Going the Distance

Text:/ Derek Powell

BACKS TO THE WALL

Next, we reviewed the strengths and weaknesses of the chosen space. One side was lined with windows. On the plus side, the windows ensured a light filled space but could also provide contrasty, backlit video if we weren’t careful about camera placement. With the light in mind, we settled on a large bright LCD monitor as the main display. We kept the display wall and the main presentation locations opposite the windows. As there was a row of storage cabinets under the windows, we commandeered space in the centre of the wall for two, half-height equipment racks with a broad shelf above it on which to mount a control station.

To avoid backlighting, we mounted the two videoconference cameras on the window side, which allows for shooting away from the light. Camera locations were confirmed by spending time with a stills camera, taking shots of room zones we knew we needed to cover with the video cameras. It soon became apparent that mounting the cameras on the ceiling produced a ‘helicopter’ view of activities that resulted in unsuitable eyelines. Because of the windows, however, there wasn’t any wall space to mount PTZ cameras. The compromise was to pole mount our cameras above the benchtops at standing eye height, using custom manufactured ceiling pole mounts.

These cameras would be used for recording activities, but also (and crucially) for live video and web conferencing of the activities to remote students. To provide the correct eyelines for two-way conferencing we made sure the monitors that would show the ‘far-end’ view were located close to the cameras. These were fixed on swivel mounts so they could be easily adjusted to be visible regardless of where the teachers were in the space. The monitors were specified to be bright (450 nit) to allow for easier viewing against the light from adjacent windows.

EXPERIMENTAL AV

To film the experiments, we decided on two flexible and easy-to-use cameras. The first was the familiar ‘Ladybug’ style of document camera. Its bendable gooseneck head could be twisted to cover anything from benchtop experiments to test tube reactions. Larger-scale practical experiments on the vinyl floor area would be covered in the wide shot by the nearest PTZ camera. But we also wanted a close-up option. For this we decided to use a GoPro since it had higher resolution, good high or low light performance, and was small enough to be handheld whenever it was needed. 

All the switching between cameras and control of the PTZ camera presets was handled by a familiar interface on a 10-inch AMX touchpanel. To make it easy for teachers to be sure they had good shots of the action, any camera could be switched to the large 48-inch swivelling confidence monitors, clearly viewable from anywhere in the room. 

TEACHING TWO WAY

All would be lost, though, if we couldn’t provide good, echo-free, two-way audio between the classroom and the remote students. Audio problems are the most common reason that video conference teaching sessions aren’t effective, so we invested a great deal of design time to devise bulletproof coverage for any possible scenario. Shure Microflex wireless microphones formed the backbone of the system. Two Shure radio lapel mics were chosen to cover the teacher and demonstrator, along with a handheld mic – that was the easy part. To pick up discussions at group tables, we settled on three of the new Shure Microflex wireless boundary microphones while the rest of the space was covered by four ceiling-mounted Audix wired mics. Rather than conventional ceiling speakers, we chose to use ten  RMU105 speakers from the Bose RoomMatch range. Wired in five zones, these produced excellent, controlled coverage patterns along with great articulation of spoken word sources. A Biamp Tesira Forte DSP provided horsepower for mixing, EQ and the all-important echo suppression duties.

The care and effort invested by our integrator, Videopro, really made this AV design work, especially the time invested in tuning the audio system. During testing, we set up a three-way test scenario from our new space to an existing VC room and also to a typical student laptop in another room. We spent several hours testing from every part of the space and fine tuning both the speaker and microphone levels until we had a system that worked everywhere without needing constant volume adjustments.

IT JUST WORKS

All the effort in planning and testing really paid off when it came time for the initial training sessions with the academic staff. They instantly understood the familiar touchpanel interface and were already at home with using the document camera to show small-scale images. Even using the GoPro proved intuitive as they could hand-hold the camera and easily see the images on the confidence monitors. 

The best plaudits came when the teachers realised that the audio was genuinely ‘plug ’n’ play’. Simply clipping on a lapel mic and placing boundary mics at any of the group tables instantly facilitated natural real-time Q&A interactions for everyone. The sense of relief amongst the teachers was palpable as they realised “it just works!”