The hf2 and hf5 each come with a nicely designed carrying case, two replacement filters, a filter-replacement tool, and a small assortment of eartips. Fitting the eartip to your ear canal is crucial, for both good bass response and comfort, and Etymotic offers a much wider assortment of tips than are provided in the package. I generally prefer the three-flange models to the compressible foam or dome models, but choosing what to stick in your ears is a very personal choice. Later this year, Etymotic will introduce a program for custom-molded eartips for the hf2s and hf5s with a target price of about $100 (which includes having molds taken by an audiologist).

Head to head
If there were frequency-response differences between my review samples of the hf2 and hf5, I couldn't hear them. I began my audition with the hf5, thinking that simple is always superior. One night, having lost my preferred eartip for the hf5s' right transducer, I grabbed the hf2 as I went out the door. It sounded exactly like the hf5, and, much to my surprise, I found the microphone's Start/Stop feature unbelievably convenient—a convenience worth, to me, the $30 price difference between the models. The hf2 became my go-to headset. For the rest of this review, I'll describe the sound of the hf2, but the comments also apply to the hf5.

Late in my auditioning, I did find a use for the hf2's microphone: The iPod Touch has a Voice Memo app, and I started using it instead of my trusty Moleskine pocket notebook, mostly because I broke my right hand last year and my handwriting was becoming indecipherable even to me. The mike is handy (I couldn't stop myself), but I still think of the control function as the more useful feature.

Driven without a headphone amplifier, both headsets played louder than I ever required—a result owing much to the noise isolation that results from the in-canal placement of the transducers and the flanged eartips. As with the ER-4S 15 years ago, the isolation from external noise is welcome, but probably makes the hf2 or hf5 a poor choice when you need to be aware of your environment. High fidelity should not be a choice between life and death.

Although the hf2 was sensitive, it did benefit from being driven by a headphone amplifier such as Ray Samuels Audio's Emmeline The Hornet. For travel, when I knew I'd be listening for long periods in the same place, I'd always pack an external amp in my go-bag, but for daily use around the house or on the run, I never bothered with it.

Feed your head
Paul Bley's Solo in Mondsee (AIFF file, ripped from ECM 1786) begins with a crashing chord (sustain pedal depressed) that hovers in the hall's acoustic seemingly forever. The hf2 captured that long fade into silence with great precision. I could hear the sustained note puddling into the acoustic, before Bley's crisp statement of his first Mondsee Variation. The piano's timbre is convincing, even acerbic; without the warmth of the opening chord's descent into silence, I might have suspected that the hf2 was a wee bit bright. But no, that's Bley.

Paulo Angeli's Nita: L'Angelo sul Trapezio (AIFF file, ripped from Re R 2) is a wild mix of street band, vocals, harp, and avant-garde jazz. It coheres, however, and "Cussi No' la Cridia" gets me every time with its tuba-driven march rhythm and Nanni Angeli's fado vocal stylings. Think Bulgarian wedding-band music played at quarter-speed. The hf2 got the oompah of the tuba right—deep and physical—while also rendering the clarinet, soprano sax, and mariachi brass choruses with clarity and color. And that harp (obviously recorded in an isolation booth) was both fantastic and phantasmagorical.

The Word (AIFF file, ripped from Rykodisc 16002) is one of the strongest arguments I know for music's ability to elevate, electrify, and sanctify everyday life. "I'll Fly Away" melds the funky drive of the North Alabama Allstars, John Medeski's wheezy Hammond B3, and Robert Randolph's impossibly lyrical pedal steel. After the theme is stated, the track ramps up into a full-bore boogie shuffle—happy-feet music at its finest. The hf2 got the wheeze and percussive attack of the B3 just right, while Cody Dickinson's drumset hammered deep into bedrock (as John Atkinson once observed about a different musician, it takes a great artist to play that simply). But soaring above it all are the twin guitars of Randolph and Luther Dickinson—instruments that the hf2 let take flight with juice and major amperage. (Ultimately, I had to confine my auditions of this song to home; my compulsive foot-tapping, head-nodding, and emphatic hand gestures confused other passengers on the R train into suspecting I was experiencing some sort of fit. You try listening to this track without moving.)