Tannoy Corner GRF
The quintessence of British dual-concentric engineering.
The Tannoy Corner GRF combines a historically significant coaxial loudspeaker principle with a complex horn-/diffuser-based enclosure – designed for controlled directivity, high efficiency and natural sound reproduction.
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Concept
The Tannoy Corner GRF was introduced from 1955 as a dedicated loudspeaker system employing the legendary Dual Concentric™ driver in a complex, corner-loaded horn / compound enclosure.
At the core of the design is the Dual Concentric™ driver — a Tannoy invention dating back to 1948 — in which a high-frequency driver is mounted coaxially at the center of a low-frequency cone.
This arrangement forms a time-coherent point source, delivering uniform radiation and high fidelity across a wide frequency range.
The GRF enclosure additionally employs a compound expanding source principle, where the effective wavefront area varies with frequency.
As a result, low-frequency radiation couples efficiently to the room, while spatial reproduction remains natural and convincing for both solo instruments and large orchestral material.
By combining the Dual Concentric™ driver with a carefully differentiated enclosure geometry, the system achieves high efficiency, controlled bass reproduction, and a spacious, natural presentation of large-scale musical events — without the typical directivity artifacts associated with conventional multi-way horn systems.
Manufacturing & materials
The original Tannoy Corner GRF enclosures were conceived as mechanically robust and acoustically well-defined constructions.
The objective was not to create the lightest or most compact cabinet possible, but to provide a stable working environment for the Dual Concentric driver in which its complex radiation behavior could unfold in a controlled manner.
Characteristic of the GRF concept is the combination of a large internal volume, defined internal guides, and a precisely designed horn / diffuser structure.
Internal surfaces and transitions are shaped to deliberately guide and expand the wavefront generated by the driver.
This “compound expanding source” principle requires a high level of constructional accuracy, as even small deviations can influence energy distribution and spatial imaging.
Historically, multi-layer wood-based materials were predominantly used, offering a favorable balance of stiffness, internal damping, and manufacturability.
Wall thicknesses were deliberately generous to reduce cabinet resonances and to create a mechanically calm foundation for the driver.
Resonances were not intended to be damped after the fact, but minimized through construction.
A central element of the Corner GRF principle is the deliberate use of room corner placement.
By positioning the system in the corner, the effective radiating area is extended without increasing the physical size of the enclosure itself.
The GRF geometry is precisely designed to exploit this spatial coupling in a controlled manner rather than leaving it to chance.
The result is stable radiation behavior, particularly in the lower midrange and bass, with clear presence and even energy distribution throughout the room.
In the LMH interpretation, this construction principle is realized using modern CNC manufacturing.
Geometries, wall thicknesses, and internal structures follow the historical references in a reproducible manner, but are executed with higher dimensional accuracy and consistent quality.
Material selection, internal bracing, and surface finishes are defined on a project basis, with the aim of preserving the acoustic logic of the GRF concept without alteration.
For selected customers, uncompromising versions with increased wall thicknesses or Panzerholz are also possible, where maximum mechanical calmness and long-term stability are the primary objectives.
Who is the Corner GRF designed for?
For listeners who:
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appreciate the sonic character of historic Dual Concentric™ systems
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place value on time-coherent, spatially accurate reproduction
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expect horn-like controlled radiation without the compromises of conventional multi-way designs
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prefer mechanically and acoustically consistent loudspeaker solutions
The Tannoy Corner GRF is less a neutral “measurement candidate” and more a classic system with a historically defined sonic character.
It is particularly well suited for acoustically rich recordings and complex, polyphonic music.
LMH Classic Line
High-frequency horn
System Architecture
In the Tannoy Corner GRF, a Dual Concentric™ driver operates within a specially designed horn / compound enclosure:
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Low- and mid/high-frequency coordination:
The coaxial driver integrates low-frequency and high-frequency radiation into a single, time-coherent acoustic unit.
This creates a point source with controlled directivity and homogeneous radiation behavior within the listening space. -
Enclosure principle:
The GRF design employs a compound expanding source† structure, in which the effective radiating area varies with frequency — a principle already introduced in the Tannoy Autograph series.
This contributes to balanced bass radiation and fast transient response. -
Dual Concentric™ technology:
Characteristic is the concentric mounting of the high-frequency driver at the center of the low-frequency cone — a technical foundation for largely uniform directivity across the audible range.
Historically, the GRF system typically employed a 15″ Dual Concentric™ Monitor Silver / HF / 15L driver, combined with an acoustic coupling that allows bass loading down to approximately 30 Hz while acoustically optimizing front radiation in the range between roughly 350 Hz and 1 kHz.
Design Driven by Acoustics
At LMH, design consistently follows acoustic function.
Material selection, surface treatment, and construction are not decorative elements, but integral parts of the mechanical and acoustic design.
Solid Wood – Where It Makes Sense and Remains Stable
Where it is structurally and acoustically meaningful, we also build enclosures from carefully selected solid woods.
We use only woods with proven long-term stability, defined density, and good internal damping, such as:
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Beech
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Maple
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Oak
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Ash
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Walnut
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Selected tropical hardwoods (project-dependent)
Solid wood is used deliberately – not universally – only where mass, stiffness, and resonance behavior benefit from it and where climatic influences remain controllable.
Veneer on Plywood – The Technically Preferred Solution
In many cases, veneered plywood is the acoustically and mechanically superior solution.
As a core material, we use high-quality beech or birch plywood with excellent dimensional stability and uniform resonance behavior.
This core is finished with real wood veneers in virtually any available species – chosen for visual reasons without sacrificing the structural advantages of plywood.
This construction offers:
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High long-term stability
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Low tendency to warp or crack
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Reproducible acoustic properties
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Free choice of wood appearance without structural drawbacks
At LMH, veneer is not a compromise, but a deliberately chosen high-end solution.
Stains & Wood Surfaces
Wherever possible, the natural wood structure remains visible.
We use:
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Transparent stains to emphasize the grain
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Oil and hardwax systems for open, lively surfaces
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Satin-matte lacquers with minimal film thickness
Surface finishes are defined on a project basis, matched to wood species, geometry, and acoustic targets.
Paint Finish (Optional)
Where it makes sense from a design or conceptual perspective, fully painted versions are also possible.
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Color selection in nearly all RAL shades
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Opaque or satin finishes
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Multi-layer, mechanically stable paint systems
At LMH, painted finishes are not a standard solution, but a consciously chosen alternative to wood or veneer surfaces.
Project-Specific Configuration
Every LMH product is configured on a project-specific basis.
Wood species, veneer, stain, or paint finish are integral parts of the overall design – not interchangeable accessories.
The goal is a permanently stable, mechanically quiet, and visually honest system that does justice to the respective loudspeaker or enclosure concept.
System
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Historical horn / compound enclosure designed for corner placement
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Configured for Dual Concentric™ wideband coaxial drivers
Driver
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Typically: 15″ Dual Concentric™ driver (e.g. Monitor Silver)
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Coaxial layout forming a time-coherent point source
Radiation behavior
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Compound expanding source providing frequency-dependent wavefront expansion
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Efficiently coupled low-frequency reproduction down to approx. 30 Hz (historically)
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Uniform directivity in the mid- and high-frequency range
Operation
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Passive or active operation possible
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Particularly well suited for high-efficiency systems with clear presence
Applications
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Domestic listening rooms with available room corners for corner placement
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Studio and music reproduction environments with a focus on naturalness and spatial accuracy
(Technical data of historical originals may vary depending on driver type, production series, and specific configuration.)
