The Celestion F15 Bookshelf Speakers

The rise of the Home Theater phenomenon has made purchasing loudspeakers for music playback fraught with peril. To paraphrase Frank Zappa on the subject of ponchos: “Is that a real speaker or is that a home theater speaker?” Adding sonic violence to already stupidly violent Action Movies hardly strikes me as a viable aesthetic for music playback. On the other hand, overly laid-back and mellow speakers that sink music into a Lawrence Welk somnolence are an unsatisfactory alternative to Boom and Sizzle ear-frying nastiness. There is no inherent reason why HT should be so bad. Whether one is reproducing intelligible dialogue or the human singing voice does not matter. The goals are cognate. I’m naturally suspicious about HT speakers, especially when reputable manufacturers produce HT lines that are obviously inferior to their music-based speaker lines. You can sense that their hearts really aren’t into it.

There was been a revolution occurring in the UK hi-fi world. Many classic and quintessentially English companies are now owned and manufactured by the Chinese: Quad, Wharfedale and Celestion come most readily to mind. One of the grand old UK speaker companies, Celestion’s illustrious history dates back to 1928, its founders having fair claim to the invention of the dynamic cone loudspeaker. Under their Chinese ownership, Celestion speakers are designed and developed in England and manufactured in China.

Most audio enthusiasts are probably familiar with the Celestion SL 6, SL 600, and SL700 speaker series of some years ago; speakers that pioneered the successful application of the metal-dome tweeter (copper in the original SL6) and Celestion’s highly sophisticated aluminum-honeycomb cabinet construction technology. Celestion’s application of laser interferometry allowed visual scrutiny of a driver’s behavior while actually producing a sound. For the first time designers could see if a driver was working correctly as a piston, or had lost its marbles and was producing trash. Most recently, Celestion’s inexpensive “Number” series, particularly the Model 3 and 5, retailing at $289 and $399 a pair respectively, set a new standard for inexpensive speakers in rhythm, phrasing, and overall musical sense. A recent comparison of my own Celestion 3 MkII’s against a $7500 High End monstrosity found the $289 speakers outperforming the monsters by all musical criteria. The Celestions created the magic of music; the monsters just made sound.

Celestion currently produces two HT-compatible speaker lines: the rather self-conscious “Sound Style” line of plastic and metal, and the “F” series with traditional wood cabinets. The F Series is available in 3 wood finishes: black ash, maple and dark apple. There are two bookshelf speakers, a center channel speaker and two floor-standing speakers. A subwoofer is available. All are shielded. The F15 is the larger of two bookshelf speakers.

My F15’s were finished on all sides in the Dark Apple veneer, a very attractive and rich-looking finish. The bookshelf F15 has a partner in the floor-standing F20, which uses the same drivers and lowers the –2dB point of the F15’s 65 Hz to 55 Hz. Sensitivity is the same at 89 dB. This raises the familiar quandary of which speaker to choose: the smaller, less expensive speaker which, with its smaller cabinet less likely to resonate a-musically, can more closely approximate the Ideal Point Source; or the larger floor-stander which does away with the need for speaker stands and allows for lower bass response. I chose the F15 because of its similarity in size to my 3 MK II’s and because I wanted to try the F15 in a variety of rooms and placements. I also wanted to see just how little one can spend these days and still get music.

The F15’s, at $220/pair, are certainly inexpensive. Shop around a bit and they become downright cheap. Say “cheap” to the average American and the reaction is too often “cheap and nasty.” Say it to a Brit and the result is equally likely to be “cheap and cheerful.” The Celestion F Series, while HT compatible, was also forged in the demanding crucible of the ultra-competitive British budget speaker market – the archetypal sub-$400 per pair, 2-way, 6-inch reflex-loaded woofer, stand-mount. The High End dogma that only ultra-expensive gear is even worth considering is balanced by UK listeners who not only expect budget speakers to be excellent and musically compelling, but secretly expect them to be near-perfect. Both viewpoints are unrealistic; however, the UK’s pressure cooker demand has forced the evolution of the budget speaker into a very high form indeed. 

Viewed cosmetically, the F15 looks far more costly than its grandfather, the UK-built, non-HT, Celestion 3 Mk II. Its veneered cabinet looks far more deluxe than the 3’s vinyl wrap; double 5-way binding posts with removable links for bi-wiring trump the single 4-way posts of the 3; overall build quality is far more substantial. The 3 looks like a good budget speaker built to a price; the F15 looks quite luxurious, striking because the F15 is actually $70 cheaper. Score one for the lower cost of Chinese manufacture.

I ran the F15 with my usual Rogue’s Gallery of electronics, representing each of the last 5 decades, from the Eico tube preamp/power amp of the 60’s to the new digital Sonic Impact T-amp. Six turntables and three CD sources entered the fray. I played them in 4 different rooms (2 rooms 8 by 12, one 9.5 by 11, and one 14 by 40) and tried 5 different set-up/speaker stand-height combinations. I ran the F15’s through the gauntlet of my Snake Pit of cables. I even hooked them up to my 20” TV and watched Ingmar Bergmann’s movie of Mozart’s The Magic Flute. The differences in these various set-ups were clearly audible, and more importantly, the F15’s nailed the individual signature of each component.

Consistent through all these variations was the F15’s excellent reproduction of the voice; lyric intelligibility is first rate. Bass response was tight and controlled, without a built-in mid-bass (100 to 125 Hz) rise. Indeed, when positioning the speaker, care should be taken not to induce a suck-out in this crucial region, which so influences subjective bass drive. This well-damped woofer alignment leads to easy integration with a subwoofer, part of Celestion’s plan, one would logically assume. Whether a slight opacity from the bass driver was due to its reflex loading, re-radiation of signals back through the cone, or to the inherent limitations of a P-P-treated paper cone I cannot tell.

The presence range did not exacerbate the typical Pop rip-your-ears-off EQ, being slightly flattering and allowing violin to sound like violin. Celestion’s titanium dome tweeter, capable of producing fine detail and a delicate sense of the recording venue acoustic, announces the initial distress if you over-drive the speaker. It will also spotlight the weakness of sources, electronics, cables, and poor recordings. The difference between LP playback and CD was immediate and clear.

“Location, location, location.” Small speakers have an obvious and distinct advantage over their larger brethren in flexibility of placement. Indeed, placing them can be a deviously fine art, ameliorating the limitations of small speakers – limited power handling, curtailed bass response – while maximizing their strengths: vivid and uncompromised stereo imaging and near-field detail and transparency. The standard ‘mini-monitor’ set-up: 24-inch tall high-mass metal stands that position the tweeter at face height is not the only way to go. I tried shorter wooden stands (12, 16, and 20 inches tall) and applied Mapleshade Records’ technique of placing monitor speakers very near the floor to utilize the floor/rear wall boundary to reinforce bass response. I also used the Audio Physic technique of placing the speaker on the long wall of a rectangular room and placing them so that there is at 5.5 feet between the speaker and its side-wall. Finally I experimented with angling the speaker back a bit to time-align driver output, and also inverting the speaker to place the woofer on top of the tweeter to achieve similar effect.

The first limitation of small speakers – limited power-handling and thus sound pressure levels – was easily bypassed. The F15’s 89 dB sensitivity and 8 0hm load allows it to get quite loud without a lot of watts, even more so in smaller rooms. I rarely exceed 85 dB or so SPL in my listening. It sounds more than loud enough, and new standards for avoiding damaging one’s hearing now point to 85 db against the old 90 dB SPL maximum. I was able to hit the high 80’s in both my 12 ft. by 18 ft. rooms without problems, even with the 5 watt/channel Sonic Impact digital amp. On the quiet end of things, every speaker has a certain volume threshold where it seems to come alive, and while the F15 did not match the champions of that criterion, it was making music in the low 70 dB volume range.

Maximizing bass response was another matter. Personally, I demand that any speaker get down to 42 Hz in room to qualify as full-range. Despite all my sneaky set-up tricks, bass response met Celestion’s spec, extending to 62 Hz before nose-diving. Response at 40 Hz was 13 dB down from a 1 KHz reference level. Furthermore, exciting the woofer floor-bounce cancellation phenomenon by unhappy height placement could cause a suck-out in the 100 –125 Hz range, leading to a lack of both bass response and subjective bass drive. The F15’s HT-design side is hereby revealed. Rather than trade-off sensitivity or use a larger woofer or box to extend bass response another half-octave, Celestion opted for HT standards. Not enough bass? Add a subwoofer. I can hear the deafening chorus of “Duh” clearly.

Celestion makes a dedicated and inexpensive subwoofer, but in my determination to see how cheap (and cheerful) I could go, I used the $124 Dayton Loudspeaker Co. powered 10-inch subwoofer from Parts Express. Having dealt with satellite/subwoofer set-ups since the late 70’s (the original Visonik David 50 and M&K Goliath subwoofers,) set-up was quick and easy. I placed the F15’s on 24’’ metal stands, moved them far enough into the 12 by 18 foot room to optimize their already exquisite stereo imaging, placed the subwoofer exactly between them, set the crossover to 80 Hz, and began smiling like a clam.

Bass response now was rock solid to 30 Hz, and the F15’s 5¼-inch woofer, freed from most of its bass demands, danced and swung with a new-found rhythmic certainty and confidence. The stereo illusion, already superb due to the airiness of the F15’s tweeter and its point-source-approximating cabinet, became as good as it gets with the low bass information illuminating the size and subtle detail of the recording venue. The tweeter’s tendency to tell you too much news in the 5 KHz region was less obvious due to it being balanced by the bottom two octaves.

It was by isolating the speakers from their stands that the F15’s really came into song. I tried the Stillpoints, the Aurios PRO’s, and the Ganymede VCS devices (I did not have the Townshend 2-D Seismic Sink stands in-house.) State of the Art isolation produced a greater difference than type or quality of speaker stand or speaker cable. The increase in clarity and resolution was profound; the slight opacity of the bass/mid driver dropping below the threshold of perception and the thorny issue of the titanium tweeter producing too much energy at 5KHz disappeared. What I had been assuming as the inherent limitation of the tweeter was actually being caused by resonant interference. Since isolation removes the bass contamination from the environment and since it also removes the speaker-produced floor and return mechanism, the F15’s limited bottom end was more obvious, making a subwoofer essential. Isolating the subwoofer too yielded a truly exceptional 3-piece system that should satisfy all but the most picky. Since the F15’s and subwoofer can be bought for less than $300 total, this is indeed a price breakthrough for high-performance audio.

The F15’s bass/mid driver lags behind the state-of-the-art Harbeth Radial cone driver and the lower mass of electrostatics and ribbons, as well it should. Though far more controlled, refined and subtle than its Celestion predecessor the 3 MK II, it doesn’t quite match that speaker’s inherent exuberance and magical way of phrasing, rhythmic certainty, and overall immersion into the quality of the playing. Care should be taken that sources, amplifiers, and cables can do the basics of music well. Garbage in, garbage out.

So a very high recommendation for the F15 when used with a subwoofer. $300 is less than what many audiophiles spend per foot of speaker cable: in that High End context the system’s cost is practically free. Allocating funds for isolation allows the system to be truly cheap and cheerful, making one wonder what the hell High End orthodoxy means when it calls $10,000 speakers “budget designs.”

Paul Szabady

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Specifications:
2-way bookshelf loudspeaker.
¾ inch titanium dome tweeter
5¼ inch polypropylene-treated paper woofer. Bass-reflex loading at top rear of cabinet.
Sensitivity: 89 dB
Frequency Response: 65 to 20,000 Hz +/- 2 dB
Crossover frequency: 2500 Hz.
Dimensions: 12.6” x 7.8” x 10.7” (HxWxD)
Weight: 11 lbs.
Price: $220 per pair.

Address:
Celestion Consumer Division
Eccleston Road
Tovil, Maidstone, Kent
ME15 6QP UKTel: +44 (0) 1622 687442 Fax: +44 (0) 1622 687981
Free Phone: 0800 731 3410
Celestion US:
Website: www.celestion.com
E-mail: mailto:info@celestionamerica.com
 

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