Recording - January 2021 - 72

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Stay safe, and
keep it clean!

Guest editorial by Scott Dorsey

Over the past year, traditional studio work has been made
difficult. Conventional stage performances are almost impossible, but the music hasn't stopped. We're now witnessing a new
stream of online video performances that borrow techniques
from both studio and stage. As musicians, producers and engineers return to working together, everything is different, and
we need to keep things safe and clean.

Masks

Masks dramatically reduce viral transmission. [1, 2] However,
in the studio it's not possible to wear a mask all the time. Several
companies are now making bell covers for brass and woodwind
instruments. Also, some face masks are constructed with slits to
permit an instrument to be played while acting as a functional
facemask at other times. A single-layer mask has been observed
to block about 60% of particles without significantly reducing
sound quality; two layers block about 75% with some drop in
sound quality, and three layers block 92% but with a substantial
loss in sound quality and difficulty for the player. [3]

Gobos

Gobos are common in the studio and on stage to block
sound, and they also block airflow. Transparent plexiglass gobos are easy to sanitize and permit performers to see one another, but they dramatically affect the sound. They are sonically
reflective, create small areas of standing waves, and block
higher frequencies. That said, they can be a valid option.
A separate control room or booth isolated from the main
room keeps air particles in one place, but it also concentrates
particles in that space. So, please keep the posse out for now.

Pop Filters

A pop filter has always been an excellent way to keep a
microphone clean and prevent schmutz from building up on a
vocal microphone. This includes cheap foam covers for handheld mics, to hoop pop filters used with large diaphragm microphones. Those big hoop filters also keep the vocalist back from
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the microphone, which keeps possible contamination down
and almost always improves sound quality.
Pop filters are easy to clean and disinfect; some of them can
even be run through the dishwasher, and most can be sanitized
with an alcohol-based sanitizer or a benzalkonium chloride
sanitizer without harm.

Clean Microphones

One of the best ways to deal with mic contamination issues,
especially live, is to assign one microphone per performer and
don't change them.
Surface cleaning is critical. I am a massive fan of benzalkonium chloride-based sanitizers, which are very popular in
hospitals, usually don't contain alcohol (which can damage
lacquer finishes), and are readily available and effective. [4]
Put the sanitizer on a cloth, and rub the microphone grille
and body down. Don't spray the microphone! Even a handheld
mic will eventually get gunk on the diaphragm if you spray it.
For mics with removable grilles and pop filters, take them off
and clean them more rigorously. Foam covers can be immersed
entirely in a sanitizing solution. The balls from an SM-58 and
Sennheiser 431 can even be run through a dishwasher-I've seen
it done for decades at folk festivals with no apparent damage.

Ultraviolet

Hospitals have had great success with UV sanitizing, and many
broadcasters are following suit. For example, Univision has been
using a UV sanitizer on microphones. For one live event, Univision
set up an elaborate process to deal with wireless mics; a gloved
assistant would pick them out of the storage bins, wipe them down,
UV sanitize them, and put them in a sealed bag to go to the performer. Then when they were returned, the same process was done
in reverse. Of course, UV does not penetrate; it only deals with surface contamination. It also may degrade foam and some plastics.
Conclusion
Sanitize your gear effectively and vigilantly. Getting everyone to take the whole thing seriously is probably our number
one priority at present.
Scott Dorsey (dorsey@recordingmag.com) is a live sound and
studio engineer, reminding you to stay safe, keep your distance
and keep your gear clean.
References:

[1] Community Use of Face Masks and Covid-19: Evidence from a Natural
Experiment of State Mandates in the US. Lyu and Wehby. Health Affairs, 39(18).
[2] Lack of Covid-19 Transmission on an International Flight. Schwartz, et al. CMAJ
192(15) E410.
[3] Aerosol Generation from Different Wind Instruments. He, et al. Journal of Aerosol
Science. September 16, 2020 (online).
[4] In-Vitro Virucidal Effect of a Benzalkonium Chloride Hand Sanitizer
on Coronavirus. Bondurant and Jackson. Journal MSMA, 61(6/7).

Recording - January 2021

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