SABINE FBX-2020 User Manual

© 1995-2001 Sabine, Inc.
CONGRATULATIONS! You now have the state-of-the-art in feedback control. Your Sabine FBX-2020 Feedback Exterminator
®
— a single channel,
20-bit digital filtering device — gives you automatic real-time feedback control and increases the clarity and volume of your system.
The FBX-2020 incorporates the latest in digital signal processing technology. It automatically senses feedback in a sound system and determines
its pitch. It then places one of 10 Constant Q micro-filters on the resonating frequency and eliminates the feedback in typically less than one second.
Special features of the FBX-2020:
• An improved algorithm that allows the FBX-2020 to better distinguish the difference between feedback and music
• Improved 20-bit digital resolution, providing superior dynamic range and signal-to-noise ratio
• 10 feedback filters, giving the unit more feedback elimination power for the toughest venues.
• ClipGuard™ adaptive clip level control, with TURBO setup mode, increases the effective dynamic range by more than 10dB
and makes setup faster and easier.
• Standard FBX features such as lockable fixed filters and switchable 1/10- and 1/5-octave Constant Q filters are also included
and now have convenient front panel switches.
QUICK-START OPERATION
For best results, read all operating instructions before using the FBX-2020. If you're already
familiar with the FBX or just want a basic overview of FBX operation, this simple quick-start
procedure is for you. More detailed instructions are on page 7 inside this operating guide.
1. Place the FBX between the output of your mixer and the input of your power amp.
2. With the master volume down, put the FBX-2020 in active mode (red BYPASS LED off), then
slowly raise the mixer master volume to the point of feedback.
3. Keep raising the master volume until all of your fixed filters and one dynamic filter are set, then
lower the volume slightly. (Factory default is nine fixed and three dynamic filters.) The rest of
the filters continually catch and update new feedback frequencies throughout the program.
You're ready to go.
READ THE ENTIRE OPERATING GUIDE FOR COMPLETE INSTRUCTIONS.
V2
OPERATING GUIDE
QUICK-START OPERATION 1
DECLARATION OF CONFORMITY 2
APPLICATION OF COUNCIL DIRECTIVE 2
ABOUT THE FBX-2020 3
FREQUENCY RESPONSE 3
WORLD'S BEST FEEDBACK CONTROLLER 3
WHO NEEDS FBX? 3
WHY THE FBX? 3
DIRECT HIT ON FEEDBACK!3
ACTIVE/BYPASS SWITCH 4
SIGNAL LEVEL 4
RESET 4
SET TOTAL NUMBER OF FILTERS 4
SET FIXED 4
LOCK FIXED FILTERS 4
A/C POWER INPUT 4
AUDIO INPUTS & OUTPUTS 4
FBX-2020 CONTROLS 4
FIFTH OCTAVE 4
FILTER STAGE ACTIVITY 4
POWER SWITCH 4
FUSE 4
APPLICATION DIAGRAMS 5
FBX SETUP FOR MONITORS 5
FBX SETUP FOR ENTIRE MIX 5
FBX SETUP FOR SINGLE INSERT POINT 6
FBX SETUP FOR INSERT SEND & RETURN 6
FBX-2020 6
OPERATING 6
INSTRUCTIONS 6
WHERE THE FBX FITS IN YOUR SOUND SYSTEM 6
A NOTE ABOUT GRAPHIC EQUALIZERS 6
UNDERSTANDING FIXED & DYNAMIC FILTERS 6
CLIPGUARD™ ADAPTIVE CLIP LEVEL CONTROL 6
C
LIPGUARDTM TURBO MODE GUIDE 6
HOW TO OPERATE THE FBX-2020 7
HOW TO USE THE FBX-2020 FEATURES 8
USING THE LOCK FIXED FEATURE 8
SELECTING FILTER WIDTH 8
IMPORTANT OPERATING CONSIDERATIONS 8
MEMORY 8
BYPASS MODE 8
RESETTING THE FILTERS 8
TURBO MODE SETUP 8
DEFEATING TURBO MODE 8
MOBILE VS. STATIONARY MICROPHONES 8
FREQUENTLY ASKED QUESTIONS 9
INDEX 9
FBX-2020 ENGINEERING SPECIFICATIONS 10
CAUTIONS & WARNINGS 11
LIMITED WARRANTY 12

SABINE FBX-2020 Specifications

General

Input Connectors	XLR, 1/4" TRS
Output Connectors	XLR, 1/4" TRS
Channels	Stereo
Frequency Range	20 Hz to 20 kHz
Filter Bandwidth	1/10 octave
Input Impedance	20k ohms

Summary

QUICK-START OPERATION

DECLARATION OF CONFORMITY

ABOUT THE FBX-2020

Direct Hit on Feedback!

Targets feedback without reducing sound quality, using narrow filters for better gain.

Frequency Response

Compares FBX 1/10-octave filters to 1/3-octave EQ filters in terms of frequency response.

World's Best Feedback Controller

Highlights FBX advantages over graphic EQs: automatic, precise filter placement, and narrower filters.

Who Needs FBX?

Identifies users who benefit from FBX, including small bands and various venues.

Why the FBX?

Explains FBX's core benefit: quick, effective feedback elimination with superior sound quality.

FBX-2020 CONTROLS

Active/Bypass Switch

Controls unit's active/bypass mode; red LED indicates bypass.

Signal Level

LED ladder shows signal strength; red CLIP LED indicates clipping or TURBO mode.

Reset

Resets all filters by holding button until filter LEDs are off.

Set Total Number of Filters

Allows setting total active filters by pressing and releasing button.

Set Fixed

Sets number of fixed filters by holding button and selecting desired number.

Lock Fixed Filters

Locks fixed filters and exits TURBO mode; LED indicates status.

Fifth Octave

Selects wider 1/5-octave filters for new filters; mixable with 1/10-octave.

Filter Stage Activity

LEDs show activated filters; blinking indicates the most recently activated one.

Power Switch

Push-button switch to turn unit on/off; power LED indicates operation.

A/C Power Input

Details correct voltage selection (115/230 VAC) to prevent damage.

Audio Inputs & Outputs

Specifies 1/4" TRS and XLR connectors for balanced/unbalanced audio.

APPLICATION DIAGRAMS

FBX Setup for Monitors

Illustrates FBX connection for monitor outputs to amplifier inputs.

FBX Setup for Entire Mix

Shows FBX placement for main mix output to amplifier input.

OPERATING INSTRUCTIONS

Where the FBX fits in your sound system

Advises common placement between mixer output and power amp input or on mixer insert.

A note about graphic equalizers

Contrasts wide EQ filters for tone with narrow FBX filters for feedback control.

Understanding FIXED & DYNAMIC filters

Explains FIXED filters retain settings, DYNAMIC filters adapt; default is 9 fixed/3 dynamic.

ClipGuard™™ Adaptive Clip Level Control

Describes ClipGuard's automatic level matching for extended dynamic range and easier setup.

How To Operate The FBX-2020

Setup Procedure Steps

Details the 10 sequential steps for operating the FBX-2020 for feedback elimination.

ClipGuard™™ TURBO Mode Guide

Understanding TURBO Mode

Explains TURBO mode benefits, activation, and how to turn it off.

TURBO Mode Operation During Program

Warns against using TURBO mode during program playback due to clipping risks.

Troubleshooting TURBO Mode Filter Setting

Addresses issues with fixed filters not setting when TURBO mode is exited early.

FBX-2020 Features and Operation

Using the LOCK FIXED Feature

Locks fixed filters after setup to prevent them from deepening beyond preset depth.

Selecting Filter Width

Allows selection of 1/10-octave (music) or 1/5-octave (spoken word) filter widths.

Operating Considerations

Covers memory, bypass mode, filter resetting, TURBO mode setup, and mobile microphone use.

FREQUENTLY ASKED QUESTIONS

Q. Can I place the FBX in the mixer's EQ loop?

Yes, it can be placed in an EQ loop.

Q. Can I place the unit in the mixer effects loop?

Not recommended; may cause issues mixing dry/effects signals.

Q. The signal input LEDs do not light. The unit will not catch feedback. Why?

Check connections; unit may not be in signal path or program interrupted.

Q. Can I mix balanced and unbalanced inputs and outputs?

Yes, but may cause 6 dB dynamic range loss or bypass issues.

Q. Why does one of the FILTER ACTIVITY LEDs blink?

Confirms unit response by indicating the last updated filter.

Q. Sometimes during the initial setup, the first filter LED will blink before any feedback has been introduced into the system. Why?

May indicate system hum; check grounds and try resetting filters.

Q. Why does the FBX cause a noticeable hum?

Can occur if main power voltage drops significantly below specified levels.

Q. Why does my system sound thin and muffled?

Try bypassing FBX; if issue persists, check EQ or reinitialize.

Q. Why does my program sound clipped and distorted?

Ensure TURBO mode is off before program; check CLIP LED status.

Q. Why won't the rest of the fixed filters set after I press LOCK FIXED to turn off TURBO mode?

Press LOCK FIXED again before a dynamic filter sets to continue setting fixed filters.

FBX-2020 ENGINEERING SPECIFICATIONS

FILTERS

Details 10 independent digital notch filters, user-selectable width, resolution, and speed.

INPUT/OUTPUT

Specifies signal levels, output drive, impedance, and connector types.

PERFORMANCE

Lists spectral variation, SNR, and THD specifications.

POWER INPUT

Details voltage configuration (115/230 VAC) and power consumption.

FUSE REPLACEMENT

Instructions for replacing the fuse with the correct rating.

DIMENSIONS

Provides rack mount dimensions in inches and centimeters.

WEIGHT

States the nominal weight of the unit.

OPTIONS

Mentions optional input/output transformer.

NOTES

Clarifies filter width below 200Hz and output capability with balanced connectors.

FBX-2020 SIMPLIFIED INTERNAL BLOCK DIAGRAM

Visual representation of the unit's signal processing flow.

CAUTIONS & WARNINGS

General Safety Precautions

Covers grounding, avoiding moisture, proper ventilation, heat sources, cord handling, and unplugging when unused.

FCC, Canadian, and Japanese Compliance

Details FCC, Canadian, and Japanese EMI compliance statements for the device.

Voltage and Fuse Handling

Warns about correct input voltage selection and proper fuse replacement procedures.

Service and User Limitations

Specifies conditions requiring professional service and advises against user maintenance.

CAUTION! Noise Exposure

OSHA Noise Level Exposure Limits

Details permissible noise level exposures according to OSHA to prevent hearing loss.

LIMITED WARRANTY

Warranty Terms and Conditions

Outlines the one-year limited warranty terms, conditions, and exclusions.

Obtaining Warranty Service

Provides instructions on how to obtain warranty service, including proof of purchase.

Online Product Registration

Information on registering products online.