I could not find any specs on the Denon but in general you would want speakers that are 6-8 ohms. The greater the efficiency the louder they will play with the limited power of the Denon. If you have the owners manual for the Denon it should have some specs there. Take that with you to a local audio shop with some music and listen to some speakers. They will be able to advise you based on your preferences and the specs. If you can't find any specs then see if you can try the speakers you like to make sure they work with the Denon.