The University of Massachusetts Amherst has instituted a mask mandate for the start of the Fall 2021 Semester. The mandate goes into effect today (August 11th) and will be reviewed in mid-September. During this mandate, masks will be required in all public indoor spaces which includes faculty members who are actively teaching. Making sure that you are clear in speech is critical, particularly in large lecture halls. To that end, Heath Hatch and I did some tests on various types of masks. I am posting the results here for folks’ reference.
Overview of the Mask Types
Mask #1: A Simple Cloth Mask
This is a simple cloth mask. I like these for simple around-town use as I find them comfortable and, due to their crush-ability, easy to carry around.
Pros:
- Comfortable (at least for me).
- Easy to breathe.
- Easy to wash.
Cons:
- Falls off your face when talking!
- Some people find the closeness to the face uncomfortable.
- Only one layer of fabric.
Mask #2: A More Elaborate Cloth Mask
This mask has two thinner layers and a metal piece for the nose.
Pros:
- Stays on face while lecturing.
- Comfortable.
- Easy to breathe.
- Multiple fabric layers.
Cons:
None really.
Mask #3: A Cone-Style KN95
This is cone-shaped KN95 mask. The particular brand (no brand endorsement implied) is Bio-th which was permitted under the FDA’s Emergency Use Authorization.
Pros:
- Stays on face while lecturing.
- Stays away from face while talking, making articulation easier.
- Easy to breathe.
- Tight seal.
- Kn95 by FDA EUA.
- Folding makes it easy to carry.
Cons:
- The tight seal makes it a bit of a jaw workout to talk. Your jaw will be tired by the end of the day at first.
Review of Sound Quality
We tested the masks in the empty Hasbrouck 20 lecture hall. The lecture hall has a concrete roof and floor with brick walls and hard-plastic chairs resulting in a lot of echo. Given that the room was empty, we are not sure that the results will be representative when the room is full, but we cannot find that out until the students come back!
Summary and Recommendation
My Pick: Mask #3 – A Cone-Style KN95
This particular mask was the overall winner. The mask stayed on while speaking and the cone shape resulted in the clearest voice while using a microphone in the empty Hasbrouck 20.
Mask #1, the simple cloth mask kept slipping off the nose while talking and Mask #2, the more sophisticated cloth mask, had noticeably muffled sound quality.
Future work and mask equity
The opacity of the mask results in students obtaining less information because they cannot see the instructor’s lips. This is particularly true for Deaf and other students with hearing difficulties. I plan to try a mask with a clear window in the future to see if this feature works and its impact on sound quality.