Active dsp crossover Owner’s Manual

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BAX-1 Active DSP Crossover

Owner’s Manual

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The lightning flash with arrowhead symbol within an equilateral triangle, is intended to alert the user to the presence of uninsulated “dangerous voltage “ within 

the product’s enclosure that may be of sufficient magnitude to constitute a risk of electric shock to persons

. 

 

The exclamation point within an equilateral triangle is intended to alert the user to the presence of important operating and maintenance (servicing) instructions in the 

literature accompanying the product.  

WARNING: TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK, DO NOT EXPOSE THIS APPARATUS TO RAIN OR MOISTURE.

DO NOT EXPOSE THIS EQUIPMENT TO DRIPPING OR SPLASHING AND ENSURE THAT NO OBJECTS FILLED WITH LIQUIDS, SUCH AS VASES, ARE PLACED ON THE EQUIPMENT.

TO COMPLETELY DISCONNECT THIS EQUIPMENT FROM THE AC MAINS, DISCONNECT THE POWER SUPPLY CORD PLUG FROM THE AC RECEPTACLE.

THE MAINS PLUG OF THE POWER SUPPLY CORD SHALL REMAIN READILY OPERABLE.

BRYSTON LIMITED WARRANTY

Bryston analog audio products are warranted to be free from manufacturing defects for twenty (20) years from the original date of manufacture. The warranty includes parts and labour.

Bryston digital products and cables are warranted for five years from the original date of manufacture. The warranty includes parts and labour. 

Bryston products having motorized moving parts, excluding motorized volume controls, are warranted for three years from the original date of manufacture. The warranty includes parts 

and labour. 

Bryston will remedy the problem by repair or replacement, as we deem necessary, to restore the product to full performance.  Bryston will pay return shipping only for the full length of 

the specific product's warranty.

In the event of a defect or malfunction, contact Bryston’s repair centers for return authorization. Products must be returned using original packaging material only. Packing material may 

be purchased from Bryston if necessary. This warranty is considered void if the defect, malfunction or failure of the product or any component part was caused by damage (not resulting 

from a defect or malfunction) or abuse while in the possession of the customer. Tampering by persons other than factory authorized service personnel or failure to fully comply with Bryston 

operating instructions voids the warranty. This warranty gives you specific legal rights and you may also have other rights which may vary from province to province and country to country.

As of 2006-02-22 Bryston will only warranty Bryston products purchased through authorized Bryston dealers.  Bryston products with a date code of 0608 or higher (date code format is 

“yyww”, where “yy” is the two least significant digits of the year and “ww” is the week of the year) must be accompanied by a copy of the bill-of-sale from a Bryston authorized dealer to 

qualify for warranty service. The warranty is transferable from the original owner to a subsequent owner as long as a copy of the bill-of-sale from the original authorized Bryston dealer 

accompanies the re-sale. The copy of the bill of sale to any subsequent owner need ONLY include the Name of the Bryston Authorized Dealer and the Model and Serial number of the 

Bryston product The warranty will only be honored in the country of the original purchase unless otherwise pre-authorized by Bryston.

Postal address: 

P.O. BOX 2170, Stn.  Main

 

PETERBOROUGH, ONTARIO

 

CANADA  K9J 7Y4

Courier address: 

677 NEAL DRIVE

 

PETERBOROUGH, ONTARIO

 

CANADA  K9J 6X7

PHONE: [phone]

FAX: [phone]

E-mail: [e-mail]

79 COVENTRY ST., Suite 5

NEWPORT, VERMONT

U.S.A.   05855-2100

PHONE: [phone]

FAX:  

802-334-6658

E-mail: [e-mail]

BRYSTON SERVICE in CANADA:

BRYSTON SERVICE in the USA:

contact your local distributor or

CHECK OUR WEB SITE: 

  www.bryston.com 

E-MAIL BRYSTON DIRECTLY: 

[e-mail]

FAX BRYSTON DIRECTLY: 

01-705-742-0882

PHONE BRYSTON DIRECTLY: 

01-705-742-5325

BRYSTON SERVICE outside Canada and the USA:

Important Safety Instructions

1. 

Read these instructions.

2. 

Keep these instructions.

3.    Heed all warnings.

4. 

Follow all instructions.

5. 

Do not use this apparatus near water.

6. 

Clean only with dry cloth.

7. 

 Do not block any ventilation openings.  Install in accordance with the manufactur-

er’s instructions.

8. 

 Do not install near any heat sources such as radiators, heat registers, stoves, or 

other apparatus (including amplifiers) that produce heat.

9. 

 Do not defeat the safety purpose of the polarized or grounding-type plug.  A polar-

ized plug has two blades with one wider than the other.  A grounding type plug 

has two blades and a third grounding prong.  The wide blade or the third prong are 

provided for your safety.  If the provided plug does not fit into your outlet, consult 

an electrician for replacement of the obsolete outlet.

10.   Protect the power cord from being walked on or pinched particularly at plugs, 

convenience receptacles, and the point where they exit from the apparatus.

11.  Only use attachments/accessories specified by the manufacturer.

12.   Use only with the cart, stand, tripod, bracket, or table specified by the manufactur-

er, or sold with the apparatus.  When a cart is used use caution when moving the 

cart/apparatus combination to avoid injury from tip-over.

13.   Unplug this apparatus during lightning storms or when unused for long periods of 

time.

14.   Refer all servicing to qualified service personnel.  Servicing is required 

when the apparatus has been damaged in any way, such as pow-

er-supply cord or plug is damaged, liquid has been spilled or objects 

have fallen into the apparatus, the apparatus has been exposed to rain or moisture, 

does not operate normally, or has been dropped.

15.  Do not open. NO USER SERVICEABLE PARTS INSIDE

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Table of Contents

Important Safety Instructions ....................................2

General.........................................................................4

Welcome ................................................................4

Description ............................................................4

Features .................................................................4

Shipping Box and Packing Material ......................4

Installation ...................................................................4

Ventilation .............................................................4

Connecting to A/C Power ......................................5

Connecting to an Audio System ...........................5

Connection Diagram .............................................5

Choosing Amplification.........................................5

Bass Adjustment ..........................................................6

A Word About Room Tuning ..................................6

Measuring In Room Response ..............................6

DSP Filter Setup ....................................................7

Front Panel ..................................................................8

Rear Panel ....................................................................8

Specifications and Dimensions ..................................9

Network Connection .................................................10

Firmware Update.......................................................10

Remote Control .........................................................11

Serial Protocol .....................................................11

Command Format ...............................................11

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4

Welcome

Thank you for your purchase of a Bryston  

Active Loudspeaker System! Our class leading 

loudspeakers and ultra high performance DSP 

crossover platform combine with your choice 

of Bryston amplification to form a unique high 

performance playback system through which you 

can hear details you never thought possible. We 

welcome your feedback and hope you enjoy your 

new Bryston Active Loudspeakers for many years to 

come.

Description

Fully active loudspeakers dispense with passive 

crossovers that are built into conventional 

loudspeakers in favor of crossovers inserted before 

amplification is applied. The benefits are many 

including increased flexibility with filter shapes, 

the ability to make fine-grained adjustments 

which result in improved on and off axis response 

(these are often competing objectives in passive 

loudspeakers), direct coupling of the loudspeaker 

to the driver which avoids losses inherent in passive 

crossovers and more. Bryston Active Loudspeakers 

combine decades of research into acoustics, 

electronics, amplification as well as state of the 

art components to recreate your recordings with 

stunning realism. The BAX-1 Active DSP Crossover is 

a core component of this system.

The BAX-1 is a state of the art DSP crossover that 

has been specially programmed at the factory 

for compatibility with your specific model of 

Bryston Active Loudspeakers. It is comprised of 

two channels of analog to digital conversion which 

convert incoming full range analog audio from your 

preamplifier to an equivalent digital audio signal 

sampled at 96kHz and decimated to 24 bits. This 

signal passes to a high powered DSP core which 

performs the 3-way crossover function for each 

channel and any user selected filters desired for 

altering the bass response of the loudspeakers 

in the room. Three bands of audio per channel 

are then passed to 6 digital to analog converters 

followed by fully discrete balanced analog outputs 

which in turn feed 3 amplifier channels per 

loudspeaker. The BAX-1 only accepts balanced input 

and provides balanced output. No single ended 

audio connections are available. If you require 

single ended connections, XLR to RCA adapters can 

be used.

The system can be user controlled through a simple 

and intuitive web-application for setup. Network 

connection is required for those who desire to 

tailor the bass response of the loudspeaker to the 

room and for firmware updates but is not otherwise 

necessary. 

Features

Bryston BAX-1 includes the following features:

•  6 DACs and 2 ADCs by AKM

•  Audio sensing auto-power on

•  Network connectivity for control and firmware 

updates 

•  Balanced XLR input and output

•  Three position gain switch 

•  Available in either 17 inch or 19 inch wide 

C-Series dress panel in silver-toned (clear 

anodized) or black anodized aluminum.

Shipping Box and Packing Material

Please keep the original shipping box and all 

packing material. This will ensure the BAX-1 is 

protected in future transport.  In the unlikely event 

you have a problem and must return it for service, 

you must use the proper packing material. Ship 

the BAX-1 only in the original packing material 

as the unit is not insurable by carriers otherwise. 

Replacement packing materials consisting of a 

shipping carton with plastic foam inserts is available 

from Bryston for a small fee.

Installation

Ventilation

The BAX-1 is a cool-running line level component. 

It generates far less heat than amplifiers and many 

other components. It can be safely placed inside 

furniture or an equipment rack. However, it should 

General

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BAX-1 Active DSP Crossover

5

not be tightly enclosed. Some airflow is desired. 

 

Connecting to A/C Power

Please check the Data Plate on the right rear of 

the crossover to verify power requirements agree 

with your location. Plug the IEC-320 C14 end of the 

power cord into the BAX-1, then plug the other end 

into an approved and grounded A/C receptacle. 

Connecting to an Audio System

Though the BAX-1 is a DSP driven digital audio 

component, all audio connections are analog only. 

This is to accommodate a broad range of pre-amps 

and front-ends while operating the digital circuitry 

at optimum conditions. Contrary to some beliefs, 

converting analog to digital inside the crossover 

does not create a compromised sonic experience.

From your stereo preamplifier, connect the left and 

right outputs to the BAX-1 left and right inputs using 

good quality balanced XLR cable. The left and right 

channels each have 3 outputs marked low mid 

and high. The low output for each channel goes to 

the amplifier designated to drive the bass section, 

mid should drive the midrange, and high drives the 

tweeters of your speakers. 

Connection Diagram

The connection diagram below shows one channel 

connected of a Bryston BP-26 Preamplifier → BAX-

1 Crossover → 21B³ Amplifier → Model T Active 

Loudspeaker.

Choosing Amplification

Bryston Active Loudspeakers have been optimized 

for use with Bryston amplifiers however other brand 

amplifiers may be suitable as well. Each amplifier 

used must have the same gain as there is currently 

no provision to compensate for mis-matched 

amplifiers within the DSP.

CANADA

ACTIVE CROSS-OVER

MADE IN

FABRIQUE AU

Ontario

Peterborough

BAX1

ETHERNET

USB

RS232

STATUS

TRIGGER IN

AC IN

LEFT

IN

TRIGGER 

OUT

TRIGGER 

OUT

HIGH

LOW

MID

RIGHT

HIGH

LOW

MID

IN

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6

Bass Adjustment

A Word About Room Tuning

The BAX-1 permits some degree of loudspeaker 

tuning below approximately 150Hz. Many 

competing systems provide full bandwidth 

adjustments, or attempt to automatically tune 

loudspeaker response based on measurements 

taken by microphone. Bryston certainly advocates 

tuning loudspeaker performance based on 

measurements, but electrically altering loudspeaker 

response is a last step, not a first step. DSP 

application is most certainly not a replacement 

for proper loudspeaker placement, well informed 

gear choices, proper room construction and wise 

room treatment. In other words, take care to 

choose upstream equipment and cables wisely, and 

position your speakers carefully in the room before 

attempting corrections with the BAX-1. It is for this 

reason we limit the adjustment window to 9dB per 

band.

Further, narrow bandwidth anomalies are less 

audible than wide bandwidth anomalies. Your 

focus should be correcting broadband deviations 

from zero before attempting to correct narrow band 

issues. 

Finally, do not obsess over getting absolute flat 

response!

Measuring In Room Loudspeaker 

Response

Though you can attempt to equalize the response 

of your loudspeakers by ear, it is strongly advised 

to measure the response in your room instead. 

There are numerous inexpensive measurement 

microphones and free software available to 

accomplish this. For those unaccustomed to 

measuring loudspeakers, Bryston recommends that 

your dealer do the setup and calibration for you.

Enter the DSP menu of the BAX-1. Select Pink Noise, 

set the level in -dB (entering 40 results in output 

40dB below full scale). Press the button “Click to 

Update Source” and both loudspeakers will be 

playing pink noise. 

Use your measurement system of choice to measure 

frequency response. It may be useful to limit your 

measurement band to 20-160Hz. Note the center 

frequency, magnitude and width of any peaks or 

dips. 

Using the 10 band parametric equalizer, enable the 

filters with the center frequency nearest to those 

you wish to correct. Note that each EQ band can 

accommodate the following adjustments: Center 

Frequency can be adjusted up to 10Hz above 

nominal for each band, magnitude can be -6 to 

+3dB, and Q can be set between 1 and 5 where 1 is 

broad and 10 is narrow. Filter changes are reflected 

in real time. You should both hear the changes and 

see them reflected in your measurements. 

Monitor the graph near the bottom of the page 

to see your changes. Also note that an aggregate 

maximum gain of 3dB is permitted. 

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BAX-1 Active DSP Crossover

7

DSP Filter Setup

Bass equalization can be access through the web 

user interface by clicking the DSP tab. This can be 

done from the listening position from most modern 

web enabled devices. See “Network Connection” on 

page 10 for details on how to connect the BAX-1 

to your network.

1.  10 Band Parametric EQ

For each band you would like to edit, enter 

desired center frequency, boost or cut in dB, and 

width. Center frequency can be the preset value 

or raised by up to 10Hz. Boost cut range is -6.0 to 

+3.0 dB, and Q is 1.0 to 5.0 where 1 is the widest 

and 10 is narrowest.

2.  Increase / Decrease

Especially useful when making adjustments 

from a touchscreen device, these buttons will 

increase or decrease the selected value by the 

precision shown with each button press or tap.

3.  Memory

Store a preset by creating a correction curve, 

then pressing SAVE ALL. Reset all filters to flat 

by pressing RESET ALL. Recall a saved preset by 

pressing RECALL ALL.

4.  Audio Output

Normal function of the BAX-1 is to pass audio 

received at the input jacks on the back of the 

unit. You can also engage a built in sine single 

tone generator and pink noise generator for 

testing. Press the desired audio source then 

press ‘Click to Update Source’ to engage the 

desired audio source. ‘Click to Play IP’ reads the 

unit’s IP address through the audio system. 

5.  Peak Gain Indicator

A maximum aggregate gain of 3dB can be 

achieved by the system. If two filters with 

overlapping bands are engaged and maximum 

gain would exceed 3dB, the 2nd filter is 

restricted to a figure that maintains no more 

than 3dB peak gain. Peak gain is limited to 

ensure internal electronics are not creating 

distortion. 

6.  Correction Curve

The result of your applied filters is indicated 

in graphical form here. Ideally, this will be 

the opposite of your measurements before 

compensation is applied. Note that this graph is 

20-160 Hz and shows -12 to +4dB

1

2

3

4

5

6

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8

Front Panel

1.  Power Button

Press this button to toggle the BAX-1 on or into 

standby mode. 

Unlit BAX-1 is not receiving power. Plug unit into 

AC mains power. 

Red Plugged into AC Mains but in standby 

mode.

Green or

Blue

BAX-1 is on and operational.

Blinking 

Red

Secondary power supply failure. Contact 

Bryston technical support.

2.  Audio Channel Indicators

The left and right channels both feature LEDs 

which indicate the incoming audio status of 

each channel.

Unlit BAX-1 is not receiving audio to the 

indicated channel

Green or 

Blue

BAX-1 is receiving audio at the indicated 

channel

Blinking 

Orange

Audio received is too loud to be processed 

without distortion. Reduce preamplifier 

volume.

Rear Panel

3.  Channel Input Output

The BAX-1 includes Left and Right channel 

input and output. Analog audio is received 

through a balanced audio interconnect from a 

stereo preamplifier to the left and right channel 

inputs respectively. The internal DSP divides 

and processes that signal into 3 bands - low, 

mid and high to drive the bass, midrange, and 

high frequency amplifier channels respectively. 

Preamplifiers and amplifiers that do not feature 

balanced audio connections can be connected 

to the BAX-1 by using commonly available XLR 

to RCA adapters. 

 

Each channel also includes a trigger out jack 

on a ‘mono’ 3.5mm jack which can be used 

to trigger the power state of compatible 

downstream amplifiers. The tip is +12V and 

sleeve is GND. When the BAX-1 is powered on 

either by actuating the front power button or 

through the trigger input, voltage is applied to 

the trigger outputs.

4.  RS232 Input

The BAX-1 can be controlled via two-way RS232 

using a connector terminated by a 3.5mm TRS 

‘stereo mini plug’. Terminate the plug as follows: 

Tip: Transmit 

Ring: Receive 

Sleeve: Ground

5.  USB Control Input

USB is provided for diagnostic information by 

Bryston technicians.

6.  Status LED

LED lights to indicate the following status: 

Red: Standby

Green: On

Amber: Starting up Blinking Amber: Updating firmware

Blue: Self programing. Do not power off

7.  Ethernet Input

Ethernet connectivity is provided for user access 

to a web based interface which is useful for 

firmware updates and control over the internal 

DSP. Discrete commands can also be sent by 

custom integration systems. See page 10 for 

BAX-1 ACTIVE DSP CROSSOVER

RIGHT

POWER

LEFT

1

2

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BAX-1 Active DSP Crossover

9

partial documentation or the HELP tab from the 

BAX-1 web interface for full documentation.

8.  Trigger Input

Power/Standby can be toggled from a master 

component such as a preamp using this input. 

The connector is a standard 3.5mm tip sleeve 

commonly referred to as a “mono mini plug”. 

Signal should be AC or DC between 3 and 12 

volts. When voltage is present at the tip, the BAX-

1 will remain powered on. The BAX-1 powers off 

when voltage is removed.

9.  IEC Power Inlet:

The IEC -320 C14 power inlet accepts IEC-320 

C13 equipped power cords such as the unit 

provided. Use only appropriate power cords that 

have been approved for your region.

10.  Data Plate

The data plate is located on the bottom of 

the unit. It indicates hardware version, serial 

number, and A/C mains voltage of your unit. 

LEFT

POWER INLET

IEC 320-C14

TRIGGER IN

STATUS

RS232

USB

ETHERNET

TRIGGER

OUT

IN

LOW

MID

HIGH

TRIGGER

OUT

BAX-1 ACTIVE DSP CROSSOVER

RIGHT

IN

LOW

MID

HIGH

3

9

5

7

8

10

4

6

Specifications and Dimensions

Max Voltage

Input:

Output:

4.0V

5.6V (+3dB)*

Frequency 

Response

20Hz - 20kHz:  ± 0.1dB

Noise

Balanced Out:

Single Ended Out:

-140dB

-140dB

IMD

≤0.0003%

THD + Noise

20Hz-20kHz : ≤0.0009%

Weight

4.7kg | 10.3 lbs

Dimensions

Inches: 17 or 19  W x 2.75 H x 11.11 D

Cm: 43. or 48.3 W x 7 H x 28.2 D

Power 

Consumption 

at 120V/60Hz

Standby: 

Idle: 

Playing

1.8W 

11W 

13W

* System operates at unity gain and only boosts or 

attenuates bands as set by the user in DSP.

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10

Network Connection

You may connect your BAX-1 to your local area 

network using CAT5 or better cable to facilitate use 

of the built in web-based user interface or to control 

and monitor the unit using an automation system. 

Once connected to the network, you may access the 

web user interface with a web browser by entering 

the host name into the address bar. The host name 

is formatted like so where the last 6 digits are the 

serial number of your unit: 

 

http://bax1-000000 

Some web browsers and networks ignore NetBIOS 

names such as above. In this case, you will need to 

use the numerical IP address of your unit to access 

the web user interface. You can find the IP address 

by logging into your network router or with popular 

network information apps on iOS and Android such 

as Fing.

Firmware Update

As with many other Bryston products, the BAX-1 

may receive occasional firmware updates to ensure 

reliable operation and add new features. Check 

your installed version and for any new updates by 

using the File menu on the BAX-1 web user interface. 

Internet connection must be available to show 

correct information.

Available Version

Installed Version

 

To update the firmware:

1.  Download the firmware file by clicking the 

“Download Internet File...” button. Save the file 

in an easy to remember location.

2.  Click “Go to Choose .bin...” button. You will be 

taken to a mostly blank page.

3.  Click “Choose File” or “Browse”. Navigate to the 

location to which you downloaded the BAX1.bin 

file in step 1. This is most likely your Downloads 

folder. Click the file and press “Open” or “OK” 

You will be returned to the upload page. Press 

the Upload button to initiate firmware upgrade.

4.  Uploading takes up to 5 minutes. The power 

LED will turn off during the update. 

5.  Do not power off. The BAX-1 will reboot itself. 

You may check the web user interface to verify 

that the new firmware version agrees with the 

version you just downloaded. You may need to 

force refresh your browser window to see any 

changes.

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BAX-1 Active DSP Crossover

11

Remote Control

The BAX-1 can be controlled and monitored through 

a variety of mechanisms including TCP/IP when 

connected to your local area network, USB, RS232, 

and DC trigger.

Serial Protocol

The BAX-1 can receive commands and can send 

responses to each command. It can also (optionally) 

broadcast automatic responses to certain system 

events such as front panel button presses. 

Commands can be sent over RS232, RS485 (with an 

RS232 to RS485 interface) and TCP/IP using HTTP 

cmd.cgi.

The RS232 input is a 3.5mm mini-jack configured as:

Tip

Ring

Sleeve

Transmit

Receive

Ground

Command Format

RS232 #

7

D2 C1 C2 C3 C4 P1 P2

... CR

TCP/IP %23 7

D2 C1 C2 C3 C4 P1 P2

... .

The command format always begins with a 

command start character.

The next two digits are the Device ID. The first of 

which is always “7” for BAX-1s, and the second will 

be “0” except when using RS232/RS485 in a multi-

drop configuration. 

Next are C1 through C4 which comprise the 

command name. These are typically uppercase 

ASCII letters.

Following the command name are the arguments 

or parameters for that command. These are two or 

more ASCII characters.

The command is always terminated with a carriage 

return character. For RS232, this is ASCII code 13. 

TCP/IP commands are terminated with a  

 

period (.)

Example:

#70MPWRQS command: query power status 

Responses are returned in the same format as 

commands. Note that responses may contain up 

to 320 characters. All characters preceding the 

# or 

%23 and following  or . are ignored. Do not 

insert 

#, spaces, ,  or other non-ASCII 

characters inside the command string.

The following are selected commands most 

pertinent to initial setup and everyday operation. 

Find complete documentation by accessing the 

BAX-1 web UI or by contacting Bryston.

Comm. Param.

Description

SDSP

Set DSP Parameters

QS or ?

Display list of all FILT 

command options

FILTnnfffsggqq

select filter number nn(01...10), 

set frequency ff (030...120Hz), 

set filter gain or reduction, s=1 +, 

s=0 for - 

set filter gain gg (00...30, 0.1dB) 

set filter Q factor qq (10...50, 0.1)

ex: #70FILT0305002530. for filter 3=50Hz, 

-2.5dB, Q 3.0

FILTQS

Displays last settings as 

above

FILTSAVE 

FILTRECALL 

 

DSRCxx

Save filter values to EEPROM 

Recall saved filter values 

from EEPROM 

Set DSP source xx=00 for 

analog inputs, 02 for sine, 04 

for pink noise

MPWR

Switch between On and 

Standby

00

Off (standby)

01

On

02 

QS

Toggle On/Standby 

Query Status

INIT

Re-initialize parameters

00

Re-initialize all but TCP/IP

01

Re-initialize all inclding TCP/

IP

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Bryston Limited | 677 Neal Drive | Peterborough, Ontario K9J 6X7  

Canada | Phone: [phone] | www.bryston.com

06-29-2017

300067-2