For our tests, we performed both subjective and objective assessments. First I assembled a four-person panel (including Brent Butterworth and myself) that covered a range of ear sizes: One panelist generally finds that small tips fit her best, another prefers medium, Brent prefers XL, and I prefer large. Over the course of several weeks, we wore the best earplugs for musicians during a variety of activities, including trips to loud bars, music rehearsals and performances, group exercise classes, and concerts.
Each panelist evaluated the different earplugs based on several performance traits:
At the end, each panelist reported back, detailing each earplug set's pros and cons, as well as choosing their favorite.
As the resident audio experts, Brent and I also spent some time listening to music we know very well at maximum volume through over-ear headphones while wearing the earplugs. This process enabled us to separate out the specific sonic effect of each earplug and removed variables such as the EQ of speakers used at a club or the soundboard settings. Since we knew these tracks in detail, we could suss out the differences much more clearly.
In addition to doing the hands-on testing, we wanted to gauge the attenuation of each earplug in an objective way that took the human element out of the process. To measure the performance of the earplugs, we used the same technique commonly used to measure the performance of noise-canceling headphones. Brent used the same device he uses for almost all of his headphone measurements: a GRAS 43AG ear and cheek simulator, equipped with a KB5000 simulated pinna, which represents an average human earlobe shape. A test microphone inside the ear and cheek simulator picks up whatever sound comes into the ear.
He played pink noise through four speakers positioned around his lab, plus a subwoofer, at a level of 85 dBC. By measuring this sound at different frequencies using TrueRTA audio spectrum analysis software and then making the same measurement with an earplug inserted into the KB5000 pinna, he could see how much sound each earplug blocked at different sound frequencies. (For reference, most airplane cabin noise spans about 100 to 1,000 Hz, and the human voice spans about 150 to 3,000 Hz.)
You can see the results in the chart below. The lower the line is on the chart, the more sound the earplug blocks. (We included a set of custom-made Microsonic earplugs for reference.) In a perfect world, the result for each pair of earplugs would look like the red dotted line: It would run straight across at the manufacturer's stated reduction level.