ALESIS ADAT XT20 Reference Manual Introduction/Contents INTRODUCTION Thank you for purchasing the Alesis ADAT-XT20 20-Bit Digital Audio Recorder. To take full advantage of the XT20's functions, and to enjoy long and trouble-free use, please read this user's manual carefully. HOW TO USE THIS MANUAL This manual is divided into the following sections describing the various modes of the XT20. Though we recommend you take time to read through the entire manual once carefully, those having general knowledge about multitrack recorders should use the table of contents and index to reference specific functions while using the XT20. Chapter 1: Introduction. Deals with the necessary preparation before recording and playing, including connections to external devices. This chapter also discusses the difference between "threaded" and "unthreaded" tapes. Chapter 2: Your First Session with the ADAT-XT20. This section provides a brief tour of the XT20, shows you how to format a tape, record and playback, set locate points, auto punch-in and out, bounce tracks, and points out other various features. Chapter 3: Connections. Details rear panel connections (like inputs and outputs, footswitches and the ADAT Optical Digital Interface), and proper hook-up procedures. Chapter 4: Basic Operations. Covers the user interface of the XT20 and the way to use its basic control features, how to read the display, and how to navigate through and edit parameters. Chapter 5: Multiple ADAT Operation. How to lock together multiple ADAT CompatibleTM devices, and how to record and transfer digital audio between them. Chapter 6: Applications. Describes several real-world examples of how the XT20 may be used. Appendices. Features an explanation of digital audio recording concepts, troubleshooting, maintenance and service information, specifications, a Glossary and an Index. CONVENTIONS All front panel buttons, LEDs, display icons and rear panel connectors are referred to in this manual just as their names appear on the XT20, using all capital letters and in brackets (Examples: [PLAY] button, [AUTO INPUT] button, EDIT icon, etc.). When something important appears in the manual, an icon (like the one on the left) will appear in the left margin. This symbol indicates that this information is vital when operating the XT20. ADAT XT20 Reference Manual 1 Introduction/Contents 2 ADAT XT20 Reference Manual Introduction/Contents CONTENTS SETTING UP 7 Unpacking and Inspection 7 AC Power Hookup 7 Avoiding Ground Loops 8 Line Conditioners and Protectors 9 About Audio Cables 9 Basic Audio Hookup 10 Input Normaling 10 "Threaded" vs. "Unthreaded" 11 A Word on ADAT's S-VHS Cassette Tape Operating Environment 12 Thermal Considerations in Rack Mounting Mounting on a Shelf or Non-Rack Enclosure Avoiding Electromagnetic Interference 12 Power-up, and Tape Insertion 13 Formatting A Tape ­ A MUST! 15 Word Length (16/20 Bit) Selection Sample Rate Selection 15 Formatting a New tape 15 Recording While Formatting 16 Making A Recording 17 Track Selection and Setting Levels Time Counter 17 Transport Buttons 19 Recording 19 Playback 20 Reviewing and Cueing 20 Locating 22 Creating A Loop 23 Automated Recording 24 Rehearsing 24 Pitch Control 25 Track Delay 25 Track Copy 26 Display Brightness 26 11 12 12 YOUR FIRST SESSION WITH THE ADAT-XT20 15 13 17 CONNECTIONS 28 Analog Audio ­ Unbalanced Inputs 28 Input jack characteristics 28 Typical input jack hookups 28 Analog Audio ­ Unbalanced Outputs 28 Analog Audio ­ Balanced Inputs and Outputs Analog Input Select Mode 30 Sync In/Out 31 Digital Audio In/Out 32 About 16-bit and 20-bit signal transfers 32 Footswitches 34 The XT20 Remote 34 29 BASIC OPERATIONS 35 ADAT XT20 Reference Manual 3 Introduction/Contents Tape Formatting 35 Formatting Considerations 35 Complete Format 36 Recording While Formatting 37 Format Extend 37 Write Protect Override 39 Reading The Display 40 Display Icons 41 TIME Counter & ABS/REL Button 44 Locate 0 44 Basic Editing 46 EDIT Value Button 46 v and w Buttons 46 Entering Numeric Values 46 Editing Individual Digits 46 Input Select 48 Analog Input 48 Digital Input 48 Track Copy 49 Input Monitor 50 Auto Input Monitor 50 All Input Monitor 50 Meters 52 Peak Mode Button 52 Peak Clear Button 52 Fine Meter Mode 52 Recording a "Benchmark" Tape 53 Record Enable 54 Setting Levels 54 Transport Controls 56 Eject 56 Rewind/Review 56 Fast Forward/Cue 56 Play 58 Record/Punch In or Out 58 Stop 59 Sample Rate (Clock) 59 Record Crossfade Time 60 Displaying Frames vs. 100ths/Seconds 60 Pitch Control 62 About Pitch Changing 62 Track Delay 63 Autolocation Controls 65 Absolute (ABS) Time vs. Relative Time65 Locate 0 65 Setting Locate Points 67 Locating 67 Auto Looping 68 Auto Return 68 Auto Play 68 Loop Limit 68 Looped Recording 68 Auto Record 69 Rehearsal 69 4 ADAT XT20 Reference Manual Introduction/Contents Tape Length 70 Footswitch Controls 71 Footswitch Controlled Punching Footswitch Controlled Autolocating Using the XT20 LRC Remote 72 71 71 MULTIPLE ADAT-XT20 OPERATION 74 Overview 74 Synchronizing Machines 75 Master/Slave Interaction 75 Achieving Lock76 Independent Slave Mode 76 Formatting Multiple Tapes 76 Master Format Enabled, Complete Format Master Format Enabled, Format Extend 76 Master Format Disabled 78 Master Format Disabled, Format Extend Recording Digital Audio 79 Bouncing Tracks Between ADATs 79 Reassigning Channels to Different Tracks Making Digital Backups 81 Making a 16-bit copy from a 20-bit master Recording Digital Audio from Other Sources Digital Clock Considerations 83 Tape Offset 85 Combining XT20s and ADATs 86 XT20 Transport Speed 86 Sample rate vs. Pitch Control 86 Input Monitoring 86 Polarity Differences 88 Connections 89 76 78 80 82 83 APPLICATIONS 91 Overview 91 Combined Multitrack/Mixdown Deck 91 Live/Long-Term Recording 92 Locking to Video: Code-Only Master 93 Computer Control 93 MIDI Systems: Virtual Tracking 93 MIDI Machine Control: Virtual Remote Control93 The ADAT-PCR Computer Interface 94 Libraries and Archives 94 Modular Recording 94 Using Track Copy as a Digital Router 95 Calculating Tape Offset using the Locates 95 DIGITAL RECORDING CONCEPTS 97 Analog Recording Basics 97 Digital Recording Basics 97 The Advantages of 20-Bit Recording Why S-VHS? 98 98 TROUBLESHOOTING Trouble-Shooting Index 99 Re-initializing 99 Checking Software Version Error Rate Display 100 99 100 ADAT XT20 Reference Manual 5 Introduction/Contents About Error Rate Readings ADAT Head Life 100 ADAT Head Maintenance Drum Time Display 102 Tape Maintenance: Safe Tape Maintenance/Service 103 Cleaning 103 Maintenance 103 Obtaining Repair Service 100 101 102 103 107 ERROR CODES SPECIFICATIONS GLOSSARY 112 INDEX 119 105 110 Automatic Brake Calibration Procedure Steps To Take Before Calling For Help 107 6 ADAT XT20 Reference Manual Setting Up: Chapter 1 CHAPTER 1 SETTING UP UNPACKING AND INSPECTION Your ADAT-XT20 was packed carefully at the factory. The shipping carton was designed to protect the unit during shipping. Please retain this container in the highly unlikely event that you need to return the XT20 for servicing. The shipping carton should contain the following items: · · · · · · · ADAT-XT20 with the same serial number as shown on shipping carton Power Cable Optical Cable XT20 remote control unit This instruction manual Blank S-VHS ST-120 cassette Alesis warranty card It is important to register your purchase; if you have not already filled out your warranty card and mailed it back to Alesis, please take the time to do so now. AC POWER HOOKUP With the XT20 off, plug the female end of the power cord into the XT20's [POWER INPUT] socket and the male (plug) end into a source of AC power. It's good practice to not turn on the XT20 until all other cables are hooked up. The XT20 works with any AC voltage from 90 to 250 volts, 50 to 60 Hz. This eliminates the need for transformers or voltage switches. Your XT20 was supplied with the correct power cord for your country or local area, however only the following alternative power cords are approved for use with ADAT: · For 90-120 VAC 50/60 Hz operation in the US, Canada and/or Japan, use Alesis UL/CSA power cord #7-41-0001. · For 240 VAC 50 Hz operation in England, use Alesis Power cord #7-410004. · For 220 VAC 50 Hz operation in Europe and Scandinavia, use Alesis EU power cord #7-41-0002. · For 240 VAC 50 Hz operation in Australia, use Alesis AS power cord #741-0003. The XT20's IEC-spec AC cord (do not substitute any other AC cord) is designed to feed an outlet that includes three pins, with the third, round pin connected to ground. The ground connection is an important safety feature designed to keep the chassis of electronic devices such as the Alesis ADAT - XT20, BRC and AI-1 at ground potential. Unfortunately, the presence of a third ground pin does not always indicate that an outlet is properly grounded. Use an AC line tester to determine this. If the outlet is not grounded, consult with a licensed electrician. ADAT XT20 Reference Manual 7 Chapter 1: Setting Up When AC currents are suspect of being highly unstable in VAC and Hz, a professional power conditioner should be used. Alesis cannot be responsible for problems caused by using the XT20 or any associated equipment with improper AC wiring. AVOIDING GROUND LOOPS In today's studio, where it seems every piece of gear has a computer in it, there are many opportunities for ground loop problems to occur. These show up as hums, buzzes, or sometimes radio reception and can occur if a piece of equipment "sees" two or more different paths to ground, as shown below. shielded cable Device A path 1 Device B path 2 To AC power service One path goes from device A to ground via the ground terminal of the three-conductor AC power cord, but A also sees a path to ground through the shielded cable and AC ground of device B. Because ground wires have a small amount of resistance, small amounts of current can flow through ground and generate a voltage along the cable shield. This signal may end up getting induced into the hot conductor. The loop can also act like an antenna into which hum is induced, or can even pick up radio frequencies. Furthermore, many components in a circuit connect to ground. If that ground is "dirty" and contains noise, it might get picked up by the circuit. Ground loops cause the most problems with high-gain circuits, since massive amplification of even a couple millivolts of noise can give an audible signal. Most ground loop problems can be solved by plugging all equipment into the same grounded AC source. However, it is important to make sure that the AC source is not overloaded and is properly rated to handle the gear plugged into it. For really tough cases, you may need to break the connection that causes the loop condition. If your circuits are balanced, one way to do this is to simply break the shield of the shielded audio cable at some point, usually by disconnecting it from ground at one jack. (The other end 8 ADAT XT20 Reference Manual Setting Up: Chapter 1 should remain connected so that the shielding properties are retained, even if there is no direct path for ground.) Please note that not all hums and buzzes are caused by ground loops; your cables must be of very high quality, particularly with -10 dBV setups. Refer to page 9 for more information. ADAT XT20 Reference Manual 9 Chapter 1: Setting Up LINE CONDITIONERS AND PROTECTORS Although the XT20 is designed to tolerate typical voltage variations, in today's world the voltage coming from the AC line may contain spikes or transients that can possibly stress your gear and, over time, cause a failure. There are three main ways to protect against this, listed in ascending order of cost and complexity: · Line spike/surge protectors. Relatively inexpensive, these are designed to protect against strong surges and spikes, acting somewhat like fuses in that they need to be replaced if they've been hit by an extremely strong spike. · Line filters. These generally combine spike/surge protection with filters that remove some line noise (dimmer hash, transients from other appliances, etc.). · Uninterruptible power supply (UPS). This is the most sophisticated option. A UPS provides power even if the AC power line fails completely. Intended for computer applications, a UPS allows you to complete an orderly shutdown of a computer system in the event of a power outage, and the isolation it provides from the power line minimizes all forms of interference--spikes, noise, etc. ABOUT AUDIO CABLES The connections between the XT20 and your studio are your music's lifeline, so use only high quality cables. These should be low-capacitance shielded cables with a stranded (not solid) internal conductor and a low-resistance shield. Although quality cables cost more, they do make a difference. Route cables to the XT20 correctly by obser ...