Altec Model 15 (1972–1980s)

Ninety pounds per cabinet, rated down to 28 Hz, and efficient enough that a single-ended tube amp will make the walls move.

Overview

The Altec Model 15 is a three-way, bass-reflex floorstanding loudspeaker, and a big one. Figure roughly 42 inches tall, 22 wide, and 16 deep, at approximately 90 lbs per cabinet. That's why sellers on the used market routinely list them as local-pickup-only. You don't ship these. You and a friend carry them up a flight of stairs and then argue about placement for a week.

The drivers are a 15-inch high-efficiency cone woofer, a 6-inch cone midrange, and a 3-inch compression driver on a horn, crossed at 700 Hz and 5,500 Hz. The rated response runs 28 Hz to 18 kHz, which is remarkable extension for a cabinet of this vintage and a big part of why the Model 15 has stayed in circulation. Impedance is nominally 8 ohms, and Altec rated power handling at 75W continuous. Sensitivity is listed at 99 dB. That figure appears in Altec's own feature material and in the company's comparison against the smaller Model 14, though the specs table itself leaves the sensitivity row blank. Treat 99 dB as the working figure, but it's single-sourced.

Efficiency is the whole point. Altec built the Model 15 around the idea that a speaker should reproduce music effortlessly, not merely measure flat. The company's own design language for the line put high efficiency, wide dynamic range, and minimal compression ahead of the flat-response-at-any-cost approach many hi-fi makers of the era took. At 99 dB, a few watts go a very long way.

One thing worth flagging up front: a 1976 Reverb listing describes the Model 15 as a two-way design with a recommended maximum of 60 watts RMS continuous and "silky smooth response to 20k." That conflicts with the three-way, 75W, 28 Hz–18 kHz figures above. The three-way description is the widely reported configuration, and the 60W/2-way listing appears to be a single outlier — but the discrepancy exists, and buyers comparing listings should know it.

Key Features

15-Inch High-Efficiency Woofer in a Bass-Reflex Cabinet

The low end is handled by a 15-inch cone woofer - 380mm - loaded into a vented enclosure. The rated 28 Hz extension is the headline number, and it's the reason the Model 15 was pitched for "full orchestral and cinematic impact." A 15-inch driver in a ported box moves air in a way smaller woofers can't, and combined with the cabinet's efficiency, the bass arrives with very little amplifier strain. The trade-off is size. There's no compact version of this speaker.

Horn-Loaded High-Frequency Section

Above 5,500 Hz, a 3-inch compression driver on a horn takes over. This is the classic Altec approach, and it gives the speaker its dynamics and detail in the top end. Altec's advertising around this period made much of the "Tangerine" phase plug - a small radial disk inside the driver - which the company claimed delivered greatly extended high-frequency response and a wider band of clean, natural highs. High Fidelity (October 1977, p.155) and Audio (October 1977, p.101) both ran the Tangerine campaign, and Altec's copy noted that a unique dividing network was created specifically for the Models 15 and 19 to work with it. That's marketing language, not an independent verdict. It does confirm the Model 15 shared its high-frequency architecture with the larger Model 19.

Crossover Network

The crossover splits at 700 Hz and 5,500 Hz. Owners who have opened theirs describe a simple network: two inductors, two capacitors, two resistors, and two potentiometers. The inductors are reportedly air-core, wound with solid-core wire on a white plastic bobbin. That's good news for anyone planning a rebuild, since there's not much in there and the parts are accessible. It's also the first thing that needs attention on a 40-plus-year-old pair.

Heavy Braced Cabinet

Altec built the Model 15 into a heavy cabinet with internal bracing. At roughly 90 lbs per speaker, most of that mass is doing acoustic work, stiffening the enclosure so the 15-inch woofer's energy goes into the room rather than the walls. Surviving examples are frequently finished in oiled walnut, at least judging by the listings that specify a finish.

Historical Context

Altec positioned the Model 15 as the larger sibling to the Model 14, and the spec sheet backs that up: 28 Hz bass extension against the Model 14's 30 Hz, 99 dB sensitivity against 98 dB, and 75W power handling against 60W. Altec's own material frames it as the step up for listeners who wanted more low end and more headroom.

Production is documented as running from 1972 into the 1980s, though the exact end year isn't confirmed. Individual units surface in listings dated 1973, 1976, and 1979, which fits that window. The resale market has a nickname for the speaker: "Baby 19's." It's not an official designation, but the Model 15 did borrow the high-frequency thinking of the Model 19 in a smaller, less expensive package. Owners report the Model 15's crossover is a drop-in fit for Model 19 networks.

Altec intended these for large home listening rooms, high-fidelity systems built around tube amplifiers, and professional monitoring in some installations. The company's material even pitched them for home theater, before the term was in common use.

Collectibility & Value

Pricing on the Model 15 is messy, and anyone shopping should understand why before they bid. Completed eBay sales over the past year show a range of roughly $45 to $156 with a median around $83. That figure is almost certainly dragged down by parts, grilles, and magazine clippings rather than complete speakers. A single charted sale hit $1,000 in May 2026, and that number likely reflects a working pair. The source data doesn't distinguish between whole speakers and accessories, so treat the low median as a floor for parts and the $1,000 point as closer to what a good pair commands. Volume is thin, roughly three sales a month, so comps are scarce.

Off-forum sales give a better read on complete pairs: a set with 412c woofers and modified crossovers sold for $750 with local pickup in Indianapolis. A restored 1973 pair in oiled walnut was listed as "90% restored." Restored examples clearly sit well above the parts-driven median.

Maintenance is the other half of the equation. The capacitors in these crossovers are decades past their service life, and the most common advice from long-term owners is blunt: replace them. One owner who recapped both Model 19 and Model 14 crossovers described the improvement in sound quality as impressive. Recapping isn't foolproof, though. One Model 15 owner rebuilt their crossovers with Solen capacitors and rewired the network, only to end up with extremely low volume afterward. If you're doing the work yourself, verify the wiring against the original before you button the cabinet back up. Drivers are also a long-term concern. At least one documented pair had its 12-inch drivers reconed by GPA in 1991.

Original horn lenses are another weak point. One restorer noted that replacing them was the only non-original part on their pair, and that sourcing close matches required searching worldwide. Crossover assemblies occasionally turn up for sale with broken wiper stems or missing knobs, so inspect the potentiometers carefully if you're buying a loose network.

For collectors, the Model 15 is rare enough to be worth seeking out, common enough that parts and knowledge circulate, and efficient enough to work with the tube gear most vintage buyers already own. A properly restored pair, in Altec's own framing, can hold its own against modern speakers costing many times more.

Market Value

┌──────────────────────────────────────────────────────────────────────────┐
│ ALTEC MODEL 15                                                  Nov 2026 │
├──────────────────────────────────────────────────────────────────────────┤
│ High      $1,000                                  Latest          $1,000 │
│ Median    $83                                     Trend                — │
│ Low       $35                                     Volume           ~3/mo │
├──────────────────────────────────────────────────────────────────────────┤
│ $1,000 ┤                                                                .│
│        │                                                                 │
│        │                                                                 │
│   $571 ┤                                                                 │
│        │                                                                 │
│        │                                                                 │
│        │            .                                             .      │
│     $0 ┤.    .         ..          ...          .                        │
│        ├─────────────────────────────────────────────────────────────────│
│    vol │▂    ▂      ▂  █▂          ▂▂▂          ▂                 ▂     ▂│
│        └─────────────────────────────────────────────────────────────────│
│         2026-02                      2026-03                      2026-05│
└──────────────────────────────────────────────────────────────────────────┘

eBay completed sales. Excludes accessories, parts, and non-working units. Hover points for details.