An acoustic device includes a resonance chamber and a noise reduction unit. The noise reduction unit serves to combat noise in the resonance chamber, and includes first and second electro-acoustic transducers, a controller, and a sound-absorbing member. The first electro-acoustic transducer generates a first electrical signal that corresponds to the noise in the resonance chamber. The controller generates a second electrical signal. The second electro-acoustic transducer generates a sound wave that corresponds to the second electrical signal and that counteracts a portion of the noise in the resonance chamber. The sound-absorbing member includes a porous body that is mounted in that resonance chamber and that absorbs another portion of the noise in the resonance chamber.