Sonic Union announces promotions & new hiring
July 14, 2021

Sonic Union announces promotions & new hiring

NEW YORK CITY — Sonic Union ( has promoted sound designers/mix engineers Kelly Oostman and Michelle Kerzner, while also adding sound designer/mix engineer Rob DiFondi to the company. The trio join a team that specializes in creative sound production for advertising and entertainment. 

Photo (L-R): Kelly Oostman, Michelle Kerzner and Rob DiFondi

“Our very reason for being is to help our clients deliver projects at the highest creative and technical level, and the pandemic provided an incredible lesson in making rapid change to meet them in every moment,” says Steve Rosen, co-founder & sound designer/mix engineer. “It was also a year that showed the strength of relationships, both our clients and the team, despite not meeting in a room.”

Oostman has spent the past four years at Sonic Union, working on projects such as Anomaly, a podcast she sound designed and mixed, which was featured in Tribeca Film Festival’s first-ever Podcast Selections. She also provided sound design for the indie feature Give or Take, and handled recording, sound design and mixing for the musical feature A Trip to the Moon.  Some of her commmercial credits include work for IBM, Comcast and Smart Water, among others. 

Prior to joining Sonic Union as an assistant engineer in 2018, Kerzner was at Beatstreet in New York and Apex Post in New Orleans. At Sonic Union, she has worked on a variety of projects, including a recent Summersault campaign about female empowerment, and A Song of Grace by Arielle Knight, a film that premiered at Tribeca 2021. In addition to her mixing and sound design work for advertising clients, like Dove, Heinz and Catholic Health Services, she recently voiced a Chase campaign, and is part of Sonic Union’s casting department. 

DiFondi’s vast experience includes successful tenures at AudioEngine and Sound Lounge, working with a variety of clients to deliver audio that enhances narratives and engages audiences. Having worked in the industry for nearly 20 years, DiFondi’s credits include work for brands such as M&M’s, Calvin Klein, Chobani, and Dunkn’ Donuts. 

“I am excited to join Sonic Union for a variety of reasons,” says DiFondi. “We share a common appreciation for the people-driven nature of the industry. They place great emphasis on fostering community, even as they’ve embraced the idea of remote and hybrid collaboration which feels very forward-thinking. They do all of it with a feeling that’s down to earth and true to who they are as a group and as individuals.”