LEAK Sandwich 250 Loudspeaker - Walnut

Why choose the LEAK Sandwich 250 loudspeaker

The LEAK Sandwich 250 loudspeaker is a three-way, stand-mounted design built around LEAK's Aluminium-Foamcore Sandwich cone, a construction method the brand first introduced in 1961 and has re-engineered for the current range. It's built for a buyer who wants full-range output and low cone distortion from a stand-mounted cabinet rather than a floor-standing speaker, and who is ready to match it with an amplifier capable of driving a 6Ω load across a 25-250W range. Because the cabinet and driver array are larger than a typical bookshelf speaker, the Sandwich 250 also asks the buyer to think about stand height and system placement before purchase, not just sound.

What makes the LEAK Sandwich 250 loudspeaker different from conventional bookshelf speakers?

The LEAK Sandwich 250 loudspeaker is built around an aluminium skin bonded to a core of polymethacrylimide (PMI) structural foam for both its bass and midrange cones, a material pairing more commonly associated with aerospace and automotive construction than home audio. Conventional cone materials, including paper, impregnated fabric, plastics and plain aluminium, generally lack stiffness relative to their weight, so larger areas of the cone continue moving after the voice coil signal has changed, producing hangover, amplitude peaks and troughs, and intermodulation distortion. The aluminium-foamcore sandwich construction keeps the cone rigid enough to move as a single unit, so the diaphragm tracks the voice coil signal more accurately across its operating range. This construction is used on both the 11-inch (280mm) bass driver and the 4.25-inch (108mm) midrange driver, while the treble is handled by a separate 1.2-inch (30mm) coated textile dome. An auxiliary bass radiator (ABR) works alongside the bass reflex enclosure to extend low-frequency output without adding a second powered driver, contributing to a quoted bass extension of 32Hz at -6dB and an overall frequency response of 42Hz-26kHz (±3dB).

Which amplifiers suit its impedance and power handling?

This loudspeaker is rated at a nominal impedance of 6Ω, compatible with 8Ω-rated amplifiers, and a minimum impedance of 4Ω, so it needs an amplifier or receiver comfortable driving loads in that range rather than one designed only for a straightforward 8Ω speaker. LEAK recommends amplifier power between 25W and 250W, giving a buyer room to run the speaker from a modest integrated amplifier or push it harder within a larger system, with a peak SPL rating of 112dB indicating the maximum output the drivers can handle before distortion becomes audible. Sensitivity is rated at 88.5dB (2.83V at 1m), which determines how much amplifier power is needed to reach a given volume in a given room; a less sensitive amplifier pairing or a larger listening space will need more of that 25-250W range to reach comfortable listening levels. There's no AV magnetic shielding on this model, so it's suited to a dedicated stereo system rather than placement next to equipment that requires shielded speakers.

How should the LEAK Sandwich 250 be positioned for accurate stereo imaging?

The LEAK Sandwich 250 is supplied as a matched, handed pair, meaning the left and right cabinets are built as mirror images of each other with driver placement calculated for correct stereo alignment rather than two identical boxes. At 655mm high, 370mm wide and 330mm deep (including terminals), and weighing 27.3kg per cabinet, the Sandwich 250 is taller and heavier than a typical bookshelf speaker, so many standard speaker stands won't position the driver array at the correct listening height. LEAK addresses this with an optional Sandwich 250 stand, a precision-measured plinth designed specifically to hold the driver array at its intended height and position, and the two are intended to be bought and set up as a matched pair of furniture and loudspeaker. Rubber feet are supplied as standard for buyers who plan to position the cabinets directly on furniture or a shelf instead.

Who should choose the LEAK Sandwich 250 within LEAK's range?

The LEAK Sandwich 250 is one of three loudspeakers in LEAK's current Sandwich range, offered alongside the Sandwich 150 and Sandwich 100 and complemented by the dedicated Sandwich 250 stand. Its own specification, an 11-inch bass driver in a three-way layout with a crossover splitting duties at 470Hz and 3.1kHz, a 45.5-litre cabinet volume plus a 2.7-litre ABR chamber, and a bass extension down to 32Hz at -6dB, is built for a buyer who wants a stand-mounted design with the deepest bass extension and highest output headroom LEAK states for this model. LEAK's other Sandwich models are not detailed here, so a buyer weighing the 250 against the 150 or 100 will need each model's own specification to compare cabinet size, driver count and power handling directly.

How does the crossover integrate the treble driver with the rest of the array?

The LEAK Sandwich 250's treble driver is fitted with a damped rear chamber that absorbs the output from the back of the dome, isolating the high-frequency unit acoustically from the rest of the cabinet and lowering its resonant frequency. Taking that resonance below the 3.1kHz crossover point allows the bass, midrange and treble outputs to be blended without needing to artificially boost or roll off the top end to compensate for a rising resonance close to the crossover region. LEAK describes the crossover network itself as developed through extended listening evaluation alongside simulation, rather than simulation alone, reflecting how the 470Hz and 3.1kHz crossover points were set for this particular driver combination.

How is the cabinet constructed to support the driver array?

The LEAK Sandwich 250 cabinet is built from a layered composition of MDF and composite board, bonded together to form a second sandwich structure distinct from the cone material, with the layering intended to add cabinet strength and damping. Front-to-rear internal bracing supports the panels against flexing, and the rear panel carries a visible countersunk screw, a detail carried over from the original 1961 cabinet design. The exterior is finished in real-wood walnut veneer with an aluminium trim insert matched to the driver trims, and the cabinet uses a grille cloth specified for acoustic transparency.

What's included with it, and what else does the system need?

This loudspeaker is supplied with rubber feet as a standard accessory and a user manual, with the matching Sandwich 250 stand available as an optional purchase for buyers who want the driver array positioned at its designed height. Beyond the speaker itself, building a system around it means sourcing an amplifier able to handle its 6Ω nominal (4Ω minimum) impedance within the 25-250W recommended range, along with source equipment and cabling suited to a dedicated two-channel or stereo setup rather than an AV system requiring magnetically shielded speakers.