How big is the bar? Is it separate from the restaurant?
How many speakers are you planning to employ? You might be better served with multiple smaller speakers.
Remember, these environments are not the same as home use. People near the speakers nmay get blasted out while diners further away might hear nothing.
While loud music in a bar might be doable, assuming the clientele is up for it (and if they are drunk they generally don't mind) but most people come to a restaurant to eat and converse as the main thrust of their visit, not to be entertained by listening to music. The music should enhance the dining experience, not dominate it.