Thiel CS3.7 Product Support Bulletin page 2

"The world should experience the performance of this exceptional loudspeaker."
Cabinet
The cabinet plays an enormously important role in the quality
of music reproduction, and so the engineering of the CS3.7's
cabinet incorporates several innovations that contribute to
the speaker's stunning clarity, its utter tonal neutrality and its
exceptionally realistic imaging.
The cabinet's most important function is to completely contain
the energy generated by the drivers to the inside of the cabinet.
If even a miniscule amount of this internal energy escapes
through vibration of the cabinet walls, distorted sound will be
generated that will obscure the music's delicate details. Cabinet
wall motions of even one ten-thousanths of an inch or less will
produce audible distortion, and so it is very important that all
cabinet walls are as strong and rigid as possible. In this regard
the CS3.7 performs extraordinarily well, with all the cabinet
elements innovatively engineered to provide exceptional
rigidity.
Another task the cabinet must perform is to allow the sound from
the drivers to radiate freely without encountering cabinet edges or
cavities that will diffract some of the energy, causing interference and delayed sounds that produce tonal colorations and obscure
spatial information. In this regard, the CS3.7 provides exceptional results with its gently rounded cabinet top and sides.
Yet another cabinet function is to position all the drivers properly so that the listener hears the sound of each driver at the same
time. The CS3.7's sloping front is designed to achieve time coherence between the sonic output of the woofer and the midrange/
tweeter array.
And finally, the cabinet should avoid cavity resonances and standing waves in its internal spaces. Here also, the CS3.7 performs
well, with the curvature of its sides and top, along with its angled baffle, presenting virtually no parallel walls.
The speaker's front baffle is
machined from aluminum, a
material more than 30 times
as strong as the usual MDF. In
addition to reducing unwanted
vibrations, aluminum also
provides a rigid mounting of
the drivers so they cannot move,
even a miniscule amount, in recoil
from the forces they generate to
accelerate the diaphragm (every
force has an equal and opposite
force).
The baffle's sloping angle positions
the drivers for proper
coherence.
6
—Matthias Böde, STEREO Magazine, January 2008
time
www.thielaudio.com
Reducing Diffraction
This diagram illustrates how
energy from the tweeter (blue) is
diffracted from cabinet edges and
a nearby driver cavity (red).
The cabinet top is made of
die-cast aluminum whose
shape provides several
important advantages.
First, it provides
enormous strength,
virtually eliminating unwanted
vibration. Also, its rounded
shape around the midrange eliminates diffraction of
energy from the midrange and tweeter. In addition, the
rounded shape helps minimize resonances within the
cabinet.
The construction of the cabinet sides also plays its
part in the CS3.7's rigid, low vibration cabinet.
The sides are made of 15 layers of hardwood
laminated together into a curved shape
under high pressure. This
results in a much stronger
panel than usual, with the
curves adding greatly to
its rigidity. The rounding
at the front of the
speaker also reduces
unwanted diffraction,
and the gentle rounding along the cabinet sides creates
non-parallel walls
to minimize internal resonances.
Here it is illustrated how the
CS3.7's rounded baffle edges and
flat midrange diaphragm allow
the tweeter's energy to leave the
cabinet without being diffracted.