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Station Renovation’s Sound Solution

ST. PAUL, MN—Twin Cities Public Television (TPT) is putting the finishing touches to its 105,000-squarefoot headquarters in downtown St. Paul, MN, where a $20 million renovation is almost complete.

ST. PAUL, MNTwin Cities Public Television (TPT) is putting the finishing touches to its 105,000-squarefoot headquarters in downtown St. Paul, MN, where a $20 million renovation is almost complete. As post production engineer Bob Sturm and the rest of the facility’s audio and engineering staff moved into their new audio control room, one remaining challenge was how to treat the acoustics.

“Television audio is always a compromise,” comments Sturm. TPT may be the top-rated public television station in the country, as it just recently announced, but as a non-profit organization in the Public Broadcasting Service, it has to make every dollar count. “A lot of times, you make do with the money that you have,” says Sturm, a 30-plus-year veteran with TPT.

The new audio control room at Twin Cities Public Television’s renovated headquarters includes a Calrec Omega console and extensive RealTraps acoustic treatment. Happily, there was a solution to handling the room flutter and low frequency build-up: “There was some bond money, so we could do some acoustic treatment.”

A friend offered some pieces of RealTraps treatment and Sturm and the crew jumped at the chance. “I didn’t know about RealTraps until then. I thought this could really make a difference, so I ordered more to match up with what we had.”

More than a dozen semi-reflective MiniTrap bass traps cover all four walls in the control room. A floor-to-ceiling stack of MegaTraps, which use proprietary limp mass membrane behind the front fabric to provide maximum absorption at bass frequencies, sit in each of the two front corners. A pair of Diffusers, which marry a high-performance bass trap with a QRD “well” diffuser, effective down to the low mid-range, are affixed to the rear wall.

“It’s both visually and aurally pretty nice stuff,” he reports. “Having that metal frame makes them a little heavier, but it makes them easier to deal with. You’re not trying to glue boards with construction adhesive onto drywall. You’re working with something that you can rearrange if you want to.” Sturm has also treated the facility’s two Pro Toolsbased audio sweetening rooms with the panels.

The control room is tied into two studios—one 80 feet x 52 feet, the other 50 feet x 50 feet. The room features a 56-frame Calrec Omega console loaded with 48 channels and a surround spill panel. The two sweetening rooms are also set up for surround, he says, “Although we do very little surround.”

The audio mixers especially enjoy mixing the musical segments, he says. “Most of the audio guys here were band people at one time or another,” says Sturm, who grew up in Nashville and went to film school. “A couple of my neighbors were session players, so I ended up at a lot of studios, but never thought of it as a career. But I realized I was pretty good at listening; I know how things should sound.”

The TPT control room is responsible for producing Almanac, an award-winning public affairs show featuring a mix of news, politics and culture—including music—that has been running for 30 years. Minnesota Original, a weekly arts show focusing on the local community, also features music.

All the audio engineers try and perform the best live mix they can as it’s initially laid down to the AJA Ki Pro, says Sturm. “We have Pro Tools Light, but we’ve started tracking with Reaper. We have a [Calrec] Hydra IO in the studio and we MADI to a Mac running Reaper. Then it gets polished in one of the two Pro Tools sweetening rooms. We take pride in being able to go into post and really tweak it and get it right, and treat all the instruments correctly.”

There is more music at Christmas, says Sturm, when TPT produces choral concerts by a local college, St. Olaf ’s, which is uplinked live to theaters. “We also track that in the truck and make a DVD. We now do three or four different local college choirs. We love the fact that we get to do music here because of what we’ve all done growing up. If we were working at one of the news stations, we wouldn’t get that as much,” he says.

“We do some really interesting things here; that’s why we’re all still here.”