Bass decay – Dayton Audio OmniMic V2 Precision Measurement System User Manual
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Bass Decay
Use the Bass Decay analyzer to measure how bass notes decay in a room.
Use only the provided "bass sweep" tracks to perform this test. Other signals will not
provide meaningful results.
When a bass note is stopped within music, the sound in the room at some frequencies may
still continue for some time. That is because the sound reflects back and forth between walls,
resonating and forming "modes" before eventually dying down. This is not altogether bad and
some reinforcement is normally desirable for natural sounding playback, but you would like to
keep it under control and not have some notes sounding muddy or lingering much longer than
others.
The top graph on the Bass Decay display shows the frequency response of the bass range,
similar to that shown with the Frequency Response analyzer. The bottom graph shows how
long it takes the sound to decay at each frequency. As shown on the legend to the right of the
decay graph, the white area extends upward to indicate when the level drops no more than 5
decibels (dB). The light blue indicates when the level has dropped between 5dB and 10dB,
etc.