The THX logo has labeled a
profusion of audio and video product for decades. Yet
many folks wonder, what is THX? THX is simply a
standard 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
- 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
- Listener placement near room boundaries creates excessive
- Rear channel effects are often unconvincing via dates
surround sound encoding.
As a result, THX standards institute the following
modifications to the electronic processing and the speaker
- 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
A single source of low bass, the subwoofer,
simplifies the management of distorting low-frequency room
- 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.
In addition, consider a horn speaker design for the larger
room with many rows of seating. Though not THX
prescribed, a mid/tweeter horn array can broaden mid and
high frequency dispersion from the front row to the
last. However, this design will also sacrifice optimum
performance at the focal point of the room, which might be
your seat. In any case, if you accept THX assumptions
and concur with their solutions, then this is your design