The complaint about the noise, and all of the cars and people, will most likely give the police officers probable cause to suspect that crimes are occurring (for example, minors in consumption of alcohol). When a police officer develops probable cause, which means that by drawing on his or her experience as a police officer he or she believes that a search will find evidence of a crime, they have the legal right to make the search. In this case, so long as the probable cause (viewing the people and hearing the noise) is developed from the public street, the officer will likely have the right to make the search.

Yes, you do have the right to refuse to allow the police into your house if they do not have a search warrant. However, the police may enter anyway. If this happens, anything found in the house may or may not be admissible as evidence. If the police officers had probable cause to believe that a crime was being committed (underage consumption and drugs), and that the evidence would disappear if the police waited for a warrant, then the police may be allowed to search the house without a warrant and the evidence found would be admissible in court.