The THX logo has labeled a profusion of audio and video product for decades.  Yet many folks wonder, what is THX?  THX is simply home theater standards that manufacturers and installers must meet to be THX certified.  THX, originally a division of Lucasfilm, is now an independent company.  THX is not a standard such as Dolby or DTS.  Yet THX does outline minimum specifications for amplifiers and speakers such as flat frequency response, low distortion, and low noise.  In addition, THX makes the following assumptions:

- Many movie soundtracks mixed with a mid-range boost cause harsh-sounding playback in a home theater.

- Acoustical reflections from the floor and ceiling smear sound fields and distort the mid and higher frequencies.

- Compromised speaker placement stimulates room modes that distort audio.

- Listener placement near room boundaries creates excessive bass.

- Rear channel effects are often unconvincing via dated surround sound encoding.


  As a result, THX standards institute the following modifications to the electronic processing and the speaker system.

- THX processing features 'ReEQ' and 'Timbre Match' that alters high frequency and mid-range output, which results in less harsh sound.

- THX standards decrease vertical dispersion of the front speaker system, which should result in less distorting acoustical-reflections from the floor and ceiling.

- THX specifies smaller front and rear speakers with processing that re-routes low-frequency sound to a subwoofer. 
  A single source of low bass, the subwoofer, simplifies the management of distorting low-frequency room modes.

- THX adds 'Boundary Gain Compensation' that filters excessive bass for seating near a room boundary.

- THX implements rear dipole speaker designs, which creates a more-diffused, less localized sound.

- THX offers 'Adaptive De-correlation', which creates a more spacious image from older rear channel sound mixes.