Why you can trust Tom's Guide Our writers and editors spend hours analyzing and reviewing products, services, and apps to help find what's best for you. Find out more about how we test, analyze, and rate.
Sennheiser's CX 685 Adidas Sports In-Ear headphones work just as hard as you do when you're working out. Their solid and balanced audio quality will keep you focused during training sessions, and their adjustable, sliding wing design make them comfortable to boot. At just $40, these earbuds will be a favorite both in and out of the gym.
Design
The Sennheiser CX 685 Adidas Sports In-Ear headphones have an elongated design. Each earbud connects to a long, thin piece of plastic that curves at both ends. The top curves are the ear wings, which have a unique "slide-to-fit" construction, and the bottom curve attaches to the cord.
The ear inserts are typical domelike pieces of silicon, and the ones for my review units were dark blue. The superthin cord was the same color, with the rest of the buds accented in black and silver.
While I appreciate the CX 685 Sports' simple design, I wish these earbuds had an inline remote like the $79 SMS Audio STREET by 50 Wired Sport earbuds and Sennheiser's own new $69 CX 686G Sports earbuds. The remote made it easier to skip through songs and adjust the volume without pulling my smartphone out of my pocket.
These CX 685 Sports are also prone to tangling, which is a hassle. After fishing them out of my gym bag, I had to spend a minute or two detangling the cord before I could plug in and zone out.
MORE: Best Headphones
Comfort and Fit
The Sennheiser CX 685 Adidas Sports In-Ear headphones come with three sizes of ear inserts. I chose the medium inserts, which sealed off my ears completely without being constrictive or uncomfortable. When I jogged on the treadmill or lifted weights, these earbuds stayed put and required little to no readjustment.
You can move the buds' slide-to-fit ear wings up and down to adjust them to your ears. I put the buds in my ears by sliding the wings all the way up, securing the ear inserts and the sliding the wings down until they fit in the outer part of my ears.
These earbuds don't have interchangeable ear wings like the SMS Audio earbuds do. While SMS Audio's wings are made of more flexible silicon, I liked being able to adjust the CX 685 Sports' wings on the fly.
Audio Quality
The Sennheiser CX 685 Adidas Sports have the most balanced audio of any sports earbuds I've yet tried. The earbuds took Eminem's biting vocals and Charmagne Tripp's melodious tones and married them well in "We Made You," making the entire track sound punchy.
In P!nk's "Try," I could hear the vocals, pianos, strings and tambourines much better on these buds than on the SMS Audio STREET by 50 Wired Sport earbuds, which overpowered the same track with heavy bass.
Imagine Dragons' "I Bet My Life" had the same balanced sound. While I enjoy the superpowerful bass that shook my core when I listened to this track on the SMS Audio earbuds, the background vocals that came through on the CX 685 Sports were completely lost on the SMS buds.
I also didn't hear as much distortion at high volumes on the CX 685 Sports as I did on the SMS Audio earbuds. I could raise the volume to at least 80 percent before tracks became harsh.
The Sennheiser CX 686G Sports earbuds are very similar to the CX 685 Sports. The CX 686Gs offer similarly balanced audio with slightly more pronounced lows, which deepens the bass and drums, giving each track fuller sound.
MORE: Best Bluetooth Speakers
Bottom Line
While they're made for the most active parts of your day, the $41 Sennheiser CX 685 Adidas Sports In-Ear headphones are solid earbuds for any situation. They're a steal at $41, providing well-rounded sound in a comfortable design that will keep your head in the game at the gym or wherever your workout takes you. Just keep in mind that you don't get an in-line remote and that the cords are prone to tangling.
If you have more to spend, Sennheiser's $69 CX 686G Sports earbuds are more well-rounded because they offer full, balanced audio; a convenient inline remote; and a sporty design. Bass enthusiasts will want to opt for the $79 SMS Audio STREET by 50 Wired Sport earbuds. Overall, though, the CX 685s deliver a lot for a little.
Follow Valentina Palladino at @valentinalucia. Follow Tom's Guide at @tomsguide and on Facebook.
