Grace Design m905 Users Manual

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Digital and Analog Versions

Owner’s Manual Revision D

ACU Firmware v1.13

RCU Firmware v1.13

XMOS Firmware v1.13

1 Welcome

Welcome and thanks for purchasing the Grace Design m905 reference monitor controller. We build all of our products to be completely reliable and straightforward to use, so you can concentrate on doing great work. While you will find the m905 is fairly straightforward to use, it is a very powerful unit and a great deal of user configuration is possible, so we recommend that you spend some time reading this manual to help avoid any common user difficulties.

In the event that you do encounter any technical difficulties with this or any of our products, feel free to call us at 303-823-8100. Our office hours are 9:00 to 5:00, Monday through Friday, MST, or you may e- mail any technical questions to: info@gracedesign.com. Also, please check out our website for complete product information, owner’s manuals and technical documents http://www.gracedesign.com

Grace Design has been building audiophile quality products for the recording industry for over 20 years. The technology in the m905 is the result of extensive research, listening, testing and careful refinement. Your m905 represents a combination of absolutely pristine audio performance, robust mechanical construction and complete reliability. We sincerely hope it helps you achieve a new level of excellence in your work!

Contents

1 WELCOME

2 IMPORTANT SAFETY INFORMATION 3 SAFETY MARKING SYMBOLS

4 SERVICE INFORMATION 5 M905 FEATURES

m905 Audio Control Unit Rear Panel Audio Control Unit Front Panel Remote Control Unit (RCU)

m905 Graphical User Interface

7 UNPACKING AND INSTALLING

Your m905 Box Will Contain

Open and Inspect the Box

8 CONNECTING THE M905

Power Connections

Power-Up Sequence

System Connections

9 NORMAL OPERATION MODE

Input Selection

Volume Control, Preset & Headphone Mute

Speaker Output Selection

Monitoring Option Controls

Display

Save / Recall of User Configuration

Optional IR (infrared) Remote Control Operation

Analog Only Option

10 SETUP MODE

Entering and Exiting Setup Mode

Input Setup

Speaker Setup

2	Dim Setup	21
3	SUB / DAC / METER setup	21
3	SUB / DAC / METER setup	21
3	CUE Output Setup	22
3	CUE Output Setup	22
3
4	Headphone Setup	23
5	Talkback Setup	24
6	Mute / (solo)	24
6	11 GENERAL SETUP	25
7	Display Setup	25
8	IR (infrared) Remote Setup	25
8	DIGI LOOP Setup	26
8	Digital Input Setup	26
8	System Setup	27
8	SPL Meter Setup	27
8	12 ABOUT CROSS-FEED	28
8	12 ABOUT CROSS-FEED	28
8	13 COMMUNICATION ERROR HANDLING	29
9	14 COMPUTER AUDIO SETUP	29
11	Asynchronous USB Audio	29
11
11	USB Up Channel Setup	30
11	Computer Audio Requirements	31
12	Using the m905 for DAW playback	32
12	15 UPDATING FIRMWARE	32
14	Updating RCU Firmware	33
14
15	Updating ACU Firmware	34
15
15	Updating XMOS Firmware	35
15
17	16 SPECIFICATIONS	37
17	17 BLOCK DIAGRAM	39
17	17 BLOCK DIAGRAM	39
17	18 PCB JUMPER LOCATIONS	40
17	18 PCB JUMPER LOCATIONS	40
17	19 WIRING DIAGRAMS	41
	19 WIRING DIAGRAMS	41
18	20 CLEANING AND MAINTENANCE	42
20	21 WARRANTY INFORMATION	42
20	22 MANUAL REVISIONS	43
	22 MANUAL REVISIONS	43

2 ImportantSafetyInformation

•Indoor use only

•Ordinary Protection: This equipment should not be exposed to dripping or splashing

•Avoid placing objects filled with liquids, such as vases or glasses, on this equipment

•Class I Equipment (grounded type)

•Electrical rating: 100-240V~ 50-60Hz 60W

•Mains supply voltage fluctuations are not to exceed ±10% of the nominal supply voltage

•Pollution Degree 2

•Installation (Overvoltage) Category II for transient overvoltages

•Maximum Relative Humidity: <80%

•Operation temperature range: 10 °C to 40 °C

•Storage and transportation temperature range –40 °C to 70 °C

•Maximum altitude: 3000m (9843 ft)

•Equipment suitable for continuous operation

•Weight: ACU 7.8lbs, RCU 2.2lbs

3 SafetyMarkingSymbols

CAUTION: READ ACCOMPANYING DOCUMENTS - This symbol, located on the equipment and in this manual, refers to important instructions. Read this manual thoroughly before operating this equipment.

WARNING: ELECTRICAL SHOCK HAZARD - This symbol, located on the equipment and in this manual, indicates the potential for electrical shock hazard.

4 ServiceInformation

The Grace Design m905 contains no user serviceable components. Contact Grace Design for repair and upgrade information. In the event that your Grace Design m905 needs to be returned to the factory, contact us for a return authorization number.

5 m905features

•Analog inputs - unbalanced, balanced (2nd pair balanced available on m905 Analog) , CUE, talkback mic

•Digital inputs - 2x AES3, 1 S/PDIF, 1 TOSLINK, ADAT (selectable in 4 pairs, or 2 pairs in S/MUX), USB, AES3 Dual Wire mode. AES and S/PDIF connectors support DSD64 or DSD128 via DoP Version 1.1

•Audio circuitry designed for completely transparent and musical playback performance

•Asynchronous Class 2 USB playback supports up to 24bit /196kHz and DSD64 or DSD128 via DoP Version 1.1, configured for two channels down from computer and 10 channels up to computer

•Mastering quality DAC circuitry with configurable de-emphasis filtering

•s-lock dual-stage Phase Lock Loop for ultra low jitter clock regeneration

•Hybrid RCU with hardware switches, large level encoder and graphical LCD

•LCD display shows input, level, output, SPL and DAC status plus a full calibration menu

•RCU includes built in microphone for talkback and onboard SPL meter

•SPL meter features include level, peak, fast and slow modes, A & C weighting

•Precision .5 dB step level control for speakers and headphones, volume displayed in absolute or custom reference level

•Reference headphone amplifier circuitry, with outputs on both the RCU and ACU

•Dedicated mono, dim, mute and sub mute switches

•Mono mode can be set to L+R summed, L only in both channels, or R only in both channels

•L solo, R solo, L -R and sub solo modes are available

•3 available stereo speaker outputs, with two assignable mono sub outputs (or single stereo sub output)

•Multi-mode SUB/ DAC/ METER out

•Optional IR (infrared) remote control via Grace Design Remote, Apple Remote or iOS and Andriod with the Logitech Harmony Hub Remote

•SUB out mode for stereo or multiple mono subwoofer outputs

•DAC out mode for a fixed DAC output fed by the selected digital input

•METER out mode fed by selected input signal (digital or analog), configurable with a fixed level or to fol- low the monitor level

•Detachable RCU tilt base

•Five year transferrable warranty

M905 AUDIO CONTROL UNIT REAR PANEL

100-240 VAC / 50-60Hz

60 Watts Max

RoHS

COMPLIANT

GRACE DESIGN

LYONS, CO USA UPGRADE

3 4

DIGITAL IN

DIGITAL OUT

SUB/

OUT

DAC OUT R

CUE OUT R

TALKBACK OUT

WORDCLOCK

AES 1

AES 2

S/PDIF

TOSLINK

ADAT

USB 2

AES3

S/PDIF

REMOTE

TALKBACK SWITCH

SPEAKER 1

SPEAKER 2

SPEAKER 3

CUE IN

BALANCED IN

UNBAL IN

TALKBACK MIC IN

SUB/

DAC OUT

CUE OUT R

TALKBACK OUT

100-240 VAC / 50-60Hz

60 Watts Max

L BALANCED IN 2

RoHS

COMPLIANT

GRACE DESIGN

LYONS, CO USA UPGRADE

REMOTE

TALKBACK SWITCH

SPEAKER 1

SPEAKER 2

SPEAKER 3

CUE IN

BALANCED IN

UNBAL IN

TALKBACK MIC IN

1 AC mains input universal 100-240 VAC, 50-60Hz, 60 Watts max. This connects m905 (with the supplied AC power) cable to AC power source.

2 Word Clock termination switch used to properly terminate a connection from an external clock reference source to the m905 Word Clock input.

3 Word Clock input for incoming word clock signals from a master clock or other equipment passing a master clock signal.

4 Word Clock output for sending or passing word clock signals from the m905 to other equipment.

5 Two AES3 input XLR connectors used to receive stereo AES3, Dual Wire AES3, and DSD64 or DSD128 via DoP V1.1

6 */PDIF INPUT RCA jack input accepts a S/PDIF format digital stereo signal or DSD64 or DSD128 via DoP V1.1

7 TOSLINK INPUT Optical connector accepts a TOSLINK format digital stereo signal.

8 ADAT INPUT LIGHTPIPE™ connector provides a 2 channel input selectable in 4 pairs (or 2 pair S/MUX) of an ADAT format digital source.

9 USB Class 2 interface provides an asynchronous mode computer interface PCM up to 24bit/196kHz and DSD64 and DSD128 via DoP V1.1. Configured for two channels down from computer and 10 channels up to computer.

10 Digital out provides a buffered digital loop-through of a selected source via AES or S/PDIF.

11 Multi-mode SUB / DAC / Meter output can be used as either a subwoofer output (mono or stereo), a fixed level DAC output, or a dedicated meter output. Configurable in the setup menu.

12 Cue out stereo output includes sum of the CUE input signal with talkback mic signal.

13 Talkback output mono output of talkback microphone signal.

14 USB upgrade port for future ACU firmware revisions.

15 DB15 Remote connector connects the m905 ACU and RCU with supplied 15 pin serial remote cable

16 Talkback switch input, momentary or latching operation, configured in the setup menu.Speaker 1 output stereo balanced

17 Speaker 1 output stereo balanced 18 Speaker 2 output stereo balanced 19 Speaker 3 output stereo balanced

20 Cue input for studio headphone mixes, sums with talkback mic signal for CUE output.

21 Analog Balanced Input via XLR connectors. 22 Analog Unbalanced input via RCA connectors.

23 External Talkback mic input, for any type of external microphone, 7-70dB gain, 48V configurable in the setup menu.

24 m905 Analog Rear panel - digital inputs are not available - a second set of balanced Analog inputs via XLR is installed.

AUDIO CONTROL UNIT FRONT PANEL

1 2

REFERENCE MONITOR CONTROLLER

GRACE DESIGN USA

1 HEADPHONE OUTPUT standard TRS 1/4” jack for head-							2 AC mains power standby switch Illuminates green
phones. Wired in parallel with the jack on the RCU.							when m905 system is powered on. ALL SYSTEMS GO!
Connection to headphones should be made using
standard ¼”TRS stereo connectors.
REMOTE CONTROL UNIT (RCU)
1	2	3	4	5	10	11	12 13	14 15	16

			SPEAKER 3	MUTE	SUB MUTE	SETUP
				solo	sub solo
			SPEAKER 2	DIM	MONO	MON > CUE
				x-feed	L - R	spl clear
			SPEAKER 1			TALKBACK
				VOLUME
				push for phones
6	7	8	9		17	18

19 20 21

Note: for all the dual function buttons on the RCU, the primary push release function illuminates solid, and the push and hold function flashes.

1 Graphical user interface (GUI) This color LCD displays all operating parameters and setup menus.

2 Analog input unbalanced selects input source connected to the unbalanced RCA analog input.

3 Analog input balanced selects input source connected to the balanced XLR analog input.

4 CUE input selects input source connected to the balanced XLR CUE input.

5 TOSLINK input selects input source connected to the

TOSLINK optical input.

6 ADAT / AES DW INPUT When ADAT mode is active selects ADAT format digital stereo signal. Once selected, pushing the switch toggles through available input pairs. When AES Dual Wire mode is active, AES DW selects the Dual Wire source connected to the AES1 and AES2 inputs.

7 S/PDIF selects input source connected to the S/PDIF RCA style connector

8 AES selects the last used AES source. Once selected, pushing the switch toggles between AES1 and AES2.

9 USB selects computer input source connected to the USB connector.

10 Speakers 1, 2, 3 illuminated switches select any one pair of the three available speaker outputs.

11 Mute / solo switch mutes the speakers or press and hold to toggle solo channel.

12 Dim / x-feed reduces the monitoring level by a prescribed amount. Press and hold to toggle on / off cross-feed in headphones.

13 Sub-mute / sub-solo button mutes the subwoofer. Press and hold solos the subwoofer.

14 MONO sums to mono (L+R) the current signal being monitored. Press and hold subtracts the right channel from the left channel (L-R).

15 SETUP enters the setup menu.

16 MON>CUE routes currently selected monitor source to the CUE output. Press and hold to clear SPL peak level.

17 Volume adjusts speaker and headphone levels. Push to toggle between either level. On speaker, press and hold recalls volume preset. On headphones if level is 0.0, push and hold recalls headphone preset. If headphones are on, press and hold toggles headphone mute.

18 Talkback activates the talkback microphone, either built in or external.

19 DB15 serial connector connects RCU to ACU with supplied 15 pin serial cable.

20 1/4”TRS headphone jack wired in parallel to headphone jack on frontpanel of ACU. Note: this output is not connected on standard m905 Analog units unless RCU cable upgrade is purchased

21 USB upgrade port for future RCU firmware revisions.

m905 GRAPHICAL USER INTERFACE

Input buttons - these 2 rows at the top and the bottom

4 Headphone level and x-feed status - this area shows

of the screen represent the available system inputs.

the current headphone monitoring level (0-100dB in

Each button directly corresponds to its particular

.5dB steps) and cross feed status (push and hold ‘DIM’

input select switch and its corresponding input source.

hardware switch to activate / deactivate crosssfeed).

Custom labeling is available via the setup menu. Active

Level numbers highlight green when selected and are

input button is a friendly shade of blue.

adjustable via the volume encoder.

2 Main speaker level and speaker set - this area shows

5 DAC clock status - this area displays the main clock-

the current speaker set selected and the current

ing functions and status of the m905’s DAC. Top row

monitoring level in 0.5dB steps. When the standard

displays the selected digital input source, S/MUX

level display mode is active (configured in SETUP) the

(if enabled) and de-emphasis (if enabled). Second

range is 0-100. When reference level display mode

row displays the DAC’s operating sampling rate and

is configured the display range is user defined. See

s-Lock status if active. Third row displays the selected

Speaker SETUP for more information. Level numbers

clocksource and selected clocksource lock status.

highlight green when selected and are adjustable via

Fourth row displays the bitstream status: pro/cons (for

the volume encoder.

TOSLINK, S/PDIF AND AES), S/MUX (for ADAT) and de-

3 SPL meter - this area shows the current SPL level, me-

emphasis (for TOSLINK, S/PDIF AND AES).

tering mode, and peak level. Setup menu allows user

6 m905 Analog screen showing digital inputs are not

to select between A and C weighting, fast and slow

available. Available analog inputs are automatically

mode. Resetting peak level is done by pushing and

shifted the the bottom row.

holding the ‘MON>CUE’ hardware switch.

7 UnpackingandInstalling

YOUR m905 BOX WILL CONTAIN

•The Audio Control Unit (ACU)

•The Remote Control Unit (RCU)

•The RCU tilt base and accompanying hardware, premounted to the RCU

•25’ serial cable to connect the RCU and ACU

•m905 Analog comes with an ethernet cable and 2 serial adapter jacks . For RCU headphone operation a RCU cable ugrade is required. This is available from youe dealer or from the Grace Design factory)

•6’ AC power cable which connects to the ACU’s universal power supply

•A bag with rubber feet and rack screws

•The owner’s manual and warranty registration

OPEN AND INSPECT THE BOX

Please take care when removing the m905 from its OEM packaging. Our packaging is designed with ‘Korrvu©’ suspension inserts, which provide the best protection from the dubious underworld of freight handling – so save your packaging material. Inner boxes will contain all the items listed above. If you think you are missing anything, give your dealer or us a call and we’ll get you taken care of right away.

REGISTER YOUR UNIT

Also, we strongly urge you to fill out your warranty registration card. We provide a 5 year transferable warranty on all of our products, but without your registration it’s hard for us to help you if and when help becomes necessary. So please take a few minutes to complete and send in the enclosed card, or simply fill out the warranty registration form on our website. We always keep your information private. Thank you!

8 Connectingthem905

Okay, let’s get started in making the necessary connections to get your m905 up and running. First thing to do is mount the m905 in a rack. If you’re not rack mounting the unit, you should attach the supplied rubber feet on each corner of the bottom cover so you won’t scratch it or the surface you place it on. If you are installing the ACU in a rack, use the supplied rack screws and nylon washers which prevent the rack ears from getting marred. The ACU will not run terribly hot, so it can be mounted with other gear directly above or below. However, you should avoid mounting equipment that can radiate noise near the m905 (ie power amp, power conditioners, etc).

POWER CONNECTIONS

The m905 ACU has a built-in universal power supply which accepts line voltages of 100 to 240VAC. We include power cable specified for the country where it was ordered, so it should be supplied correctly. If not, please contact your dealer or distributor for help. For safety, it is recommended that the AC power cable be connected to a grounded outlet.

POWER-UP SEQUENCE

Before powering up your m905, make sure your monitor speakers or power amps connected to your monitors are turned OFF. Once the m905 and the rest of your audio system are powered up, turn on the power to your speakers. When powering down, we recommend that you first power off your speaker system and then power down the m905.

SYSTEM CONNECTIONS

The m905 input, output and interface connections are detailed here. Pinout diagrams for various connectors are located in the cable and connector wiring diagrams (page 41) section of this manual. If you have an m905 Analog system, all digital inputs, digital loop thru outputs and wordclock will be unavailable.

UNBALANCED ANALOG INPUT - This stereo input is for interfacing with consumer level (-10dBv) unbalanced analog sources. Connections are made using standard RCA cables.

BALANCED ANALOG INPUT - The balanced stereo analog input is via female XLR. Connections are made using standard balanced XLR cables, wired to the pin 1 shield, pin 2 positive, pin 3 negative.

CUE ANALOG INPUT - The balanced stereo analog CUE input is via female XLR. Connections are made using standard balanced XLR cables, wired pin 1 shield, pin 2 positive, pin 3 negative.

TALKBACK MIC INPUT- A standard microphone input which can be used with dynamic or condenser microphones. Phantom power (+48V) is available (see Setup Mode). Wired pin 1 shield, pin 2 positive, pin 3 negative.

AES3 DIGITAL INPUTS 1 & 2 - Two stereo AES3 inputs are provided via female XLR connectors. Each of these conforms to the AES3 standard. In AES Dual Wire mode, the AES1 input is used for the left channel and the AES2 input is used for the right channel. Note that AES Dual Wire mode requires moving a jumper on the m905 digital PCBA inside the unit. See AES DW Setup in section 9 of this manual for details. Use of a high quality 110 Ohm balanced cable is recommended.

S/PDIF COAXIAL INPUT - Standard coaxial stereo digital input. The input impedance is 75 Ohms. Use of a high quality 75 Ohm cable is recommended.

TOSLINK INPUT - Standard stereo optical input connector for use with consumer devices. Use a standard TOSLINK optical cable for connections to this input.

ADAT INPUT -This input accepts a standard 8 channel ADAT optical input. 44.1kHz - 192kHz sample rates are supported (S/MUX for 96kHz-192kHz). The user can select any of the four channel pairs for monitoring. Use a standard optical / LIGHTPIPE cable for connections to this input.

USB CLASS 2 AUDIO INTEFACE. - USB input for streaming audio to and from a host computer. Use a standard USB type A -to- type B cable (included with your m905). The type A connector is to be plugged in to the HOST computer and the type B connector to the m905 input. PCM 44.1kHz – 192kHz/24 bit and DSD (64x 2.8224MHz via DoP V1.1) are supported. Please refer to ‘computer audio setup’ for further details about using this input.

SPEAKER OUT 1 / 2 / 3 - Balanced stereo analog speaker outputs are provided via male XLR connectors, which connect to your stereo monitor systems (power amps or powered speakers). Connections are made with standard balanced XLR cables. These inputs are wired to the pin 1 shield, pin 2 positive pin 3 negative. Note: See the unbalanced termination wiring diagram for connecting any of these outputs to unbalanced equipment. (p.37)

CUE OUTPUT - A balanced stereo CUE output is provided via male XLR connectors. Normally, this output is fed by the CUE input signal and would typically be wired to your studio’s headphone cue system. Connections are made with standard balanced XLR cables. These inputs are wired pin 1 shield, pin 2 positive pin 3 negative. Note: See the unbalanced termination wiring diagram for connecting these outputs to unbal-

anced equipment. (p.37)

SUB / DAC / METER OUTPUT - Meter OUTPUT – Can be configured as either two mono balanced subwoofer outputs, one stereo subwoofer output, a stereo balanced fixed DAC output, or a stereo balanced configurable meter output.. These output options are configurable in the setup menu. Subwoofer outputs settings are configured with each speaker output. As a DAC out, the last selected digital input is converted and sent to this output at all times. Typically this output is used to utilize the high performance m905 DAC when connected to an analog mastering deck or other analog outboard gear. The meter output can be configured at a fixed level or to follow the speaker monitoring level. Connections are made with standard balanced XLR cables. Connectors are wired pin 1 shield, pin 2 positive pin 3 negative.

STEREO HEADPHONE OUTPUTS - HEADPHONE outputs are provided via ¼”TRS (Tip, Ring, Sleeve) jacks, one on the frontpanel of the ACU and the other on the RCU (RCU cable upgrade required for m905 Analog units). These outputs are wired in parallel. The headphone output amplifier is capable of delivering very high currents to the headphones and can drive loads down to 25 Ohms.

DIGITAL OUTPUTS (AES3, S/PDIF) - Two stereo digital (loop-thru) outputs are provided via AES3 XLR and S/ PDIF RCA connectors. These provide a buffered output of a user selectable digital input. Use of high quality 110 Ohm balanced cable for the AES3 out 75 Ohm cable for the S/PDIF out is highly recommended.

WORDCLOCK IN - The m905 can accept a Word Clock signal from an external clock generating unit via this BNC connector. This might be a stand-alone clock source or via, for example, the Word Clock output from your digital audio workstation. It should be noted that referencing the m905 from an external Word Clock is not necessary for the unit to function properly as the m905 will also function very well by stripping embedded clock data from a connected digital audio source. However, you may have your entire digital audio system referenced from a single master clock, hence the ability for the m905 to receive and lock itself to this clock.

WORDCLOCK OUT - The Word Clock output allows the user to synchronize other digital audio equipment to the m905. It functions in two modes: When monitoring a digital input with the clock source set to “word clock” the word clock output will be a buffered copy of the word clock input. If the input being monitored is not set to have word clock as the clock source then the word clock output will be the clock recovered from the the incoming digital audio data stream. In the case of USB the word clock output will be derived from the m905 internal clock. The output is buffered and is designed to drive a 75 Ohm line.

WORD CLOCK LOAD SWITCH - The switch labeled 1M Ohm/75 Ohm is used to terminate the Word Clock input. If the Word Clock signal in your studio is being daisy-chained from unit to unit (including the m905), you’ll want to set the switch to 1M Ohm, which is essentially an unloaded setting. If the m905 is the only device being clock referenced (or the last unit in a daisy-chain of other high impedance units), you’ll want to select the 75 Ohm load position for proper termination. NOTE: Selecting the 75 Ohm load position when there is already another device on the line that has a 75 Ohm load will create a total load of 37 Ohms, which will attenuate the signal to a point where the m905 may not lock.

REMOTE CONNECTOR - The m905 RCU handles all system control. Connection to the m905 RCU is via this DB15 connector, which carries RS422 serial data, DC power and headphone signals. The m905 ships with a high quality 25’ cable. While the serial data can travel over 1000 feet we do not recommend cables longer than 50’ for headphone use. Be sure to use the supplied DB15 cable. If you need a longer, cable contact your Grace Design dealer or us directly. Do not use an off the shelf DB15 cable as the pinout will be incompatable. Important Note: The m905 Analog ships with a standard ethernet cable for connecting the RCU. This cable does not carry the headphone signal to the RCU, so the headphone jack on the RCU will be deactivated and a small jack plug will be installed. If you wish to use the headphone jack on the RCU, a cable upgrade is available for purchase from your Grace Design Dealer or directly from the Grace Design Factory.

TALKBACK SWITCH - The talkback switch input allows the connection of an external switch, such as a footswitch, for remotely activating the talkback mic input, or the built in talkback mic on the RCU. The input is a TRS jack and is used with a “normally open” switching device. Note that when using this jack the

talkback function can be activated at both the RCU and the remote switch. See the remote talkback cable diagram at the end of this manual for connection details.

9 NormalOperationMode

m905 operation is categorized in two different modes: normal operation mode and setup mode. Once the RCU and ACU are connected and power is turned on, the system boots up into normal operation mode.

In normal operation mode, all of the ACU controls are active and the LCD display shows the main operating screen with input, level, SPL and DAC status. Setup mode is entered by pushing the ‘setup’ button, which switches the LCD display to the setup menu. Upon entering setup mode, current monitoring function is preserved, but the display and controls will be dedicated to setup menu navigation and input.

The m905 is a closed loop control system to ensure that the status reported on the RCU matches the actual hardware setting in the ACU. Any changes made to the configuration of the system are transmitted to the ACU where they are processed and reported back to the RCU for confirmation. In the following sections all of the controls and features of the normal operation mode are detailed.

INPUT SELECTION

The RCU features 8 dedicated input select buttons, in 2 rows of 4, above and below the LCD display. The m905 Analog has 4 dedicated input select buttons along the bottom of the LCD display. Pressing any of these buttons will select the associated input source and connect it to the main monitor path. The currently selected input source is indicated by the blue input icon on the LCD, while inactive inputs

are indicated by the gray input icons. NOTE: The displayed name is user configurable in setup mode. The names used here are the defaults.

UNBALANCED - Selects the unbalanced analog input for the monitoring path.

BALANCED - Selects the balanced analog input for the monitoring path.

BALANCED 2 - (m905 Analog only) Selects the second balanced analog input for the monitoring path.

CUE - Selects the balanced cue analog input for the monitoring path.

TOSLINK - Selects the TOSLINK digital input for the monitoring and DAC path.

ADAT / AES DW - When ADAT mode is active - Selects the ADAT digital input for the monitoring and DAC path. Once selected, pressing the ADAT input button again increments sequentially through the channel pairs (1-2, 3-4. 5-6, 7-8 for regular ADAT and 1-2, 3-4 for S/MUX ADAT). When AES Dual Wire mode is active (configured in SETUP), selects the AES Dual Wire input for monitoring and DAC path. Note that AES Dual Wire mode requires moving a jumper on the m905 digital PCBA inside the unit. See AES DW Setup in section 9 of this manual for details.

S/PDIF - Selects the S/PDIF digital input for the monitoring and DAC path.

AES1 / AES2 - Selects the AES1 or AES2 digital input for the monitoring and DAC path. Once selected, pressing the AES input button again toggles the AES1 or AES2 selection. The system remembers the last AES input that was selected (as indicated by the input icon display).

USB - Selects the USB digital input for the monitoring and DAC path.

VOLUME CONTROL, PRESET & HEADPHONE MUTE

The m905 utilizes a single rotary pushbutton encoder for control of the speaker and headphone volume levels, level preset recall and headphone mute. Switching between speaker level and headphone

level control is done by pushing and releasing the volume control knob. The current volume levels are indicated on the display with the active control being green and the inactive control in light gray. The volume control is speed sensitive, so the turning the knob at a higher velocity results in faster volume changes.

WITH SPEAKER CONTROL ACTIVE:

•Clockwise rotation of knob increases volume in 0.5dB increments (max level = 100 in standard display mode and is user configurable in reference level display mode).

•Counter-clockwise rotation of knob: Decreases the volume in 0.5dB increments (min level = 0).

•Press + hold knob: Recalls global speaker output preset level (configured in SETUP).

WITH HEADPHONE CONTROL ACTIVE:

•Clockwise rotation of knob: Increases volume in 0.5dB increments (max level = 100).

•Counter-clockwise rotation of knob: Decreases the volume in 0.5dB increments (min level = 0).

•Press + Hold knob: If the headphone level is 0.0, press and hold will recall the headphone preset level (configured in SETUP).

•If the headphone level is greater than 0.0, press and hold will mute the headphone output. This state is indicated by the headphone mute icon on the display.

SPEAKER OUTPUT SELECTION

The speaker output selection is accomplished using the three illuminated ‘speaker’ push button switches. The active speaker output is indicated by its switch illuminated green, while inactive outputs are not illuminated. The user defined name (configured in SETUP) is also visible on the display.

SPEAKER 1- Selects the speaker 1 output monitoring path, selects the speaker 1 sub (configured in SETUP) and mutes speaker 2 and 3

SPEAKER 2- Selects the speaker 2 output monitoring path, selects the speaker 2 sub (configured in SETUP) and mutes speaker 1 and 3

SPEAKER 3- Selects the speaker 3 output monitoring path, selects the speaker 3 sub (configured in SETUP) and mutes speaker 1 and 2.

MONITORING OPTION CONTROLS

MUTE / (SOLO) - The multi-function MUTE / (solo) button controls speaker MUTE and monitor path SOLO features.

Speaker MUTE mutes the signal going to the selected speaker and sub (if assigned) output(s). When the speaker MUTE is active, the switch is lit solid red and the speaker MUTE icon is shown on the speaker status display.

SOLO mode provides a means to monitor left or right channel program material exclusively. When SOLO mode is active, the button flashes red. The active SOLO channel is indicated on the speaker and headphone status display. In left channel SOLO mode, the right channel is muted in the speaker and headphone outputs.* In right channel SOLO mode, the left channel is muted in the speaker and headphone outputs.* (NOTE: Enabling MONO during SOLO mode routes the active solo channel to both left and right outputs.

* The operation of the sub output in SOLO mode depends on the selected sub configuration. In L + R stereo sub mode, the left and right solo feature is available and follows the speaker / headphone solo. For any other sub configuration, the sub output mutes when SOLO is active.

PRESS AND RELEASE BUTTON:

•Toggles the speaker output mute on and off (if solo mode is off ).

•Disables speaker / headphone solo if solo mode was active.

PRESS AND HOLD BUTTON:

•Enables the solo mode if solo mode was inactive. The last used solo mode (left or right) is activated upon entering solo mode.

•Toggles the left / right channel solo mode if solo mode is already active.

SUB MUTE / (sub-solo) - The multi-function SUB MUTE / (sub-solo) button controls the sub-mute and sub -solo features. NOTE: These features are only available when the SUB/DAC/METER is configured for sub output mode in SETUP.

SUB-MUTE mode mutes the signal going to the sub output (if assigned). When the SUB-MUTE is active, the switch is lit solid red.

Sub-solo mode provides a means to monitor the sub output program material exclusively. In Sub-solo mode, the speaker output is muted and only the sub output is on. When Sub-solo mode is active, the button flashes red.

PRESS AND RELEASE BUTTON:

•Toggles the sub output mute on and off (if sub-solo is disabled).

•Disables sub-solo if sub-solo mode was active.

PRESS AND HOLD BUTTON:

• Toggles sub-solo mode on and off.

DIM / (x-feed) - The multi-function DIM / (x-feed) button controls the speaker DIM and headphone x-feed features.

Speaker DIM attenuates the speaker and sub (if assigned) by the preset attenuation level configured in SETUP. When speaker dim is active, the switch is lit solid yellow.

Headphone x-feed engages the cross-feed circuit in the headphone output. When x-feed is active it is indicated on the headphone status display. X-feed (cross-feed) simulates the acoustics of a loudspeaker listening environment which can significantly improve imaging while reducing listening fatigue when using headphones. This feature employs carefully designed signal cross-feed, filtering and delay circuits to simulate hrtf (head related transfer functions).

PRESS AND RELEASE BUTTON:

• Toggles the speaker DIM function on and off.

+ 30 hidden pages

Grace Design m905 Users Manual

1 Welcome

M905 AUDIO CONTROL UNIT REAR PANEL

AUDIO CONTROL UNIT FRONT PANEL

REMOTE CONTROL UNIT (RCU)

m905 GRAPHICAL USER INTERFACE

YOUR m905 BOX WILL CONTAIN

OPEN AND INSPECT THE BOX

REGISTER YOUR UNIT

POWER CONNECTIONS

POWER-UP SEQUENCE

SYSTEM CONNECTIONS

INPUT SELECTION

VOLUME CONTROL, PRESET & HEADPHONE MUTE

SPEAKER OUTPUT SELECTION

MONITORING OPTION CONTROLS