LEAK Sandwich 250 Loudspeakers - Walnut - Pair

LEAK Sandwich 250 Loudspeakers - Walnut - Pair

What It Does in Your System

A 1961 Breakthrough, Rebuilt for Today

LEAK introduced the original Sandwich speaker in 1961. The idea came from aircraft design: build the cone from two stiff outer skins bonded to a light core, and you get something far more rigid than a conventional cone without adding weight. It was a genuine milestone in speaker design.

The Sandwich 250 is the flagship of the revived range. It uses the same principle, rebuilt with modern materials. Aluminum skins bond to a core of PMI foam, an aerospace material, giving the cone immense stiffness for its mass.

Why a Stiff Cone Matters

A speaker cone should move exactly the way the signal tells it to. When a cone isn't stiff enough, it starts to flex and ripple instead of moving as one piece. That's called break-up, and it adds distortion you can hear as hardness and blur.

The Sandwich cone is rigid enough to move as a single unit across its range, so it tracks the signal cleanly. Both the 11-inch bass driver and the 4.25-inch midrange use this construction. Above them sits a 1.2-inch textile dome tweeter.

A Tweeter with Its Own Chamber

The tweeter has a damped chamber behind it that soaks up the sound coming off the back of the dome. That isolates it from the rest of the cabinet and lowers its resonant frequency — the pitch where the driver naturally wants to ring.

Pushing that resonance below the crossover point lets LEAK blend bass, midrange, and treble together without heavy-handed correction. The crossover itself was tuned over thousands of hours of listening rather than by computer simulation alone.

Is This Right for You?

A few things to think about before you order:

• These are large and heavy for a standmount. Each speaker weighs about 27.3kg — roughly 60 pounds. Most off-the-shelf stands won't handle them properly. LEAK builds a matching stand designed for the job, and it's worth planning for.
• Check what your amplifier can drive. Nominal impedance is 6 ohms and it dips to 4 ohms at the lowest point. LEAK recommends 25 to 250 watts. An amp that's comfortable with a 4-ohm load will serve you best.
• Give the room some size. An 11-inch bass driver in a 45.5-liter cabinet moves real air. These will play in a small room, but they're built to fill a larger one.

Setup & Installation

Place the speakers on stands that put the tweeter near seated ear height. LEAK's own stand raises the speaker to 655mm and is built to match both the acoustic requirements and the walnut and aluminum finish. The cabinets are mirror-imaged left and right, so check which is which before you set them up.

The cabinet uses a bass reflex port, so leave some space behind it and adjust from there. Move the speakers closer to the wall for more bass weight, farther out for a tighter, more open sound. Two people should handle the lift.

Features & Specifications

Aluminum and PMI Foam Sandwich Cones
Stiff aluminum skins bonded to an aerospace foam core give the bass and midrange drivers rigidity without added weight.

11" Bass Driver
A large cone in a 45.5-liter cabinet delivers deep, full bass with real scale.

Rear-Chamber-Damped Textile Dome Tweeter
A damped chamber isolates the tweeter and drops its resonance below the crossover for a smoother blend.

Hand-Veneered Walnut Cabinet
Real wood veneer with aluminum trim, front-to-rear bracing, and the countersunk rear screws that marked the original.

Specifications

• Type: 3-way bass reflex standmount loudspeaker
• Bass Driver: 11" (280mm) aluminum-PMI sandwich cone
• Midrange: 4.25" (108mm) aluminum-PMI sandwich cone
• Tweeter: 1.2" (30mm) rear-chamber-damped textile dome
• Frequency Response: 42Hz – 26kHz
• Crossover Points: 470Hz and 3.1kHz
• Sensitivity: 88.5dB (2.83V at 1m)
• Nominal Impedance: 6 ohms (8-ohm compatible), 4-ohm minimum
• Recommended Amplifier Power: 25 – 250W
• Peak SPL: 112dB
• Cabinet Volume: 45.5L bass, 2.7L midrange
• Weight: About 27.3kg (60 lbs) each
• Finish: Real-wood walnut veneer with aluminum trim
• Quantity: Pair (stands sold separately)

Frequently Asked Questions

Do I need LEAK's stands?
We'd recommend them. At 60 pounds each, these are heavier than most standmount speakers, and many aftermarket stands won't support them safely or put the drivers at the right height. LEAK's stand is built for both.

What is a sandwich cone?
It's a cone built like an aircraft panel. Two stiff aluminum skins bond to a light foam core in between. The result is far more rigid than a normal cone of the same weight, so it moves as one piece instead of flexing and adding distortion.

What amplifier do they need?
LEAK recommends 25 to 250 watts, which is a wide range. The more important detail is the 4-ohm minimum impedance. Pick an amp that's happy driving a 4-ohm load and you'll have no trouble.

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