60% might be fine for consumer electronics, but this is /r/audioengineering. IEMs have much higher sensitivity, and typically lower impedance, so that's even more risk twice over. On top of that, the built-in amplifier can add 10 dB just 'cause. If you track at -6 dBFS (+3 dB) or turn it up to 60% (+6 ~ +8 dB) ( see graph), you're over the limit. At "half volume", that's 103 dB SPL full scale, and with 9 dBFS of headroom, that's 94 dB SPL. That gives us a max output of 105 db SPL + 4.8 dB + 13.6 dB = 123 dB SPL. One milliwatt into 44 ohm occurs at √(1 mW * 44 Ω) = 0.21 V, so 1 mW corresponds to 20*log(0.21 V/V) = -13.6 dBV, that 0 dBV is 13.6 dB louder. The SRH440 has 105 dB SPL / mW, and 44 Ω impedance. The Scarlett Solo has 7 dBu max headphone output, or 4.8 dBV, and less than an ohm output impedance (so no loading effect). (That and dBFS to clipping is never specified.)Įxample calculation. Even if that weren't the case, even at the extremely conservative -18 dBFS, the 131 dB figure becomes 113 dB SPL. So, mixing at 12 dBFS doesn't necessarily give you 12 dB more safety. I have ignored digital consideration since headphone amplifiers typically have enough gain that < 0 dBFS can still clip. That gives us 99 ~ 131 dB SPL, ranging from above safe to acute hearing loss. An A-law logarithmic potentiometer †, aka volume knob, has 20 dB attenuation at 12 o' clock (50%). An audio interface ‡ will have over 0 dBV output, but let's call it 0 dBV to be conservative. At 0 dbV, that is 119 dB SPL (min–min) to 151 dB SPL at 0 dBV (max–max). Link to article.Ī high sensitivity †, low-impedance †, circumaural ‡ headphone has a sensitivity of 95~115 dB/mW and impedance of 16 ~ 64 Ω. ![]() Safety advice that can cause injury in common circumstances is terrible advice.įor reference, the CDC exposure limit of 94 dB is safe for an hour. If you still think it's terrible advice, you've probably already damaged not only your ears but also your brain. The rule isn't meant to encompass your myriad of audio devices and define their technical limits, it's meant to caution people about damaging their ears and I think it works because the ears are a funny thing that are far more sensitive than we think because we can't just turn them off like we can close our eyes and we don't use them with great impact like we do with our feet while running.Įar damage is a very elusive thing, so that's why they made the 60/60 rule. Many people know an hour is not that long and 60% of anything is just over half. This is why it's a percentage AND a time frame which both are easy to comprehend. However, it's not MY rule, it's one of those formed by doctors and scientists, not to define any sort of technical boundary, but to simply raise awareness of the dangers regarding headphones. I kinda think so also, which is why I only wear them for a maximum of 10 minutes and keep my volumes low enough to still hear my surroundings. Headphones are easily the most unhealthy habit musicians have and its just made worse because the habit is so widely accepted. ![]() Personally I only wear headphones for 10 minutes at a time and keep the levels low enough that I can still hear what's going on around me.that's yet another thing no one grasps: if you can't hear your immediate surroundings, your brain severs its connection to sound and more or less considers you deaf. When you wear headphones and music is pumping, the bacteria lose that air and heat up to points where they die. People never think about the bacteria inside your ears.those guys need air and certain temps to keep out infections and dispose of microscopic debris. No more than 60 minutes at a time and NEVER exceed 60% of max volume, but in the case of studio equipment, keep it well below 85db as that seems to be the level where most people's ears begin to suffer. They destroy your ears, but if you have no other choice, try to use the 60/60 rule. You really should not think of headphones as a viable alternative.
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