User`s Guide - Bel (Digital Audio)
BM-A1-E16SHD
V2.1
Manual
BM-A1-E16SHD
16 Channel Digital Audio Monitor
User’s Guide
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BM-A1-E16SHD
V2.1
BEL (Digital Audio) Ltd., has made every effort to ensure the accuracy of information contained within
this document, which is nevertheless supplied for information purposes only and does not constitute any
form of warranty or guarantee.
All trademarks acknowledged.
The information in this document is subject to change without notice.
Bel (Digital Audio) Ltd.
Unit 3
Horwood Court
Bletchley
Milton Keynes
Bucks
MK1 1RD
United Kingdom
Tel: +44 (0)1908 641063
Email: [email protected]
Web: www.beldigital.com
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BM-A1-E16SHD
V2.1
Contents
Contents..................................................................................................................................................3
Introduction............................................................................................................................................4
Mainfeatures..........................................................................................................................................5
Frontpanelrotarycontrols.....................................................................................................................6
Operation................................................................................................................................................7
Selectingsources.................................................................................................................................7
SDIinputmode...................................................................................................................................7
Dolbymode.........................................................................................................................................7
DecodingAESinputs...........................................................................................................................7
DecodingSDIinputs............................................................................................................................7
UsingtheDOLBYMIXswitch...............................................................................................................8
TheDolbymix-down...........................................................................................................................8
Independentmode.............................................................................................................................8
Directingsourcestospeakers.............................................................................................................8
Statusdisplay..........................................................................................................................................9
Rearpanelinputs....................................................................................................................................9
Rearpaneloutputs..................................................................................................................................9
Menu.....................................................................................................................................................10
Toplevelmenupage.........................................................................................................................10
LevelMeterAdjustment...................................................................................................................11
Lineleveloutputadjustment............................................................................................................12
Analogueoutputlevel.......................................................................................................................13
DolbyInformation.............................................................................................................................14
Installation............................................................................................................................................15
Analogueaudioinputsandoutputs..................................................................................................16
Specifications........................................................................................................................................17
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BM-A1-E16SHD
V2.1
Introduction
The BM-A1-E16SHD is a 1U high-quality sixteen-channel video/audio monitor with multiple
I/O as standard. The unit accepts audio from any one of four AES input pairs, eight analogue
inputs or one of two SDI inputs and produces four pairs of AES outputs and eight analogue
outputs. The SDI inputs automatically detect SD or HD or 3G video and de-multiplex all 16
audio channels. An active loop-through output is available for the SDI inputs.
The headphone output is taken before the limiters and mutes the speakers when used. Eight
high-resolution tri-colour bargraphs are provided with user-selectable ballistics and colour
break points. Up to sixteen PCM audio inputs can be selected individually or mixed and
directed to each speaker.
Bargraph meters are arranged in two groups of eight, they can display 1 to 8 or 9 to 16 using
the select button under the status display. Stick-on graticule scales, which may be applied to
the spaces between the front-panel bargraphs, are supplied with the machine.
An integral Dolby decoder can accept Dolby Digital or Dolby E from any AES input pair or
from any of the SDI embedded audio channel pairs. Dolby E is implemented using two
operational modes; ‘Independent’ where all eight channels are available and Dolby Mix-Down
or ‘Program’ mode where a selected mix of channels is available according to the encoding
used. An example would be 5.1 +1 +1, where three ‘programs’ are available; the 5.1 mix
down and the two additional programs, +1 and +1. In independent mode a 16 by 2 mixer
allows any of the Dolby decoded channels to be fed to either or both audio output channels.
This special mix-down facility allows a stereo version of a complete Dolby encoded signal to
be heard for all programs. This is particularly helpful with Dolby E encoded signals where up
to 8 audio signals of a surround sound + source can be heard using individual audio elements
or a complete aural impression by summing some or all of the channels.
The eight audio channels are provided at the rear of the unit as four pairs of AES signals on
BNC connectors and four pairs of differential analogue signals. The analogue outputs and line
outputs can be at a fixed level or slaved to the front panel volume control. The analogue and
two line outputs can be muted independently from the menu or under the control of the front
panel mute switch.
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BM-A1-E16SHD
V2.1
Mainfeatures
Four pairs of unbalanced (BNC) digital audio (AES) inputs, eight analogue line
inputs
Two auto-sensing SD/HD/3G inputs with loop-through
Two groups of four tri-colour bargraphs
Dolby® Digital or Dolby® E decoder
Dolby mix-down program select switch
Analogue line output and 8 analogue audio outputs, four pairs of AES outputs
Headphone connector with speaker mute
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BM-A1-E16SHD
V2.1
Frontpanelrotarycontrols
Volume
The volume of the speaker and headphone output can be adjusted using this control.
Pressing the end of the control will mute the speaker audio. This can also mute the line
and analogue outputs.
Balance
This control will differentially adjust the level of the speaker and headphone output.
Pressing the end of this control will centre the audio output.
Channel Pair select
This control will select which pair of audio inputs is applied to the Dolby decoder.
Dolby Mix
This control will set the way in which the monitor will treat the incoming audio. The PCM
position will treat the current audio input as straight PCM encoding and reproduce it
unprocessed on the 16 available channels.
The IND position will decode Dolby encoded information from the selected Dolby pair and
produce 8 audio outputs. These can then be mixed as required.
The positions 1 to 8 will provide a stereo mixdown of the program’s encoded in the Dolby
input.
Menu
Pressing the end of this control will enter the menu mode described in the Menu section.
Input select
Rotating this control will select one of the four audio input sources; Analogue, AES, SDI1
or SDI2.
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BM-A1-E16SHD
V2.1
Operation
Selectingsources
The input source select switch determines which source (Analogue, AES, SDI 1 or SDI 2)
is available to the speaker selectors and bargraphs. AES inputs can be at 44.1 kHz or
48 kHz sampling rate.
SDIinputmode
The unit automatically detects SD, HD or 3G video. The four SDI groups will be demuxed
to give 16 audio signals
Dolbymode
To enable the Dolby decoder, select the ‘Independent’ or ‘Program’ position using the front
panel DOLBY MIX switch. The unit will decode Dolby Digital and Dolby E from the AES
inputs or embedded audio carried in an SDI signal.
Dolby E encoding allows several separate ‘programs’ or groups of audio to be carried in
the same data stream. The program switch is provided to allow the individual programs to
be selected and their channels directed to bargraphs.
See the section entitled, Using the DOLBY MIX switch for more information about the
Dolby E monitoring features available.
DecodingAESinputs
Rotate the CHANNEL PAIR switch to select the input carrying the Dolby encoded audio.
The unit will automatically detect and decode the Dolby signals and display up to 8 audio
signals on the bargraphs.
DecodingSDIinputs
Dolby E or Dolby Digital bit-streams embedded in a pair of audio signals in an SDI stream
can be decoded with up to eight audio signals being shown on the bargraphs. The type of
Dolby encoding used will be shown on the display.
Selecting the channel pair carrying the Dolby encoded signal is achieved using the
CHANNEL PAIR rotary switch. For example, if the Dolby signal was encoded in the
second pair of audio signals in SDI Group 1 this corresponds to channels 3/4 and is
selected by rotating the CHANNEL PAIR select switch to position 3/4.
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BM-A1-E16SHD
V2.1
UsingtheDOLBYMIXswitch
Dolby E encoding allows several separate ‘programs’ or groups of audio to be carried in
the same data stream. The DOLBY MIX switch allows individual mix-downs and channels
within a Dolby E program to be monitored. Available mix-downs are selected with the
DOLBY MIX switch. The selected signal is sent to the left and right speakers and the first
two bargraphs (left most looking at the front of the unit).
The following example may help to explain the facilities provided. Consider the situation
where a studio wants to convey a surround sound music signal together with two technical
commentaries for transmitter operators. For the surround sound component, a 5.1
configuration might be ideal since it has 5 audio channels and one LF effects channel.
However, the two independent engineering feeds (two different languages and not for
transmission) can be encoded into two unused channels to give a configuration of
5.1+1+1.
TheDolbymix-down
The operator at the transmitter might want to listen to the music but not necessarily in full
surround sound. Fortunately, the Dolby decoder has an internal buss, which carries a mixdown. This is a stereo signal that contains a mixture of, in this case, all 6 music signals with
any phasing or special effect applied. The Dolby decoder ‘knows’ that the audio is encoded
as 5.1+1+1. In order to listen to the engineering feeds it must be possible to direct the
decoder to select the 5.1, +1 or other +1 signals and output the appropriate mix-down to
the buss. The three separately encoded audio ‘programs’ can be selected using the
DOLBY MIX switch. Clearly the mix-down of the +1 signals will be a simple mono signal.
When the BM-AV1-E16SHD is in any of the P1 to P8 program select modes (or Dolby
Down-Mix modes), the stereo audio available on the internal buss is sent to the left and
right speakers and to bargraphs 1&2.
Independentmode
All of the Dolby E audio signals can be decoded and made available on their own (i.e., not
mixed) by setting the DOLBY MIX switch to the independent position (IND).
In the 5.1 +1 +1 example, music might be presented on bargraphs 1 to 6 and the two
engineering feeds on bars 7 and 8. It is then easy to select which of these to listen to by
pressing the button under the appropriate bargraph. A mix down of some or all of the
channels can be obtained by selecting several audio signals to be sent to each speaker.
Note: Independent mix-down does not apply all of the phasing effects of the Dolby mix
down modes.
Directingsourcestospeakers
Where more than two audio signals are present it may be useful to direct and combine
sources to selected speakers. The left speaker is indicated by a red LED and the right by a
green LED on the top of the bargraphs.
To direct a particular source to the left or right speakers proceed as follows:
Repeatedly press the button under the bargraph corresponding to the input audio signal
required until the top LEDs of the bargraph shows red for the left speaker, green for the
right or both to direct the audio to both speakers. Each speaker can receive a mix of audio
from inputs 1 to 16. Select either lower or upper 8 sources using the select button.
Note that the mix button assignments are retained over power-down.
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BM-A1-E16SHD
V2.1
Statusdisplay
The Status display will show general status information related to the currently selected
input such as the source selected and video standard where applicable.
Rearpanelinputs
The BM-A1-E16SHD accepts SDI video, AES and analogue audio inputs. Eight differential
analogue inputs are provided on a 25 way ‘D’ type connector. Four pairs of AES
unbalanced inputs are available on BNC connectors. Two SD, HD, 3G auto select SDI
inputs are provided.
Rearpaneloutputs
The BM-A1-E16SHD provides both digital and analogue audio outputs on the rear panel.
Eight differential analogue outputs on a 25 way ‘D’ type connector and four pairs of AES3 on
BNC connectors are available. The audio carried on the AES outputs are derived from the
currently selected input source (analogue, AES or SDI). In effect, these audio outputs are a
copy of the signals shown on the unit’s bargraphs. The analogue outputs are derived from
the lower 8 inputs (ch1-8). They can thus be a copy of the AES inputs, or two of the
currently demuxed SDI groups. Two line outputs are provided which carry the same audio
as the speakers. The levels of the analogue and line outputs are adjustable in the menu. It is
possible to mute the output from the unit’s speakers by pressing the end of the VOLUME
control. It is also possible to independently mute the analogue outputs and the line outputs
using the volume control.
An SDI loop-through is available which carries a reconstituted SDI signal from the currently
selected SDI input.
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BM-A1-E16SHD
V2.1
Menu
Many of the characteristics of the BM-A1-E16SHD can be adjusted in the menu. When
the menu is activated, by pressing the NAV rotary encoder, the top level of the menu will
appear. The items in this level can be selected by rotating the encoder and then pressing
it for approximately 0.5 seconds. The second level will then appear and the required item
selected by rotating the encoder and then pressing it. At this point in the menu the value
of the current parameter can be adjusted. To go back one step in the menu press and
hold the encoder for longer than 1 second.
Tip: Simultaneously pressing the buttons under the bargraphs 7 and 8 will completely exit
the menu.
The characteristics that can be adjusted in the menu are shown below.
Toplevelmenupage
The top level of the menu carries the main areas of operation of the BM-A1-E16SHD that
can be adjusted.
1. Level meters - This section allows access to the bargraph colour break points and
ballistics.
2. Line levels - The line output level control can be selected here (either fixed level or
controlled by the volume control). The line output can also be muted, or slaved to the
main speaker mute control.
3. Analogue levels - The analogue output level control can be selected here (either fixed
level or controlled by the volume control). The analogue output can also be muted, or
slaved to the main speaker mute control.
4. Dolby – Various aspects of the Dolby operation can be accessed here.
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BM-A1-E16SHD
V2.1
LevelMeterAdjustment
Various aspects of the audio level indication can be adjusted here.
1. Amber threshold - The point at which the bargraph changes from green to amber can be
adjusted here. Bargraph 16 is forced to full scale to allow easy control of the colour
transitions.
2. Red threshold - The point at which the bargraph changes from amber to red can be
adjusted here. Bargraph 16 is forced to full scale to allow easy control of the colour
transitions.
3. Ballistics - The scales and dynamics of the bargraphs can be selected here. The options
are AES, DIN, VU and BBC. The appropriate scales should be affixed to the front panel.
4. Analogue offset - When an analogue input is selected and the bargraph ballistics are
AES the way in which this is displayed is adjusted here. If 0 dB analogue is applied to the
unit the bargraph can be configured to show either -18 dB or -20 dB.
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BM-A1-E16SHD
V2.1
Lineleveloutputadjustment
The audio currently selected for the two front panel speakers is also available on two XLR
connectors on the rear panel. The level of these can be adjusted from this menu.
1. Line level - The line output level can be fixed or controlled by the front panel volume
control and this can be selected here.
2. Fixed line level - When fixed output level is selected its level can be adjusted here.
3. Line mute - The line outputs can be muted here or the mute can be slaved to the front
panel volume control.
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BM-A1-E16SHD
V2.1
Analogueoutputlevel
The audio currently showing on the 8 bargraphs are directed to 8 analogue outputs on a
25-way ‘D’ connector on the rear panel. The level of these can be adjusted here.
1. Analogue level control - The analogue output level can be fixed or controlled by the
front panel volume control from here.
2. Fixed analogue output level - When fixed analogue output level is selected, its level can
be adjusted here.
3. Analogue output mute - The analogue outputs can be muted here or the mute can be
slaved to the front panel volume control.
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BM-A1-E16SHD
V2.1
DolbyInformation
The firmware version of the Dolby decoder card and MetaData information can be
accessed from this menu.
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BM-A1-E16SHD
V2.1
Installation
The BM-A1-E16SHD is designed to be installed in 19" bays on an equipment tray.
Ventilation is by natural convection.
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BM-A1-E16SHD
V2.1
Analogueaudioinputsandoutputs
Pi
n
Description
1
A 1+
2
A 1-
3
GND
4
A 2+
5
A 2-
6
GND
7
A 3+
8
A 3-
9
GND
10
A 4+
11
A 4-
12
GND
13
GND
14
GND
15
A 5+
16
A 5-
17
GND
18
A 6+
19
A 6-
20
GND
21
A 7+
22
A 7-
23
GND
24
A 8+
25
A 8-
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BM-A1-E16SHD
V2.1
Specifications
Audio inputs
Digital
AES3-id 4 x 75 ohm (BNC connector). Sample rate 44.1/48 kHz.
Analogue
8 differential (25-way ‘D’ connector). Clipping +15 dB
Audio outputs
Digital
AES3-id 4x 75 ohm (BNC connector) sample rate 48 kHz.
Analogue
8 differential audio channels, level adjustable (25-way ‘D’
connector).
Line output
Copy of speaker outputs, level adjustable on 2 x XLR3M
connectors.
Analogue noise
Noise+THD: -108 dB w.r.t clipping
Analogue frequency response: 20 Hz to 20 kHz ±1dB
Video inputs
Video format
SDI SD, HD or 3G
Video output
1 SDI active loop-through (BNC connector).
Main drive amp
Noise +THD -80dB w.r.t. maximum output.
Speaker driver units
Peak acoustic level (@2ft)
100 dB SPL
Shielding
Magnetic
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BM-A1-E16SHD
V2.1
Meters
8 tri-colour LED bargraphs with adjustable colour break points and ballistics.
DIN PPM: Overall dynamic range: 55 dB (+5 to -50 dB)
Attack time: 10 mSec
Fallback: 1.5 Sec per 20 dB decay
BBC PPM: Overall dynamic range: (+12 to-12 dB from mark 7 to mark 1)
Attack time: 10 mSec
Fallback: 2.85 Sec (from mark 7 to mark 1)
VU: Overall dynamic range: 23 dB (+3 to -20 dB)
Attack time: 300 mSec
Fallback: 300 mSec
AES/EBU: Overall dynamic range: 60 dB (0 to -60 dB)
Attack time: 1 mSec
Fallback: 1.5 Sec per 20 dB decay
Dimensions
19” Rack Mount: 1U high.
Outline Dimensions: 483 mm(W) x 256 mm(D) x 44.3 mm(H)
Outline Dimensions: 19 inch(W) x 10 inch(D) x 1.75 inch(H)
Environmental
Temperature 0° C to 30° C Humidity 70% max (non-condensing)
Weight
6 kg (14lbs)
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