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Soul Run Free Pro Bio Review

I thought I knew everything that fitness headphones can do. Soul Electronics’ new Run Free Pro Bio, however, shows me there’s more that fitness headphones can do. These headphones take personalised fitness coaching to a new level.

The Soul Run Free Pro Bio is designed specifically for running. Although it lacks heart-rate monitoring functions, Soul has managed to pull off several rather fascinating coaching capabilities for runners. They’re telling us the Soul Run Free Pro Bio is the first headphones to use AI technology with gait analysis to monitor running and provide real-time voice coaching.

I’ve to say I was very impressed when I took the Soul Run Free Pro Bio out for a test run. It immediately pointed out my left leg was weaker. It was correct, because my left knee was indeed injured, although I wasn’t even aware it was showing up in my running. The Soul Run Free Pro Bio also detected that I was trying to consciously correct my stride, and complimented me for that.

The Run Free Pro Bio uses what Soul Electronics refer to as “biomechanical sensors” to track numerous aspects of your running. This is what gives the “bio” suffice to the name of this fitness gadget. To use these running features, you’ll need their mobile app, and have your smartphone accompany you during your run. I would have preferred not to have to carry a smartphone, but alas perhaps there’s too much complex processing than the headphones can handle on its own.

The biomechanical sensors track several data points: head angle, vertical oscillations of each leg, cadence, step width, symmetry, and shock. The voice coaching feature, which Soul Electronics calls Beflex BiomechEngine, then tells you if you’re doing something wrong, and commend you when your running form is right.

It almost sounds like these headphones are reprimanding me: my left leg is weak, my steps are too wide, my head angle is low, etc. Occasionally, I even start to feel a little annoyed. However, and fortunately, you can tune the coaching settings.

The level of sensor data that the Soul Run Free Pro Bio analyses is quite impressive. The constant nagging from the voice coach will likely actually help to improve your running form, if not only because you just want the reprimands to stop.

All the Soul Run Free Pro Bio features are geared towards running. The coaching works only for running. The design of the headphones also revolves around running. If you are looking for other types of fitness coaching, then you need to look elsewhere.

For example, the reflective neck strap is designed to make you more visible. In fact, there’s also a module down from the left earpiece which incorporates an LED light to ensure that you can be seen when you’re running at night (or very early morning). This module nicely balances out the weight of the inline controls on the right side.

The inline controls allow you to skip tracks and adjust volume, play/pause music, and that’s where the Micro-USB port is also located for charging the headphones.

The earpieces themselves are magnetic, so they stick to each other if you just let them hang down from your neck. The earpieces are somewhat large, but you should be able to stick them securely into your ears with the variety of attachments included in the box.

Other than the incessant coaching from the Beflex BiomechEngine, the Soul Run Free Pro Bio also plays music. What fun is a run if not for some upbeat music, right?

The Soul Run Free Pro Bio supports Bluetooth 4.1 with aptX codec. Sound quality is decent. While the bass lacks energy and the treble isn’t very bright, it’s good enough for a run. If, however, you just want to listen to music, you’ll likely want something more engaging.

Battery life is rated at 11 hours for just music and talk, and up to 5 hours when using the Beflex BiomechEngine. The Soul Run Free Pro Bio is IPX5 rated, which makes it sweat resistant. You can’t take it for a swim, which is fine, since this is clearly designed for running.

Included with the Soul Run Free Pro Bio, you’ll find a number of comply and silicon ear tips, as well as ear wings, shirt clip, Micro-USB charging cable, and a carrying pouch.

The Soul Run Free Pro Bio retails for S$249.90.


Soul Electronics shows there’s a lot more that they can do to coach runners, even without having a heart-rate monitor. Their AI voice coaching will probably really help improve your running form.


  • Impressive voice coaching technology for running
  • Will probably help improve your running form
  • Good battery life


  • Music quality is only just okay

1 thought on “Soul Run Free Pro Bio Review

  1. Good review. One of the very few reviews that is more focused on the running metrics of the Bio engine. Soul currently has an indiegogo funding on a true wireless Soul Blade. Would you think it’s a good one? Initially I was skeptical of the coaching, but later read the Bio engine is already in use on this existing model, that alleviates some of my skepticism.

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