[robmiller]

I am an acoustics consultant who designs buildings with architects, then sees them through construction. Doors intended to isolate noisy rooms regularly underperform, whether due to manufacturing or installation problems. Lots of fingerpointing when we call it out on project sites, and having a camera show the weaknesses due to the perimeter gasketing, frame, door leaf, or wall construction surrounding the door would provide the necessary visual for contractors to see the problems we are pointing out.

[martyvis]

I wonder how many building projects use and engage acoustic engineers (unless sound is specific to the use like for theatres or conference facilities)?

I had the "opportunity" as a patient in a very new hospital wing some 7 years ago for about 13 days. While I had a private room, the door was always open to the walkway, I guess as is normal to allow quick response by medical staff. But at one point I really felt overwhelmed by all the external noise that I could hear from the other rooms in the ward, nurse stations, and so on. I really felt that the hard surfaces and even the angular nature of the floor layout was conspiring against me - almost focussing noise into my room. I imagine given enough data you could show the poorer rest of patients prolonged their recovery period and hence increased bed occupancy and cost to the health system (important in a state run public hospital service that is predominant in Australia).

As such it would be nice to think hospitals, schools, offices would include thorough acoustic assessment to at least allow appropriate mitigation of noise during design (before having invoke more active measures like soft furnishings, etc).

[robmiller]

My response is US-centric, but most hospital projects do have an acoustics consultant involved. Improvements have been made, but not nearly enough. Challenges include the need for sound absorption to be porous, but this is at odds with cleanability. Increased focus has been on patient room doors, which are increasingly sliders. They work well when they're closed, but the challenges include getting a good bottom seal when the threshold has to accommodate beds and equipment being rolled in and out. Hospital equipment manufacturers are also improving the sounds of their equipment, away from the cheap piezo beepers.

Schools very often have acoustics reviews, although more often in cities than rural areas. Classrooms in addition to auditoria, gyms and common areas. Standards exist for those too.

Office buildings are hit or miss. The developer may hire us for a base building review. Tenants' architects hire us as they design their workplaces. There's a lot of push and pull to find a balance of the modern open ceiling industrial aesthetic and glass conference rooms with reasonable acoustical goals.

[cameron_b]

Some, but Not enough

Working in conference rooms, people far too often are concerned about the look ( big windows, natural light, great table ) and less concerned about acoustics than would be reasonable. In my experience, Architects think people just sit around the table, and chat.

I once had a brand new office upfit project with a "flagship room" that was a large flex space, (could be a board meeting, could be a hackathon). There were three sides of glass, a concrete floor and metal ceiling structure. If you clapped in the room, it could be heard for 1.5 seconds as it bounced across all those surfaces before decaying.

My bosses were furious at the microphone quality, the installer was unhelpful and bailed on us. We hired a consultant to perform an evaluation and he told us that the room was awful, with lots of numbers ( figures for acoustic reverberation at different frequencies ) and told us of certain products that could help in those ranges.

It is a lot easier to design rooms with acoustic features than it is to retrofit them in terrible sounding rooms.

[loxias]

I think you're talking about a different problem, though that one could also be helped with the right tool.

After setting up the array, once could answer questions like "where is that darn squeak coming from!", and even characterize the undesirable noise, both spatially and spectrally. You could also measure how effective noise isolation materials are, but I don't see what the spatial information gets you.

However, if weaknesses due to "perimeter gasketing, frame, door leaf, or wall construction" result in some sort of localized noise, then a system like this would certainly pinpoint it.

[robmiller]

Yes, this is in reference to noise passing through a door that is localizable. Typically we would play pink noise (broadband, equal energy per octave band) on one side and listen for "hotspots" on the quiet side. I would wonder about the precision of being able to tell in the image the contribution of the door frame from the perimeter gasketing.

Acoustic cameras like from Noiseless Acoustics are on the market though they seem to be marketed to industrial customers. There are similar mapping systems using a scanning mic like from Soft dB.

[loxias]

Ah! In that case yeah, this tech could possibly help. At least, I'd love to give it a shot! (I hope you don't mind an email from me later...)

It's sensitive enough to noise that I can pick up (and locate) the air vents in a room, even when the sound is at the threshold of hearing. Noise (pink and white), and even more so MLS (maximum length sequence) really "jumps out" (it's very obvious), well below my threshold of hearing.

There's so many interesting areas of research I've never had the time/money to fully investigate. I'd love to play with an "active" system, not just "passive", with a goal of experimentally finding modes of resonance of objects in a room.

I bet once can tell the relative contribution to noise of one physical object over another, but I don't know enough about construction to know if one would be able to separate the door frame from the perimeter gasketing. You do need line of sight for it to work. At the least, you'd have a way to quantify the sound leak, with numbers and reproducibility.

FWIW the Noiseless Acoustics camera costs ~$18k(!)