Thiel CS2.4 User manual

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Product Review – Thiel CS2.4 Floor-Standing
Speakers – July, 2003
Introduction
Thiel Audio is a medium sized speaker
manufacturer, co-owned by Jim Thiel,
who is Chief Engineer and CFO, and
Kathy Gornik, who is President and
Marketing Director. Located in
Lexington, Kentucky, the company is 25
years old and has garnered many
awards for their various models.
The Design
This is our first review of Thiel speakers,
with the newly released model CS2.4.
They are a floor-standing speaker, with
a tweeter and midrange driver that
share the same voice coil.
This results in a coincident sound for
the highs and mids, meaning that they
are coming from the same spot on the
enclosure. It is a technology developed
in 1997 for the CS2.3s, and has also
been used in their PCS and MCS1
speakers. The version in the CS2.4 is
improved over the one in the CS2.3.
The photo below shows a close-up of
the tweeter/mid driver. The center 1" is
the tweeter, with a small black rubber
surround, then the midrange driver, and
its surround. The crossover between the
midrange and tweeter is mechanical
rather than having capacitors and
inductors in the signal path.
The woofer is 8" in diameter, and below
this is a 7 1/2" x 11" passive radiator. All
the drivers use metal cones.
Electrical crossover between the woofer
and tweeter/mid is first order, at 1 kHz.

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The enclosure is finished on all sides
(including the insides) with wood
veneer, having several choices,
including my favorite, natural cherry.
The grilles are metal frames that attach
by use of small magnets embedded in
the enclosure front metal plate.
The speaker binding posts are of very
high quality, are extremely heavy, and
gold plated. They are not bi-wirable.
If you notice from the photos, the
speakers are angled back. This aligns
the voice coils of the drivers in a vertical
plane, since the woofer voice coil would
otherwise be farther back than the voice
coil of the tweeter if the speaker were
straight up and down. As a result, the
sound from the tweeter and woofer
reach your ears at the same time. Why

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doesn't everyone do this? Because it is
more expensive to build an enclosure on
an angle.
The front edges of the enclosure are
beveled. This reduces air turbulence
from the drivers, and reduces coloration
of the sound. Again, it's an expensive
piece of carpentry to do this.
The CS2.4s are 4 Ohms nominal and
medium sensitivity, so a high quality
amplifier must be used to drive them.
The Sound
I tested the CS2.4s with a McCormack
CD Transport and DAC, Balanced Audio
Technology VK-5i preamplifier,
Balanced Audio Technology VK-500
Power Amplifier, McIntosh MC-602
Power Amplifier, and Nordost Cables. I
toed the speakers in at about 150
towards my listening position.
It took several days of constant music
playing to break these speakers in, but
the major change occurred in the first
couple of hours. They started out with a
slightly harsh upper end and thin bass,
but they soon opened up. I broke them
in with some pretty heavy music, played
at medium volume, with about 30 - 60
watts of power.
I have to say right off the bat that the
CS2.4s are some of the best speakers I
have ever heard. The soundstage was
very tall, as if the whole wall were alive,
almost like listening to my planar
speakers. However, planar speakers
sometimes tend to lose a bit of detail
because the sound is coming from such
a large surface. The CS2.4s, on the
other hand, although having a large
soundstage, still maintained a
magnificent amount of detail, probably in
part because of the coincident tweeter
and midrange drivers.
The bass was tight, never boomy or
chesty, the mids were clean and never
overly sibilant, and the upper
frequencies were crisp without being
edgy.
One of my favorite CDs of all time is the
Telarc recording of Copland's Fanfare
for the Common Man. It has high
pitched trumpets and thundering bass. It
is also a good test for any audio system.
The Thiel's handled this piece in stride,
without breaking up at all. The bass was
tight and clean, and the huge bass drum
used in this recording is a stress test to
end all tests. (You can click on any of
the album cover art photos to see more
details, including catalog numbers.)
Tony Bennett, Mary Chapin Carpenter,
and Natalie Cole stand close to their
microphones, and their voices are so
clear, that any chestiness or sibilance
produced by speakers becomes very
apparent. The CS2.4s put these terrific
performers into my room for a private
concert, with no hint of such artifacts.

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Dukas' La Peri on Erato is another great
recording that does not use dynamic
compression. The brass, as presented
by the CS2.4s, raised the hair on the
back of my neck, as it should, but will
not if the speakers are incapable.
For violins, Tchaikovsky's Serenade for
Strings is a fine test. The CS2.4s gave
me a clear view of all the string sections
here. No mushiness or bloated
midrange that would be suggestive of
high THD.
I found I needed about 30 watts for the
listening level that I like, with peaks from
60 watts to about 120 watts (as
indicated on the McIntosh MC-602 level
meters that measure voltage and
current to display the watts).
On the Bench
Distortion at 40 Hz and 100 dB
(microphone was 8" away from
respective drivers for distortion tests),
showed excellent results, with less than
2% THD.
At 50 Hz and 100 Hz, distortion was less
than 1%. This is very good performance.

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At 1 kHz and 100 dB, distortion is very
low.
IMD measurements showed very low
distortion using a combination of 1 kHz
and 1.5 kHz, or 5 kHz and 6 kHz.
With a 10 kHz sine wave input,
distortion again, is very low.
The frequency response is quite flat.
The dips and peaks are somewhat
larger than what I get with some smaller
speakers because I have to put the
microphone farther away (I use a
distance equal to the distance between
the outer edge of the upper driver and
the outer edge of the lower driver, which
in this case, includes the passive
radiator). See how the response
fluctuates around the - 20 dB line. This
is flat!

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The impulse response shows the peaks
for the drivers are very close together,
indicating that the time alignment design
of this speaker is working. In the bottom
plot, the time interval between the
vertical red line on the left, and the 2.8
ms line on the right, is 2.8 - 2.229 =
0.571 ms.
Impedance/Phase results show that the
impedance stays down around 4 Ohms
at 100 Hz and above, while the electrical
phase is within + 300to - 600throughout
the audible frequency range. Don't try
and drive these speakers with a mass
market receiver. At least 200 watts RMS
per channel into 8 Ohms, with a rating
into 4 Ohms, will be a good choice.
Conclusions
Thiel's new CS2.4 speakers are superb.
They have no noticeable tonality
aberrations, i.e., they sound neutral
throughout their range, they have a big
soundstage, and have marvelous detail.
They will undoubtedly be one of the
great speaker introductions of 2003. At
their price, I have never heard anything
better, and many are not nearly as
good. They are beautifully constructed
and pleasing to the eye. Recommending
the CS2.4s is one of the easiest jobs I
have had to date.
- John E. Johnson, Jr. -
Specifications:
_ One 1" Metal Tweeter, One 3 1/2" Metal
Midrange Driver, One 8" Metal Woofer, One
7 1/2 x 11" Passive Radiator
_ MFR: 33 Hz - 37 kHz - 3 dB
_ Phase Response: ±100
_ Sensitivity: 87 dB/2.83V/M
_ Nominal Impedance: 4 Ohms
_ Size: 41.5" H x 11" W x 14" D
_ Weight: 70 Pounds Each
_ MSRP: $3,900/Pair (Available in a variety
of veneers - review samples were in
Amberwood)
Thiel Audio
1026 Nandino Boulevard
Lexington, Kentucky 40511-1207, USA
Phone: [phone]
Fax: [phone]
www.thielaudio.com
July 23, 2003
Reprinted from Secrets of Home Theater and
High Fidelity, July, 2003. © Copyright SDI, Inc.
All rights reserved.
http://www.hometheaterhifi.com