I just now read the product manuals for HF's various hearing protectors. The
$2 red ear muffs give only 2 db reduction @ 125 hz while their
foam earplugs are 38 db reduction @ 125 hz. (All the strings on a bass guitar are below 125 hz for comparison.)
What I read confirmed my experience of these products, that the $2 muffs weren't adequate to prevent fatigue from my clanky 24 hp 2 cylinder Yanmar. I've described its sound as 'sledges hammering on a manhole cover'; an overwhelming and tiring pounding if I use the backhoe just above idle all day. (Higher rpm is hardly better just higher frequency).
I looked at some of the other manuals.
The
earplugs-on-a-string are only 1 db @ 125 hz.
$6 red ear muffs, the ones some users say have a too-small headband: -5.43 db reduction @ 125 hz. Negative!!! Maybe an echo chamber? But it has good numbers at mid-frequency.
$10 yellow ear muffs: 9.6 db reduction @ 125 hz and excellent numbers at mid-frequency.