“There also couldn’t be anything sticking up from the podiums and MPs don’t (and won’t) wear lavalier mics,” adds Geoff Maurice, Technical Sales Manager of GerrAudio. “Given the need for clarity and intelligibility, and for a product invisible to cameras in the House, Martin was searching for a very specific type of microphone in a form factor that wasn’t publicly available; and he wanted it to be a DPA solution.”
Van Dijk knew his specific mic needs required a high degree of cooperation from the manufacturer to create a truly custom solution that met the performance requirements. “That prompted me go to a brand with a proven ability to build something that provided studio-grade performance in terms of noise floor,” he says. “I knew DPA also wouldn’t just put one of its existing products in a different housing. The company really put effort into engineering this microphone, and GerrAudio helped facilitate that.”
The initial stages of the custom mic began with Maurice creating a prototype. “We started with a DPA TSM 4001 shock mount, which fits the existing cutouts in the millwork,” he explains. “I took one apart, cut some bits and pieces out of it, hot glued an existing DPA
4081 microphone inside of it, and added foam for dampening. The 4081 reduces the noise floor and increases rejection, which helped get the pattern we were looking for. Initially, I was concerned about changing the cardioid pattern by placing that element against a boundary element. But, after significant testing, we discovered that, rather than break apart, the pattern shifted upward off the surface, which worked to our advantage.”
To ensure all the Commons’ requirements were met, GerrAudio built a rough mock-up of the podiums to test the prototypes. “MPs typically speak from between the podiums, not from directly behind their own,” continues Maurice. “For redundancy, we mounted two microphones at the outer corners of each podium and turned them towards the outside of the podium to catch the speaker in the middle. After mounting the prototypes in the appropriate configuration, we ran the signal to a mixing console and recorded speech from different angles and heights before sending the recordings to Engineering Harmonics for further review.”