SIARE Delta 400 Speaker System Review

The SIARE (pronounced C-R) Delta 400 is a three-way speaker system manufactured in France and imported into this country by SIARE Corporation of Ronkonkoma, New York. The Delta 400 presents a distinctive appearance, with a “stepped” profile characteristic of its “phase-aligned” design. The woofer is mounted forward of the other drivers, with the tweeter at the top of the cabinet being farthest to the rear. The sloping portions of the cabinet under the treble and midrange drivers are covered with foam plastic to reduce diffraction effects.

The Delta 400 uses a single long-excursion woofer whose cone has a nominal diameter of about 9 inches. It operates in a fourth-order vented enclosure (designed according to the criteria established by Thiele) with a 2-inch-diameter port. There is a 12-dB-per-octave crossover at 500 Hz to a 4-3/4-inch cone driver operating in its own sealed sub-enclosure. The second crossover, at 4,000 Hz, is to a 1-inch soft-dome tweeter.

The woofer cone is formed of paper with a polyvinyl-chloride surround. The midrange driver cone is made of woven fiberglass coated with a hardened resin which is said to have a lower mass and greater rigidity than an equivalent paper structure.

The internal surfaces of the enclosure are covered by specially slotted wooden panels which the manufacturer calls “acoustical stabilizers.” They are claimed to stiffen the enclosure walls and to damp undesirable panel resonances. The system has a rated impedance of 8 ohms and a sensitivity of 89 dB measured at 1 meter with a 1-watt input. The entire front is covered with a large dark-brown cloth grille stretched on a heavy wooden frame that weighs some 4-1/2 pounds. The cabinet is veneered in walnut.

The SIARE Delta 400 is 30-1/2 inches high, 13-3/4 inches wide, and 16-1/4 inches deep at its maximum point (in the woofer section). It weighs 66 pounds and can be installed on the floor, on stands, or on a table or other surface that will place the higher-frequency drivers close to a listener’s ear level. The price is $800.

Laboratory Measurements

The smoothed and averaged frequency-response curves from the left- and right-channel Delta 400s, measured in the reverberant field of the room, showed only moderate beaming from the midrange and treble drivers. The difference between the curves measured on axis and 30 degrees off axis began to be measurable at about 2,500 Hz but differed by only about 2 or 3 dB up to 12,000 Hz and increased to 6 dB at 20,000 Hz. When the average response was corrected for room absorption, it showed only slight irregularities through the midrange and treble, with a gradually rising characteristic above 4,000 Hz.

The close-miked woofer response, when combined with the frequency response measured at the port, produced a surprisingly extended bass curve. The effective crossover between the cone and port radiation was at 50 Hz. The bass and mid/high-frequency curves could be spliced unambiguously because of their considerable overlap, and the resulting frequency response was within ±3 dB from 30 to 20,000 Hz.

Each Delta 400 speaker comes with its individually measured frequency-response curve, made in an anechoic chamber. In view of the very different test conditions, our measurements could not be expected to duplicate these curves, but it was gratifying to find that the various small variations in the response occurred at about the same frequencies in the factory curves and in ours, and with approximately the same amplitudes. The anechoic curves did not show the rising high-end response we found in our “live” room measurements, but our bass response was considerably better than the manufacturer’s response curve.

The measured sensitivity of the Delta 400 was close to its 89-dB rating. We obtained a sound-pressure level of 88 dB at 1 meter when the speaker was driven with 2.83 volts (1 watt) of pink noise in an octave band centered at 1,000 Hz. The speaker impedance was 8 ohms at its normal rating frequency (150 to 200 Hz) and reached its minimum of 7 ohms between 10,000 and 15,000 Hz. There were impedance maxima of 20 ohms at 60 Hz and about 14 ohms at 700 Hz, as well as a rising impedance as the frequency went below our 20-Hz minimum measurement limit.

Clearly, these performance measurements are those of an excellent speaker. However, the Delta 400 woofer does have its limitations in the form of greater low-bass distortion, especially at high power inputs, when compared with the performance of larger bass drivers. At a nominal 1-watt input, the bass distortion was very low (under 1 per cent) down to about 65 Hz. Below that frequency the output from the woofer began to fall off rapidly, so that we used the distortion measured at the port below 50 Hz. It reached 5 per cent at 40 Hz, which is not at all excessive, especially for a cone the size of this one. When the power input was increased to 10 watts, the distortion changed negligibly in the woofer cone’s operating range, but it rose precipitously at the frequencies where the port radiation was dominant. The distortion was about 10 per cent at 50 Hz.

Comment

These measurements do little more than confirm that the Delta 400 is a good speaker, which could also be inferred from its general design, construction, size, and price. Only listening can show the true mettle of any speaker, and we listened to these speakers by themselves as well as in comparison with some other fine speakers. Several conclusions could be drawn from these tests.

First, the Delta 400 is not at all bass-shy, but neither is it going to satisfy the pipe-organ and/or bass-drum buff. With this bass quality there comes a refreshing freedom from tubbiness or mid-bass coloration, common defects among speakers of all types and prices. We have heard few systems as uncolored in the lower midrange and upper bass as the Delta 400.

According to the importer, the qualities of the Delta 400 favor the reproduction of the human voice, especially those of male singers. We found the sound of the Delta 400 to have a slightly crisp, sharply defined quality on some voices and a silky-smooth neutrality on others. It never added boom or muddiness to any voice, and all things considered we would have to agree that it is an umcommonly fine vocal reproducer.

Aside from questions of aesthetics (this is certainly a “different” looking speaker!), the “bottom line” has to be one of cost. The Delta 400 is a rather expensive system with no evidence of corner-cutting anywhere. It is always clean and musical in its sound, which is as distinctive as its appearance.

Read all

SIARE reviews

Read all