Canon S-35 Speaker System Review

Canon’s new S-35 is truly a unique loudspeaker. At first glance it resembles a stylized bust of Darth Vader. The rounded, matte black, die-cast zinc upper portion is approximately the size of a human head, and its glossy black plastic base resembles an upward-facing 90-degree cone. Inside the “helmet,” facing downward, is a small cone driver (Canon refers to it as a 5-1/4-inch cone, but its effective diameter is only about 4-1/4 inches). Concentrically mounted with the cone is a 3/4-inch soft-dome tweeter. The enclosed volume of the helmet is vented by two small openings on its rear, which also contains the recessed multiway binding-post terminals.

Canon’s term for the unique character of the S-35 (which, like all Canon speakers, is manufactured in Great Britain) is Wide Imaging Stereo (WIS), since the acoustic output is radiated into a considerably wider horizontal angle than with a conventional forward-firing design. Canon says the S-35’s horizontal dispersion is within +3 dB from 1 to 15 kHz over a 100-degree forward angle.

The system’s rated frequency response is 70 Hz to 22 kHz ±3 dB, with an axial (anechoic) sensitivity of 88 dB sound-pressure level (SPL) at 1 meter with a 2.83-volt input. The speaker is rated to handle up to 75 watts (a 50-watt amplifier is recommended), and it has a nominal impedance of 6 ohms. An internal overload-protection system senses signals of excessive level and duration and reduces the input to the drivers until a safe level is restored.

The S-35 speakers can be mounted on wall brackets or stands and should be angled inward toward the listening area by 35 to 45 degrees for optimal imaging. According to Canon, their integral magnetic shielding allows them to be installed close to a TV monitor or receiver without affecting the picture.

We placed the Canon S-35’s on 30-inch pedestals about 9 feet apart and 2 feet from the wall behind them. Initially they were facing forward, but we angled them as recommended for listening tests. The averaged room-response curve showed maximum output points at 260 Hz and 20 kHz and a uniform response (±2.5 dB) from 400 Hz to 4 kHz. The crossover to the tweeter appeared to be at about 5 kHz (quasi-anechoic MLS measurements confirmed that by revealing a narrow notch of about 12 dB at 4.9 kHz).

The close-miked woofer response indicated a ±3-dB variation from 85 Hz to 2.5 kHz (with some unevenness above 1 kHz, where this measurement began to become invalid). Bass output fell off at 12 dB per octave below 100 Hz but remained useful at least to the rated 70-Hz limit.

The composite response curve, combining the close-miked bass response and the smoothed room response (which overlapped for several octaves), showed the usual variations due to unavoidable boundary effects. The curve’s most obvious features were a broadly emphasized region between 100 and 600 Hz, a moderate variation in response between 1 and 10 kHz, and a rise of about 8 dB in the top octave, between 10 and 20 kHz. The MLS measurements revealed (in addition to the 5-kHz notch mentioned above) a tweeter resonance peak of perhaps 8 dB at 19 kHz, accounting for the rising high end in the room-response measurement.

The S-35’s horizontal dispersion was, as might be expected from its design, very good. Over the 45-degree angle that we usually use for this test, the 15-kHz output varied only about 4 dB, essentially confirming the manufacturer’s rating. But since the speaker’s output has no clear access to the rear, a 90-degree off-axis measurement showed a drop of 10 to 15 dB in the range from 10 to 20 kHz.

The impedance characteristic was distinctive, with three large, narrow peaks, to 27 ohms at 30 Hz and 100 Hz and to 23 ohms at 1 kHz. The minimum reading of 5 ohms at 250 Hz and 20 kHz, however, justifies the speaker’s nominal 6-ohm rating.

Our measurements confirmed the rated sensitivity (88 dB SPL at 1 meter with a 2.83-volt input). Woofer distortion measured between 0.6 and 1.5 percent from 100 Hz to 2 kHz, rising at lower frequencies to 5 percent at its rated 70-Hz limit and to 10 percent at 30 Hz (where its output was too low to be useful).

In listening tests, the Canon S-35 sounded pretty much the way its response measurements would suggest. It had a pleasant warmth, almost certainly due to its slight emphasis in the lower midrange. The highs, though clearly present, were not prominent (the tweeter resonance peak being at the upper limits of human hearing). There was none of the sizzle that sometimes signals a peaked top end. The overall sound character was distinctively different from that of more conventional speakers, imparting a sense of air and space that seemed to fill the entire region between the speakers but had little correlation with the apparent source of the music. In spite of that effect, spatial imaging with the Chesky JD37 test disc was as good as we have ever heard.

Our pulse power tests proved the effectiveness of the speaker’s protective system. At 100 Hz, the circuit effectively “soft-clipped” the drive signal at a point where the sound took on a hard quality (in the vicinity of 200 watts). With further increases in level the signal was merely clipped a bit harder (we did not attempt to test the limits of the protection, since the sound became rather ominous at about 250 watts). At higher frequencies, the speaker’s impedance rose to the point where our amplifier’s output was voltage-limited to the equivalent of about 300 watts at 1 kHz. At 10 kHz the tweeter output was severely clipped at 800 watts, but without any permanent damage.

To check Canon’s claim of magnetic shielding, we measured the field at the outer surface of the S-35. It never exceeded 2 gauss and was typically much less. The speaker is obviously safe to use in an A/V system.

Once you accept the odd appearance of the Canon S-35, it is a very easy speaker to live with and listen to. Its subjective bass is all one would expect from a conventional speaker of its size (or two or three times its size), and it is designed for flexible installation. In fact, with a little imagination in its placement, it might never be taken for a loudspeaker!

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