bhi Noise Eliminating Marine Speaker NEMS Operation and Installation Manual 1077-102D Issue A NEMS operating manual Page 1
Important Information. 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 This publication, including all photographs and illustrations is protected under international copyright laws, with all rights reserved.
Table of contents 1 Overview 1.1 1.2 1.3 1.4 bhi Introduction Audio DSP Noise cancellation Unpacking 4 4 5 6 2 Installation 2.1 2.2 2.3 2.4 Installation overview Mounting Audio connection Power connection 7 8 8 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 6.2 6.3 6.4 6.5 6.6 6.7 6.
1. Overview 1.1 bhi bhi Ltd are specialists in the design, development and manufacture of Digital Signal Processing (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. It is suitable for use in many applications where high background noise and interference mean that you cannot clearly hear what is being said.
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. Speech Noise Original signal. Speech with a lot of background noise 1. Overview Figure 1. Audio signal before processing. Processed speech. Speech with reduced noise Figure 2.
1.4 Unpacking Check that the following items are included in the package: • • • NEMS Speaker complete with mounting bracket. Audio lead Customer feedback card 1. Overview Please report any missing items or damage to your supplier as soon as possible.
2. Installation 2.1 Overview The following diagrams show the main components of the NEMS noise cancelling loudspeaker. Noise cancelling/power on/off switch Audio connections (beneath cover) Bracket locking screw 2. Installation. Fused power lead Figure 3. NEMS features.
Audio connections (cover removed) Figure 4. NEMS rear view. Fused power lead Mounting bracket 2.2 NEMS mounting 2. Installation. 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.
Piano key connectors Wiring cover Rear view of speaker Audio Cable Connect the Red wire to the +Ve Red connector. Connect the white wire to the -ve Black connector. Remove the audio connector cover from the rear of the speaker. Insert the audio cable through the hole in the cover. The piano key connectors are opened by pressing the bottom of the coloured lever. Insert the wires into the correct speaker connection as shown in the above diagram.
2.4 Power connection 2. Installation. 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 will be necessary to use a power adapter (not supplied), to convert the voltage to within 12 - 18Vdc these limits. white stripe = +ve The cable with the white stripe is the Radio positive lead. Connect the cable to the power supply. If the power lead is shortened ensure the Audio lead fuse holder is still into connected.
3. Operation 3.1 Operation The NEMS speaker provides noise cancellation when power is applied to the speaker and it is switched on. Removing the power, or switching the NEMS off will remove the noise cancellation and the speaker circuitry will be bypassed. In this mode the speaker acts as a normal extension speaker. To check the operation tune the radio into a band where there is a lot of background noise (turn the squelch off). Turn on the NEMS, the red led will illuminate in the switch.
4. Specifications 4.1 ELECTRICAL CHARACTERISTICS i (Vs=16V, Tamb= 25 C unless otherwise stated) S ym bol Vs P a ra m e te r Te s t C o n d itio n s S up p ly vo lta g e M in . Ty p . M ax. 12 16 18 U n its V 12V 1 .7 16V 18V 3 .1 7 Vs W 50 4300 Hz Po O utp ut p o w e r d = 10% f = 1K Hz B F re q ue nc y re s p o ns e (-3 d B ) P o = 1W RL = 8W d D is to rtio n f = 1K Hz P O = 0 .2 - 2 .
5. Troubleshooting No Audio No audio out from the speaker. Switch NEMS off Check audio connections Yes Can Audio be heard now? No Radio switched on? No Switch Radio on Yes Power LED on? No Check power Connection Yes Audio Now? No Faulty Yes Finish Figure 7. Fault finding chart. NEMS operating manual Page 13 5.
6. Other products Other noise cancellation products from bhi. Visit www.bhi-ltd.co.uk for more information. 6.1 NES10-2 MKII Noise Eliminating speaker. Features: • Fully adaptive noise cancellation 9 -35dB • 8 user selectable noise cancellation levels • Mono earpiece socket • Input sensitivity control • Noise cancellation On/Off switch • LED indication of power and noise cancellation • 12-24VDC operation • On/Off audio bypass switch.
6.3 NEIM1031 In-line module. Then NEIM1031 provides a flexible solution to noise reduction. It features both amplified inputs and outputs, along with line level signal processing. The unit also features an audio bypass when the unit is switched off, so there is no need to disconnect when not in use.
6.6 Switch Box Order code: 1042 Switch Box Need to Connect more than one piece of equipment to your bhi Noise Eliminating Speaker or module? 6.7 Adapters and power supplies 6. Other products from bhi Power adapters: 1030-UKPA 12V DC UK power adapter 1030-EUPA 12 VDC European adapter 1030-VEPL Fused vehicle power adapter Audio leads: ALD-001 1.2m 3.5mm - 3.5mm mono lead ALD-002 2.5m 3.5mm - 3.5mm mono lead ALD-003 phono -phono plug ALD-004 3.5mm stereo plug - phono plug ALD-005 3.
6.8 Other products. NCH Noise Cancelling Headphones BBRP Banner Badge These headphones feed an inverted copy of the ambient noise to cancel it out. The headphones effectively remove noise such as blower noise, ambient noise, jet engine noise or music from another room. The headphones are supplied with an aircraft adapter, so you can now listen to the film, or CD player without all the jet engine noise. Also supplied with carry bag.
Notes: Page 18 NEMS operating manual
Notes: NEMS operating manual Page 19
Sound Engineering Solutions bhi DSP Noise Cancellation bhi Ltd P.O. Box 318 Burgess Hill West Sussex RH15 9NR tel: +44 (0)845 217 9926 fax: +44 (0)845 217 9936 sales@bhi-ltd.co.uk www.bhi-ltd.co.
