The Heil Sound Pro Set is a lightweight, versatile boom mic/headset designed for comfort, durability, and, above all, performance. The earpieces are full sized, with heavily-stuffed cushions for operator comfort during long operating stints. The ear pad covers are removable, for washing, and replacement pads are also available. Besides sealing out noise passively, the Pro Set now includes Heil Sound's exclusive phase reversal technology, which allows the user to "move" the incoming signal by engaging the phase-reversal switch; this creates a unique spatial widening sound that can, in some situations, significantly improve copy in a tough DX pile-up. The earphone speakers in the Pro Set Series are 200too-Ohm devices, with a -3 dB point at 8000 Hz. This combination reduces a lot of the hiss found in receiver audio stages. These speakers exhibit medium sensitivity, but they are easily driven by most rigs if you turn the AF Gain control up to about 2 o'clock. The Pro Set 5 (PS 5) is equipped with the HC-5 full-range element, which rolls off at 300 Hz on the low side, matching the IF or DSP filters of most modern HF transceivers.
