BHI NEMS Specification sheet

Page 1NEMS operating manual
Noise Eliminating Marine
Speaker
1077-102D Issue A
bhibhi
bhibhi
bhi
Operation and Installation Manual
NEMS

Page 2 NEMS operating manual
No user serviceable parts inside. Warranty void if speaker
opened.
Prolonged exposure to high sound levels may lead to hearing
damage. bhi accept no responsibility to damage to hearing
through incorrect operation of this equipment.
Although this product is waterproof it isn’t designed to be
submerged.
Copyright
Thispublication,includingallphotographsandillustrations
is protected under international copyright laws, with all
rights reserved. Neither this manual, nor any of the
material within, may be copied or reproduced without the
written consent of bhi Ltd.
Disclaimer
The information in this document is subject to change
without notice. bhi Ltd. makes no representations or
warranties with respect to the contents hereof and
specifically disclaims any 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.
Important Information.

Page 3NEMS operating manual
1 Overview
1.1 bhi 4
1.2 Introduction 4
1.3 Audio DSP Noise cancellation 5
1.4 Unpacking 6
2 Installation
2.1 Installation overview 7
2.2 Mounting 8
2.3 Audio connection 8
2.4 Power connection 10
3.Operation
3.1 Setup and operation 11
4. Specification
4.1 Specifications 12
5. Troubleshooting
5.1 Troubleshooting guide 13
6. Other bhi products
6.1 NES10-2 dsp speaker 14
6.2 NES5 dsp speaker 14
6.3 NEIM1031 In line module 15
6.4 NEIM1031 In line module accessories 15
6.5 DSP modules 15
6.6 1042 switch box 16
6.7 Audio adapters 16
6.8 Other bhi products 17
Table of contents

Page 4 NEMS operating manual
The speaker mounts like any standard external speaker and is
powered by any 12 – 18 Vdc unregulated power source. The
speaker is fitted with a fused power lead.
The speaker is supplied with a 1.2 metre long audio lead
terminated in a 3.5mm mono jack plug.
Note:
This product is designed for speech only, and isn’t suitable for
music broadcasts, unless the noise cancellation is switched off.
1.1 bhi
bhi Ltd are specialists in the design, development and
manufactureof DigitalSignalProcessing (DSP) noise cancelling
products and other specialist electronics.
1.2 Introduction
The bhi NEMS Noise Eliminating Marine Speaker greatly
improves the clarity and intelligibility of speech in radio
communications. Itissuitableforuseinmanyapplicationswhere
high background noise and interference mean that you cannot
clearly hear what is being said. The NEMS enables the user to
listen and concentrate “stress-free”.
The NEMS is compact and easy to install. It incorporates DSP
technology and is fully adaptive to any change in noise levels
and interference, requiring no further adjustment.
When the power is switched of the NEMS’s circuitry is
disconnected and the speaker behaves as a normal extension
speaker.
1. Overview
1. Overview

Page 5NEMS operating manual
1.3 Audio DSP Noise cancellation.
The bhi DSP processes the incoming audio signal and then
differentiates the speech from the noise. The unwanted noise
and interference are then attenuated to leave only the speech.
The following diagrams are taken from actual audio signals and
illustrate how the audio signal is being processed.
Figure 1. Audio signal before processing.
Figure 2. Audio signal after processing.
Original signal.
Speech with a lot of
background noise
Speech Noise
Processed speech.
Speech with reduced
noise
1. Overview

Page 6 NEMS operating manual
1.4 Unpacking
Check that the following items are included in the package:
•NEMS Speaker complete with mounting bracket.
•Audio lead
•Customer feedback card
Please report any missing items or damage to your supplier as
soon as possible.
1. Overview

Page 7NEMS operating manual
2. Installation
2.1 Overview
The following diagrams show the main components of the
NEMS noise cancelling loudspeaker.
Noise
cancelling/power
on/off switch
Fused
power
lead
Audio
connections
(beneath cover)
Bracket
locking screw
Figure 3. NEMS features.
2. Installation.

Page 8 NEMS operating manual
2.3 Audio connection
Before fitting the audio lead, ensure that the radio has a 3.5mm
mono extension speaker socket for the NEMS to connect to. If
theradio has adifferentconnector then anadapterwill be require
(see your dealer or bhi for more information). The free end of
the lead is connected to the NEMS as shown in figure 5.
Audio
connections
(cover removed)
Fused power
lead
Mounting
bracket
Figure 4. NEMS rear view.
2.2 NEMS mounting
The NEMS needs to be mounted so that it can be connected to
a 12 - 18Vdc power source, and the radio. Locate a suitable rigid
position to mount the NEMS speaker. The NEMS is mounted by
holes in the adjustable metal bracket. The bracket swivels to
allow the NEMS to be adjusted to suit the listener.
Fix the speaker using suitable fixings (not supplied), it may be
necessary to remove the bracket to assist installation.
2. Installation.

Page 9NEMS operating manual
Figure 5. Audio connections.
Remove the audio connector cover from the rear of the speaker.
Insert the audio cable through the hole in the cover. The piano
keyconnectorsareopenedbypressingthebottomofthecoloured
lever. Insert the wires into the correct speaker connection as
shown in the above diagram. Ensure that the blade of the
connector is clamping the exposed strands of the wire and not
the insulation. Push the cover over the connections.
Run the audio cable to the radio. Ensure the radio is switched off
and connect the 3.5mm mono jack plug to the socket marked
extension speaker (using any adapter if required).
2. Installation.
Audio
Cable
Rear view
of speaker
Wiring
cover
Piano
key
connectors
Connect the Red wire to the +Ve Red connector.
Connect the white wire to the -ve Black connector.

Page 10 NEMS operating manual
2.4 Power connection
The NEMS is fitted with a fused power lead. The NEMS requires
12 - 18Vdc to operate. If the supply voltage is higher than this it
willbenecessarytouseapoweradapter(notsupplied),toconvert
the voltage to within
these limits.
The cable with the
white stripe is the
positive lead. Connect
the cable to the
power supply.
If the power lead is
shortened ensure the
fuse holder is still
connected.
Figure 6. Connection overview.
2. Installation.
Note:
If any of the cables pass through
walls, bulkheads etc. ensure that
they adequately protected
from damage. Also ensure
the wires are properly
secured and do not present
a trip hazard.
Audio lead
into
extension
speaker socket
12 - 18Vdc
white stripe = +ve
NEMS
Cover
Fuse
Radio