Apparatus (20) for hearing assistance includes a spectacle frame (22), including a front piece (30) and temples (32), with one or more microphones (23) mounted at respective first locations on the front piece and configured to output electrical signals in response to first acoustic waves (64) that are incident on the microphones. A speaker (28) is mounted at a second location on one of the temples outputs second acoustic waves (66). Processing circuitry (26) generates a drive signal for the speaker by processing the electrical signals output by the microphones so as to cause the speaker to reproduce selected sounds occurring in the first acoustic waves with a delay that is equal within 20% to a transit time of the first acoustic waves from the first location to the second location, thereby engendering constructive interference between the first and second acoustic waves.