Floor Reflection Simulator
Software platforms: Excel | OpenOffice | LibreOffice
I recommend the Room Boundary Simulator to simulate room reflections.
This simulator calculates and displays the frequency response of an ideal speaker standing on a reflective surface. In a room we hear not only the direct sound from the loudspeaker, but the reflected sound from the walls, the floor and the ceiling. Early reflections (reflections earlier than 10 msec) have got the largest energy and thereby the greatest impact on the frequency response.
Due to the high interaural cross-correlation between the reflected and direct wave, the reflection from the floor is heard as a change in the timbre and not suppressed as in the case of a lateral reflection (Precedence effect). From Loudspeakers And Rooms by Floyd E. Toole: "The comb filtering effect is audibly obvious... if there is a single, strong vertical (median plane) reflection in an otherwise echo-free environment." Fortunately, the threshold of detection of reflections is higher in a normal reverberant living room than in reverberant-free anechoic chamber (see Søren Bech: Timbral aspects of reproduced sound in small rooms part 1). According to Søren Bech's paper, the threshold values in a reverberant field for a floor reflection with 1.6 msec delay are 4 dB for speech and 7 dB for pink noise.
Format: xls (Microsoft Excel 2003 Workbook)
Required software: LibreOffice Calc | Microsoft Excel | OpenOffice Calc