An apparatus for determining a position estimate for an audio source, the apparatus comprising: a first microphone for generating a first microphone signal; a second microphone for generating a second microphone signal; an acoustic element providing an acoustic effect to sound from sound source positions to the first microphone, the acoustic effect being asymmetric with respect to an axis between the first and the second microphone; a position processor comprising: - a first position circuit for estimating a first possible position and a second possible position for a sound source in response to time of arrivals at the first microphone and the second microphone for audio from the sound source, the first possible position being a position in a first area on one side of the axis and the second possible position being a position in a second area on an opposite side of the axis; - an estimator for determining a first acoustic effect measure for the first microphone signal, the first acoustic effect measure being indicative of a degree to which an acoustic effect of the first microphone signal matches an expected characteristic of the acoustic effect for sound sources in the first area; - a second position circuit for determining the position estimate for the sound source by selecting between the first possible position and the second possible position in response to the first acoustic effect measure. a first microphone for generating a first microphone signal; a second microphone for generating a second microphone signal; an acoustic element providing an acoustic effect to sound from sound source positions to the first microphone, the acoustic effect being asymmetric with respect to an axis between the first and the second microphone; a position processor comprising: - a first position circuit for estimating a first possible position and a second possible position for a sound source in response to time of arrivals at the first microphone and the second microphone for audio from the sound source, the first possible position being a position in a first area on one side of the axis and the second possible position being a position in a second area on an opposite side of the axis; - an estimator for determining a first acoustic effect measure for the first microphone signal, the first acoustic effect measure being indicative of a degree to which an acoustic effect of the first microphone signal matches an expected characteristic of the acoustic effect for sound sources in the first area; - a second position circuit for determining the position estimate for the sound source by selecting between the first possible position and the second possible position in response to the first acoustic effect measure. - a first position circuit for estimating a first possible position and a second possible position for a sound source in response to time of arrivals at the first microphone and the second microphone for audio from the sound source, the first possible position being a position in a first area on one side of the axis and the second possible position being a position in a second area on an opposite side of the axis; - an estimator for determining a first acoustic effect measure for the first microphone signal, the first acoustic effect measure being indicative of a degree to which an acoustic effect of the first microphone signal matches an expected characteristic of the acoustic effect for sound sources in the first area; - a second position circuit for determining the position estimate for the sound source by selecting between the first possible position and the second possible position in response to the first acoustic effect measure.