For those who are not familiar with Ella, it is a sight-singing app available on the App Store for free. This article details the design process behind the Tempo Multiplier in the app.
In the early days of prototyping Ella, the curriculum only had exercises with quarter notes. For every question the user was asked, it was possible to change the tempo to make the sequence faster or slower. In this situation, the user would have the same amount of time to read a note and readjust their singing to the next pitch in every single note.
To improve the app experience and expand on the curriculum, one obvious improvement was to increase the number of possible note durations to allow for more complex questions that sound more like music. This change significantly reframed the way we had to think both about time and difficulty when recording in the app.
When we started experimenting with different note durations for questions, we noticed that our musicians needed to be constantly adjusting the tempo after trying to record the sequence. This was because the app forced them to follow a fixed tempo, not effortlessly adjusting to their comfort.
One misconception I had about what slower/faster means is that they are directly associated with easier/harder. This is not so in music. There are two problems that impede people from singing a sequence in a given fixed tempo:
- When the question is too fast, singers miss notes
- When the question is too slow, singers lose their breath mid-note
This prompted us to discuss what would be the appropriate speed for singing each sequence and how to calculate it. We hypothesized that every sequence has an optimal tempo for singing based on the shortest note duration. And, should we try to make it easier, there could be a slightly slower tempo.
Given the overall goal of the app is to evaluate correct singing, not party tricks, having a harder/faster tempo was not considered a viable solution.
Upon running tests with our musicians, we found that they were not completely confident about the solution. Particularly they found that the level of control was too low for users that would like to drill through exercises faster and more efficiently when they attain higher levels of proficiency.
This prompted us to reframe the concept of slower and faster in relation to a multiplier that would affect the optimal tempo of each sequence in an exercise.
This solution proved to have the correct frame for dealing with tempo while also providing the correct level of control for the user. We were thus able to reduce cognitive strain while improving efficiency for learning for the first time and daily drills.
Though we did try a handful of solutions to arrive at something that provided the correct amount of freedom to the users, the final solution significantly reframes what tempo is to music and how to treat it in a tutor.
By adjusting what is the optimal tempo instead of a fixed value, we allow students to worry more about singing and less about adjusting the app. Furthermore, exercises now can have more diversity of questions without negatively impacting singer-performance with extraneous barriers.