Celestion A1 Speaker System Review

Celestion, the highly respected British manufacturer, recently introduced its A Series of loudspeakers, which currently consists of three ported systems featuring a new family of drivers specially developed for them. The speakers in the A Series were designed to meet the needs of home-theater installations as well as of conventional music systems, and the drivers are magnetically shielded to prevent interference with the picture quality of a TV or video monitor.

The Celestion A Series was developed with the aid of advanced techniques such as Finite Element Analysis, used to design portions of the drivers, including the proprietary titanium-dome tweeter in all three models. A Faraday ring reduces impedance variations in the tweeter voice coil, thereby maximizing its power-handling ability. For better imaging, the tweeter is located very close to the woofer’s edge (portions of their structures actually overlap). A cast bar in front of the tweeter dome prevents damage to the delicate dome from contact with the closely spaced grille.

The subject of this report, the A1, is the smallest and least expensive member of the new series. It is a compact two-way system intended for stand mounting, which ideally should place it about 24 inches above the floor. The middle member of the family, the A2, is a compact floor-standing speaker, and the top-of-the-line A3 is a large floor-standing system.

The A1, though small, is surprisingly heavy (31 pounds). Its construction is robust, to put it mildly. Although no specific information was provided on its internal construction, it has probably the most rigid, solid-feeling enclosure we have encountered in a long time. Knuckle raps on any part of its exterior had the tactile and audible effect of rapping a marble block.

The driver complement is a (nominal) 7-inch cone woofer, with an active portion of just under 6 inches in diameter, and a 1-inch titanium-dome tweeter. The front panel of the speaker

is normally hidden by a black grille cloth, which is easily removed to reveal the drivers. The Celestion A1 is fully finished in wood veneer on all exterior surfaces, including the bottom (the cherry finish is shown in the photo), and has rounded front and rear comers.

The rear panel of the cabinet contains the bass port and two pairs of recessed gold-plated binding posts paralleled by gold-plated jumper straps. If the jumpers are removed, the system can be driven in a bi-wired or bi-amplified mode (with separate power to the tweeter and woofer sections). The connectors accept wires, lugs, or single or dual banana plugs.

The Al, which is recommended for use with amplifiers delivering between 30 and 150 watts into 4-ohm loads (its nominal impedance rating), carries a sensitivity rating of 88 dB sound-pres-sure level (with 2.83 volts input) into free space and 90 dB SPL in a semi-reverberant environment, which is essentially its normal operating condition. Our measurement confirmed the 90-dB rating.

Minimum system impedance measured just over 5 ohms at 45 Hz and between 150 and 250 Hz. The maximum readings were 42 ohms at 75 Hz and 34 ohms at 26 Hz, and there was a broad peak to 20 ohms in the 1.5-kHz range. The combination of high sensitivity and a comfortable impedance characteristic makes the Al an easy speaker to drive with any amplifier.

Following our usual practice, we placed the two speakers on stands about 7 feet apart and 3 feet in front of the room wall. The room response was measured separately for each channel with the microphone 12 feet in front of the left speaker, and the two curves were averaged to obtain a “typical” room response. This definitely nonstandard measurement, made in much the same way for every speaker we test, is intended to indicate a more or less typical frequency response from the speaker in a fairly good “normal” home acoustic environment.

The resulting curve indicated an overall variation of ±4 dB from 32 Hz to 20 kHz, with a broad maximum located between 150 Hz and 1 kHz. The higher frequencies remained strong and relatively uniform all the way to 20 kHz, with a +3-dB variation over the range from 1 to 20 kHz.

Quasi-anechoic (MLS) response measurements at distances of 1, 2, and 3 meters resulted in curves that had the typical rather ragged appearance, but they nevertheless demonstrated the exceptional high-frequency qualities of the Al’s tweeter. They clearly confirmed the system’s exceptional performance in the uppermost octave of audibility, with a strikingly uniform output up to 18 kHz and an actual rise, by another 4 dB, from 18 kHz to the 20-kHz measurement limit (a region where the response of most tweeters is well on its way down).

Celestion’s response rating for the Al is 43 Hz to 20 Hz ±2 dB. We would expect a good metal-dome tweeter to handle the treble range competently, and this one certainly did. But what about the low bass? How much bottom end can you expect from a single small driver in a modest-size enclosure?

Listening provided a clear indication that the woofer went down at least to the 50-Hz range, but as you head deeper into the bass, each additional hertz of extension becomes more difficult to achieve (and to hear, for that matter). We measured the low-end response using two microphones, close to the woofer cone and port, weighting and combining their outputs in proportion to their respective areas.

The resulting curve was virtually ideal in its shape and smoothness. As the Audio Precision system stepped downward from 100 Hz the response curve rose smoothly by 3 dB, leveling off between 50 and 40 Hz and then falling at 12 dB per octave from 40 Hz to the 20-Hz lower measurement limit. It is especially satisfying, and unusual, to find the measured performance of a speaker actually meeting or surpassing its manufacturer’s ratings despite the numerous inevitable differences in details of the measurement process.

As always, the ultimate proof of a speaker’s performance is in the listening. Not too surprisingly in view of our test results, the Celestion Al sounded very much the way it measured, using a variety of program material. Its stereo imaging was excellent, as natural as we have heard from any speaker in the same environment, with a totally seamless and believable image across the front of the room.

We were especially curious to learn whether the subjective bass response corresponded to the near-ideal measurements (it is not uncommon to find inconsistencies between the measured and audible qualities of speakers). The low-bass response of the Al proved to be quite real, however, and actually contributed useful output down to the range of 32 Hz or so. This is definitely not typical of small speakers with cones only 6 inches in diameter!

Although the Celestion A1 is not inexpensive, its performance indicates that it is an excellent value for the money. In fact, our experience with the junior member of the company’s A Series makes us wonder about the sound of the top-of-the-line A3 (which costs more than twice as much and weighs over 100 pounds).

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