Description
The LEAK Audio Sandwich 250 is the pinnacle of innovation that commenced in 1961 with the original LEAK Sandwich.
Those technological advancements are implemented with the utmost regard for tradition, as well as the continual aspiration to forge sound reproduction equipment of the highest quality, accessible to every discerning audiophile.
A major loudspeaker invention
Throughout the history of broadcasting and recording, certain exceptional developments have become milstones in the progress of sound reproduction. One such milestone was the world’s very first low distortion amplifier – the famous original LEAK Point One, in 1945. Another was the pioneering major breakthrough with the invention of the fantastically rigid LEAK sandwich cone diaphragm – which was demonstrably of great strength and many times stiffer than all conventional forms of cone, of its time.
To understand the impact of this innovation, one must remember that to obtain low distortion, the movement of a loudspeaker diaphragm, or cone, should follow as accurately as possible the waveform of the signals applied to its voice coil. The ability of the current to follow these impulses accurately depends upon the lightness and stiffness of the cone assembly. Many conventional cones: paper, impregnated fabric, plastics, aluminium etc all generally suffer from low stiffness. This results in significantly larger areas of the cone vibrating in motion, uncontrolled by the voice coil.
All of these shortcomings are overcome by the LEAK Sandwich construction. Originally presented in 1961, the Sandwich used engineering and design principles applied to airframe construction. Now, reintroduced and re-engineered with modern-day learnings, the new LEAK Sandwich cone comprises of a stiff aluminium skin for the outer surfaces (where the stresses are greatest) bonded to a thick core of a polymethacrylimide (PMI) based structural foam, often used aerospace and the automotive industries.
This applied, precision-engineered use of the most suitable materials in optimum proportions and dispositions gives immense rigidity. This means the LEAK Sandwich cone reproduces the signal applied to the voice coil, totally free from mechanical break-up and its associated distortions.
It is not often sufficiently realised how profound the influence of the loudspeaker housing (the cabinet) is on the overall acoustic performance. Its design requires a great degree of electroacoustic knowledge as a design of the motor units themselves. The new LEAK Sandwich cabinet benefits from 60 years of technological development since the original.
The structure consists of a composition of MDF and composite board, thus creating a second ‘sandwich’ reference, with the boards layered for optimum cabinet strength.
The technology found within LEAK audio devices presents science and innovation in abundance, yet the industrial design often draws favourable attention. Just like the warmly received LEAK Stereo 130 and 230 integrated amplifier models, the new LEAK Sandwich 150 and 250 loudspeaker models maintain the understated, classic LEAK styling.
Finished in a sumptuous walnut, real-wood veneer, the cabinet is decorated with an aluminium trim insert matched and finished to the same exemplary standards of the driver trims and cone materials. The decorative grille cloth is purpose chosen to match the classic LEAK styling with a specification for maximum acoustic transparency. A keen eye will also notice that the new LEAK Sandwich 150 and 250 are supplied in perfectly matched pairs with a ‘handed’ array presentation.
Taking the resonant frequency below the crossover region means the audible spectrum of the bass, mid and high frequencies can be sewn together with an added dimension of detail and harmonics, eliminating the requirement to harshly adjust the definition of the high-frequencies.
Such is the format of the LEAK Sandwich 250, many traditional stands would not allow for sufficient presentation of this loudspeaker. To address this consideration, the Sandwich 250 is complemented by a precision-measured plinth that positions the loudspeaker’s driver array at the optimum level and position.
SPECIFICATIONS
Model
Sandwich 250
Design philosophy and core technology
Enclosure type
Bass reflex
Transducer complement
3-way
ABR
Bass driver
11″(280mm) Aluminium-Foamcore Sandwich cone
Midrange driver
4.25″(108mm) Aluminium-Foamcore Sandwich cone
Treble driver
1.2″(30mm) Coated Textile Dome
Full-range driver
AV shield
No
Sensitivity (2.83V @ 1m)
88.5dB
Recommended amplifier power
25-250W
Peak power handling
Peak SPL
112dB
Nominalimpedance
6Ω (8Ω Compatible)
Minimumimpedance
4 Ω
Frequency response(+/-3dB)
42Hz – 26kHz
Bass extension(-6dB)
32Hz
Crossover frequency
470Hz & 3.1kHz
Cabinet Volume (in litres)
2.7L, 45.5L
Dimensions(mm)
Height
655mm
Width
370mm
Depth (with terminals)
(300+30)mm
Carton size
500 * 430 * 790mm
Net weight
27.3kg/pcs
Gross weight
30.2kg/ctn
Finish
Real Wood Veneer – Walnut
Standard accessories
Rubber feet
Optional accessories
Leak Sandwich 250 stand
