Thiel CS1 loudspeaker manufacturer Thiel has acquired a reputation for the coherence of sound presented by its range of distinctive, sloping-baffle, floor-standing loudspeakers. Designer Jim Thiel gives a high priority to linearity of phase response; as a result, he chooses to use phase-linear, first-order crossovers in his designs, the target response being the combination of electrical and mechanical filtering. As the out-of-band rejection is then only 6dB/octave, it places demands on his chosen drive-units to be well-behaved, not only in their passbands, but also outside of them. In effect, the loudspeaker has to be designed as a whole system, the interaction between the drive-units and crossover being considerable.

The CS1 ($950/pair) is the least expensive in the Thiel range, combining a Norwegian plastic-cone, diecast magnesium-chassis woofer with a 1" soft-dome tweeter in a well-built, heavily braced cabinet, finished in real-wood veneer. The woofer is reflex-loaded with a 2.5"-diameter, 4"-deep port placed just above the name-badge trim. The complex crossover features separate legs in parallel for the two drivers, and is constructed from high-quality components, with air-cored inductors and all electrolytic capacitors bypassed with film caps and polystyrenes. Electrical connection is via high-quality, gold-plated 5-way binding posts on the base of the cabinet.

Unusually in a speaker at this price, considerable attention has been paid to the construction of the grille, in order to minimize deleterious diffraction effects. The cutout for the tweeter, for example, is profiled so that the soundwaves never see a sharp edge. The CS1s were therefore auditioned with grilles in place.

The speakers were used over an extended period of time for all my recreational listening; once I had become happy that I was getting the best sound, a more critical series of listening tests was performed using an identical selection of music to get an idea of the comparative strengths and weaknesses of each design. The tracks used were as follows: Chopin Waltz in C-sharp minor, HFN/RR test CD (my own recording, made with the Calrec Soundfield mike in crossed figure-eight mode); the drumkit recording on the HFN/RR test CD (again recorded with the Soundfield mike); Beethoven "Pathetique" sonata, Performance Recordings PR-5 (recorded with crossed figure-eight ribbon mikes); Stan Rogers' Northwest Passage (Fogarty's Cove Music FCM-004, a naturally recorded collection of Nova Scotian-style songs sung by a baritone, recommended to me by Mission's Armi Leonetti); Ray Noble's "The very thought of you" (Ken Kessler's favorite test track, the incomparable Ella Fitzgerald backed by a naturally miked big band, recorded in 1962 when engineers didn't know enough to spoil the music); and Stravinsky's Firebird suite, on Sheffield Lab CD-24 (pure Blumlein-miked orchestra, using Coles ribbon mikes). Particularly useful for judging accuracy of timbre on voice was the Freehold, New Jersey, recording of "Papa-oom-mow-mow" (Rhino RNLP 70827).

The two things these recordings have in common, apart from the fact that I know them all intimately, is that they all were recorded in such a way as to produce a tightly defined, tonally neutral soundstage, and that none have been "doctored." As I have pointed out before, how on Earth can a reviewer make valid value judgments if he doesn't know what to expect from the recordings he uses to make those judgments? Somehow he or she has to break the circle of not knowing what a recording sounds like apart from judging it using loudspeakers, the properties of which he or she doesn't know apart from judging them using the unknown recording.

A comment on the nature of my subjective assessments will be in order. There is no doubt that both readers and manufacturers prefer bold, definitive statements of opinion, all black and white with nothing in between. With speakers in this price range, however, we are dealing very much with assessing the quality and quantity of different shades of gray. My subjective comments will therefore tend to concentrate on departures from neutrality and ideal behavior, but this doesn't mean that the models reviewed were bad; rather, the compromises inherent at this price level will be more obviously audible than with speakers costing, say, $2000/pair. Nevertheless, in the right system and room, at least half of these speakers will shine, musically.

A note to those who condemn tweakery out of hand: At the start of the auditioning, I had the other loudspeakers I was reviewing for this issue in a pile in the corner of my listening room, some 10 feet from the left-hand speaker. Sitting listening to my chosen test tracks, I starting noting down adverse comments regarding stereo imaging: unstable center imaging, different image width at different frequencies, etc.

The penny dropped; I removed all the other speakers from the room; now, the imaging was actually very good. So I advise you to insist upon auditioning loudspeakers one pair at a time before making a final purchase decision. Dealers won't like you, but only then will you get a true idea of the soundstage capability of a pair of speakers. Reviewers also hate auditioning loudspeakers one pair at a time, particularly if the speakers are heavy, but I can assure you that that will be Stereophile's policy.

With the CS1s placed well away from room boundaries, there was an immediate impression of a light, airy tonal balance, coupled with excellent low-frequency definition. The woofer alignment seemed to be well-nigh perfect, with very good bass transparency. This speaker should work well with classic tube amplifiers. Midrange timbres were excellent, though strings were a little thin-sounding, and bass guitar was somewhat reticent. High frequencies were a little excessive in level, with surface noise and recorded tape hiss "whitening" a little. Breath and key noise on woodwind instruments was slightly accentuated, and snare drum acquired a few more snare wires than usual.

The slightly tilted-up HF balance seems to be an inherent feature of a Jim Thiel design; while not unmusical in itself, it does make demands on the rest of the system that there be no treble nasties. If you use a Quad 34 preamplifier, then I would recommend applying a little down tilt; otherwise, it's very easy to knock up a little passive network to fit between pre- and power amplifier or in the preamplifier's tape loop (see fig.1). As shown, this gives a response hinging down above 2kHz to level out as a –3dB shelf above 8kHz: increasing the value of the 6800 ohm resistor (use metal-film types) reduces the depth of the shelf; increasing the size of the capacitor (use a polystyrene or polypropylene dielectric) lowers the hinge frequency.


Fig.1 Simple HF shelf filter to fit in a preamplifier's tape loop.

Imaging was very precise, laterally as good as the Celestion SL6S, but there was slightly less depth apparent than with the British loudspeaker. That tilted-up HF response projected vocal sibilants forward a little, and treble depth was shallower than midrange. Instrumental delineation was excellent, however, and the CS1s were never less than musical.

The CS1 is truly an affordable high-end loudspeaker, offering a well-balanced performance with no significantly weak areas, and losing out to the more expensive competition in terms of midrange/treble transparency, low-frequency extension, and ultimate loudness.

Thiel Audio Products Co.
566 Mainstream Drive, Suite 500
Nashville, TN 37228
(615) 913-8532

jtshaw's picture

I recall the uptilt in the treble, but soundstaging, imaging, and tuneful bass were utterly transfixing at the price.

At the time I had a Proton D-940 receiver and then an Adcom GFA-535 amp and GTP-500 tuner/preamp. This system kept me listening happily deep into the evening, especially when the source was an Acoustic Research ES-1 turntable with Rega RB-300 tonearm and Audio-Technica AT-140ML cartridge.

I don't mean to namedrop equipment, but I remember the system so vividly because it was my introduction to the high end. Such a delight for a young person with a first-job modest salary in the late 1980s. Thanks so much for posting this review. It made my day.

Jikester's picture

Great equipment that also got me started in high-end audio as well. I still have the D940 (best receiver I've ever used) and Adcom GFA-535 and GTP-500.

BradleyP's picture

I recommended these to opera-loving friends in 1998 or so to upgrade their system to actual hi-fi status, and they loved them. What a terrific value they were and probably still are.

tonykaz's picture

I sold scads of these, back in 1984-5.

They performed way over their weight class with good solid State electronics. They even worked ok with Harmon Kardon stuff.

I could never get any of the Thiel range to work well with the Conrad-Johnson Tube Gear including the MV-45a ( my favorite ), the MV-75 or the Premier Amp.

I was a Huge Monster Cable Dealer ( I carried every single thing they offered and had a complete 40 foot wall featuring the stuff ). Monster was my most financially successful line. Phew!!

Still, Bruce Brisson's MH750 speaker cables ( $500/pr. ) were able to take the Thiel stuff to wonderfully addictive heights. I was a Cable denier for engineering reasons but those big MH750s were superb. go figure!

I'd like to have a pair of Thiel speakers now, perhaps these 1s or maybe the CS3s but Jim is long gone and his Nandino Blvd place is gone too. I'd order a pair in Teak.

Sad Memories

Tony in Michigan

ps. I never realized that JA actually reviewed Thiel stuff, I'd kinda thought that it was Tony Cordesman's exclusive territory.

RH's picture


I'm surprised by your comment about Thiels not working with Conrad Johnson tube gear. Over the years I've found Thiels a particularly synergistic combination with CJ gear. It started with the old Thiel 02s (before Jim moved to time coherence) and a CJ MV55 amp which was a match made in heaven. I later on upgraded to CJ Premier 12 mono-blocks, 140Wside which I used to drive (among many other speakers) the Thiel CS6. The premier 12s have the CJ magic midrange with enough grunt to drive many speakers, including the Thiels. It was an incredible combination, giving me the strengths of the Thiels - precision in imaging, density of images, tonal density and neutrality, transient precision, bass pitch, etc...but with just enough CJ character to render it all just that much more smooth and organic sounding.

I went through many different speakers since then and have gone back to Thiel. Currently I own both the CS 3.7 and the 2.7s and both are gorgeous on the CJs. I fact, I have never heard sound so coherent, and bass so in control and tonally articulate, anywhere else. (So sad that Jim passed away!!! Such a loss).

All that said, I don't have experience driving many of the older 80's/early 90's Thiels which may be different. Though I do know that I've often seen Thiel 3.6 owners laud Thiel with tubes, including with CJ amps.


tonykaz's picture

I carried the entire CJ line because it was reputed a success with Thiel, I liked the people and I favored tube gear.

I also carried Electrocompaniet which was Superb or even beyond Superb.

I had CJ's better stuff & Electrocompaniet both in my Main Room, able to play those deep impacting CS3s. The Electrocompaniet Ampliwires consistantly crushed every other Amp, phew.

I tried to carry a successful option to the CS3 Thiel but never found anything, the big Thiels would stagger everyone, I sold loads of them.

I also had the Quad 63 and various Magnapan ( I loved the MG2 & MV45 ) but they didn't sell well against any Thiel/Electrocompaniet system. go figure.

Loudspeakers & Electronics were not my/our main venture, we were a Turntable Shop offering Belt Drives & MC Phono carts & Arms.

When Vinyl died I went back to the Transportation Industry and (mostly) GM Corp. I didn't look back till I met Tyll at RMAF 2011. Now Audio is only an Old Hobby.

Tony in MichIgan

ps. Because I was importing from England, at the time, I brought a wide range of British Gear into my Esoteric Audio Salon, we had loudspeakers from nearly every British manufacturer. The British Small loudspeakers were wonderful with the Pro-Ac Tabletts being the consistent best!!
I also liked the B&W 801s but even they couldn't sing & dance compared to those Big Thiel CS3s!!!

Ahhhhh, the good ole days

Allen Fant's picture

Another +vote for Thiel loudspeakers. Thanks! for sharing this historic piece- JA.

How do I get a copy of your HFN/RR cd ?