Carnegie Acoustics CST-1 Leaning Transmission Towers
A very tantalizing $2k two-way speaker.
Review By A. Colin Flood
Acoustics' Ron May is as interesting as his loudspeakers. "My background is
acoustics and physics," he said. "In 1972 I was introduced to high end audio by
a neighborhood friend whose brother was sending him components back to Kentucky from
Japan while he was in the service. I became intrigued instantly with
loudspeakers and their design. I started designing and building a few different
loudspeakers." He admits his first designs were okay, but May felt he wasn't
great at building cabinets and couldn't find anyone to build them for him. So he
went to vocational school and became certified as a custom cabinet builder in
the residential building industry. "Then when I could build better cabinets, I
realized the off-shelf drivers, which I had access to, were riddled with
problems, so I started working on the designs of my own." Years later, May
started a company that made car audio speakers that became globally successful.
May said he grew up without much. Living in
Eastern Kentucky, he couldn't afford "the nicer gear that my buddy had." So, May
vowed that if he ever had the money, he'd start a loudspeaker company that
performed exceptionally well and was a tremendous value so that everyone could
afford nice gear of their own. "I cut my teeth on gear," he said, "that would be
hard to be beaten even by today's standards but couldn't afford it. Carnegie
Acoustics is better than the loudspeakers I grew up listening to! Interestingly
enough, the retail cost of the CST-1's is less today than the ones I was so fond
of back in 1972." Carnegie uses different global vendors for the components. "All
components are proprietary and made to our strict specifications." All Carnegie
Acoustics loudspeakers are designed by May and his engineering department/team.
Like the company's model Skates, the CSTs slope
backwards. The front and matching back angle slope is five degrees. "We think of
our speakers as art and want to share something beautiful," May said. "The
contemporary style is aggressive and sexy at the same time." "Consumers aren't
used to getting this high-end performance; artistic style and superior finish
quality at anywhere near our incredibly affordable prices. We felt that
continuing the slope in the back gave it a more unique and attractive look.
Trust me, it definitely didn't make it easier to manufacture! But I just like
the look better so we worked it in."
The internal transmission line is a cascading labyrinth of
Carnegie's own, proprietary and confidential design. May got the frequency
response so flat by choosing "how we want this speaker to perform and at what
value can we bring it to market?" He said "with all that in mind, we then design
the drivers, fine tune them to be as accurate and dead flat as possible and then
design the cabinet around them. Then we design the crossovers, sit down and
listen for days. We also take into consideration the fact that all loudspeakers
have a break-in period and that 99 times out of 100, a customer will be
listening to our products while in a retail store with the speakers having very
little break in time, so they have to sound really good fresh out of the box."
Even so, May suggests about 100 hours to break the CSTs in. "After
a few months of playing them and letting them meld into your room," he said, "you
will hear them open up even more. The thing I notice the most when they are
broken in is that they reproduce with great ease and it seems even more natural
to me. They are also very easy to listen to for hours. You'll realize how well
they really sound when you listen to another brand of speakers. Then I think
you'll notice how much more pleasing and sensible the CST-1's truly are. I hope
you enjoy them as much as we do and see them for what they truly are...
Affordable Audiophile." Carnegie has about 25
authorized dealers in the United States that carry an inventory of the product
and can deliver immediately. Orders placed from areas of the US that do not have
a retail store will be shipped that day.
The specifications said plus or minus two decibels. That means
an incredibly flat 2dB frequency response, within 20 Hz to 20 kHz, in a slim
$1999 tower! Almost in the same league as very expensive full-range speakers,
the CST-1s are down only 3dB @ 40 Hz. Dimensionally, they are not quite four
feet tall and only 8 inches wide. At first glance, CSTs are merely
black-on-black, cones in boxes. They don't have B&W's distinctive yellow
Kevlar drivers. Or Klipsch's trademark copper cones. (Just like Audi's LEDs at
night, you can easily spot Klipsch or B&W drivers from miles away! Smart
marketing.) Make no mistake, the CSTs are slim, phase-aligned, backwards-leaning
towers with 0.75" medium-density fiberboard walls and composite dampeners,
deploying a planer magnetic tweeter and 5.25" VipaCore woofers. Voice coil size
is 26 mm. Free air resonance (Fs) is 53.5 Hz on the woofers and 550 Hz on the
tweeters. Carnegie designed the drivers and manufactures them in China. The CSTs
are black gloss piano finish with black magnetic grills and a five-year
warranty. Efficiency is an above average @ 91dB/W/m. The ‘CST' stands for
Contemporary Series Tower and the '1' means it is first generation.
Another, similar loudspeaker I remember fondly was the
deep-digging Newtronics Skates.
Also back-wards leaning towers, also only $2000, the Skates also used an
interior folded transmission line, like a horn, to wrap bass to its lowest
frequencies. The Skates were the only average size loudspeakers I reviewed to
reach the inaudible 20-Hz at normal listening levels. In fact, both loudspeakers
made me think they "may not need a sub-woofer for music... well, maybe not right
Tests Reveal Above Average Notes
When I review, I consciously listen to a
variety of music (See "Test Discs, Reference Recordings For Subjective and
Analytical Comparisons"*). While Jaton's pleasing Operetta A2300AX* amplifier
was "in the house," I experienced the same semi-somatic bliss of audio nirvana
with the CSTs as I did with the six-times-more-expensive Jaton
A3s and the single driver Supravox Carlas* (also $2000) loudspeakers. On
the Enjoy the Music.com judging
system (See "Our Reviewing Standards"*), four Blue Notes is better
than the average equipment the reviewer has auditioned. I really
enjoyed the Jaton A3s and slathered Blue Notes all over their categories. The
A3s are a far more complex and expensive speaker than the elegantly simple
Carlas. They have a much wider frequency response and require a more powerful
amplifier. Yet I see the Carlas are covered with Blue Notes also. In comparison
to those two speakers, the CSTs only appear
average across the board; their score reflects their even balance through-out.
Like an Audi sports car, they handled well both day and night.
With Don Garber's charming new 1.5-watt Fi X4 tube amplifier (review
coming) on the CSTs, I heard tantalizing details and textures. This was even
more apparent with Red Wine's more powerful, battery-powered Clari-T amplifier
(15-watts). Yet while I loved Garber's X4, it did not wake the CSTs up the way
that the far more powerful Operetta did. Tonality was smooth, just not as
single-driver focused, nor warm and soft as the Carlas.
(10Hz – 60Hz)
Reaching down as low as they go, the CSTs clearly earn an extra Blue Note
in the deep category. For all but the most purist tweaking audiophile, the CSTs
are going to come across as a very well-balanced, even performer. In fact, only
for the powerful dynamics and extremely wide frequency response of orchestral
music and the "slam-bam" of action, did I ever need my ACI Titan sub-woofer. In
this regard too, once again, the CSTs resemble the Skates in performance.
(80Hz - 200Hz)
This characteristic is notable throughout all of the Enjoy the
Music.com categories: where speakers have wide and general neutrality, there
is not only less to notice about them, but there is also less color to add.
Mid-bass is fairly even and flat. Not a lot of punch, but not a lot missing
either. You don't need
above-average sensitivity loudspeakers for simple tasks like mid-range vocals at
moderate volumes. You do need them
for the rumbling moan of tympani, sonic boom of kick-drums, pop
of gun-shots, liquid quaver of piccolos and tingle of triangles. Simply see Our
Reviewing Standards for frequency range chart.
While the Garber X4 is so delightful on my big ole Klipsch
horns, and it certainly was everything most music and movies in my smallish
listening room required, the CSTs needed something a little more powerful than
1.5-watts. I tried to get one of new tube amps I heard at AXPONA to review with
these leaning towers, but to no avail. When you listen to CSTs with something as
nice as the Operetta, you will hear all the bass, and everything else, you want.
(200Hz - 3000Hz)
In fact, I was able to hear some $7000 loudspeakers with Cary front-end
electronics recently in an ideal room, an acoustically treated recording studio.
Indeed, the mid-range of the $7000 loudspeakers was lush, soft, warm, enticing
and smooth. By comparison, the CST mid-range is smooth and accurate sounding,
without being overly lush or soft. In all other respects, they are serious
competitors to the more expensive loudspeakers. For the same price, the Carlas
also give you a warm, soft, engaging mid-range, but leave you wanting more
treble and bass.
frequencies (3000Hz on up)
The Mundorf tweeter in the Jaton A3s and the Garber X4 on my big ole
horns spread sweet icing all over their home-made musical cakes. It was hard to
come back down to store-bought cakes. The CST is more of the typical retail
off-the-shelf treble. I don't have serious complaints about it; but I can't
shower it with Blue Notes either. No faults here. CST treble was always capable,
just not sparklingly obvious. By comparison, the treble on the Carlas is also
obvious missing as is typical of many single-drivers designs due to not having a
Many loudspeakers are designed for showy bass and/or treble.
Designers intentionally tip up the bass and/or treble response. This includes
smart marketers of some very famous and expensive loudspeakers with yellow
Kevlar cones. Nothing necessarily wrong with that. It helps loudspeakers sound
impressive in the show room, and maybe even at home. Only tweaking audiophiles
eschew such artifices in favor of purist flat response.
Again, this yet another category where the CSTs are... well, average. In
a good way. Not speed kings like the Classic Audio Reproductions' Cinema
Ensembles SEE REVIEW*, but not sluggish either, like a low-efficiency speaker
that really needs a lot of amplifier push (damn! I am I picking on those yellow
Kevlar cones again?). Small cones can be very responsive in both attack and
decay. The CSTS are no exceptions. One problem with small cones is the lack of
mid-bass. The solution, like the CSTs and the Skates, is to pipe the sound down
the tower to the rear port – hence, the impression of depth. It works on
single-driver Lowther designs (see this
link). It works here with dual 5.25" VipaCore mid-bass woofers. The
drivers have a natural (free air) resonance peak at an already low 53 Hz; the
folded transmission line inside simply extends the mid-bass down to 40 Hz.
Sustain is the plateau of a note before it hits the downhill side of the slope.
A powerful amplifier like the Operatta can hold and extend the plateau; it makes
mountains out of note hills. Here again, the CSTS are good enough to show off
the capabilities of a quality amplifier.
With small cones, difficult-to-define inner resolution can be quite
enticing. A very good example of this capability is the otherwise dull Vince
Christian E6c system. During orchestral music, with so many various
instruments playing at the same time, the multiple small drivers of E6c had a
notable ability not only to differentiate delicate details, but also to paint a
wide, wrap-around soundstage! That doesn't mean that small drivers are "the end
all and be all" of speaker design. Oh no, far from it! Small loudspeakers suffer
from a sack of sorrows (see exceptional Axiom Audio Millennia M3Ti SEE REVIEW).
Yet the small drivers of the CSTs don't struggle to reproduce music. Instruments
are not "jambled" together. Separation is good. Dynamics are also
good. Better with power of course. Still, they do capture the joyous essence of
Soundscape: Width Front,
Rear, Depth & Extension
In my listening room, speakers auditioned here rarely project a sonic 3D
holograph into the room. Yet, positioned out in the center of the room,
the CSTs exhibited very good imaging and sound staging. Whether small rock
group or large symphony orchestra, their soundstage was wide at the front and
rear, deep at the back. Singer and musicians displayed in a realistic sound
stage, just not forward, in front of the speakers.
positioned and in phase, the CSTs created a good 3D phantom of the singer's
voice. Accompanying instruments were not obviously three-dimensional, but then
they rarely are, except on really large or exceptional speakers. The CSTs easily
replicate the cozy cafe or intimate studio recording session that many tweaking
audiophiles seek. In comparison, the Carlas easily image only the lead singer,
while the Jatons add three-dimensionality to most of the band.
Fit and Finish
No other nits to pick. No complaints here. The basic black "speaks" came as many
do, doubled boxed in two inches of foam with a thin Styrofoam wrap. I think a
plastic layer is a better moisture barrier. Since there is no awkward plate
screwed on to their smooth back-sides, the CSTs have a tiny gold hole in their
backs, where a banana plug goes. The only way to attach spade cable connectors
to the CSTs is with an adapter. The connectors are Electra Cable solid copper
tube connectors. The pinholes were a problem for me at first, but swap around a
couple of speakers and amplifiers a couple of dozen times and you learn to love
the simple and tight push-in connection.
Carnegie Acoustics' Ron May said this design provides the
greatest surface area contact with the least mass resistance. "They are the best
connectors money can buy and the closest thing to having no connectors in the
signal path," he said. "When a manufacturer uses a big shiny speaker terminal,
it's usually gold plated brass and brass is a horrible conductor of electricity.
Additionally, when using a big shiny speaker terminal, the amplifier has to
charge the entire speaker terminal "mass" which causes a resistance in
the signal path. We know how resistances fluctuate during play, so we eliminate
this from the beginning by not adding the mass and the added probability
in the first place."
May said that for customers who do not have banana plugs, they supply
gold plated, solid copper banana studs in the box as an added performance
convenience. The studs they provide are for permanent soldering to a customer's
cables. "That is obviously the method that we prefer." Adapters are available
from Best Buy and Kimber Kables. May said "if a customer had spades soldered to
their cables and did not want to cut them off and instead use our solid copper
studs, I would recommend them getting the adapters from Kimber."
Internal dampening is polyfill and a proprietary asphalt
dampening material. The front of the cones are treated and sealed. There was a
set of brass feet (best for carpets). If you didn't know they are in the box,
you wouldn't find them.
Value for the Money
At one end of the spectrum are superior loudspeakers like the $12,000 Jaton A3s
and the $20,000 Klipsch Palladium. Let's face it, for that kinda dough, that
level of loudspeaker rarely does anything seriously wrong, especially when
coupled with the proper amplification. Because I powered the CSTs with one of
the sweetest tube amplifiers I have ever heard, the Garber Fi X4, and also the
solidly capable Operetta, I can say the CSTs also do nothing seriously wrong!
Their surprisingly flat 20 Hz to 20 kHz frequency response, within a narrow 2dB,
down only -3dB at 40 Hz, belies an amazing capability for the money. Compared to
the $7000 loudspeakers I heard recently, the CSTs are a solid bargain. Because
of their price, I can easily award the CSTs another Blue Note in this category.
In my own Enjoy the Music.com
category, the CSTs are indeed a fourth Blue Note – above average. I was very
pleased with a many aspects of their performance. Despite not having the oomph
to wake the CSTs up during the workday, the Garber X4s on the CSTs easily
tempted me into late-night smooth jazz sessions. I did enjoy the music. Given
their relatively medium size the CSTs never failed to impress with the depth of
their bass for such a small loudspeaker. The CST sound, efficiency, looks,
construction, specifications and price make them one of the most competitive and
compelling offers in a very crowded market. We will certainly be seeing more of
this company. Doug Smith of sub-woofer king, Velodyne, signed on to Carnegie for
sales and marketing. He says "what impressed me the most about Carnegie
Acoustics and drew me to the company is its overall integrity. From quality of
parts and construction, to the clarity, dynamics, transparency and musicality of
the products, Carnegie Acoustics truly is Affordable Audiophile."