A hearing system comprises respective input and output transducers operationally coupled via a forward path comprising a configurable output combination unit having first and second signal inputs and a signal output. The first and second signal inputs are a signal of the forward path, and an output probe signal, respectively, and the output signal is electrically connected to the output transducer and configurable to consist of either of the first or second signal inputs, or a mixture thereof. The hearing system further comprises a configurable probe signal generator for generating the output probe signal, an adaptive feedback estimation unit for generating an estimate of an unintended feedback path, and a control unit for generating a control signal for controlling the output probe signal, which may comprise a perfect or almost perfect sequence and/or an almost perfect sweep sequence.