Direct Reflections

Statistical Measures of Early Reflections of Room Impulse Responses

An impulse response of an enclosed reverberant space is composed of three basic components: the direct sound, early reflections and late reverberation. While the direct sound is a single event that can be easily identified, the division between the early reflections and late reverberation is less obvious as there is a gradual transition between the two. This paper explores two statistical measu...

What does the ability to suppress a single reflection tell us about localisation performance in rooms?

Localisation in rooms is characterised by the presence of multiple reflections interfering with the direct sound from source to listener. Nevertheless, due to the “precedence effect”, normal hearing listeners are able to cope in such situations by apparently ignoring the later arriving reflections. In studies on the precedence effect this situation is abstracted by playing a sound (the “lead”) ...

Unwanted reflections during slit lamp assisted binocular indirect ophthalmoscopy

Subjective Response to Simulated Sonic Booms with Ground Reflections

The Sonic Boom Simulator at NASA Langley Research Center was used to (1) quantify subjective loudness of simulated composite sonic booms, each of which was comprised of a simulated direct (non-reflected) boom combined with a simulated reflection of the direct boom, and (2) evaluate several metrics as estimators of loudness for these composite booms. The direct booms consisted of selected N-wave...

Modeling Auditory Distance Perception in Rooms

Although the direct-to-reverberant energy ratio is an important cue for distance perception in rooms, it is not known how it is determined by the auditory system. One clue is provided by certain systematic errors made by listeners, which can be modelled by calculating the direct energy from the impulse response using a fixed time window (thus including some early reflections). This model cannot...

Directly Visible Pairs and Illumination by Reflections in Orthogonal Polygons

We consider direct visibility in simple orthogonal polygons and derive tight lower and upper bounds on the number of strictly internal and external visibility edges. We also show a lower bound of ⌈n2 ⌉ − 1 on the number of diffuse reflections required for completely illuminating an orthogonal polygon from an arbitrary point inside it. Further, we derive lower bounds on the combinatorial complex...