had been having conversations with a few other acoustic artists and noticed that there was a definite need for a DI that would sound good with piezos. The challenge is that unless the pickup sees a very high input impedance, it tends to sound peaky and edgy. We had just finished building a prototype and I sent him the first one to play with. The PZ-DI can be set to 10 meg ohms to address this and has a built-in highpass filter to eliminate resonance, which can cause runaway feedback. After Brad did some tests, he was pleased with the results and we sent them a bunch more."
The Clockwork Angels string section complement of six violins and two cellos is all run through Radial's newest addition to its line of DI boxes.
Madix continues: "With the PZ-DI, we were able to integrate multiple piezoelectric devices seamlessly and with glorious results. Anyone who is just plugging a PZ transducer into any random DI and hoping for the best is probably missing out on much better tonality and dynamic range. It's nice that there are passionate designers and engineers out there paying attention to these details. Radial has once again proven they are a cut above the rest."
Madix's toolbox for this tour also includes some other key Radial gear. "We have Radial DIs everywhere—keyboards, drum electronics, samplers, guitar effects. They are all over the stage! Also, we are using the SW8s for switching to redundant backup systems on the tour."