THX ARENDAL, Handbook

Page: 34 / 48

Positioning - Surround Speakers
Our 1723 Surround & Surround S TriAxial surround
speakers come in a confi guration of Left and Right speaker.
This design is a culmination of a regular direct-fi ring two-
way speaker, with two full range drivers added to the sides.
It is a mix of a monopole and dipole confi guration and
in our opinion this is the superior layout for a surround
channel.
The reason for the left and right specifi c speakers is that
the side mounted drivers in this TriAxial surround are
mounted out of phase with each other, is to create a large,
rear surround fi eld. The side driver that is in phase with
the front mounted drivers, needs to be the one pointing at
the front speakers for optimal surround effect placement
and steering. This means that the TriAxial surrounds are
mirror image pairs.
This speaker works equally well as height or presence
channels as well and can even be mounted on the ceiling
with our wall-mount brackets.
Ideally you have a rectangular room, with at least 38%
of the room behind the listening position, solid front
and rear walls and nothing to block the forward and
rearward radiation of the TriAxial Surrounds. Unlike the
front speakers, the strong front and rear wall refl ections
are very much part of how the TriAxial (and any other
surround with side fi ring drivers) surround works.
TriAxial surround speakers should be ideally mounted
50-60cm above head height and directly to the side of, to
10deg behind the listening position. Higher will work too,
as will a bit further back.
Surround Back Channels
When mounting as the surround back channels in a
seven channel system, the in-phase drivers should be
mounted pointing at each other in the center of the
rear wall. Meaning, the Left speaker should be placed in
Right position at the back wall, and the Right speaker
on the Left side. This means the out of phase drivers are
working in phase with the out of phase drivers on the side
channels. Between them, this pairing continues to assist
with placing pin-point images at the rear, whilst working
with all of the other drivers to diffuse the sound fi eld
around these effects.
Height Channels
When mounting as front heights, the in-phase drivers
should point outward so they are working in concert
with the same driver on the side surrounds - If you follow
the logic, it’s easy to see how you can get and expansive,
seamless sphere of sound from the height channel deck,
that is also capable of passing objects around between
the 1723 Surround TriAxial speakers with real precision.
Meaning, the Left speaker should be placed to the Right
and the Right speaker the the Left side.
Recap
• Try to avoid enclosing the center speaker in a cabinet
or between shelves of a rack.
• Position the speaker at ear level. If you can’t point
them up or down so they point at ear level.
• Position the left and right speakers at a maximum of
60deg, but no closer than 30cm to the nearest wall
and preferably more to the sides.
• Cover the fi rst refl ection point on the fl oor with a rug
as a minimum.
• Toe the speakers in to point directly at the center
listening position, even if you habitually sit off axis.
Now you can press the Auto EQ button!