The evaluation and control of acoustical standing waves.

The team built a small sound chamber for pigeons. They worried that sound waves could bounce and pile up in spots, making some tones louder than others.

To check, they played 1–3 kHz tones and measured how loud the sound was at every corner. The biggest bump was only 3 dB—about the jump you hear when you whisper “ah” to “AH”.

Birds needed a 10 dB change before they noticed any difference. The chamber’s own 3 dB wobble was too small to cue them.

Result: the box is clean enough for fine pitch work. No extra padding or re-build needed.

RISLEY (1964) first mapped how pigeons sort tones into “high” and “low” groups. Tracey et al. (1974) now show the gear used back then was valid—no hidden loud spots skewed the birds’ choices.

Gurley (2019) gives the same thumbs-up for cheap Raspberry Pi boxes, but for lights and nose-pokes instead of sound. Both papers share the same spirit: test your box before you trust your data.

Malouff et al. (1985) used the same single-case lab style to study matching law. The method link reminds us: tight environmental control is what lets tiny effects shine through, whether the cue is sound or food rate.

Before you run any auditory discrimination study, map the sound field. If the loudest standing wave is smaller than your subject’s detection threshold, you can move on. If not, add foam or change the shape. One afternoon with a meter can save months of muddy data.