Great audio for music and an in-ear running coach

The Run Free Pro BIO Bluetooth earphones offer great sound quality with punchy bass and clear vocals. What sets these apart from other sport headphones, however, is the AI Beflex Biomech Engine, which offers in-ear coaching while you run. Used through the Soul Fit app, the coach suggests corrections to your running form to decrease risk of injury and to make sure you’re working out efficiently.


I had a generally positive first impression of the Run Free Pro BIO earphones. The packaging is well-designed and secure, they come with all necessary accessories, and the earphones themselves look pretty nice. I reviewed the Soul earphones in gray, though they also come in a bright red color. I’m pretty happy with the option I received, as I’ve seen photos of the red versions and feel like the gray adds a more sophisticated or premium feel to the overall appearance. One design feature that immediately caught my attention was the reflective cord connecting the two earphones, which is a nice touch for safety. The left earphone also has an LED that you can set to stay on or activate when you run.

Soul Run Free Pro BIO REVIEW


The BIO earphones come with a carrying case, short USB to micro USB charging cable, a cable clip, two sets of earlocks, and eight pairs of ear cushions of varying sizes. I really appreciated the variety of custom wear options because sport earphones especially require a good fit. I tried both earlock styles and five ear cushion sizes before finding the right configuration, but once I got the correct combination, the earphones required very little adjusting during the rest of the tests. I mostly chose to wear them over-ear style for added security. The longest period of time I wore them was about an hour (just listening to music, not running), and they proved slightly more comfortable than average for in-ear headsets I’ve tried. I like that they are sweat-resistant thanks to the IPX5 rating, and they can also be rinsed off as long as you don’t get water directly in the speakers.


The biggest issue with my chosen way of wearing the Run Free Pro BIO earphones is that all the controls ended up at the back of my head. The earphones have a small, slender remote with plus, S and minus buttons that allow you to adjust volume, skip tracks, play, pause, and answer or ignore calls. Though the buttons have raised symbols denoting what they are, they’re small enough that they’re difficult to differentiate by feel. The mic is also on the remote, so it’s inconvenient to answer calls when wearing the cord behind your head.


Beyond that one minor snag, the earphones are as straightforward to use as any Bluetooth earphones should be. It does require downloading the Soul Fit app and both pairing to your device and within the app itself, but beyond that, everything is pretty self-explanatory.


Maybe because these earphones have the gimmick of the AI running coach, I didn’t expect much from the audio, but the sound output is great. The bass, particularly is nice and punchy, which is perfect for running along to the rhythm. The mids are acceptable, and the highs are clear and not at all tinny. All ranges are there and balanced well, making for a good listening experience. The fit of the earphones is also great for sound isolation, so you can hear your music when running outside or at the gym.

Soul Run Free Pro BIO REVIEW


Of the product’s features, I admittedly tested the AI running coach the least. I’m not a runner, but I was curious what the coach would have to say about my very unpracticed form. In the Soul Fit app, I set sensitivity for all types of coaching to high and started a very brief run. I immediately realized that I had the cadence set to too many steps per minute, because I got low cadence warnings every 20 seconds for the first minute. After adjusting that, the coach harped on my high head angle, which is a fair criticism, though something I cannot currently control due to an issue with my spine. I turned off notifications for head angle and continued. The one suggestion I did find helpful were the shock warnings, which basically tell you to step lighter.

Soul Run Free Pro BIO REVIEW

After I was finished running, I reviewed the activity in the app’s log. This gives you four pages of insights about your run: basics like distance, speed, and time; an overview of your form throughout the run; an assessment of your risk of injury based on your form; and your running splits. I found this interesting and probably more helpful than the in-ear coaching, as while you’re running, the coaching can often tell you what you’re doing wrong but not offer suggestions on how to fix it. The coach can also be triggered by abnormalities. For example, I stumbled a bit during my run and was pretty immediately chastised to take lighter steps, which isn’t particularly helpful.

Were I to continue running with these headphones, I would most likely turn off the voice coaching and rely more on the overview at the end of each run. This is both because I did not find the coach necessarily helpful from the suggestions it gave me and because the voice coach interrupts music playback. When speaking, the coach is louder than the music and can be a little jarring, especially if you’re running along to the beat of the music. On high sensitivity, the voice coach pops up a few times a minute if you don’t have perfect form, which gets irritating very quickly. On low sensitivity, the voice pops up much less frequently but still interrupts the music. I’m not entirely sure how this could be handled more smoothly, but as it is, I don’t like it. That said, I still think the coaching insights are neat–just not in my ear while I’m running.


The Run Free Pro BIO by Soul are good Bluetooth earphones. Even without pairing with the Soul Fit app, the design details from the reflective cords to the variety of fit options complement the earphones’ focus on running. With the app, you get useful insights to help improve your form and decrease the chances of injury.

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