Cerwin-Vega AT-10 Floor standing speakers
Cerwin-Vega and rock music have grown up together with good reason: From its early days, the company knew how to build speakers that would reproduce the high acoustic levels demanded by rock, and most of its competitors didn't-at least, not at first. At hi-fi shows in the '60s, the staid audio establishment continued to tout the finesse of its products using Mozart minuets, tsk-tsk-ing the thunderous sounds emanating from the Cerwin-Vega display. Meanwhile, the crowds were going where the action and the decibels were, and Cerwin-Vega has since demonstrated that it has all the staying power of rock itself.
The AT-10 is a fairly recent addition to a series of Cerwin-Vega "residential" speakers introduced last summer. At first glance, it looks like a traditional bookshelf acoustic suspension model of roughly two cubic feet. But two factors set it apart from that familiar genre: its integral base (clearly indicating that it must stand upright on the floor) and the ducted port on the back panel, which instantly disqualifies it from acoustic suspension status.
The only other back-panel feature is a pair of color-coded, spring-loaded connectors for the electrical leads. The rest of the enclosure is clad in wood-grain vinyl, which wraps over the beveled edges of the front baffle and continues behind the removable grille. The grille's black stretch fabric is supported by a thick pressboard frame.
Behind the grille are three drivers. Centrally located near the bottom of the panel is a 10-inch woofer. Above it, and to the right of the central axis, are a 5-inch cone midrange and a l-inch Mylar-dome tweeter. Each of these drivers has its own rotary level control on the front panel. Crossover frequencies are listed as 400 Hz and 3 kHz.
The AT-10's power ratings are 5 watts minimum and 125 watts maximum. The first spec would seem a trifle optimistic if this weren't a bass-reflex design. Diversified Science Laboratories' sensitivity measurement of 95.5 dB SPL from a drive level of 2.8 volts (equal to 1 watt into 8 ohms) confirms that you get a lot out for what you put in-one method by which Cerwin-Vega models manage high playback levels when needed. The maximum-power rating is 21 dB louder, implying output of at least 116.5 dB SPL. But on actual pulsed 300-Hz waveforms, DSL got the speakers to produce a calculated peak level of 123.2 dB SPL (above the threshold of pain for normal hearing). There was no indication that the speakers were overtaxed, even though this required power equivalent to 595 watts.
Confirming the impression of unfettered dynamic range is the pattern of the measured distortion, which doesn't increase as rapidly with rising levels as in most speakers we test. At the minimum test level (85 dB SPL), distortion averaged about 1/2 percent from below 100 Hz and didn't run much more than 1 percent even in the deepest bass (where the figures always are the least reliable because of the inherent rolloff in response). At the highest level (100 dB SPL), it averaged about 1 percent to below 100 Hz.
Cerwin-Vega justifiably rates the AT-10's impedance at 6 ohms-between the 7 ohms measured by the lab across the whole audio band and the 5.7 ohms measured across our "music band" (250 Hz to 6 kHz). The impedance curve actually dips to a minimum of 4.0 ohms above woofer resonance (say, in the 200-Hz range), which is sometimes used as a rating point. Just below 30 Hz, in the impedance trough between the woofer resonance (just above 60 Hz) and that of the port (below 20 Hz), the curve also hits 4.3 ohms. The maximum in the audio band is at the woofer resonance. Impedance values in the treble vary between 4.3 and 11.2 ohms, depending on the level-control settings. With the controls centered, the impedance curve is quite flat, lying between about 6 and 10 ohms from 1 kHz up.
The controls seem to do relatively little. Turned all the way up, the tweeter control does supply about 5 dB of boost (6 dB at 10 kHz, as measured by DSL), but its minimum setting and both extremes of the midrange control alter response only slightly. Furthermore, the measured midrange alterations occur only in the region of the 3-kHz crossover -not across all of the frequencies handled by the midrange.
A clue to why this occurs may be visible in the lab's near-field driver measurements, which show a peak near 3 kHz in the midrange driver's response and considerable overlapping of the midrange and woofer at lower frequencies. In the overall response (as shown in our graph, for a speaker nine inches from the back-up wall), the peak is an octave lower. The near-field measurements, however, indicate that much of this energy may be coming from the top of the woofer range, rather than from the midrange driver.
On the basis of these measurements and my listening, I cannot say that the AT-10's midrange is particularly smooth or uncolored. Rather, it is lively and somewhat forward-and therefore appealing on much music, particularly pop. But for a listener who, like me, is strongly oriented toward acoustical music, it constitutes the least attractive element in a design that otherwise has much to offer. Alternative settings of the midrange and tweeter controls do little, if anything, to alter the intrinsic character of the speaker.
The owner's manual, though useful and well written, applies to all of the company's residential speakers and therefore does not indicate specific room positions for the AT-10. It does address the proposition that the tweeters should be near ear level, however, so I tried a low stand. The stand's influence on midrange coloration was anything but salubrious. The AT-10 clearly is designed for floor placement and should be used in that way. The choice of distance from the backup wall is a question of taste. The vent needs some breathing room, of course, but the lab's nine inches is plenty for that purpose. When the speaker is placed farther out in the room, the bass is less prominent and extended than the graph implies. But the bass is sufficiently strong and well defined that some of it can be spared in the interests of crisper imaging (which would be made possible through a placement that avoids early wall reflections).
The top treble and the deep bass are both smooth and very extended-unusually so for a speaker of this size and price-and the dynamic range is exceptional. These salient strengths of the AT-10 should win it many admirers, particularly among listeners who lean toward' pop and rock-where its qualities show to best advantage.
