Return to Home Page

Parametric Receive
Audio System

Return to Audio Filters Index

Audio Receive Processing System 

Heil logo




The Heil Parametric Receive Audio System (PRAS SYS) is a state-of-the-art audio system that enhances the internal audio systems of amateur radio, shortwave, commercial, and CB receivers. The PRAS allows radio operators to modify, shape, and improve the audio output of their receivers using three separate equalization controls. There are easy to use controls on the main unit. Midrange frequencies are the most critical for achieving clear voice articulation in receive audio. The Parametric Receive Audio System allows operators to have unique control over these important frequencies. First, operators can adjust the parametric midrange filter from 400 Hz through 4 kHz, with the recommended sweet spot being at 2.5 kHz. In addition, operators can control the presence of these midrange frequencies plus or minus 15 dB. Combined with a low-frequency filter down to 160 Hz, and a high-frequency filter up to 6 kHz, the Parametric Receive System provides operators unparalleled control and quality of their receive audio.

Connecting the PRAS to your radio is simple. The PRAS rear panel has three audio inputs: standard XLR and 1/8 inputs, and an 8 ohm input that can be used with the 8 ohm speaker output of any receiver.

There are three audio outputs on the PRAS: balanced XLR and 1/4 outputs on the rear panel, and a 1/8 output on the front panel for recording audio. The PRAS also has two built-in headphone amplifiers with separate level controls and dual 1/8 headphone outputs. The PRAS is intended to be used with the Heil HPS-5 powered speaker (the PRAS must be used with a powered speaker). The HPS-5 consists of a 24-watt, two-way, low-distortion amplifier using a titanium midrange tweeter and a 5 low-frequency speaker. The HPS-5, in combination with the PRAS, provides superb audio balance without distortion. The PRAS SYS comes with an XLR-to-XLR cable to connect to the HPS-5, as well as a 12-volt DC power supply.

The Heil HPS-5 Powered Speaker is a two-way, powered speaker designed to be used with the Heil Parametric Receive Audio System (PRAS). The HPS-5 in combination with the PRAS provides unmatched speech articulation and brings new dimensions to receive audio quality. The end result is a fantastic listening experience that relieves ear fatigue for operators. The HPS-5 has a low-distortion, highly efficient Class D 24-watt amplifier that drives a specially designed 5 low-frequency speaker with a 3 magnet assembly mounted in a resonant sealed enclosure. A passive extended crossover drives a 2 high-frequency tweeter.

The HPS-5 has two rear panel inputs: a balanced 600 ohm XLR input and an unbalanced 1/8 input. A single level control adjusts the input signals for both inputs. There is also a balanced 600 ohm XLR output for combining two or more HPS-5 powered speakers. Included with the HPS-5 is a 12 volt, 2 Amp power supply, and a 2 Amp fuse is mounted on the rear panel. Dimensions are 9 H x 7 W x 6 D.
NOTE:  Heil is now packing the equalizer and speaker separately. It is no longer available as a bundled system.

Order # Model Includes List Price Your Price Order
  PRAS SYS PRAS System: Equalizer and speaker. Discontinued
#4251 PRAS EQ Parametric Equalizer only. $249.00 $219.95 Order
#3139 HPS-5 Powered speaker only. $199.00 $179.95 Order

Developer Bob Heil, has produced an informative 7 minute video explaining this innovative product:

Heil Sound has kindly provided an active display of the Heil PRAS system for our showroom.
     Stop in to see and hear this amazing device!

Copyright 2018-2020 Universal Radio, Inc.