Removing shoes is best, though wearing them does not spoil the test: the breath that meets the land carries the reading, and barefoot the current also enters through the bhoomi chakra of the earth element in the right big toe.
The breath works like a stethoscope that never fails. Just as one smells sandalwood on someone 50 feet away, the breath reports the land's energy, and with practice an expert can tell from the elements within the elements whether the defect lies in the South-West, North-West or North-East. Reading from a distance, when someone calls from the plot, also becomes possible.
Swar vigyan was called the greatest of all methods: it works where astrology, vastu, tantra, mantra and yantra fail, and costs nothing, so even a poor family's vastu can be balanced with swar alone. First comes karma (karmoday), then swar (swaroday).