Decoder™ Development

When the Radial R&D Team first discussed building a dedicated mid/mide matrix, we debated whether or not a device like this was needed. Engineers have been using recording consoles to track M/S for years, and today workarounds exist in the digital domain as well. So we started talking about mid/side recording with various engineers, and soon discovered that they loved the idea of a simple M/S interface. Less people are using analog mixers, and digital tools don't have the same feel. A plug and play box with quiet preamps would save time (and channels!) while recording in the studio, or in the field.

Microphone preamp

The first step in building the Decoder was to develop a set of quiet, yet powerful microphone preamps. To this end, we borrowed the design from the 500 series Pre-Max™. Three preamps were added to the Decoder overall, with one dedicated to the source (MID) microphone and 2 preamps dedicated to the side microphone. Traditionally the SIDE microphone in M/S needs to have a figure-8 polar pattern, but an extra preamp would allow the user to experiment with stereo pairs of cardioid or omnidirectional mics, and different spacing techniques. A switchable 180° phase reverse switch was added to the 3rd preamp to allow for the same Sum-Difference M/S processing, regardless of microphones being used. We felt this would give the engineer limitless options for unique M/S stereo mixes. 48V phantom power had to be individually selectable for both mid and side so it could be used with dynamic, condenser, or fragile ribbon microphones. High-pass filters were also considered mandatory to reduce low frequency rumble while tracking.

Decoding the Mid and Side

Next came the stereo M/S matrix. We wanted the Decoder to do all the tedious stuff for you. Duplicating the side mic, panning, and reversing the phase needed to happen automatically in the box. By keeping controls at a minimum, one would need to simply adjust the three level controls to set the desired stereo image.

Reamping™ pre-recorded tracks

While recording in M/S is great, Reamping pre-recorded signals through an analog mid/side matrix can give the engineer a lot of different options during the mix-down. After performing various listening tests we concluded that the Decoder must allow both Mic and Line level inputs for even more versatility. Each channel can be individually switched to +4dBu line level, and the user can Reamp up to three channels. With the Decoder you can record a figure-8 SIDE mic while tracking, or experiment with any stereo mic combination later on.