Fourth Iteration
The next week I continued to iterate on the visual treatment of the app, focusing on smoothing the friction discovered from the previous week and creating a more intuitive experience through incorporating familiar patterns from existing popular running apps into my own interface.
Most notably, I added a map view and run stats monitor on the home page to allow the user to view their run progress and to ground the app in it's running use case. I also explored various color ideas, and refined the start button.

Color & Start Screen Explorations
At this point I was refining the identity of the app through color and experimental layout choices. Below are some of these explorations:
It was important for me to have a visual signifier of the core audio functionality of the app, which differentiated it from other run tracking apps. My solution was to create a start button that had radial soundwave iconography, visually informing the user that this button not only starts the tracking of their run, but also starts the audio generation.
To create a cohesive branding for the app, I eventually incorporated this start button icon into the app logo, substituting the linear soundwave iconography from the original logo idea with the geometric language of the start button.
User Testing Round 4
For this round of testing I conducted 2 tests: one was another live run with 5 new people. I also had a beta tester remotely download the app from testflight and use the app on their own device, without me being there, and record their reactions.
Brendan, Remote Beta Tester

Live 5-Person Group Run Test

"I usually run pretty hard, so I liked the messaging that it was a race"
Brendan, Remote Beta Tester

"When I'm racing, there are other people cheering - this (app) gives that."
Osmond, Live Tester