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Metric Halo gear used with new XYtri surround mic technique

The compact size of Metric Halo’s eight-channel Mobile I/O 2882+DSP and two-channel ULN-2+DSP interfaces have been of significant benefit to Andrew Levine, a location recording engineer based in Hamburg, Germany. Levine, who is founder of Blumlein Records and developer of the XYtri surround mic method, carries his entire recording setup with him, making reliability and portability as important as pristine, high-resolution audio. He also owns a pair of Metric Halo’s flagship ULN-8s.

Levine records everything from orchestras, small ensembles and vocal groups to more avant-garde music, jazz and spoken word. He says that he has always had the idea of recording in surround in the back of his mind, leading to the development of the XYtri mic setup.

His XYtri method solves the problem of reliably monitoring surround with headphones, and maps discretely to a 7.1 environment by extracting sum-and-difference information in the front-most channels. It also folds down to 5.1, stereo and directed mono, he says. “Most people doing location work don’t have a separate room where they can set up a monitoring system, and I can’t lug around that much stuff. So I was thinking of what I can do to make surround recordings that I can monitor with more confidence. I thought maybe I could have a Decca tree, but using three 45-degree XY pairs. You have three XY perspectives, and you also have these runtime stereophonic perspectives, one facing frontal left, one frontal right.”

He continues, “This is where the Metric Halo interface and the 2d mixer come in. It’s so flexible to set up a matrix while you’re auditioning stuff, even if you do it from scratch, and also while you do a downmix. While you’re setting up or recording, you can monitor each microphone pair separately. This way you can listen to all the different angles and you know that every angle is OK, which you can’t do for setups that are not based entirely on traditional stereophonic configurations.”

The improved, flexible routing matrix functionality in the new Metric Halo 2d upgrade also allows a stereo downmix to be generated and recorded alongside the individual mic inputs, he says, although sometimes a little rebalancing is required after the fact. “I use SpectraFoo [Metric Halo analysis software] as an extra aid. There are some things like power balance that you can’t judge reliably with headphones — really small things where I pull down one side by a decibel or half a decibel in the studio. But on more than half of the recordings that I do, I already have the stereo mix finished at the end of the performance.”

Symmetry is very important to his recording technique, Levine says, which aids the surround-sound mix. “If I have a mic 30 degrees on the left, I might have an equidistant spot mic 30 degrees on the right side of the axis. So the positions and runtime delays are symmetrical to the central setup. That enables me to do orchestral recordings with no more than eight microphones. If the acoustic space is less than ideal, I feed the back-facing pair of microphones on the left and right of the XYtri to Altiverb and generate a very nice reverb to fill in the back.”

The routing matrix within the Metric Halo software additionally streamlines the workflow when Levine brings the recordings back to his mix room. “The monitor controller within Metric Halo maps my analog line-level outputs onto the physical studio layout, controlling interchannel gain with 0.5dB accuracy, and all DSP processing occurs with nearly no latency. It’s very, very easy to use,” he says. “I have templates to do mixes from the XYtri to stereo or 5.1 or quadraphonic. If I place the XYtri setup inside a curved ensemble, I can unfold the soundstage then pull it out, and this maps into a 7.0 or 7.1 setup.”