RDL STEQ3 Data Sheet

STICK-ON® SERIES

Model ST-EQ3
3-Band Audio Equalizer

ANYWHERE YOU NEED...

• 3-Band Audio Equalizer

• Custom Tailored Audio Bandwidth

• To Pass Voice-Band Audio

• To Produce Smile-Curve for Music

• Low-Noise, Low Distortion Equalizer

You Need The ST-EQ3!

The ST-EQ3 is a unique audio equalizer in the STICK-ON product series by Radio Design Labs. The
durable bottom adhesive permits quick, permanent or removable mounting nearly anywhere or it may be
used with RDL’s STR-19A or STR-19B racking systems. The ST-EQ3 offers the ultimate flexibility in
audio bandwidth adjustment, with the big PLUS, you can put it right where you need it!

APPLICATION: The ST-EQ3 features a balanced bridging input, which may be also connected
unbalanced if desired. The output driver is 150 Ω balanced, and is intended to drive unbalanced or
balanced lines of 150 Ω or higher impedance. Three active circuits accomplish equalization, each
controlling a separate audio band. These bands were carefully selected to yield a module that works
effectively in a wide variety of systems. Each band’s center frequency can be either boosted or
attenuated by at least 12 dB. The Q of the low and high band equalizers was selected so that those
controls can be functionally considered as a total bass band or treble band control. The midrange control
is optimized to voice band adjustment, with the overlap tailored to provide smooth operation for wideband
music applications.

A feature unique to the ST-EQ3 is the CLIP indicating LED. When audio signals are equalized, the
boosted level can cause the output circuit to clip. Alternatively, if prominent frequencies are attenuated,
the input is likely to be turned up so that its amplifier can clip. In either event, there is a risk of distortion.
Unlike many products, which show only input clipping, the ST-EQ3s CLIP indicator flashes if EITHER the
input or output stages would clip!

For general equalization requirements in both music and voice applications, the ST-EQ3 is the optimum
choice. Its low-noise and low distortion performance makes it suited to the most critical installations.
Used in conjunction with other RDL RACK-UP®, STICK-ON, TX™, or FLAT-PAK™ series products, the
ST-EQ3 can provide the foundation for many creative audio systems!

RDL •• P.O. Box 1286 •• Carpinteria, CA., USA 93014 •• [phone] •• FAX [phone] •• http://www.rdlnet.com

STICK-ON® SERIES

Model ST-EQ3
3-Band Audio Equalizer

Installation/Operation

EN55103-1 E1-E5; EN55103-2 E1-E4

Typical Performance reflects product at publication time
exclusive of EMC data, if any, supplied with product.
Specifications are subject to change without notice.

TYPICAL PERFORMANCE

Input: 100 kΩ balanced or unbalanced bridging; line level
Gain: Adjustable OFF to unity (+/- EQ Adj.)
THD: < 0.030%; 0.010% typ. (1 kHz, +4 dBu ref.; flat response)
CMRR: > 60 dB @ 100 Hz
Frequency Response:
Into 600 Ω: 20 Hz to 22 kHz (EQ set flat; +/- 0.5 dB)
Into bridging load: 10 Hz to 22 kHz (EQ set flat; +/- 0.5 dB)
Noise: < -80 dB below +4 dBu
Center frequencies:
Low Band: 80 Hz
Mid Band: 1 kHz
High Band: 30 kHz
Bandwidth at 3dB EQ:
Low Band: 20 Hz to 300 Hz
Mid Band: 200 Hz to 7 kHz
High Band: 3 kHz to 30 kHz
Power: 24 to 33 Vdc @ 25 mA, Ground-referenced

Radio Design Labs Technical Support Centers

U.S.A. [phone], [phone]; Fax: [phone]

891-0025H

Europe [NH Amsterdam] (++31) 20-6238 983; Fax: (++31) 20-6225-287