DEI Holdings, Inc. is the US parent company of several brands of consumer audio electronics and vehicle security/remote start systems.

DEI Holdings is owned by New York City and Boston-based private equity firm Charlesbank Capital Partners.

[1] In 2000, Darrell Issa was elected to the House of Representatives, and Jim Minarik replaced him as CEO.

[6] In April 2013, the company combined Polk, Definitive Technology and the Boom Movement brands into a new division called Sound United.

[9] In March 2021 Sound United LLC acquired Australia's leading importer and distributor of home entertainment systems QualiFi Pty Ltd. QualiFi Pty Ltd was the Australian importer and distributor for Blustream, Denon, Elan, Forte, Furman, HEOS, Jamo, Klipsch, Marantz, Niles, Stealth Acoustics, Sunfire, Thorens and Xantech brands of high-quality Home Entertainment components and systems.