Studies: Alert when close crosses a Moving Average

Q: I have a 30 min chart and I’d like to create a Study alert, that will trigger a sound the moment a bar touches or crosses a 21 EMA and not at the closing of the bar (witch may be up to 30 minutes to late).

A: Put a Moving Average on the chart. Put a Study Alert on the chart and reference the MA crossing as shown on this example:

Note that the Close Only box is unchecked so the alert tests every tick.