BHI NEIM 1031 User manual

Page 1
Noise Eliminating In-Line Module
1031-106D
Issue C
bhi
NEIM 1031
7
10
7
10
Connections
NEIM1031
Overload
Output Level
Input Level
Line Out Level
Noise Eliminatin
g
In-Line Module
4
2
3
1
Power
56
Off On
OK
2
1
3
456
Out
Audio
Headphone Socket
Noise Cancellation
9
8
Filter Level
On
bhi
0=MIN
9
8
7=MAX
12-24VDC Input
Input Selector
+-
AudioLine In Line
SOUND ENGINEERING SOLUTIONS

Page 2
Important Information
Copyright
This publication, including all photographs and illustrations
isprotectedunderinternationalcopyrightlaws,withallrights
reserved. Neitherthismanual,noranyofthematerialwithin,
maybe copied or reproducedwithout the written consentof
bhi Ltd.
Disclaimer
Theinformationinthisdocumentissubject to changewithout
notice. bhiLtdmakes no representations orwarrantieswith
respecttothecontentshereofandspecificallydisclaimsany
implied warranties of merchantability or fitness for any
particular purpose. Furthermore, bhi Ltd reserves the right
to revise this publication and to make changes from time to
time in the content hereof without obligation of bhi Ltd to
notify any person of such revision or changes.
The NEIM1031 may be connected to audio recording
equipment. The user is responsible for complying with any
copyrights, or legislation regarding recording of material.

Page 3
Contents
1. Introduction 4
2. Packing List 4
3. Connections 5
3.1 Connector description 5
3.2 Connectorlayout 6
3.3 Typical connections 7
3.4 Radio communications 8
3.5 Audio restoration 9
3.6 Surveillance/CCTV/Video 10
3.7 Recording using a PC sound card 11
3.8 Connecting several audio sources 12
4. Controls 13
4.1 Controllayout 13
4.2 Control functions 14
5. Setup 16
5.1 Signal levels 16
5.2 Noise cancellation 16
6. Troubleshooting/FAQs 18
7. Specifications 19
8. Accessories 21
8.1 Power 21
8.2 Audio 21
8.3 Audio adaptors 22
8.4 Headphoneadaptors 22
9. bhi Support 23

Page 4
1. Introduction.
The NEIM1031 In-line Noise Eliminating Module
incorporates DSP technology to remove unwanted
background noise and interference from speech.
It has 8 switchable levels of noise cancellation to allow
the user to optimise the unit for their level of noise and
interference.
Themodulehas connections forhighand low levelaudio
signals.
Theunitisdesignedtobe easilyconnectedintotheaudio
path of noisy signals where the intelligibility and clarity
of speech needs to be improved.
Note:
The NEIM1031 is not designed to pass music.
2. Packing List.
The NEIM1031 is shipped with the following:
Description bhi Part No.
nNoise eliminating module NEIM1031
nFused Power Lead 1030-FPL
nMono Audio lead 1.2M ALD-001
nOperating manual 1031-106D

Page 5
3. Connections.
All audio connections are at the rear of the unit. The
headphone connection has been placed at the front of
the unit for easy access.
As the audio signals are bypassed when the power is
removed there is no need to disconnect the unit when
not in use.
The diagram on the following page shows the position
of all the connectors.
3.1 Connector Description:
Line In: Phono socket.
Low level audio input.
Audio In: 3.5mm mono jack socket.
Speaker level input (for example an
extension speaker socket).
DC Power: 2.1mm power connector. Centre +Ve.
12-24VDC 500mA Input.
Headphone: 3.5mm mono jack socket.
Amplified output. This connection
over rides the audio out socket. This
socket may also be used to drive an
extension speaker.
Audio out: 3.5mm mono jack socket
Amplified output to drive an extension
speaker. This socket is disabled when
the headphone socket is used.

Page 6
7
10
7
10
Connections
NEIM1031
Overload
Output Level
Input Level
LineOutLevel
Noise Eliminatin
g
In-Line Module
4
2
3
1
Power
5 6
Off On
OK
2
1
3
456
Out
Audio
Head phone Socket
Noise Cancellation
9
8
Filter Level
On
bhi
0=MIN
9
8
7=MAX
12-24VDC Input
Input Selector
+-
AudioLine In Line
Audio In
Line In
Audio out
Line out
3.2 Connector Layout.
DC Power
Supply
Headphones
(or extension speaker)
Line out: Phono socket
Low level audio out. For connection to
an amplifier, recorder, or any other line
level device.
Top View

Page 7
14.2000
000
14.195.00
bhi
3.3 Typical Connections.
Audio Amplifier
Headphones
(or extension
speaker)
Extension Speaker
Recording Device
Audio source
OR
3
4567
8
9
10
3
4567
8
9
10
1
2
OK Overload
Input Level
Line Out Level
Output Level
Power
Noise Eliminating In-Line
M
Headphone Socket
ConnectionsInput Selector
Out
Audio Line InAudio
Line
bhi
On
Off
Filter Level
0=MIN 7=MAX
On
Noise Cancellation
12-24VDC Input
+-
0
NEIM1031
1
2
Note:
Audio adaptors are
available to suit most
applications, see
accessories in
section 8.
DC
supply
Optional Mains
adaptor
Line in
Line Out
Audio In
Audio
Out
12-24V DC
(EXSPR-001)
(See page 20)

Page 8
14.2000
000
14.195.00
bhi
3
4567
8
9
10
3
4567
8
9
10
1
2
OK Overload
Input Level
Line Out Level
Output Level
Power
Noise Eliminating In-Line
M
Headphone Socket
Connections
Input Selector
Out
Audio Line InAudio
Line
bhi
On
Off
Filter Level
0=MIN 7=MAX
On
Noise Cancellation
12-24VDC Input
+-
0
NEIM1031
1
2
3.4 Radio communications.
The following pages show typical applications and
connections to the NEIM1031. For connection of
headphones or extension speakers refer to the diagram
on page 7. Numbers in brackets indicate bhi part
numbers. These are available as optional extras - see
accessory section.
(ALD-001 3.5mm mono-mono)
Receiver
or
Transceiver
Extension Speaker
(EXSPR-001)
Audio Out
Audio In

Page 9
3
4567
8
9
10
3
4567
8
9
10
1
2
OK Overload
Input Level
Line Out Level
Output Level
Power
Noise Eliminating In-Line
M
Headphone Socket
ConnectionsInput Selector
Out
Audio Line InAudio
Line
bhi
On
Off
Filter Level
0=MIN 7=MAX
On
Noise Cancellation
12-24VDC Input
+-
0
NEIM1031
1
2
3.5 Audio restoration.
Connect the audio source and recording device as
shown. If the source is monaural, one channel may be
fed directly into the recorder to copy the unprocessed
audio for comparison.
(ALD-003 phono-phono)
Line Out
Line In
Line In
Audio Source
Recording (ALD-003 phono-
phono)
(ALD-003 phono-phono)
Left
Right
Line In

Page 10
3
4567
8
9
10
3
4567
8
9
10
1
2
OK Overload
Input Level
Line Out Level
Output Level
Power
Noise Eliminating In-Line
M
Headphone Socket
ConnectionsInput Selector
Out
Audio Line InAudio
Line
bhi
On
Off
Filter Level
0=MIN 7=MAX
On
Noise Cancellation
12-24VDC Input
+-
0
NEIM1031
1
2
3.6 Surveillance/CCTV/Video.
In applications where the un- altered audio needs to be
recorded. The raw signal can be recorded, and the
cleaned audio is monitored using headphones, or an
extension speaker.
This will record a true copy of the CCTV footage. The
unit can then be used on playback to remove any noise.
Connection to video recording equipment (audio).
Inthisapplication theNEIM1031is beingusedto remove
the background noise being recorded from the video
camera.Again inthisapplication boththe processedand
raw audio are being recorded simultaneously.
Line Out
Line In
Video Camera
Video connection
Unprocessed audio
Video Recorder
(ALD-003 phono-phono) (ALD-003 phono-phono)
Line In Line out

Page 11
3
4567
8
9
10
3
4567
8
9
10
1
2
OK Overload
Input Level
Line Out Level
Output Level
Power
Noise Eliminating In-Line
M
Headphone Socket
Connections
Input Selector
Out
Audio Line InAudio
Line
bhi
On
Off
Filter Level
0=MIN 7=MAX
On
Noise Cancellation
12-24VDC Input
+-
0
NEIM1031
1
2
14.2000
000
14.195.00
3.7 Recording using a PC sound card.
PC Sound Card Audio Source
Line In
Line Out
The sound capturing capability of the PC sound card
may be used to record (or playback) audio signals.
(ALD-004 3.5mm stereo - 2 x phono)
For more detail on connection, setup and recording
please refer to your PC/sound card manual.
Unprocessed audio
Line In
Line Out
(ALD-003 phono-phono)

Page 12
3
4567
8
9
10
3
4567
8
9
10
1
2
OK Overload
Input Level
Line Out Level
Output Level
Power
Noise Eliminating In-Line
M
Headphone Socket
ConnectionsInput Selector
Out
Audio Line InAudio
Line
bhi
On
Off
Filter Level
0=MIN 7=MAX
On
Noise Cancellation
12-24VDC Input
+-
0
NEIM1031
1
2
14.2000
000
14.195.00
14.2000
000
14.195.00
3.8 Connecting several audio sources.
Using the bhi 1042 Switch Box it is possible to connect
up to six separate audio sources to one NEIM1031.
The 1042 switch box has 3 loaded inputs (for an
extension speaker socket) and 3 unloaded for
headphone socket connections.
Please contact bhi for more information. Contact details
can be found on the back cover of this booklet.
1042 Switch Box
Audio Sources
bhi
1
2
34
5
6
1042 Switch Box
14.2000
000
14.195.00

Page 13
4. Controls.
4.1 Control layout.
The NEIM1031 Controls are identified in the following
diagram and described on the following page.
Filter Level
Selector
Switch
Input Level
LEDs
Input Level
Control
7
10
7
10
Connections
NEIM1031
Overload
Output Level
Input Level
Line Out Level
Noise Eliminatin
g
In-Line Module
4
2
3
1
Power
5 6
Off On
OK
2
1
3
45 6
Out
Audio
Headphone Socket
Noise Cancellation
9
8
Filter Level
On
bhi
0=MIN
9
8
7=MAX
12-24VDC Input
Input Selector
+-
AudioLine In Line
Input Selector Switch
Power On/Off
LED
Output
Volume Control
Line Out Level
Control
Noise
Cancellation
On/Off LED
Noise Cancellation
On/Off Switch
Power On/Off
Switch

Page 14
4.2 Control functions:
Input Selector Switch:
Selects between line level input (phono connector) and
high level input (jack socket). Both inputs may be
connected at the same time. Only the selected input will
be passed through the DSP circuit.
Filter Level Selector Switch:
The 8 position rotary switch selects the amount of DSP
processing. Level 0 is the minimum, and level 7 the
maximum. The selected level can be seen in the small
cutout in the switch knob.
Noise Cancellation LED:
Indicates if noise cancellation is on/off.
Noise Cancellation On/Off Switch:
Selects noise cancellation on/off.
Input Level Control:
Sets the input level into the NEIM1031. This adjusts the
audio signal level through the DSP for optimum
performance.
Input Level LEDs:
These give a visual indication of the input signal level.
No LED: Signal level too low
Green LED: Signal level correct
Red LED: Signal too high

Page 15
Power On/Off Switch:
Applies power to the NEIM1031. Switching off removes
power to the circuit and connects all inputs to outputs.
With the power off the line in connects to line out and
audio in connects to audio out - with no amplification.
This allows the unit to remain connected in circuit, even
when it is not in use. There is no need to disconnect.
In the event of a power failure to the NEIM1031, then
the inputs and outputs will bypass, allowing continuation
of signal.
Power On/Off LED:
Indicates power on/off.
Output Volume Control:
Adjusts the volume of the audio signal present at the
audio out and headphone sockets. This does not alter
the line out level.
Line Out Level Control:
This preset control allows the line out signal from the
NEIM1031 to be matched to the equipment connected
to the unit. This level is not altered by the main output
volume control.
Changes in either input will affect the line out level.
Irrespective of which input is selected, the noise
cancellation is available on both the line and audio
outputs (only while the unit is powered).

Page 16
5. Setup.
5.1 Signal Levels.
Turnthe input level,outputlevelandlineout level controls
to the minimum - fully anticlockwise.
Connect to the equipment to suit your application as
shown in section 3.
Switch off the NEIM1031, all signals will be connected
straight through the unit. Switch on all the other
equipment and select a typical audio signal to be
processed.
If necessary adjust the output of the audio source to the
desiredlevel. Ifanextension speakeris beingused,then
set the level to a comfortable listening level.
Ensure noise cancellation is switched off, and the input
selector switch set to the input being used.
Adjust the input level control on the NEIM1031 until the
red overload LED just illuminates on the peaks of the
audio signal. Reduce the input level slightly.
Adjust the output level control, to the desired level.
The module should now be transparent to the audio
signal. Switching the module on and off, should not
significantly alter the signal level.
5.2 Noise Cancellation.
The noise cancelling switch has 8 positions, starting at 0
throughto7.Level0is theminimum,and7themaximum.
Switch postions 8 and 9 are not used.

Page 17
The selected noise cancellation level can be seen in the
small cutout on the switch knob.
Starting at level 0 switch the noise cancellation on, listen
to a typical noisy signal. Adjust the level of noise
cancellation to suit.
Note:
The higher levels of noise cancellation will remove
virtually all the background noise, but the user will note
thefollowing possibleeffectsifhigh levelsof background
noise are present.
nVoice has a slightly robotic sound.
nBackground noise becomes a watery sound.
Switchingoffthe noise cancellation will restorethe audio
to its original form.
If there is a lot of noise present on the audio signal it
may be necessary to increase the output volume (or line
level out) with the noise cancellation on.
Note:
Pleasenote thatif the volume is increasedand thenoise
cancellation (or power) is switched off the resulting
unprocessed signal will be at a higher level. Care must
be taken to avoid excessive signal levels, as they may
result in damage to hearing or equipment. bhi Ltd does
not accept responsibility for damage to equipment or
hearing however caused.

Page 18
6. Troubleshooting/FAQs
No audio output from extension speaker.
nCheckthe inputselector switchis setto thecorrect
input.
nCheck the input level is correct , ie the green input
LED is illuminated.
nCheck output level.
The noise cancellation does not appear to improve
the quality of the audio signal.
nCheck the noise cancellation is on, the green LED
will be illuminated.
nChange the level of noise cancellation.
nCheck the green power on/off LED is illuminated.
Sometimes there is a short delay before the noise
cancellation is active.
nThis is due to the time the DSP takes to start
processing the signals. This gives the opportunity
to check that the DSP is not taking out any detail
from the signal.
No audio output when the power is switched off.
nWhen the power is removed the line in connects to
lineout,andaudiointo audioout.Iftheinputsource
is connected to the line input, and the output to the
audio out, then no signal path will be present with
no power.

Page 19
7. Specifications.
Noise attenuation: 9 - 35dB
Noise attenuation levels 8
Level Attenuation
1 9dB
2 11dB
3 13dB
4 15dB
5 17dB
6 20dB
7 24dB
8 35dB
Tone rejection 65dB max
Audio output power 2.5W RMS max.
Audio bandwidth 50Hz - 4.6KHz (-3dB)
Audio connections:
Line level in/out RCA phono
Audio in/out 3.5mm mono jack
Line input impedance 10K
Line output impedance 100R
Line in sensitivity 300mV - 2V rms
Headphone socket 3.5mm mono jack
Headphone power 2.5W rms max.

Page 20
DC power: 12-24 VDC
500mA
DC connector: 2.1mm power
connector
(centre +ve)
Size: 170 x 85 x 34mm
Weight: 265 gms