I first became aware of Nureva’s “microphone mist” technology when I watched a promotional webinar that featured raves from some of their customers. Apparently a single soundbar, mounted high on a wall, could pinpoint and clearly capture people speaking anywhere in the room. I had to check it out.
The HDL line uses sophisticated acoustic modeling and audio processing to place hundreds of “virtual microphones” out in the space. At least that’s how it’s described. Needless to say the processing is serious, and it’s not necessary to understand the math to appreciate the result. Nureva supplied an HDL-310 for evaluation, which is recommended for rooms up to 30x30ft. Several other models are available for larger and smaller spaces.
The setup was easy and fast, as the soundbar itself is connected to a small processor via a single CAT cable. The processor powers the soundbar and provides USB, network, and analog audio connections. Correct placement of the soundbar is important but not difficult to accomplish. The unit comes with a simple guide that shows acceptable and unacceptable orientation in the room, and the soundbar has (helpfully large) keyhole slots on the back for hanging.
Once mounted and connected, upon first turn-on the unit plays some audio test signals to analyze the room conditions. The setup test can be repeated if conditions change significantly, but the HDL also performs adjustment continuously as it operates. A light on the soundbar indicates system status.
A QR code on the processor can be used with a phone or tablet to enroll the unit in the Nureva Console cloud, which allows remote adjustment of various mic, speaker, and processing settings, and activates a few specific features. Cloud-based management could be useful for a large deployment, but for simplicity I preferred to use the Nureva Console Client local app (Mac or Windows). With the larger HDL410 it’s possible to get a visual display of the sound sources being picked up in the room, which would be very cool.
Field Testing
To do some testing, I installed the HDL310 in a medium-sized classroom belonging to one of my clients. The main unit was mounted in the front of the room, but off to one side of a central projection screen, at about 10 feet high. This was considered one of several acceptable locations in the setup guide. The processor was connected to a local computer via USB and was seen by Zoom as both a “mic” and “speaker” device. However, my client preferred to use their distributed ceiling speakers, rather than the HDL’s speakers. When we did use the HDL speakers in a test, they sounded fine, but not surprisingly, didn’t cover the room like those in the ceiling.
Over the course of several months the room was used for hybrid classes with varying numbers of on-site students and instructors. Feedback from the teachers was very positive, but my attempts to listen in to the hybrid classes were a bust. Sometimes there weren’t enough people in the room, and other times I was pretty sure the HDL had not been selected as the Zoom mic. Ultimately, with help from the school’s AV staff, I ran some specific tests on site. We dialed up a Zoom meeting and I connected on a laptop from a remote location in the building. As people moved to different parts of the room, I could converse with them and directly hear their voice quality.
What I found was that anyone, speaking anywhere in the space, would sound a bit distant at first, but after about a second their voice would “lock in” with clarity and no appreciable room tone. That was interesting! Nor were there any acoustical echo problems from my remote audio coming out of the ceiling speakers (though I cannot say how much AEC was being done by the HDL and how much by Zoom). Hearing people anywhere in the room as though they were “on mic” was impressive, and that is the point of this technology.
We also did an alternative test using a portable system with two round desktop mics on a counter near the front of the room, which is what had been used previously. As expected, the desk mics did pick up everyone to some degree, but distant people were not nearly as clear, and with obvious room tone in their sound.
While writing this review I also set up the HDL310 in my home office so I could play with the settings and do some other tests. The space is about 12ft wide by 20ft deep, with an 8ft ceiling, full of furniture and stuff. I mounted the HDL on the back wall about 6ft off the floor. This setup was both less than ideal, based on Nureva’s instructions, and not much of a challenge in terms of covering a space. Using Zoom as the UCC platform, as expected the Nureva did a fine job picking up spoken audio from various places in the room (and even down a hallway).
I spent quite a bit of time trying different noise reduction settings in both Zoom and Nureva Console to see how they interacted. To be honest, in this particular situation I found that Zoom did a better job of removing background sounds (including fan noise and impact noise) while also maximizing the voice audio. It’s possible that Nureva’s algorithms would be more effective under more sensible conditions. The real takeaway here is that installers should be aware that processing can occur in multiple places and may need to spend time optimizing the settings. I cannot say how this would work with Microsoft Teams or other UCC platforms.
The HDL has analog audio I/O for limited functions, including a “voice amplification” feature that allows voice-lift through the unit’s speakers for a directly connected mic. The main application would be to amplify a lecturer or presenter for the audience; it does not currently amplify audio from the virtual mics. Lastly, Nureva’s online resources are fairly extensive, with lots of specs and guides for setting up the various models.
These products are not inexpensive, and they don’t magically cure all the sonic ills of conferencing audio. But being able to pick up participants anywhere in a room, particularly a large room, is often a real challenge. The Nureva HDL line aims to address this problem in a new way, and do it with a simple, unobtrusive, mic/ speaker combo on the wall. These are well worth considering for appropriate applications.
Many thanks to David Currie and the staff of the Georgetown University School of Continuing Studies for their invaluable assistance!
