ENGLISH DEUTSCH ACOUSTIC ECHO CANCELLER CARD ESPAÑOL ITALIANO EN DE ES IT RU ZH 取 扱 説 明書 中文 FR JA 日本語 Owner’s Manual Bedienungsanleitung Mode d’emploi Manual de instrucciones Manuale di istruzioni Руководство пользователя FRANÇAIS MY4 - AEC
FCC INFORMATION (U.S.A.) 1. IMPORTANT NOTICE: DO NOT MODIFY THIS UNIT! This product, when installed as indicated in the instructions contained in this manual, meets FCC requirements. Modifications not expressly approved by Yamaha may void your authority, granted by the FCC, to use the product. 2. IMPORTANT: When connecting this product to accessories and/or another product use only high quality shielded cables. Cable/s supplied with this product MUST be used. Follow all installation instructions.
PRECAUTIONS PLEASE READ CAREFULLY BEFORE PROCEEDING * Please keep this manual in a safe place for future reference. WARNING Always follow the basic precautions listed below to avoid the possibility of serious injury or even death from electrical shock, short-circuiting, damages, fire or other hazards.
Information for Users on Collection and Disposal of Old Equipment This symbol on the products, packaging, and/or accompanying documents means that used electrical and electronic products should not be mixed with general household waste. For proper treatment, recovery and recycling of old products, please take them to applicable collection points, in accordance with your national legislation and the Directives 2002/96/EC.
Introduction Thank you for choosing the Yamaha MY4-AEC. The MY4-AEC is an acoustic echo canceller card designed for use with the DME64N/24N Digital Mixing Engines that can effectively reduce troublesome acoustic echoes due to secondary pickup of speaker output and reflections from room surfaces in teleconferencing situations. It is also capable of reducing feedback as well as ambient noise from air conditioning and fans.
Principle of Operation How Acoustic Echo and Noise are Reduced Acoustic echo occurs in a teleconferencing system when the sound from a speaker or reflections from surfaces of the room are picked up by a microphone and transmitted to the other party, resulting in a loss of intelligibility. Projectors and air conditioning systems also produce noise that can interfere with clear teleconferencing.
MY4-AEC Signal Flow The local and remote locations in a teleconferencing system are referred to as the “near end” and “far end”, respectively. The MY4-AEC acoustic echo canceller (AEC) works by comparing the reference signal received from the far-end with the signal from the microphone in order to determine which components of the signal are echo, and then subtracts only the far-end echo component from microphone signal. The near-end sound is thus clearly transmitted to the far end without echo.
The Connectors and Their Functions AES/EBU IN and OUT Connectors These connectors support four channels of AES/EBU format digital audio input and output to and from the host DME64N/24N unit, but those signals are not directly routed via the MY4-AEC processing section. Signals from the host’s analog or digital inputs must be routed to the MY4AEC card’s AEC processing section via the host’s processing section in order to apply echo cancellation, as shown in the illustration below.
DME Processing DME64N/24N AEC Processing MY4-AEC SRC Analog Out Mic In AES/EBU [OUT1/2][OUT3/4] SRC AES/EBU [IN1/2][IN3/4] MY4-AEC Owner’s Manual 9
Euroblock Connection Please be sure to use the supplied Euroblock plugs to connect the AES/EBU [IN] and [OUT] connectors. Cable preparation • To prepare the cable for attachment to a Euroblock approx. 7 mm connector, strip the wire as shown in the illustration using stranded wire to make connections. With a Euroblock connection, stranded wires may be prone to breakage because of metal fatigue due to the weight of the cable or due to vibration.
1 Loosen terminal screws. 2 Insert cables. Loosen. Slotted Screwdriver + – Terminal Screw G Euroblock Plug Tab NOTE 3 Securely tighten terminal screws. Pull the cables (not too strongly) to confirm that they are securely connected. A slotted screwdriver with a blade width of about 3 millimeters is recommended.
4 Bundle the cables and the Euroblock tab using the supplied cable tie. NOTE Trim any excess part of the cable tie as necessary. 12 MY4-AEC Owner’s Manual 5 Insert the Euroblock plug into the AES/EBU [IN] or [OUT] connector of the MY4-AEC.
Basic Connection and Setup Example 1: Teleconferencing with a Remote Location This is an example of a teleconferencing system set up to allow multiple participants to hold conferences with a remote location (“Office X”). Preparation The first step is to make the basic local (near end) connections and determine the optimum microphone and speaker locations as well as gain settings. The AEC system will have the best possible effect if these initial steps are carried out properly.
Meeting Room (Near End) Microphone 1 Speaker 1 OUT (Analog) Microphone 2 Speaker 2 Microphone 3 Microphone 4 DME24N + MY4-AEC IN (Analog) 3 Make the required virtual connections in the DME Designer configuration window. • Connect the signals from microphone inputs 1 – 4 to the “Near-end Mic. 1” – “Near-end Mic. 4” inputs on the AEC component. • Place an oscillator that will be used for AEC adjustment in the configuration window and connect it to the AEC component “From Far-end A” input.
4 Speak into the microphones as you would during an actual conference and adjust the input gain of each channel. Adjust the DME24N HA Gain while watching the “Mic. In” meters in the AEC component editor so that the yellow segment lights only occasionally. NOTE AEC may not function properly if the gain is set too high.
5 Open the Oscillator component editor, set the Wave Form type to “Pink,” and engage the Output section “On” button. Go back to the AEC component editor and, while watching the “Ref. In” meter, adjust the oscillator output level so that the yellow segment lights only occasionally.
6 Check that the ERL (Echo Return Loss) meter in the AEC component is moving. If this meter is moving over a wide range it means that a large portion of the pink noise being output from the speaker is being picked up by the corresponding microphone, and therefore a large amount of echo will be transmitted to the remote location. Carefully adjust the positions and pickup directions of the four microphones in relation to the speakers in order to reduce this echo level as much as possible.
Remote Connection and Settings 1 Connect the microphones, speakers, and teleconferencing system to the analog [IN] and [OUT] connectors on the rear panel of the DME24N as shown in the diagram. Four microphones can be connected at the near-end location, allowing multiple conference participants.
2 Make the required virtual connections in the DME Designer configuration window. • Connect the signal from the four local microphones (Mic1 – Mic4) and the audio signal from the remote location (From Office X) to the appropriate inputs of the AEC component. • Mix the “Near-end Voice 1” – “Near-end Voice 4” outputs and the “Far-end Voice A” outputs from the AEC component and connect the mixed output in parallel to the meeting room speakers (SP 1 and SP 2).
3 Adjust the DME Designer AEC component editor parameters so that acoustic echo is effectively cancelled from the audio signal sent to Office X. Begin by checking that the connection with Office X is working properly and that conversation is possible. If echo can be heard with the default AEC section Effect setting of “1”, try increasing the setting in small increments.
Example 2: Teleconferencing with Two Remote Locations from Two Meeting Rooms Using one MY4-AEC card, multiple participants in two meeting rooms can teleconference with two separate remote locations (“Office X” and “Office Y”). Preparation Referring to Example 1, use an oscillator component to determine the ideal microphone and speaker positions for each meeting room. The following equipment is used.
Small Meeting Room (Near End) Office X (Remote – Far End) Speaker 1 Microphone 1 Teleconferencing system Speaker 2 Microphone 2 OUT (Analog) Network IN/OUT (Analog) DME24N IN (Analog) + IN/OUT (Analog) Network MY4-AEC OUT (Analog) Speaker 1 Office Y (Remote – Far End) Teleconferencing system Speaker 2 Medium Meeting Room (Near End) 22 MY4-AEC Owner’s Manual IN (Analog) Microphone 1 Microphone 2
2 Make the required virtual connections in the DME Designer configuration window. • Connect the signal from the microphones in the small and medium local meeting rooms (Conf S Mic1/2 and Conf M – Mic1/2) and the audio signal from the remote locations (From Office X and From Office Y) to the appropriate inputs of the AEC component.
3 In the Matrix Router section of the AEC component editor, select one or more of the “From Far-end A – D signals” to be used as the reference for each AEC channel 1 – 4. The “On” buttons in the Matrix Router section can be used to select microphones and locations for each meeting room. For this example the Matrix Router is set as shown below.
Appendix Specifications GENERAL SPECIFICATIONS Sampling Frequency 44.1kHz-10% to 48kHz+6%, 88.2kHz-10% to 96kHz+6% Power requirements 5V : 395mA 3.
Dimensions 164.1 176.
* The contents of this manual apply to the latest specifications as of the publishing date. To obtain the latest manual, access the Yamaha website then download the manual file. * Der Inhalt dieser Bedienungsanleitung gilt für die neuesten technischen Daten zum Zeitpunkt der Veröffentlichung. Um die neueste Version der Anleitung zu erhalten, rufen Sie die Website von Yamaha auf und laden Sie dann die Datei mit der Bedienungsanleitung herunter.
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