Altec Lansing 4948A User Manual

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4048A

DIGITAL SIGNAL PROCESSOR

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Altec Lansing Professional

1000 W. Wilshire Blvd. Suite 362

Oklahoma City, OK 73116 USA

A division of Altec Lansing Technologies Inc, Milford PA 18337-0277Made In USA

Operating Manual -4048Adigital signal processor

TABLE OF CONTENTS

1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

2 UNPACKIN G . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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3 AC POWER REQUIREMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

4 FRONT PANEL FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

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REAR

PANEL FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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A LTEC

LANSING MAESTROSOFTWA R E . . . . . . . . . . . . . . . . . . . . . . . .

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GETTING STA RTED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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OTHER SOFTWARE FUNCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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TROUBLESHOOTING TIPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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DIMENSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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1 2 WARRANTY INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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1 3 BLOCK DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Operating Manual-4048Adigital signal processor

The lightning flash with arrowhead symbol, within an equilateral triangle, is intended to alert the user to the presence of uninsulated "dangerous voltage" within the product's enclosure that may be of sufficient magnitude to constitute a risk of electric shock to persons.

CAUTION

RISK OF ELECTRIC SHOCK

DO NOT OPEN

TO REDUCE THE RISK OF ELECTRIC SHOCK, DO NOT REMOVE COVER. NO USER SERVICEABLE PARTS INSIDE. REFER SERVICING TO QUALIFIED SERVICE PERSONNEL.

TO REDUCE THE RISK OF FIRE OR ELECTRICAL SHOCK, DO NOT EXPOSE THIS APPlIANCE TO RAIN OR MOISTURE.

TO REDUCE THE RISK OF FIRE, REPLACE ONLY WITH SAME TYPE FUSE. REFER REPLACEMENT TO QUALIFIED SERVICE PERSONNEL.

The exclamation point within an eqilateral triangle is intended to alert the user to the presence of important operating and maintenance instructions in the literature accompanying the device.

WARNING:

THIS APPARATUS MUST BE EARTHED

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Operating Manual -4048Adigital signal processor

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1. INTRODUCTION

Your new 4048A is a flexible four input/eight output digital signal processor capable of precise control of a broad range of audio functions. Because it has no user controls, it is ideal for applications where real-timechanges are unlikely or whentamper-proofsecurity is required. All adjustments are made using Altec Lansing Maestrosoftware for Windows.

The 4048A utilizes state of the art DSP technologies, beginning with 24 bit, 48kHz delta-sigmaA/D converters with 128x oversampling. Audio processing includes Gain, Parametric EQ, Signal Routing, Crossover Functions, Time Delay, Compressor/Limiter, and Polarity Invert, all taking place in twin high performance Motorola DSP processors. D/A conversion uses 24 bitdelta-sigmaconverters with 128x oversampling. All input and output connections are precision balanced and RF protected using"Euro-Block"style two piece terminal block connectors.

2. UNPACKING

As a part of our system of quality control, every Altec Lansing product is carefully inspected before leaving the factory to ensure flawless appearance. After unpacking, please inspect for any physical damage. Save the shipping carton and all packing materials, as they were carefully designed to minimize the possibility of transportation damage should the unit again require packing and shipping. In the event that damage has occurred, immediately notify your dealer so that a written claim to cover the damages can be initiated. The right to any claim against a public carrier can be forfeited if the carrier is not notified promptly and if the shipping carton and packing materials are not available for inspection by the carrier. Save all packing materials until the claim has been settled.

3. AC POWER REQUIREMENTS

Note: The AC power switch for model 4048A is on the back panel. The Altec Lansing 4048A uses a universal input power supply which will accept any line voltage in the range of 80VAC to 260VAC, 50-60Hz, and is exceptionally resistant to voltage dips, or "brown outs". A standard IEC-320 grounded AC inlet is provided on the rear panel to accept the detachable power cord. Never remove the AC earth ground connection to the 4048A.In the event of an internal fuse failure, refer the product to a qualified service technician for fuse replacement, replacing only with the same type and rating fuse, 0.5A time delay Littlefuse 218.500 or equivalent.

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Operating Manual-4048Adigital signal processor

4. FRONT PANEL FEATURES

4.1 Input Channels

The 4048A has four input channels, each of which can be routed to any combination of output channels. Each input channel's three color Sig LED indicates input signal level of -20dB(green), 0dB (amber), and +20dB clip (red) respectively. Note that the Sig LEDs detect actual signal at the input connections, before any gain adjustments are made within the 4048A. The red input mute LED becomes lit when an input channel is turned off through software control.

4.2 Output Channels

The eight output channels on the 4048A have three color LEDs to indicate signal, limiter threshold, and clip. The green signal LED indicates -20dBoutput level. The amber limiter threshold LED depends on settings established within Altec Lansing Software, and, assuming the limiter is active, indicates that sufficient signal level has been reached for the limiter to begin the process of gain reduction. Clipping occurs at +20dB and is indicated by a red LED. The red output mute LED becomes lit when an output channel is turned off through software control.

4.3 Preset Indicator

This display indicates the currently selected preset number (1-18)for the 4048A. This display also indicates the following operating conditions within the 4048A:

-Firmware revision number is displayed during power up, and when a factory reset is aborted.

-Factory reset countdown, which occurs by pressing and holding the factory reset switch during power up.

-Contact closure event confirmation is indicated by an upper case "C" for a few seconds, followed by the active contact/preset number (1-8).

-RS-232bulk preset dump completion is indicated by a lower case "d". If the 4048A receives a corruptRS-232dump, an upper case "E" is shown.

4.4Factory Reset Switch

This is a recessed switch in the small hole below the preset display. This recessed switch is used to perform a factory reset by pressing and holding during power up. Note that a factory reset will erase all user defined presets stored in the 4048A, including the user password.

4.5 RS-232Dataport

The 4048A has two parallel RS-232dataports, one on the front panel and one on the back, for connecting to a computer for software control. See section 6.3 for details on connecting to a computer.

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Operating Manual -4048Adigital signal processor

5. REAR PANEL FEATURES

5.1 Input Connections

Balanced input signals are connected to the 4048A using the included "Euro Block" connector. A flat blade screwdriver is required to connect a stripped wire lead to the loose connector, which is then inserted into the rear panel Euroblock receptacle. It is important that both (+) and (-)inputs are properly terminated or signal loss and noise may result. In other words, if an unbalanced input signal is used, connect the signal to the (+) input, and connect the ground wire to both the(-)and ground connection.

A Note About Input Signal Levels:

+ - G

Euroblock + - G

Connector

System

There are no input trim adjustments on the 4048A, therefore all the processing (including gain) is done in the digital domain. As a consequence of this design philosophy, it is important to feed the processor with the proper nominal signal level to achieve good signal to noise performance as well as headroom before clipping. The 4048A is designed to clip at signal levels above +20dBu = 7.75Vrms which places the noise floor lower than -90dBu.The optimum input signal level which should be fed into the processor is 0dBu = .775Vrms. This input level will allow 20dB of headroom while giving a nominal signal that is >90dB above the noise floor.

5.2 Output Connections

Like the inputs, output connections are made using the included Euroblock connector. All outputs are electronically balanced, and may be wired balanced or unbalanced. For unbalanced outputs, connect the shield to both (- ) and G terminals.

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Operating Manual-4048Adigital signal processor

5.3 Contact Closure Connector

There are no user controls on the 4048A, making it ideal for permanent installations where security is an issue. There may be times, however, where audio system adjustments must be made in response to real time acoustic changes, such as room size. For these types of changes, the 4048A offers the ability to recall up to eight different presets using contact closures. Contact closures are nothing more than external, user installed switches that, when closed, recall a previously defined preset which at once applies changes to the settings of all inputs and outputs. The switches can be anything from a rotary switch on a control room panel, to automatic door sensors located throughout a conference center, to a microphone key switch, etc. Contact closures allow for flexibility while maintaining a high degree of system security.

To use contact closure switching, up to eight presets (1-8)must first be defined according to the needs of the installation. Switches are to be configured so that closing the switch contact triggers the preset recall event. Either momentory or latching switches may be used, where the trigger event is the transition from open to closed for a given circuit. Closing a circuit will automatically override any previously recalled presets. Up to eight switches can be used, with all switches sharing a common ground connection. Each pin number above the contact closure connector corresponds to the number of the preset which will be recalled when that switch is closed.Always use the 4048A contact closure ground for contact closure switches. Do not connect the 4048A contact closure ground to any other external grounds, as ground loop currents may result.

5.4 RS-232Dataport

The 4048A has two parallel RS-232dataports, one on the front panel and one on the back, for connecting to a computer for software control. See section 6.3 for details on connecting to a computer.

5.5 AC Inlet and Power Switch

D-Sub9 Pin Female

RS-232Pin-Out

5 4 3 2 1

9 8 7 6

Pin # RS-232DCE Name

A detachable AC power cord is used on the 4048A. Since the internal universal power supply works from 80 to 260 VAC 50-60Hz,the only change necessary for use with international power is the appropriate AC power cord. The AC power switch is found on the back of the unit as well.

1Not Connected

2 Transmitted Data

3Received Data

4Data Terminal Ready (tied to pin 6)

5Ground

6 Data Set Ready (tied to pin 4)

7 Not Connected

8 Not Connected

9Not Connected

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Operating Manual -4048Adigital signal processor

6. ALTEC LANSING MAESTROSOFTWARE

Altec Lansing offers a powerful software interface for the Windows PC environment, providing control for the 4048A digital signal processor. All controls are intuitively represented in a user friendly way, and on-linehelp is available for key functions.

6.1 Installing Software

The Maestroinstallation program is the same whether from the web site or from a disk. To install the software,double-clickon <setup.exe> and follow the installation instructions.

6.2 Connecting the 4048A to a computer

A standard D-Subnine pin female to male connector cable is used to connect the PC to the 4048A. If the PC lacks a nine pinRS-232port, an active USB toRS-232converter can be purchased at computer stores. Following are the suggested steps for connecting the 4048A to a PC:

1.) Plug the RS-232cable into an available serial port on the PC.

2.) Plug the other end of the cable into either the front or back RS-232Dataport on the 4048A. 3.) Turn on the power to the 4048A.

4.) Open Maestro software.

5.) Go to the <Communications> menu, click CommPort Assignment, and select the Comm port being used 6.) Go to the <Communications> menu and select <Enable Communications>.

7.) The connection should now be established.

RS-232signal will run typically to 1300 feet using high quality cable.

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Operating Manual-4048Adigital signal processor

7. GETTING STARTED

7.1 Configuration Options

Altec Lansing Maestro Software for the 4048A includes 10 permanent default configurations which can be used as starting points for setting up user defined presets. Modified configurations can then be saved to either disk (filename.alp) or one of 18 memory locations on the 4048A. Load a default setup by clicking <Configuration> within the <Options> menu. The default configuration options are:

1.4 x 2-wayCrossover

2.2 x 3-way,and 2 Aux

3.2 x 3-way+ mono sub

4.2 x 4-wayCrossover

5.1 x 5-way,and 3 Aux

6.Mono Distribution

7.Stereo Distribution

8.LCRS with mono subs

9.4 x 4 Processor

10.Muted, Flat Start-up

7.2 Metering Options

The front panel LEDs on the 4048A indicate signal present (-20dBu),0dBu (inputs only), or clip (+20dBu). For more detailed level information, Maestro has a separate metering window showing all four inputs and eight outputs, including gain reduction meters for output limiters. Meters can be set to dBu or VU in the <Options> menu. 0 VU = +4dBu (1.228Vrms).

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Operating Manual -4048Adigital signal processor

7.3 Audio Functions

Editing of audio controls is done through the use of scroll bars, numerical entry, various keyboard shortcuts, or by visually dragging filter points in the frequency response window. Ease of use, especially in the frequency response window, makes it possible for fast, potentially destructive mistakes, so plan carefully before making radical gain or filter changes.

7.3a Keyboard/Mouse Shortcuts

Convenient shortcuts allow for quick setups or edits, and are shown as follows:

Mouse shortcuts in the frequency response window . . .

Right Click-and-Drag

Change Q-Width

Left Click-and-Drag

Change Frequency

Left Click-and-Drag

Change Level

Keyboard shortcuts . . .

i Change to last input used o Change to last output used

s Change the order in which parametric and crossover filters are scanned

dChange to the Delay frame

gChange to the Gain frame

eChange to the EQ frame

r Change to the Routing frame h Change to the HpfLpf frame

lChange to the Limiter frame

mMute the current input or output channel

ESC(while dragging a filter)

Resets the filter position to its starting position

c

Cut Active Filter

 

z

Zero Active Filter

 

Ctrl-cCut Master Gain

Ctrl-zZero Master Gain

7.3b Mute

The 4048A allows the user to mute all inputs or outputs. When muted, an input or output's red Mute LED is lit. To mute or unmute all outputs simultaneously, click on the <Mute> menu heading and select the <Mute all> or <Unmute all> option. Inputs can be muted or unmuted one at a time. Additionally, when recalling a new preset to the 4048A, the user is prompted to mute all outputs, as a new preset can introduce dramatic changes to the system configuration.

7.3c Gain

For best signal to noise performance, provide an input signal with a nominal 0dBu level. Using significant input or output gain to make up for a weak input signal compromises the noise performance of the 4048A.

Input and Output Gain are separately adjustable from -40dBto +12dB. Due to limitations within the graphical interface, fine tuning gain settings in 0.1dB steps is accomplished using the <up/down arrows> on the keyboard. Changes of exactly 1dB are quickly accomplished using <PageUp/PageDown> buttons.To instantly return a gain setting to 0dB, press <Ctrl + Z> (see other keyboard shortcuts in 7.3a). Additionally, The output gain menu is also used to invert the polarity of outgoing signal for that channel.

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