How can we hear sensor alerts upstairs

Our previous security system used the keypad for audible alerts.  Because of that, we heard a chime when doors were opened, for example, whether we were downstairs, near the primary keypad, or upstairs, where we had a secondary keypad.  Installed the SimpliSafe system yesterday, & discovered -- no surprise -- that we can't hear the base station speaker upstairs.  This is a pretty important factor/feature, so we need to know if there's a way to achieve it.  Thanks.