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jeremycox 10th August 2020 12:10 PM

Pink fiberglass batt over drop ceiling to reduce ambient noise in restaurant
Hey, hope everyone is well.
I'm involved in a project renovating a charity owned restaurant, and we're trying to determine the most cost effective way of reducing the ambient noise level for the comfort of patrons. The floor is concrete, the room is around 3200 sq ft and the drop ceiling is approx 16' from the floor. My first intuition is that spreading r30 above the drop ceiling would be quite effective but i'm unsure how reflective the cheap ceiling tiles are. Presumably even cheap tiles have been engineered to be somewhat absorptive at mid and high frequencies.
Upgrading to an acoustic grade ceiling tile like Armstrong Calla is quite expensive ($5+ a foot). R30 is under $1 a foot.
Anyone have any experience with this type of installation? I've also seen egg-crate type acoustic foam installed under tables at fancy restaurants, but i image this would generally have a lot lower effectiveness and be more prone to failure.

Thanks in advance,

Jon Best 10th August 2020 12:29 PM

Others will chime in, hopefully, but my initial thought is that R30 over the existing ceiling is a fine idea for low mids and lows, but that I am not sure it's going to make a huge difference in the "intelligibility" mid/high mid range, since that'll be dictated more by the reflectivity of the surface, whick you're not changing. Fabric covered OC703/SNS panels in strategic places? usually has larger quantities of B stock acoustic fabric at deep discounts, maybe tailor made for this kind of situation.

Grovestand 10th August 2020 01:49 PM

I think R30 would reduce low-mid ambient noise reflections, but if there are HVAC mechanics in the drop ceiling, that might or might not help with that issue. Also, if the ceiling tiles are reflective at the frequency of the noise then it wouldn’t be helpful.

I think that the primary acoustic purpose of ceiling tiles is to provide privacy in office spaces where partitions do not go all the way to the real ceiling.

To that end their acoustic characteristics usually concern the reflection and absorbtion of the voice range.

Can you get a sense of the frequency range of the ambient noise?

My random guess would be that you could swap half of the ceiling tiles with fiberglass and probably improve things. I’m not sure I would want to deal with a fabric ceiling in a restaurant... yuck.

ejbragg 10th August 2020 02:41 PM

I can appreciate the “yuck” factor toward fabric on the ceiling, but replacing every other tile still seems pricey. Maybe some cheaper replacement tiles would do better; if they’re newer, maybe they’d have less reflective junk (oils, etc.)?

Although if you decided you still wanted to install cloth-covered clouds, a lot of scotch guard (or similar protectant) might help keep them clean. This still seems the most effective answer, although in the end, you may not save a lot of money, after all.

Jon Best 10th August 2020 03:20 PM

Just to be clear, I was thinking about strategic fabric panels NOT on the ceiling, since the ceiling probably does an at-least-mediocre job of not reflecting too much, and it's likely the problem lies somewhere else... :)