tELU DIO - HI-FI Clubbass port is designed to reduce air turbulence and eliminate audible port noise. Thiel says the heav - ... classic 1971 LP Blue, and my old Toto fave “Rosanna,”

trt e s t r e p o r t s s p e a k e r s

What happens when a speaker company gets sold? It depends. Definitive Tech-nology is still doing pretty much the same thing 9 years after it was acquired. Acoustic Research (AR), on the other hand, produced good speakers for 3 decades

after its original sale in 1967, yet the once-hallowed brand is now applied mostly to acces-sories. ¶ Thiel Audio was sold to an investment group just last year, so it’s too early to tell, but at least the products haven’t changed. The new CS1.7 continues design concepts that the company embraced in the late 1970s — specifically, a focus on phase coherence.

Thiel AudioCS1.7 tower SPeAKerS  /  $3,999 Per PAir /  by BreNt BUtterwortH

ELECTRONICALLY REPRINTED FROM SEPTEMBER 2013

the home entertainment authority

Most speakers alter the phase of sound as the frequency changes. For example, a 500-Hz tone might start with the speaker cone pushing forward, while a 5,000-Hz tone might have its phase shifted so it starts with the speaker cone moving backward. In a typical speaker, the phase of the sound might be flipped several times as you go from the lowest to the highest frequencies. In extreme cases, this shift could cause some fre-quencies to be substantially delayed relative to others.

Unless phase shift is radical, it’s not readily audible. To my ears, though, the few speakers that are phase-coherent — maintaining the same phase response, plus or minus a few degrees, at all frequencies — present a more realistic and dramatic sense of space than non-phase-coherent designs do.

That said, phase coherence isn’t a magic equation for sonic excellence, because there are many trade-offs. The shallow crossover slopes needed to maintain phase coherence put extra stress on the tweeter, poten-tially causing distortion or even failure. They can highlight the woof-er’s tendency to beam in the midrange and create “cupped hands” coloration. And they can increase interference between the drivers, which leads to inconsistent vertical dispersion. The late Jim Thiel — the company’s chief engineer for most of his life — openly acknowledged these problems, and he worked for decades to overcome them.

The CS1.7’s 1-inch tweeter and 6.5-inch woofer mount on a slanted baffle, so their acoustical centers are aligned vertically. The stamped-aluminum, flat-diaphragm woofer is said to be capable of smooth opera-tion to 10 kHz, although it’s crossed over to the tweeter at a very low 1.44 kHz. The unusual, slot-shaped front bass port is designed to reduce air

turbulence and eliminate audible port noise. Thiel says the heav-ily braced enclosure is 42 percent heavier than the one used for the CS1.7’s predecessor, the CS1.6.

Like other Thiel speakers, the CS1.7 uses a first-order (–6 dB per octave) crossover, the response of which allows the drivers’ outputs to sum without substantial phase shift. The CS1.7 is also like other Thiels in that its crossover uses extra filter networks to smooth the frequency response and achieve consistent impedance at all frequencies. Although a first-order crossover can be done with just one capacitor and one choke, I counted eight capacitors and five chokes arrayed across two separate circuit boards in the CS1.7.

Another trait the CS1.7 shares with other Thiels is its flawless craftsmanship, with gorgeous wood veneering done at the company’s fac-tory in Lexington, Kentucky. Let’s hope the new owners never abandon this tradition.

setup I connected the pair of CS1.7s to a Krell S-300i inte-grated amplifier (later adding a Job 225 amp), using my Firestone Audio ILTW USB digital-to-analog con-verter and Pro-Ject RM-1.3 turntable as sources.

In my experience, highly tuned and tweaked speakers such as the CS1.7 almost always benefit from careful experimentation with positioning. First, I placed the pair in the same positions I customarily use for tower speakers, then backed them closer to the wall until I got enough bass re- inforcement to produce a satisfying tonal balance.

Next, I experimented with toe-in. I started with the speakers pointed straight at me, but the tonal balance sounded a bit bright in this posi-tion. So I tried pointing the speakers straight ahead, parallel to the room’s side walls, but this reduced the focus of the center image and also muted the upper treble response a bit. I got the best sound with the Thiel speak-ers toed in a little bit more than halfway toward me.

Thiel includes a set of heavy-duty pointed feet for leveling the CS1.7. The company also offers optional

“outrigger” legs that stabilize the speaker — a good idea if young kids are around, because the speaker’s 9.5-inch width makes it a tad tippy.

performance My first Thiel speakers review — of the CS2.2 tower and the SCS book-shelf — dates to about 20 years ago. Back then and still today, Thiels had a rep for highly detailed sound that is best suited to more delicate music like classical, folk, and jazz, but not so good for rock.

Continuing my longstanding tradition of starting with material I think will sound bad with the speaker under test, I cued up an MP3 download of “Dumb Disco Ideas” by Brooklyn synthpop duo Holy Ghost! (The exclamation point is theirs.) With its jamongous ’80s-style drum sound, a bass line that sounds like it was swiped from a Cameo tune, and

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plus + incredible detail + Dramatic ambience + unsurpassed craftsmanship minus – not suited for heavy music or deep bass – a tad trebly at times

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The Thiel Audio CS1.7 measures differently from what subjective impressions suggest, with a downward (reduced treble) tilt in the tonal balance. The large ±7.2-dB variance you see here is largely due to rolloff at very high frequencies; with the measurement limited to 10 kHz, response measures ±4.8 dB. Off-axis response is excel-lent: Below 10 kHz, the CS1.7 measures almost the same at ±60° as it does at 0° on-axis. Impedance runs below 5 ohms through most of the audio range, so be sure to use an amp with a 4-ohm power rating that’s double or nearly double its 8-ohm rating. With 88 dB measured sensitivity at 1 meter, though, the CS1.7 doesn’t need a whole lot of power; even 50 watts would be plenty. Bass output is decent for a speaker with a 6.5-inch driver, averaging 113.6 dB in the low bass (40-63 Hz) octave and 84.4 dB in the ultra-low bass (20-31.5 Hz); you’ll get roughly 6 dB more output from a pair of CS1.7s. — B.B. // For more Thiel lab data, go to soundandvisionmag.com or consult the tablet edition of this issue.

percolating keyboard effects soaked in digital reverb, this is music composed to play through crappy P.A. speakers, not through $4,000-per-pair audiophile speakers.

Heard through the CS1.7, however, “Dumb Disco Ideas” astounded. The phase-coherent design worked just as much magic with EDM keyboard squiggles as it did with acoustic guitars on audiophile recordings. The ambience wrapped my room, the sounds swirled behind me, and the bass pulsed deep and tight. I turned the system up to the kind of volume this music demands, then pushed it further to see how loud the CS1.7 could get before it sounded raspy: about 98 dB from my listening position, or about 6 dB louder than I might usually listen.

This wasn’t what I was expecting. Wanting to explore the CS1.7’s bass dynamics further, I kicked over from Holy Ghost!’s fake-’80s tune to a real one: “What It Is” from Miles Davis’s 1984 album Decoy. On this record-ing, Miles, guitarist John Scofield,

and saxophonist Branford Marsalis sounded natural and detailed. But Darryl Jones’s explosive, thumb-slapped bass line lost its impact, and the sound got too thin.

While I was still in the Miles folder on my laptop, I decided to play the similarly titled “What I Say” from 1971’s Live-Evil — and suddenly, we were back to amazing. Michael Henderson’s finger-plucked bass line proved no problem for the 6.5-inch woofer; in fact, it sounded exceptionally precise and grooving. Percussionist Airto Moreira’s agogô bells imaged spookily about 2 feet from the inner side of the left speaker, nestled in the sonic wash of Keith Jarrett’s electric piano like a Chihua-hua in a beanbag chair.

The rest of my listening sessions with the CS1.7 went like that. The closer I got to heavy rock, like ZZ Top’s “Chartreuse” (from the cur-rent La Futura), the more the CS1.7 sounded thin and trebly, more like a mini-monitor than a tower speaker. The closer I got to purist, minimalist

recordings, like NYC avant-jazz group Flip City’s self-titled debut, the more the CS1.7 amazed. With that last recording in particular, the CS1.7 completely blew me away, capturing even the subtlest breaths and key clicks of saxophonist David Aaron.

I did notice as I was listening to Aaron’s tenor that the CS1.7 appeared to have a little bit of a lower-treble push — I guessed around 3 kHz — which enhanced detail but also made the sound slightly bright. Middle-of-the-road pop music, such as Joni Mitchell’s “All I Want,” from her classic 1971 LP Blue, and my old Toto fave “Rosanna,” also revealed a mild tilt toward the treble on the CS1.7.

bottom lineWhile the Thiel CS1.7 isn’t a speaker that every listener will love, it’s not intended to be. It’s a speaker for those who want to hear every last sonic detail and every subtle ambience in a recording, and who want to feel like they’re attending a live acoustical performance rather than slumping in a living-room recliner listening to a hi-fi. In other words, it’s a Thiel through and through. ••

k e y f e at u r e s

+ 6.5-in aluminum-diaphragm woofer + 1-in aluminum-dome tweeter + 36.5 x 9.5 x 11.8 in; 54 lb

tower 41 Hz to 20 kHz ±7.2 db

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Posted with permission from the September 2013 issue of Sound & Vision ® Bonnier Corporation. Copyright 2013, All rights reserved.For more information on the use of this content, contact Wright’s Media at 877-652-5295.

THIEL Audio Products ● 1026 Nandino Boulevard, Lexington, KY 40511Phone: 859.254.9427 ● Fax: 859.201.9600 ● Email: [email protected] ● Web: www.thielaudio.com