The marketing behind the SOL Republic Relays claims that they're "crossover" earphones, combining the superb fit of exercise-focused pairs with the excellent sound that exercise earphones supposedly lack. This is a pretty bizarre notion—the Sennheiser CX 685 SPORTS( at Amazon) is a great-sounding exercise earphone pair, for instance, so the categories aren't mutually exclusive. There's no denying, however, that the fit of the $79.99 (direct) Relays is quite secure and comfortable—ideal for workouts. They also deliver thunderous bass response with no distortion, even at top volumes. The overall sound signature is very sculpted and won't appeal to purists, but will probably help your heart rate stay steady if you listen to fast-paced music with booming low-end when you workout. The very concept of a "crossover" earphone pair is silly—these are simply earphones intended for exercise, and they deliver quality sound performance for the price.

Design

The in-ear, sweat- and water-resistant Relays are offered in four different colors (black, yellow, blue, and white), and include a three-button remote that allows for playback and volume control, as well as track navigation and call answering on your mobile device. A single-button remote version of the Relays is offered in black only, for the same price of $79.99 (direct).

The simple design of the earpieces actually doesn't look like it will stay in place—but a rubberized, circular fin contour stabilizes the fit quite well, and the included silicone eartips (four pairs in various sizes) do the rest of the work. Otherwise, the design is pretty no-nonsense and lacking in flair.

Also included with the Relays: a snap-on shirt clip to help minimize cable-thump during workouts, and a small black protective carrying pouch.

Performance

On tracks with serious sub-bass content, like the Knife's "Silent Shout," the Relays hold their own—not only do they deliver a tremendous amount of sub-woofer-esque thunder, but they do so without distorting, even at top, unsafe listening levels. The booming low-end is met with extremely sculpted high-mids and highs, which prevents the lows from completely dominating the mix, but it's safe to say purists seeking a flatter response should look elsewhere.

On Bill Callahan's "Drover," his baritone vocals receive a heavy dollop of added low-end—thankfully there's enough crispness to keep them from sinking into the completely muddy realm, but the mix does suffer a bit because of its heavily weighted, bass-heavy sound. The drums on this track, for instance, sound far too thunderous to seem natural. Some listeners will enjoy this, but it's far from accurate and doesn't do this type of guitar-and-vocals-focused mix too many favors.

Jay-Z and Kanye West's "No Church in the Wild," on the other hand, revels in the deep bass response. The attack of the kick drum loop is still crisp enough to slice through the mix, and it's coupled with a very healthy low-end sustain. Combine this with the sub-bass synth hits that punctuate the beat, which receive plenty of club-PA-system-like push from the Relays, and you have a powerful sound. The vocals on this track don't suffer the same fate as Callahan's because they don't occupy the lower registers as much as his do, and therefore don't receive undue boosting.

Classical tracks, like John Adams' "The Chairman Dances," actually sound quite exciting on the Relays. Again, purists might not approve, but the bass boosting comes off as a bit more subtle when it's applied to the lower register strings and percussion on this track. The higher register strings, brass, and percussion still rule the mix, but things are never either too bright, nor too booming in the lows—there's just an added, pleasant bounce in the bass realm that lends a little of excitement to the mix.

So, while I think the marketing of the Relays as a "crossover" pair of earphones is a bit perplexing, it is a fine pair of exercise earphones. And just like all other fine pairs of exercise earphones, you can pretty much wear them and enjoy them consistently when you're not working out, as well. If you're looking for a slightly more balanced sound in an exercise pair, the aforementioned Sennheiser CX 685 SPORTS is a great option, and if you have more room in your budget but still want the booming low-end, the Beats by Dr. Dre Powerbeats have plenty of it. If you prefer a wireless Bluetooth option for your exercise, consider the JayBird BlueBuds X. Meanwhile, if you're just looking for a cheap pair of earphones with big bass, you can spend far less on something like the JLab Fit, but there are no guarantees it will survive multiple workouts. At $80, the Relays are an affordable, gym-friendly option for bass-lovers, and you won't find too many reliable, exercise-oriented pairs for less than this.

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