  Sound reflections and late reverberation alter energetic and binaural cues of
a target source, thereby affecting it's detection in noise. Two experiments
investigated detection of harmonic complex tones, centered around 500 Hz, in
noise in a virtual room with different modifications of simulated room impulse
responses (RIR). Stimuli were auralized using the SOFE's loudspeakers in
anechoic space. The target was presented from the front or at 0$^\circ$
azimuth, while an anechoic noise masker was simultaneously presented at
0$^\circ$. In the first experiment, early reflections were progressively added
to the RIR and detection thresholds of the reverberant target were measured.
For a frontal sound source, detection thresholds decreased while adding the
first 45 ms of early reflections, whereas for a lateral sound source thresholds
remained constant. In the second experiment, early reflections were cut out
while late reflections were kept along with the direct sound. Results for a
target at 0$^\circ$ show that even reflections as late as 150 ms reduce
detection thresholds compared to only the direct sound. A binaural model with a
sluggishness component following the computation of binaural unmasking in short
windows predicts measured and literature results better than when large windows
are used.
