Sound for Online order Is Not Hearable

I know this feature was asked here: https://requests.lingapos.com/communities/1/topics/344-sound-for-online-order

However, I reached to the support (specifically rjohnson@lingaros.com) and the answer was: "As of now the notification sound is default and mild". We really don't hear any sound when an online orders comes. Only a pop-up notification. The sound has to be loud enough so we can hear. Currently we don't hear anything even we're next to the ipad. There are no ipad issues and the ipad sound is turned up all the way (we hear ipad sound when playing a video or a song. so there is no issues with the ipad)