August 1999 Thiel CS1.5 Loudspeakers by Paul Schumann

All the speaker most people will  need at a price most people can  afford.

Review at a Glance Sound Seamless and extended sound; bass that’s "so clean that you have to readjust the way you listen to it." Features Small footprint and attractive cabinetry; binding posts are on the bottom, hiding the connection but making hook up a little trickier. Use Perfect for systems located in rooms not dedicated to listening; above-average amplification -- quality and power output -- required. Value "A small-scale classic" whose engineering, attention to detail and sound belie its price.

In his review of the Magnepan MG20 speaker for Fi magazine, Jonathan Valin lamented the fate of new audio equipment after the initial rush of excitement surrounding its introduction has worn off. At first, all the audio publications want a review sample and the consumers are primed to read about it. After about a year, however, most of the shine is gone. Reviewer’s consider the product to be old news, and audiophiles are scanning the horizon for the next great piece of equipment. No wonder manufacturers feel compelled to keep coming out with newer versions of their products. If they don’t, the market will pass them by.

An exception to this trend is the Thiel CS1.5 loudspeaker. It first hit the market in 1994 and has remained unchanged since. While some of its larger siblings have been getting facelifts of late, there sits the CS1.5, gracefully aging. Why then do a review of a five-year-old speaker? I’ll tell you why. About two and a half years ago, I had a chance to listen to a pair of Thiel CS1.5s at a now-defunct dealership. I was only able to listen to them for about 20 minutes, but I was impressed by the big sound coming from such small floorstanding speakers. And then as one of my first assignments for SoundStage!, I was listening to the CS1.5s in my living room. Talk about fate!

With many pieces of audio gear, the more you listen, the more you hear shortcomings. With the Thiels, it’s just the opposite. The more time I spend with them, the more I gain an appreciation for Jim Thiel’s accomplishment. I’ve been delaying putting into words my observations because the CS1.5 continually shows me something new. I’ve come to realize that this process will continue for quite some time. But reviewers have deadlines, so I must now forge ahead, wondering if the best is yet to come from these speakers.

Details, details

The $2190-per-pair CS1.5, like all its brethren, utilizes Thiel’s Coherent Source technology, hence the "CS" designation. One of the implementations of this technology is the mounting of the drivers on a sloped baffle for proper time alignment. In addition, the grille board fits around the baffle and is rounded to reduce diffraction off the cabinet edges. Another part of this technology is the use of a first-order crossover for correct phase and step response. This might sound like a bunch of technical jargon to some of you, but it aims at creating a speaker that is nearly seamless from top to bottom.

The Thiel CS1.5 is a two-way speaker with a 1" metal-dome tweeter reproducing the highs and a 6.5" aluminum-diaphragm woofer covering the midrange and bass. Helping out the 6.5" driver is a passive radiator instead of the more commonly used bass port. Both of the active drivers are of high quality. The tweeter uses a large magnet, vented pole, and reinforced rear chamber to reduce resonances and increase bandwidth. The woofer uses an aluminum diaphragm for increased stiffness and cast magnesium chassis for rigidity. Two magnets weighing a total of 2.4 pounds are in the back. Like all Thiel cone drivers, the woofer for the CS1.5 utilizes a short-coil/long-gap system to improve linearity of response throughout the complete excursion of the driver.

The CS1.5s are very unimposing-looking speakers. At only 33" high and 8.5" wide, they present a small profile to the listener. The pair that I reviewed was in dark cherry finish, which is lovely. The wood veneer is not only on the top, front and sides, but the back as well. The black grille cloth fits cleanly and snugly, and gives the speaker a classy look. The binding posts are located on the bottom. This means that hooking up the speaker wires is more of a challenge than normal, but it makes the connection visually less obtrusive. All of these features taken together give the Thiels a high visual acceptance factor. My wife, who usually isn’t too keen on the looks of most stereo equipment, was delighted with their appearance in our living room. That may not mean much to you single guys out there, but to those of us with significant others, it’s worth a lot.

I have to mention one other thing about the Thiel CS1.5 before I move on to the sound. Despite their size, the CS1.5s are not the most efficient speakers. They are rated at 86dB/2.8V/1m. Their average impedance is 4 ohms, which translates the efficiency rating to 83dB/1W/1m. This doesn’t mean that you’ll need some gigantic monoblocks to feed them, but if you have an amplifier with outputs less than 100Wpc, they’d better be quality watts. That said, I found that the all-tube 40Wpc Jolida SJ202A integrated amp drove the Thiels to satisfactory levels without a hitch. The hybrid 90Wpc Anthem Integrated 2 was even better.

Sound

One the first things that strikes you about the Thiel CS1.5s is the continuousness of the sound they generate. The word that kept cropping up in my notes was smooth -- no hills and dales in the frequency response from these guys. Thiel states that the crossover point for these two-way speakers is 3kHz, but I’ll be darned if I can hear where that is. That’s way up there, where the birdies sing and most instrument fundamentals fear to tread. By avoiding the all-important center midrange, where our ears are most sensitive, and executing this passing of the baton in a time-and-phase-correct manner, the crossover of the CS1.5 is virtually invisible. The piano is one those instruments that gets up into stratosphere, so it’s a great instrument to give this crossover a workout. Mitsuko Uchida’s incisive performance of Debussy’s 12 études [Phillips 422 412-2] shows how wide the range of the piano is. These pieces can serve as both keyboard exercises and standalone compositions. They utilize the entire range of notes the piano provides. Runs spanning several octaves flow freely and continuously, with no undue emphasis of any notes along the way.

Now it’s time to do some myth busting. It seems to be common rumor that Thiel loudspeakers are bright or aggressive. I never found the Thiel CS1.5s to fit this description. On the contrary, I found the upper octaves a delight to listen to through the Thiels. Listening to Bruno Walter’s last recording of Brahms’ Fourth Symphony [Columbia MS 6113], I heard the violins shimmer with delicacy as they climbed the scale. The aluminum-diaphragm tweeter might not project the last bit of air like the finest ribbon tweeters, but it certainly never sounds less than refined in the upper octaves. As I mentioned in my review of the Anthem Integrated 2, Respighi’s Pines of Rome [Sony SK 66843] can be a real lulu when it comes to dynamics. It’s also a good recording to give your tweeter a workout. The opening of the first movement, "The pine trees of the Villa Borghese," is loaded with treble information blasting at triple forte. When played at realistic volume levels, it will give you a migraine if your equipment isn’t up to it. But try as I might, I could never get the Thiels to sound strained or rough. It quickly became apparent that my ears would give up the ghost before the CS1.5s’ tweeters would. After listening to so many speakers that would start to sound hard when the going got rough, I was delighted to hear speakers as composed as the Thiel CS1.5s.

Here’s another myth that needs to be refuted: any speaker with the frequency response down to only 42Hz won’t deliver satisfying bass. This is one I believed myself in my early days of audiophiledom. After all, the 16’ stop on the organ is at 32Hz, which is the opening note of Also Sprach Zarathustra. If a speaker can’t reproduce that, then why bother? This said, the Thiels sound as if they go deeper than their specifications claim. This is due to the quality of the bass the Thiels provide, not the quantity. I have to admit that when I first set up the CS1.5s, I was slightly disappointed in the bass. But knowing that the drivers just needed some good break-in, I bided my time. After about a month of regular use, I decided to have a good listen.

When it comes to bass, I have one recording that tops my list, Pomp and Pipes [Reference Recordings RR-58CD]. Of course, there is a lot more to this recording than just the bass, but those thundering organ pedal notes and bass-drum smacks get me every time. When I play this recording through the Thiels, the cut that impresses (and intimidates) me is Arthur Willis’ "The Vikings." At a realistic volume setting, I can feel the power of the organ as it swells behind the orchestra. The pedal notes are cleanly differentiated, with nary a bit of smudging. Yes, the Thiels will shake the room with this recording, but it’s more than that. The bass presented by the Thiels is so clean that you have to readjust the way you listen to it. I know I have become so used to hearing many of the distortions associated with bass reproduction that it takes hearing the real thing to jar me back to my senses. The Thiels act the same way on ear-brain mechanism. The drop in distortion reveals many of the components that make up a bass note.

The bass drum blows from "Alleluah! Laudamus Te!" are some of the most impressive ever recorded. I’ve used this track as a demo for quite a few speakers, with highly variable results. Most turn these percussive blasts into floor-shaking explosions, devoid of shape or form. The CS1.5s, however, give these blasts tonality and clarity. You can hear the initial impact of the mallet upon the drum skin, the tonality of the vibrating skin, and the sound of the impact as it reverberates the entire drum. The only speakers I’ve heard accomplish this feat in the same price range are the lower-priced Magnepans. The added bonus with the Thiels is greater sense of weight in the midbass.

As you’ve probably noticed, I haven’t said anything about speaker placement yet. I found the Thiel CS1.5s remarkably forgiving speakers when it comes to placement. This doesn’t mean you can leave them next to a wall and forget about them, but their nature make them easy to place in a multi-purpose room, such as my living room. As I was fooling with their location, I discovered that very few changes were made in the tonal balance of the speakers. The changes that did occur centered on the clarity of the midbass. As you would expect, clarity improved as I moved them further away from the back wall. More dramatic changes occurred in the rendering of the soundstage by the Thiels. The way my living room is arranged, I listen to music in a nearfield arrangement. I’ve read that first-order-crossover designs like the CS1.5s might not work well with such an arrangement, but I had no problems getting up close and personal with the music in my house. I found the optimal placement at 29" out from the back wall and 55" apart, with a slight toe-in. This configuration gave me the best balance of width and depth. The couch I use for listening is up against the wall, so I need to scoot up to the edge to open things up. It isn’t the most comfortable listening position, but life is full of compromises when you love someone.

Probably the most debatable aspect of the Thiels is their re-creation of a recording’s soundstage. As I mentioned previously, the CS1.5s are not particularly tall loudspeakers, with the tweeter at a height of 27" above the floor. The angling of this tweeter allows the Thiels to float images above the tops of the speakers, but you don’t get the soundstage height that you would get from taller speakers. The maximum height of images in the soundstage varies with the type of recording. On an intimate ensemble recording like the Miles Davis cut of "It Never Entered My Mind" from the Fi/Analogue Productions Sampler, you hear a soundstage that is slightly reduced in height. Davis is front and center with his trumpet, with the center of sound of the trumpet about four and a half feet high. This really isn’t miniaturizing things too much since Miles wasn’t too tall anyway.

On symphonic recordings, such as the Brahms Symphonies [Telarc CD-80450], reduced stage height is more evident, with the instruments in the back of the orchestra about four feet high. This raises an interesting philosophical point when it comes to soundstage height. When I listen to a symphony orchestra live, the vertical delineation of the orchestra plays a very small part in my enjoyment of the experience. But since recording engineers place the microphones above the orchestra, we audiophiles have come to expect a vertical spread between the sections of the orchestra (this gives us something to fret about in the wee hours of the morning while tinkering with our systems). While the Thiel CS1.5s don’t give this effect in full, I never found myself needing it.

If you really want to know how the Thiels can strut their stuff in the imaging and soundstage departments, I know the recording for you. Balalaika Favorites [Classic/Mercury SR90310] is one the six re-issues by Classic Records of some stunning Mercury albums. I’ll admit that I didn’t buy this record because I am a big balalaika aficionado, but when I was deciding which of the rejuvenated Mercurys to buy, I wanted something a little different. I am definitely not sorry for the choice. The soundstage from this album as presented by the CS1.5s is not very deep, but very wide. The shepherd’s horns on the cut Dance of the Comedians are off to the right and a good four feet outside the speaker. Also, with this and other recordings, image specificity is remarkable. The solo domora on Fantasy on Two Folk Songs is at the plane of the speakers and just left of center. Close your eyes during this cut and the Thiels will allow you to visualize the domora player as he moves his hands up and down the fretboard of the instrument.

Another recording I used to evaluate the imaging and soundstage ability of the Thiel CS1.5s is the Brahms Violin Concerto [London 444 811-2]. In contrast to Balalaika Favorites, this certainly isn’t an audiophile recording. The soundstage is poorly proportioned, the orchestra is muddied, and dynamics are pinched. So why do I listen to it? Quite simply, I love Joshua Bell’s performance. When I’ve listened to this recording through other speakers, I’ve always had trouble pinpointing Bell’s image in front of the orchestra. The Thiel CS1.5s cleared this up quite considerably. In fact, I quickly came to understand why I was having so much difficulty pinpointing his location within the soundstage. It is quite evident through the Thiels that Joshua Bell is swaying back and forth as he plays, causing his image to shift and lose focus. This shows that a close miking was used when a mike set further back might have been more fitting.

The Thiel CS1.5s are also able to telegraph nuances in remarkable fashion. One of the things that makes Joshua Bell’s performance of this difficult concerto so spellbinding is his ability to play the high notes so softly. Sometimes the tone he produces from this effect is so light and airy, you forget there are even strings involved in making the music. The Thiels bring out all of the shadings of this delicate playing, as you marvel at Bell’s ultra-pure notes before he embellishes them with vibrato. Where before these treats have been lost in the murk, the CS1.5s bring them out with crystalline clarity.

When it come to macrodynamics, the Thiels once again thrill and titillate. This is especially true with a higher-powered amplifier like the Anthem Integrated 2. At the beginning of the "Infernal Dance of King Kashchei" in Stravinsky’s Firebird Suite [Deutsche Grammophon 447 414-2], there is a quick burst from the orchestra before the main theme begins. This will definitely test a component’s ability to startle. No matter how many times I’ve heard this piece, I’m always startled by this moment when it’s played through the Thiels. But it’s more than just that one moment that makes listening to this piece through the Thiels such a treat. Most of the passages in this piece are played at pianissimo or lower. When the loud sections come, boy do they ever. But no matter how loud or violent the music gets, the Thiels never lose their composure. Sure, there is the beginning of some compression from forte on up. After all, these are only small two-way speakers. But, as I mentioned previously, when these speakers reach their limits, they don’t sound ragged or coarse.

Quick comparisons

There are a lot of speakers out there that fall into the Thiel CS1.5s' price range. I’ve been lucky enough to listen to quite few extensively in the last year. Two speakers that compare favorably to the Thiels are the Platinum Audio Studio 3s ($1700 per pair) and the Magnepan QR1.65s ($1475 per pair). The Platinum speakers do go a little bit lower in the bass (35Hz) and are easier to drive (89dB/w/m), but lack the Thiel’s clarity, precision, and fine exterior craftsmanship. The Magnepans can project a tall and deep soundstage, and are spooky in their accuracy or timbres, but they are very obtrusive (5’ by 1 1/2’ panels) in a living room, need lots of space, and lack the Thiels’ bass weight. As you can guess, all three of these speakers have certain strengths and weaknesses. The Thiel CS1.5s’ combination of clarity and composure makes them difficult to beat.

Conclusion

Doug Blackburn has explored in SoundStage! the fascinating concept of balance in audio equipment. Reading this information was a revelation for me as I was finishing up this review. What makes the Thiel CS1.5s such great speakers is their unassuming balance in their reproduction of music. Because of this balance, the Thiels may not impress upon first listen. However, long-term listening shows how true and accurate the CS1.5s are. When I listen to them now, I’m more enamored with them than when they first graced my living room.

There is so much more I wanted to write about these speakers, but because brevity is the soul of wit, I will simply say this: if you are in the market for a smallish floorstanding speaker, you must listen to the Thiel CS1.5s. If you have a listening room whose layout is dictated by factors other than music, the CS1.5s give you an added bonus. Their classy looks and easy placement make them very living-room-friendly speakers. Kathy Gornik, president at Thiel, told me that they have no plans on updating the CS1.5s anytime soon. Now that I have spent some time with them, I understand why. The Thiel CS1.5s are a small-scale classic.

...Paul Schumann
paul@soundstage.com

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