You can't make the EL device quieter. The inrush of current causes the plunger and solenoid to make noise.
A quieter option would be motorized electric latch retraction. Von Duprin has QEL for 33A/35A, 94/95, and 98/99 Series. Falcon has MEL for 24/25 Series. There are conversion kits to convert EL to motorized electric latch retraction.
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