Put briefly, researchers blasted guinea pigs with 102 decibels of music for 4 hours. They found that while both the compressed and non-compressed test tracks caused temporary damage, the compressed variant made the damage longer lasting, suggesting that there's more to ear damage than just the loudness.
From this, what I would take away is not necessarily that compression on its own is harmful but that... there's almost certainly more to ear damage than just the loudness, and compression is one way this can exhibit through. So I'd say the title and angle of the article is a bit misleading.
Naturally, when I say compression I mean it in the audio effect sense, as they do in the article.
It’s possible their compression settings were actually exaggerating the peaks instead of compressing them, and then they did nothing to control those peaks afterwards. This is a really common thing that can happen with a superficial use of compressors. Especially if you did averaged loudness-matching of the compressed signal with the uncompressed signal. It ends up being spikier than before compression. I would entirely believe a waveform with those added spikes would be more damaging than a controlled waveform that had been saturated or limited after compression. I don’t have access to the original publication, so I can’t check and find out.
Or in short (as every modern producer already knows): Put a limiter on that!
Actually, put a limiter everywhere - if you work in software, they're real cheap..
My Bitwig template: limiter on master track. My Renoise template: limiter on master track.
Now I have no fear of loading random presets.
Unless I understand compression all wrong, isn't the point to make the quiet parts loud? So in one case you have a song peaking at 102dB and in the other case virtually the entire song is that loud.
It's already known that hearing damage is cumulative, longer exposure to loudness is bad, so it seems like a common sense result in line with all existing research.
The pre-compressed and compressed versions were loudness matched to be the same overall loudness, according to the description. My guess is that they set the compressor to actually make the waveform spikier, without fully understanding what’s going on. Just a guess, though. I can’t check to find out.
If the damage is caused by overpressure, then obviously compression will deliver more overpressure for more time, i.e. a higher total transmitted acoustic energy. I didn't read the article because of paywall, but did they normalize by acoustic energy?