WHAT WE TEST
THX engineers complete hundreds of different scientifically-formulated tests to ensure the highest audio visual standards possible.
Not all “loud” sounds irritate an audience to the same extent. The irritability of sounds to an audience is frequency and duration specific. For example, breaking glass at 85 decibels is far more irritating to an audience than a foghorn at 85 decibels. THX engineers complete hundreds of different scientifically-formulated tests to ensure the highest audio visual standards possible. Rather than simply measuring “volume,” the standard seeks to measure “annoying volume.”
Leqm defines trailer volume as a decibel average over time, using a specific filter that emphasizes the mid and upper-range sound frequencies. The mid-range frequencies are most annoying to an audience. Breaking glass, shrill voices, and fingernails on a chalkboard all register in the mid-range. The filter characteristic is defined in the TASA Standard. At any given time, the TASA Standard identifies a specific Leqm number as a recommended upper volume limit for trailers in order to bring the audio level of trailers closer to the features they precede. The current upper volume limit is Leqm 85. Find out more about Certification…