SPL DeS 500 Series De-esser Module

The SPL DeS is a Dual-Band De-esser module designed for the 500 series format using phase cancellation to reduce sibilance rather than dynamic control.
The SPL DeS expands on this concept by using two frequency bands that can be used independently or together. Using two de-esser stages increases its effectiveness while preventing audible artifacts. High and Low bands offer greater precision and much focused sibilance processing.  Input signals are automatically adjusted to ensure uniform processing at all times. A Male / Female mode switch adapts the frequency response of the processor to typical male and female vocals frequencies.
Both Low and high band are connected in series as independent modules and can be activated by their dedicated On/Off switch. The Low band is first in the chain and will affect the signal fed into the high band. 
The original SPL De-esser quickly became highly popular amongst engineers and producers as well as broadcast stations in the 90’s
SPL DeS Dual Band 500 Series De-esser Module:

Sibilance reduction by phase cancellation
Very effective – very unobtrusive
2-band processing: Hi-S and Lo-S
Only 2 controls – easy and fast to use
De-S intensity LED display
Male/Female voice selection
ON/bypass switch
Signal LED
Single-Slot 500 series rack module
Made in Germany