Detecting reflected sound depends heavily on the continuity of the source signal

Evidence

Figure 6.11 shows detection thresholds for sounds chosen to exemplify different degrees of “continuity”, starting with continuous pink noise, and moving through Mozart, speech, castanets with reverberation, and “anechoic” clicks (brief electronically generated pulses sent to the loudspeakers). The result is that increasing “continuity” produces the kind of progressive flattening seen in Figures 6.7 and 6.10. The perceptual effect is similar if the “continuity” or “prolongation” is due to variations in the structure of the signal itself, or due to reflective repetitions added in the listening environment. In any event, pink noise generated an almost horizontal flat line, Mozart was only slightly different over the 80 ms delay range examined, speech produced a moderate tilt, castanets (clicks) with some recorded reverberation were even more tilted, and isolated clicks generated a very compact, steeply tilted threshold curve. Clicks showed detection of reflections at −50 dB at 30 ms delay, compared to −30 dB for castanets, and about −20 dB for speech, Mozart and pink noise. — Toole, Floyd E, Sound reproduction- the acoustics and…, 639

Categorization

• XREF: Connects to the broader psychoacoustic finding that continuous signals mask reflections far more than transient ones; links to precedence effect literature.