Ember Multiselect onchange

I have an Ember HBS template with a multiselect that I need to update the model onchange.

For regular selects, I used the following

<select id="scCalibration" onchange=>

But for the multiselect, what I need is a comma delimited list of selected values updated in the model. I'd prefer not to use a third party library like Ember-Power-Select if possible. I can't seem to figure it out...