For example: “Suppressors reduce muzzle blast noise by up to 30 dB. ” — a Glock 17 9mm un’supressed is ~167 dB….167 – 30 = 137 dB supressed (if supression is 30 dB). The pain threshold level starts at 140 dB for about 50% of the population and about ~130 dB (depending on age) for about the rest of the population. But because you do not feel pain does not mean hearing damage is not happening because immediate permanent damage to some degree (even if not noticed until later in life) starts about about ~70db in the majority of the population with steady state noise, and can happen at a lower level at ~40 – ~70 dB with repeated impulse noise exposure over time.

suppressors are not ‘hearing protective’, they are ‘protective help’ by reducing the amount of sound level – you should also wear other hearing protection when using suppressors and they indicate that with “Their benefit is additive when used with ear-level hearing protection devices such as circumaural muffs or ear plugs.”