This simulator isolates one axial room mode between two rigid walls. Choose the room length and mode number, move the source cabinet and receiver microphone along the room, and tune the drive frequency around the modal frequency to see how placement at a pressure node or antinode decides how much the room responds.
• A cutaway of a rigid room with pressure slices colored by the selected axial mode, a movable source cabinet and a receiver microphone that you position along the room length. • Controls for room length, mode number, source position, receiver position, drive-to-modal frequency ratio and damping ratio, plus a marker toggle. • Six readouts: mode frequency, drive frequency, source coupling, receiver mode shape, response amplitude and receiver signal. • Curves & measurements with the governing equations, two guided experiments with a verification bench and event log, and a Learn & assess tab.
Between two rigid walls a standing wave forms at fn = n c / (2L), and its pressure pattern is φ(x) = cos(nπx/L). Pressure is largest at the walls and at the antinodes and is zero at the nodes. A source placed on a node cannot excite that mode at all, and a microphone on a node reads nothing from it even while the mode is ringing.
The response is modeled as a single damped mode, H = φ(source) / (1 − r² + j2ζr), where r is the drive frequency divided by the modal frequency. Lower damping gives a taller, narrower peak at r = 1.
This is one normalized axial mode, not a complete room impulse response. Real rooms have many overlapping axial, tangential and oblique modes, plus furnishings and absorption. Pressure color is normalized for visibility and the true amplitude is reported numerically, and c is fixed at 343 m/s with time slowed 100 times. The value of the tool is seeing why source and listener position matter at low frequencies.
It is a standing wave formed by sound reflecting back and forth between one pair of parallel, rigid walls. Its frequency is fn = n c / (2L), where L is the distance between the walls and n is the mode number.
The source can only drive a mode in proportion to the mode shape at its position. At a pressure node the mode shape is zero, so the coupling is zero and the selected-mode response is zero even exactly at resonance.
Damping sets how sharp the resonance peak is. A small ratio such as 0.02 gives a tall narrow response at the modal frequency, while a large ratio such as 0.3 flattens and broadens it.
No. It is one normalized damped axial mode along a single dimension. It does not include the many other modes of a real room, the room impulse response or frequency-dependent wall absorption.