I'm a firm believer in earplugs. I always carry a pair of soft rubber plugs in my front pants pocket along with lip balm, an eyeglass micro cloth, and several flat-picks. But rubber earplugs often deliver too much attenuation - conversations at normal levels are muffled. As a result I don't know of too many people who put in earplugs at the start of the day and then leave them on. I know I don't. I also rarely put my earplugs in when I'm on the street since it's good to be able to hear that car before it hits you. So, although I carry my 20 dB attenuating rubber plugs everywhere I go, they don't save me from sirens, car horns, and other random hearing-killing urban phenomena.
What's an audiophile to do? Perhaps it's time to call in some professional help in the form of Etymotic's newest ear-protection devices, the Music-Pro high-fidelity electronic musicians earplugs. These are the first "active" earplugs that can, in their active mode, actually amplify sound.
Compared to the cost of a good pair of rubber earplugs the Etymotic Music-Pros are expensive (list price $399), but unlike soft plugs, which are merely a molded hunk of rubber, the Music Pros have battery-powered internal circuitry that can either amplify or attenuate incoming sound. The Music Pros have two active modes; one delivers a steady 15 dB of attenuation, the other supplies 6 dB of boost in quiet environments and then gradually attenuates sound as it gets louder. At 70 dB levels the second mode begins to attenuate sound so that it's 10 dB down by 90 dB with a maximum attenuation of 20 dB at 110 dB sound pressure levels. Etymotic claims that at above 110 dB levels the Music Pros have the same amount of attenuation (-35 dB) as their rubber earplugs due to a special limiting circuit, but I did test this feature since I rarely (on purpose) find myself in an environment with 110 dB sound levels.
After using the Music Pros for about a month I've found that they are specialized beasts. At the sound pressure levels where I normally use earplugs I found that I preferred the Etymotic Ety Plugs HD because they deliver far more attenuation (-35 dB verses -10 dB) in the environments where I need to use earplugs. For my uses the regular Etymotic plugs do an excellent job, but I can't use them in many situations where I need to hear quiet conversations or where the steady-state noise level is low with only the occasional blast of loudness. That's the sort of situation that the Music Pros were designed to handle. If I lived in NYC I'd use Music Pros every time I stepped foot outside my apartment.
Obviously if you intend to use a pair of earplugs for any length of time they had better be comfortable, very comfortable. Etymotic supplies seven different ear-tips to try to cover every type of ear canal. For me one of the triple-flange tips worked nicely, going in deeply enough to make a good seal without discomfort. Switching from active to passive mode is accomplished via a small two-way toggle switch on the plugs themselves. You can tell when the Music Pros are in active mode because they emit a low level hiss. For some prospective owners this hiss could be distracting, but after a few minutes of use I found it was less noticeable. The hiss also gives you a cue as to whether the plugs are fitting well and passing high frequency information correctly. As you reposition the plugs in active mode the hiss frequency can change. When the hiss sounds open and unattenuated, the plugs are fitting properly.
Like their very similar Gun-Sport-Pro electronic earplugs the Musician-Pro earplugs are best for reducing sudden very loud sounds. If you use earplugs primarily to reduce steady-state sounds under 110 dB you would be better served by the Etymotic Ety Plugs or another soft, rubber, passive earplug. But if you must regularly abide in environments rife with sudden loud sounds The Etymotic Music-Pro musicians earplugs could save your hearing.