Graham Chartwell LS5/5 Speakers 

The LS5/5 is a large, very cool three-way monitor designed in 1967.

A 12-inch drive unit processes the low frequencies up to 400 Hz. At this point an 8 inch midrange takes over before being handed over to the 1 inch soft dome tweeter at 3.5 kHz. Overall, the frequency response is flat to within +/- 2 dB from 40Hz to 20kHz.

You'll immediately notice that the bass and midrange drivers are mounted behind slots on the front panel. This feature is highly unusual these days, but it works to control the off-axis response of the drive units, resulting in a smoother response through the crossover regions in typical listening environments. 

Naturally, this is a BBC-style 'thin-walled' cabinet, with the relatively thin panels subjected to mass loading to ensure that resonances are diverted away from the critical mid-range. Rockwool provides air cushioning. Hand-matched veneers are applied and finished to a very high standard. The grille has been carefully designed to minimize diffraction effects and is held in place by hidden rare earth magnets.

Specifications

Type: 3 Way, bass reflex 
Enclosure Thin wall damped construction
Finish Real wood veneer
Dimensions (w/h/d) 36cm by 70cm by 48cm
Weight 35.5kg
Frequency response 40Hz to 20kHz, +/- 2 dB
Nominal impedance 8 ohms
Sensitivity 88dB SPL (2.83V, 1m)
Maximum output About 104dB for a pair at 2m
Bass 300mm long throw
Midrange 200mm
Tweeter 25mm soft dome tweeter
Recommended amplifier power 50 to 250 watts unclipped program