Sylvania AS-210A (1975–1976)
A hundred-dollar acoustic-suspension bookshelf with a tweeter that punches far above its price, and a bottom end that won't get out of its own way.
Overview
At 51 pounds and $99.95, the GTE-Sylvania AS-210A is a two-way acoustic-suspension bookshelf, and you notice the weight the moment you lift it. That's a lot of mass for a speaker this size: 24 inches tall, just under 16 inches wide, a little over 11 inches deep. Most of it is cabinet and a 10-inch high-compliance woofer. The top end is handled by a 1½-inch dome tweeter crossing over at 1.5 kHz, and the sealed box is tuned to resonate at 42 Hz. The finish is walnut vinyl. The grille is a sculptured brown foam panel held on with Velcro. It looks massive, but the reviewer who measured it found it almost perfectly transparent acoustically.
That reviewer was Richard C. Heyser, writing in Audio (August 1975, p.63). His bench work is kind to this speaker where amplifier matching is concerned. The AS-210A's impedance never dips far below 8 ohms and is resistive at four points across the band. The worst high-frequency reactance is a capacitive 11 degrees near 1,100 Hz. Heyser's conclusion was blunt: the speaker "offers no load problem." For a budget bookshelf of the mid-seventies, that means a modest receiver won't be asked to drive a reactive nightmare. The sealed-box resonance shows up as a large circular arc peaking around 43 Hz, and there's a secondary midrange resonance at 600 Hz.
On-axis anechoic output rolls off at a textbook 12 dB per octave below 55 Hz, with a crossover notch around 1,100 Hz and a smooth trend up to roughly 18 kHz. High Fidelity (1976, p.118) listed the response as 33-15,000 Hz ±3 dB and rated the speaker for a minimum of 10 watts and a maximum of 100. The two drivers are in phase at crossover with no sudden phase shift, and above 3 kHz the tweeter carries a 90-degree lag. Heyser characterized all of this as principally minimum-phase behavior. Harmonic distortion stayed generally below 1% through the usual listening range. The energy-time curve was, in his words, very good for a speaker in this price bracket: 95% of the sound energy arrives within 3.1 milliseconds, with only a late diffraction straggler at 4.6 milliseconds sitting nearly 30 dB down.
The tweeter is what wins friends. Heyser called it "the star performer in this loudspeaker system," praised its articulation and transient performance, and noted that instruments whose energy lives mostly in the tweeter's range sound "darn good." The bass is what loses them. In his listening tests the low end (200 Hz and below) ran strong enough to overwhelm the midrange even with the mid-frequency equalization switched to its high position. He also found the midrange lacking punch despite conventional tone-control boost. The rear panel gives the user two tools for this: a three-position Mid Freq. toggle (Normal, Lo, Hi) and a two-position High Freq. toggle (Hi, Lo). Heyser judged the acoustic effect of both controls modest. They won't hurt anything, but they won't fix the basic balance either. The midrange switch drew a mild complaint on ergonomics: its lowest acoustic setting is the center position, which he called less than ideal human engineering.
Placement matters more than the switches. Heyser's room measurements showed the raised, wall-mounted position gave better midrange and upper-frequency balance. The floor position tamed the bass dominance at the cost of midrange clarity. He recommended rotating the speakers in toward the listening position, since the on-axis response is distinctly better than off-axis. The foam grille is keyed so it only attaches one way, and the Sylvania logo is Velcro-mounted so it can be rotated ninety degrees for horizontal shelf placement. Given the weight, only a very sturdy shelf will do. The rear cavity houses 5-way terminals on ¾-inch spacing that accept spade lugs, twisted wire, or banana plugs, with red and black polarity caps and Pos/Neg legends printed alongside.
The warranty was generous for the class: five years on any part failing in normal use, plus replacement labor or service charge covered for the first two years. Heyser's verdict was measured. He wouldn't recommend the AS-210A as a primary stereo pair for a very large room, but he flagged two applications where it works: as rear speakers in a quadraphonic setup, where its energy distribution complements better front speakers, and as low-cost stereo speakers for a very small room such as a college dormitory, where its strong bass avoids the anemia common to budget systems. HiFi-Stereo (February 1976, p.17) ran Sylvania's own advertising billing it as "The Super Sylvania" at $99.95 with flat ±3 dB response, a 1-lb. 9-oz. ceramic magnet, and a 1½-inch voice coil epoxy-bonded to the cone. That's marketing copy, not an independent verdict, but it confirms the price and the driver construction.
This is a mass-market American bookshelf, not a cult classic. The foam grille is acoustically transparent and removable for cleaning, but it's the kind of period material that ages poorly. The bass-heavy voicing that Heyser documented is a matter of taste, not a defect, and the speaker does better pulled off the floor and angled inward. Buyers report the tweeter is the reason to own one. The cabinet mass and benign impedance are the reasons it's easy to live with. Values reflect its budget origins rather than any collector premium.
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