Normally, the noise level should not exceed 85 dB (at one metre) and hours during which such noise is prevalent should be "reasonable". Apart from this a bar needs a license to sell alcoholic beverages and operate as a "bar". But there is no license required to play music at "reasonable levels".
All of this is open to more or less generous (or strict, rarely) interpretation and enforcement. What area of PdP are you more concerned with? Any specific location or venue?