Technics SB 7000A (1978–1981)
At 36 kilograms, it takes over the room. You know it's a serious speaker the moment you see it.
Overview
The Technics SB-7000A is a big floor-standing speaker from a time when Japanese engineers chased theoretical ideals hard. Technics marketed it as a "Phase-Linear" floor monitor and built it as part of the experimental Linear Phase series. The premise was that phase coherence could matter as much to accurate sound as frequency response. It stands 845 mm tall and weighs 36 kg with its grille. Owners report it was priced at ¥90,000 per unit around 1977, a serious investment at the time, aimed at audiophiles who valued measured performance over marketing flash.
It's a three-way, three-driver bass reflex system, and the layout is what sets it apart. The drivers are aligned so their acoustic centers fall along a single vertical line when viewed from the side. The idea is better directional consistency and time alignment across frequencies. You can see it in the stepped baffle, where the 35 cm woofer sits recessed below the 12 cm midrange and the 3.2 cm dome tweeter. The tweeter uses a newly developed square-shaped strontium ferrite magnet. This wasn't off-the-shelf hardware. It was a prototype-grade effort to build a speaker that behaved predictably in space.
Size and complexity aside, the SB-7000A isn't all brute force. It has level controls for both mid and high frequencies, each with anti-resonance circuits. These aren't simple volume tweaks. They adjust the Q factor of the circuit, so users can tune the response without degrading the basic characteristics of the drivers. That suggests a product built for critical listening, perhaps even near-field monitoring, despite its domestic form. The enclosure is a damped bass reflex design, and the whole system reaches a sensitivity of 93dB/W/m. That figure isn't extreme, but it lets the speaker play loud with quality amplification.
Specifications
| Manufacturer | Technics |
| Model | SB-7000A |
| Type | 3-way, 3-speaker, linear phase bass reflex floor-standing speaker system |
| Woofer | 35 cm cone type |
| Midrange | 12 cm cone type |
| Tweeter | 3.2 cm dome type |
| Impedance | 6 Ω |
| Output sound pressure level | 93dB/W/m |
| Instantaneous maximum input | 150W |
| External dimensions | Width 480 x Height 845 x Depth 410 mm (with grille) |
| Weight | 36.0 kg (with grille) |
Key Features
Linear Phase Driver Alignment
Driver alignment is the SB-7000A's defining trait. Technics placed the acoustic centers of the woofer, midrange and tweeter along a single vertical axis, aiming for coherent wavefront propagation. This alignment reduces phase distortion across the listening window, giving more precise imaging and a stable soundstage. Collectors note the design was part of a broader push toward "linear phase/frequency response," which set the SB-7000A apart from contemporaries focused only on flat amplitude response.
Square Strontium Ferrite Magnet in Tweeter
The 3.2 cm dome tweeter has a newly developed square-shaped strontium ferrite magnet. The unusual shape was reportedly chosen to optimize magnetic field distribution and reduce distortion. The tweeter is pedestal-mounted, raising it slightly to improve off-axis dispersion. The fact sheet doesn't specify the diaphragm material. Anecdotal reports suggest a treated cloth dome, a common high-fidelity choice of the era.
Mid- and High-Frequency Level Controls with Anti-Resonance Circuits
Each speaker has adjustable level controls for the mid and high frequencies. These aren't passive attenuators. They use anti-resonance circuits that let users modify the Q of the driver's resonance without compromising transient response or phase behavior. According to available documentation, this avoids the usual sound quality loss of conventional tone controls, so the SB-7000A can be adapted to different rooms without sacrificing fidelity.
Damped Bass Reflex Enclosure
The cabinet is a bass reflex design with internal damping to control airflow and reduce port noise. Its mass and construction account for the 36 kg weight and help minimize cabinet resonance. The port is integrated into the rear or base, and the exact placement isn't documented. The design favors low-end extension without losing tightness, and owners report it holds up well with dynamic material.
Historical Context
The SB-7000A was part of Technics' Linear Phase series, a short-lived but technically ambitious line that included the SB-6000A and SB-5000A. Advertisements from 1977 show these models marketed together, which suggests a tiered approach to the same core technology. Production reportedly ran from 1978 to 1981, though some sources suggest a shorter two-year window. Its release coincided with intense innovation in Japanese audio engineering, and brands like Kenwood, Sansui and Pioneer were also exploring time and phase coherence. The SB-7000A stood out for its commitment to measured performance rather than flamboyant design.
Collectibility & Value
The SB-7000A is considered rare vintage equipment, and owners note it is hard to find in working order and complete. Common failure points include degraded woofers, blown tweeter diaphragms and aging capacitors in the crossover network. Repair discussions appear across enthusiast forums, with specific challenges noted in separating doped fiber materials during cone refurbishment. No current market prices are documented. Restoration is difficult and parts are scarce, which makes it a high-maintenance collectible.
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