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Pair of CSS EL70 EN 4 inch Fullrange Drivers

With a special thanks to Dr. Nikola Krivorov for submitting his pair of CSS EL70 EN

EL70 is paper cone full range driver produced by Creative Sound Solutions. It features 70mm cone from the creative mind of Mark Fenlon, principal designer at Mark Audio. This pair was upgraded by Planet_10 hi-fi by EnABL 2 process.

This is the manufacturer's brochure  Link To CSS EL70 Manufacturer's Datasheet

My Measurements

Driver Properties Thiele - Small Parameters
Chassis material Polymer   Parameter Measured Datasheet
Membrane material  Paper Fs 69Hz 64 Hz
Magnet System Ferrite Re 3.6 Ω 3.6 Ω
Surround Tri-mix Ei grade butyl rubber  Qms 4.3 3.23
Voice Coil Diameter 20 mm Qes 0.59 0.66
Nominal Impedance 4 Ω Qts 0.52 0.55
Sensitivity 86 dB/W/m   Vas 4.9 ltr 6.1 ltr
Rated Power 20W Le 0.25 mH 0.251 mH

SPL Responce of CSS EL70 EN at 1m on axis and 15 30 deg off axis

Frequency response at 1m with 2.83 V input RED - on axis, BLUE - 15 º off axis, GREEN - 30 º off axis.

Second, Third and Fourth Harmonic of CSS EL70 EN in 18 ltr sealed box

The second, third and fourth harmonic curves measured at 2.83V input RMS. Remarkable low distortion in the most audible frequency range between 1 and 5 kHz.

Burst decay Responce of CSS EL70 EN at 1m in 18 ltr sealed box

Burst decay response, measured at 1m on axis

The impedance of CSS EL70 EN in 18 ltr seled box

The impedance curve in 18 ltr sealed box


This driver is widely used in DIY constructions. They are several successful enclosures for CSS EL70 EN - Onken, MLTL, single or bi-pole BVR.

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