Etymotic Research ER-4S Canal Phone earspeakers:
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Where? where?
Etymotic has been making high-quality transducers since 1983, and Mead Killion, the president of the company, has been active in the field of earphones and hearing aids for more than two decades. Killion holds patents on more than 18 different headphone and hearing-aid advances, including the K-AMP amplifier, which revolutionized hearing-aid design.

The ER-4, in fact, is an extension of the design of the Tubephone insert earphone, designed for audiometric research. This device—which placed the transducers in a pack that connected to the ear canal via a 12" hollow tube—featured good crossfield isolation, wide frequency response, and flat diffuse-field reference response. Flat diffuse-field response means that the eardrum-pressure response of the transducer is equivalent to that in a diffuse soundfield—where sound arrives from all directions, favoring none. Multiple changes were rung upon the pattern of the Tubephone, some for hearing research, some for the military—these adaptations were employed in several programs developing "heads-up" instrument packages for fighter pilots—before Etymotic determined to make some low-impedance prototypes. One of these wound up in Ed Long's April 1991 review in Audio of Stax's Lambda Pro electrostatics, where he concluded that the ER-1Ms would be the headphones that he would buy—if only they were available.

Several months later, the ER-4B was on the market. What's the difference between the '4B and the '4S? The simplest answer—the one Etymotic gives—is that the '4B is designed for binaural use and the '4S for stereo. It is true that binaural recordings have an apparent dip in high-frequency response and may benefit from a slightly brighter presentation, but I've listened to binaural material on the ER-4Ses and can't really advocate tipping up the top end any more than they already do. Tyll Hertsens—a headphone maven if ever there was one—suggests that the ER-4B was simply a first draft and that Etymotic responded with the ER-4S because of the near-universal response, "They're too bright!" Maybe so, although Ed Long did prefer the ER-4Bs himself, while feeling that rock'n'rollers might prefer the ER-4Ses, because most rock records have too much sparkle to begin with. (The punk in me wants to snarl back, "Yeah, and most old fogeys don't have much high-frequency hearing left, either!" But since I'm mature and fair-minded, let's just leave it as a matter of taste.)

Your reaction to the Etymotics will very likely hinge upon how tolerant you are of putting something deep into your ear. I don't mind, really. My wife hates them—I've learned not to say hey, check this out! while traveling, because she just won't. If you intend to use them for long periods of time, or if you do a lot of traveling, you can have custom ear-molds made at a cost of about $100. Most companies that service hearing aids can do this for you, and Etymotic can recommend specific firms in most areas.

You do want to be cautious whenever you introduce foreign objects into your ear, so be careful placing the earmolds into the canal. You should also be aware that the ear canal is relatively sensitive—the more you adjust the position of the ER-4Ses, the more likely you are to cause irritation.

There! there!
Is all of this worthwhile? Absolutely. Properly seated in the canal, the ER-4Ses are capable of bass response better than many loudspeakers. The coupling is crucial; if not properly seated, their sound will be anemic. Get it right and the bass is full—flat to 40Hz, and probably only down about 3dB at 20Hz! Granted, you don't get the physical sense of slam that you do with a speaker system; but even so, you have no idea how giddy this sort of low-frequency information can make you when you're cruising at 42,000'. When I reviewed the Sennheiser HD-580s, I wrote about how silly I became listening to the deep bass-drum on the Dirty Dozen Brass Band's "Jungle Blues," from Jelly (Columbia CK 53214, CD). Back home in Charlottesville, I had my old friend Jimmy Jet listen to the track through the ER-4Ses.

"It's kind of tinny!" he shouted to those of us not wearing headphones.

"Push them in further," I pantomimed back.

"Wow!"—eyes widening in amazement. Wow indeed.