ALESIS ADAT LX20 Reference Manual
Contents CONTENTS Introduction How To Use This Manual Conventions 1 SETTING U P AND M AKING CONNECTIONS Unpacking and Inspection Operating Environment Thermal Considerations in Rack Mounting Mounting on a Shelf or Non-Rack Enclosure Avoiding Electromagnetic Interference AC Power Hookup Avoiding Ground Loops Line Conditioners and Protectors Analog Audio Connections About Audio Cables Rear Panel Input and Output Layout Inputs Typical input jack hookups Outputs Sync In/Out Digital Audio Connections About
Contents What is Tape Formatting? 3 POWER-UP AND TAPE FORMATTING Power-up and Tape Insertion Setting Tape Length How to Format Tapes About Type I and Type II Formats Defeating The Write Protect Tab General Formatting Procedure Recording While Formatting Re-Formatting a Previously Formatted Tape Notes About Formatting Recording a “Benchmark” Tape 4 RECORD AND P LAYBACK B ASICS Understanding the Time Counter Change Display Format Set the Input Mode for Analog Audio Choose Analog Or Digital Input Digit
Contents Manual Punching Options Transport Controls Record Enable Buttons Footswitch Automated Recording Looped Recording Rehearsing Adjusting Punch Crossfade Time 7 PITCH CONTROL 8 ABOUT D IGITAL A UDIO IN/OUT ADAT Optical Interface Basics About 16-bit and 20-bit signal transfers Selecting The Digital Output Mode Type II (20-bit) to Type II (20-bit) Type II (20-bit) to Type I (16-bit) 9 USING THE LX20 LRC REMOTE 45 45 45 46 46 47 47 48 49 51 51 51 52 52 52 53 10 MULTIPLE LX20/ADAT OPERATION 55
Contents Live/Long-Term Recording Locking to Video: Code-Only Master Libraries and Archives Modular Recording Computer Control and MIDI MIDI Systems: Virtual Tracking MIDI Systems: Automated Mixdown MIDI Systems: Virtual Tracks and Automated Mixdown MIDI Machine Control: Virtual Remote Control The ADAT Optical Interface and Hard Disk Recording Digital Audio Transfer Options Typical applications The ADAT-PCR Computer Interface A Real-World Example Sync Issues Hard Disk Backup Pre-Mastering with the LX20 A P
Introduction INTRODUCTION Thank you for purchasing the Alesis ADAT-LX20 20-Bit Digital Audio Recorder. To take full advantage of the LX20’s functions, and to enjoy long and trouble-free use, please read this manual carefully. Here are some of the LX20’s most significant features: • Low tape cost. The LX20 can record over an hour of audio on a standard S-VHS tape cassette. • Superb fidelity. The LX20 offers 20-bit recording to tape using the ADAT Type II format, along with a choice of a 44.
Introduction HOW TO USE THIS M ANUAL Though we recommend you read through the entire manual once, those having general knowledge about multitrack recorders should use the table of contents and index to reference specific functions while using the LX20. Here’s how the manual is organized: Chapter 1: Setting Up and Making Connections. This covers installation issues as well as how to connect up the LX20 to other gear in a system. Chapter 2: LX20 Essentials.
Chapter 1 - Setting Up and Making Connections CHAPTER 1 SETTING UP AND M AKING CONNECTIONS UNPACKING AND INSPECTION Your ADAT-LX20 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 LX20 for servicing.
Setting Up and Making Connections - Chapter 1 M OUNTING ON A SHELF OR NON-RACK ENCLOSURE To mount the LX20 on a shelf or other flat surface, Alesis recommends attaching stick-on rubber feet to avoid scratching the shelf’s surface with the deck’s bottom. Please observe the general comments on thermal considerations given under “Thermal Considerations in Rack Mounting” no matter where or how the deck is mounted.
Chapter 1 - Setting Up and Making Connections AVOIDING GROUND LOOPS In today’s studio, 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.
Setting Up and Making Connections - Chapter 1 LINE CONDITIONERS AND P ROTECTORS Although the LX20 can tolerate typical voltage variations, the AC line voltage 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.
Chapter 1 - Setting Up and Making Connections A NALOG A UDIO CONNECTIONS ABOUT AUDIO CABLES The connections between the LX20 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. Here’s how to route cables to the LX20: ✪ • Do not bundle audio cables with AC power cords.
Setting Up and Making Connections - Chapter 1 Here’s how the input jacks and plugs are wired: Signal Ground Tip TYPICAL Tip Sleeve Sleeve INPUT JACK HOOKUPS You typically patch the following into the inputs: • Console direct tape outs. With many mixing consoles, such as the Alesis Studio 24, each mixer channel has a direct output. These can patch a channel directly to tape, bypassing most mixer circuitry.
Chapter 1 - Setting Up and Making Connections OUTPUTS The -10 dBV outputs use phono jacks, and carry signals at a nominal -10 dBV level. These connect to your mixer’s channel tape returns or line inputs. You would normally connect output 1 to mixer line input 1 or tape return 1, output 2 to mixer line input 2 or tape return 2, etc.
Setting Up and Making Connections - Chapter 1 SYNC IN/OUT The two rear panel DB-9 connectors marked SYNC IN and SYNC OUT synchronize two or more ADAT-family devices, such as the LX20, XT20, M20, original ADAT, ADAT-XT, and/or a computer hard disk audio recording/editing system using the ADAT-PCR sound card or similar device. Synchronization requires a male-to-male, 9-pin D connector cable for each additional machine in the chain.
Chapter 1 - Setting Up and Making Connections DIGITAL AUDIO CONNECTIONS The digital input and output carries all eight tracks on a single fiber optical cable (called the ADAT Optical Interface, and sometimes nicknamed the ADAT “Light Pipe”). This powerful feature allows you to transfer digital audio between multiple ADAT-compatible devices.
Setting Up and Making Connections - Chapter 1 ➃ For each additional machine, connect one end of an additional fiber optic cable ➄ to the second machine’s DIGITAL OUT jack, and the other end to the third machine’s DIGITAL IN jack. Its DIGITAL OUT jack then connects to the fourth machine’s DIGITAL IN jack, and so on. Finally, connect one end of a fiber optic cable to the last machine’s DIGITAL OUT jack, and the other end to the first machine’s DIGITAL IN jack.
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Setting Up and Making Connections - Chapter 1 There are three ways to use this jack. • Footswitch only. Plug a momentary, single-pole/single-throw footswitch (either normally open or normally closed) halfway into the jack so that the footswitch plug tip connects to the jack ring connection. In other word, plug in only until the tip reaches the first detent. Plug in the footswitch prior to power-up so that the LX20 can configure itself for the type of footswitch being used.
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LX20 Essentials - Chapter 2 CHAPTER 2 LX20 ESSENTIALS A BOUT THE D ISPLAY The LX20’s display shows the current level of each of the eight audio tracks, the tape position (in hours, minutes, seconds, and 100ths of seconds or frames), and the current modes of the many available parameters. It also provides a “window” for various editable parameters.
Chapter 2 - LX20 Essentials BLOCKS There are three ”blocks” located in the lower right-hand corner: Clock, Input Mon, and Input. Each block shows the selected option for the block’s parameter. S TATUS INDICATORS These are individual status indicators. For example, to the left of the Input Mon block, there are status indicators that show whether the tape being played is in 16bit or 20-bit format.
LX20 Essentials - Chapter 2 INPUT SELECT BUTTONS These determine how signals, both analog and digital, are routed to the LX20. PITCH CONTROL BUTTONS These increase or slow down the playback and record speeds to change pitch. LOCATION BUTTONS The LX20 can find particular places on tape.
Chapter 2 - LX20 Essentials D IFFERENCES COMPARED TO A NALOG R ECORDING Recording on the LX20 is very similar to most multitrack tape machines. With a formatted tape loaded, put one or more tracks into record-ready, adjust record levels on your mixer, set the input monitor mode, locate to where you want to begin recording, and engage record. However, there are two main differences, described next. “THREADED ” VS.
LX20 Essentials - Chapter 2 CHOOSING THE R IGHT S-VHS CASSETTE TAPE We cannot overemphasize the importance of using only premium quality, name brand S-VHS cassettes such as Quantegy 489 DM Digital Mastering Audio Tape, or Alesis ADAT Mastering Audio Cassettes. Other acceptable brands include Maxell XR-S Black, JVC XZ, Sony DASV, BASF Digital Master 938, Apogee AA-40, HHB ADAT45, and TDK SP Super Pro.
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Power-Up and Tape Formatting - Chapter 3 CHAPTER 3 P OWER-UP AND TAPE F ORMATTING POWER-UP AND TAPE INSERTION Patch the LX20’s power cord between the rear panel, three-prong power socket and a properly-wired AC outlet receptacle. Please take account of the grounding considerations mentioned in Chapter 1. ✪ The LX20 can produce a transient audio signal during power up and power down. When turning the LX20 on or off, keep the monitor levels low. Turn the LX20’s power on by pressing the POWER button.
Chapter 3 - Power-Up and Tape Formatting SETTING TAPE LENGTH The LX20 can use tapes longer than the standard ST-120 length (an ST-180 tape gives over one hour of recording time, an ST-160 gives 53 minutes). The LX20 automatically recognizes ST-60 tapes and adjusts itself accordingly, but cannot tell apart ST-120, ST-160 or ST-180 tapes. The LX20 assumes you are using a ST-120 tape. Therefore, you need to set the tape length on the LX20 when using either ST-160 or ST-180 tapes.
Power-Up and Tape Formatting - Chapter 3 HOW TO FORMAT TAPES What it does: Formatting an LX20 tape “time-stamps” the tape every 1/48,000 of a second (at a 48 kHz sample rate), and stores reference information about the tape in a data header at the tape’s beginning. Caution: Formatting a tape erases audio on all eight tracks. Always check that the tape is either blank or contains unwanted material before formatting.
Chapter 3 - Power-Up and Tape Formatting GENERAL FORMATTING PROCEDURE Formatting consists of inserting the tape, selecting the sample rate, selecting the audio resolution, then initiating formatting. Following are the steps needed to format a tape. Operation Cassette insertion • • • You Do… Insert a fresh, blank S-VHS tape into the tape well. You see… The display’s FORMAT indicator lights while the counter display reads “noFO.
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Chapter 3 - Power-Up and Tape Formatting RECORDING W HILE FORMATTING To record onto tape while formatting, before pressing the FORMAT button press the RECORD ENABLE button(s) 1–8 associated with the track(s) to be recorded. These can accept analog or digital signals, as described in Chapter 4. • • Do not begin recording before the time display shows 0:00:00.00. Tracks not in record-ready (safe) will be recorded with silence while formatting.
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Chapter 4 - Record and Playback Basics CHAPTER 4 RECORD AND P LAYBACK BASICS UNDERSTANDING THE TIME COUNTER Before recording, familiarize yourself with the TIME counter in the display’s top left corner. This counter shows the time reference “stamped” on a formatted tape as hours:minutes: seconds.hundredths-of-a-second. ABS 0 H 15 M 48 S 21 CHANGE DISPLAY FORMAT You can change the display’s last two digits to show Frames Per Second (FPS; one frame is 1/30th of a second) instead of 100ths of a second.
Record and Playback Basics - Chapter 4 The reason for these three modes is to take equal advantage of 2, 4 and 8 bus mixing consoles. To select the appropriate Input Mode, hold the ANALOG INPUT button and press one of the RECORD ENABLE buttons (1–8). The blue INPUT indicators, located along the bottom of the display below the VU meters, will illuminate to indicate the selected Input Mode. While holding ANALOG INPUT Press 1 or 2… Press 3 or 4… Press 5, 6, 7 or 8… Result …to select 2-Input Mode.
Chapter 4 - Record and Playback Basics SELECT T RACK(S) FOR R ECORDING A track can be in one of 3 states: • • • Safe The track RECORD indicator (the red bar located right below the meter) is off. Record-ready The track RECORD indicator flashes Recording The track RECORD indicator is lit solid Here’s how to enable a track for recording, as well as place it in “safe” mode. Note that the Record Enable switch “toggles” between two possible states each time you press it.
Record and Playback Basics - Chapter 4 P LAY Press to start playback from the current tape location. The PLAY button also has special functions in Record and Autolocation modes, as described in Chapter 5. The following chart summarizes all possible Play button options.
Chapter 4 - Record and Playback Basics To end a Cue or Review operation, press PLAY, STOP, REWIND, or FFWD. S TEP-BY-STEP P ROCEDURES The following sections describe in detail how to record, play back, cue, and review. Note: When recording for the first time, be sure the Auto Input function is off. When recording over previous material (also known as punching), turn the Auto Input function on. Use the AUTO INPUT button to turn Auto Input on and off.
Record and Playback Basics - Chapter 4 REVIEWING CUEING AND The review and cue modes make it easy to locate a particular section of a recording. Review mode lets you play the tape in reverse 3 times faster than normal play, while hearing “fragments” of audio. Similarly, Cue mode plays forward 3 times faster than normal play. To engage Review mode: ❿ Simultaneously press REWIND and PLAY. The PLAY LED will light and the REWIND LED will flash. ❡ Press PLAY to resume Play mode.
Chapter 4 - Record and Playback Basics Record-enabled tracks monitor the… Non-record-enabled tracks monitor the… Input signal Tape Input while recording or stopped, tape while playing Tape while playing or recording, input signal when stopped ALL INPUT Selecting All Input causes all 8 tracks to monitor their inputs regardless of the record-ready/auto-input status (section QQ). This is useful for live recording when you’re more concerned with what’s going into the recorder than what’s recorded on it.
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Chapter 5 - Autolocation and Loop Functions CHAPTER 5 A UTOLOCATION AND L OOP FUNCTIONS The LX20 lets you concentrate on making music by automating several common processes, including location, recording, and playback. A UTOLOCATION Autolocation is the process of having the tape transport search for a point on the tape that was previously marked as an autolocation point. After finding the specified autolocation point, the tape “parks” at that point (or begins playback).
Autolocation and Loop Functions - Chapter 5 buttons. transport plays, and the PLAY LED lights. To edit a Locate Point: Operation Initiate Locate Point editing You press… The EDIT VALUE button Select a Locate Point to edit One of the LOCATE 1 through LOCATE 4 buttons. Change Locate Point value The PITCH UP button to move the Locate Point later, or the PITCH DOWN button to move the Locate Point earlier. Press the EDIT VALUE button again.
Chapter 5 - Autolocation and Loop Functions To enable Auto Return: Operation Store the tape position to which the LX20 should return into LOCATE 1. Enable Auto Return You press… Press and hold SET LOCATE, then LOCATE 1 at the desired time (tape can be running or stopped) Press and hold SET LOCATE, then LOCATE 4 at the desired time (tape can be running or stopped) AUTO RETURN until… Disable Auto Return AUTO RETURN until… Store the tape position to which the LX20 should return into LOCATE 4.
Autolocation and Loop Functions - Chapter 5 LOOP LIMIT To protect against unnecessary wear and tear, the LX20 automatically disables Auto Loop after completing 100 consecutive loops. To disable this safeguard, hold the SET LOCATE button and press AUTO RETURN. Pressing STOP restores the 100 loop limit. Alesis strongly recommends leaving loop limit enabled. While the LX20 is Auto Looping, you can check how many loops have elapsed by holding SET LOCATE and pressing AUTO PLAY.
Chapter 6 - Punching and Automated Recording CHAPTER 6 PUNCHING AND A UTOMATED R ECORDING Punching is the process of recording over a section of tape (for example, to replace a bad note in an otherwise good performance). Punch-in is where recording begins, and punch-out is where it ends. There are several ways to punch into and out of recording, either manually or automatically.
Punching and Automated Recording - Chapter 6 F OOTSWITCH Pressing the punch footswitch is equivalent to pressing RECORD and PLAY. If the LX20 is already recording, pressing the punch footswitch exits Record mode but the transport continues to play. Note: Footswitch-controlled recording also works in conjunction with Rehearse mode and Auto Record mode. A UTOMATED R ECORDING Auto recording stops and starts recording automatically at predetermined points on the tape.
Chapter 6 - Punching and Automated Recording ✪ If Locate 2’s position is later than Locate 3’s position, the TIME counter will temporarily read “invALid”. Initiating record past Locate 2’s position but before Locate 3’s position starts recording immediately. Initiating record after Locate 3’s position has no effect, and the transport remains in play mode. L OOPED R ECORDING You can use the Auto Return and Auto Play functions (see Chapter 5) with Auto Record to create a recording loop.
Punching and Automated Recording - Chapter 6 A DJUSTING P UNCH CROSSFADE T IME Whenever recording begins or ends, the XT20 provides a smooth transition between the audio on tape and the audio being recorded. This prevents gaps and/or noises when punching in and out of record. The Record Crossfade Time sets how long it takes for the audio to completely transition from the previous audio to the current audio when recording (crossfading always begins at the punch point).
Chapter 7 - Pitch Control CHAPTER 7 P ITCH CONTROL The Pitch function controls the tape’s speed, which changes the pitch of the audio recorded on tape. The LX20’s Pitch control range covers -300 to +100 cents with a 48kHz sample rate, and -200 to +200 cents at 44.1kHz. When adjusting pitch, the TIME counter immediately displays the current amount of Pitch change as both a percentage (%) and as cents. ABS % 00 . 00 00 .
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Chapter 8 - About Digital Audio In/Out CHAPTER 8 A BOUT D IGITAL A UDIO IN/OUT The ADAT Optical Interface carries 8 tracks of digital audio between ADAT compatible products such as: • • • • • • Multiple LX20s and ADAT QuadraVerb 2 Q20 Many Alesis keyboards ADAT-PCR computer interface card 3rd-party products (Digidesign ADAT Bridge, Yamaha 02R digital mixer, etc.) Digital bussing requires one fiber optical cable (included) for each LX20 or other ADAT-compatible product.
About Digital Audio In/Out - Chapter 8 SELECTING THE DIGITAL OUTPUT M ODE Many applications involve sending the LX20’s digital output to another device, such as another ADAT for backup, or the ADAT-PCR card for digital editing. The type of transfer will require a particular digital output mode, as set with the DIGITAL OUT button. TYPE II (20-BIT) TO TYPE II (20-BIT) Press the DIGITAL OUT button repeatedly until the display shows “OUt 20”, then release. The LX20 sends a signal with 20-bit resolution.
Chapter 8 - About Digital Audio In/Out CHAPTER 9 U SING THE LX20 LRC R EMOTE The hand-held LRC remote provides the following functions: • Transport functions: Rewind, Fast Forward, Stop, Play and Record. • Autolocation functions: Locate 1, Locate 2, Locate 3, Locate 4, Set Locate, and Auto Loop • Track functions: Auto Record and Rehearse. All buttons work the same as the front panel controls. If connected to the master LX20 in a multiple ADAT system, the LRC can control the entire chain of ADATs.
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Chapter 10 - Multiple LX20/ADAT Operation CHAPTER 10 M ULTIPLE LX20/ADAT OPERATION O VERVIEW The LX20 can work together with up to 15 other ADAT-family machines to provide a total of 128 tracks. ADAT machines have a sync bus that provides timing information for all ADATs in a system. When linking multiple ADATs together, the first machine in the chain is the “master,” and the rest are “slaves.” Each slave locks to the master and synchronizes to the master machine’s time reference.
Applications - Chapter 11 1 2 3 4 5 6 7 8 POWER INPUT 90-250 V 50-60 Hz 80 W MAX 8 POWER INPUT 90-250 V 50-60 Hz 80 W MAX ALESIS CORPORATION, LOS ANGELES INPUT U.S. Patents 5,297,181 5,321,561 5,541,781 THIS DEVICE COMPLIES WITH PART 15 OF THE FCC RULES. OPERATION IS SUBJECT TO THE FOLLOWING TWO CONDITIONS: (1) THIS DEVICE MAY NOT CAUSE HARMFUL INTERFERENCE, AND (2) THIS DEVICE MUST ACCEPT ANY INTERFERENCE RECEIVED, INCLUDING INTERFERENCE THAT MAY CAUSE UNDESIRED OPERATION.
Chapter 10 - Multiple LX20/ADAT Operation M ASTER/SLAVE INTERACTION Pressing any of the transport buttons (PLAY, STOP, etc.), or AUTO REC, PITCH ▲ or ▼, LOCATE 0 – LOCATE 4, ALL INPUT, or AUTO INPUT will automatically trigger the same functions on the slave machine(s). As slaves can operate independently, to minimize confusion initiate all operations from the master, including transport control functions.
Applications - Chapter 11 ✪ Format Mode To properly extend a format, the master and slaves should be locked before punching into format record. Slave format ind. Lit Slave formatted? Result What you see Complete Master format ind.
Chapter 10 - Multiple LX20/ADAT Operation track 1 going to input 1, track 2 going to input 2, etc. (however, tracks can be reassigned to different inputs; see next section). ✪ To create an exact (sample-accurate) digital copy from a master to a slave, both master and slave machines must have their DIGITAL INPUT buttons enabled.
Applications - Chapter 11 M AKING DIGITAL BACKUPS You can (and should!) back up LX20 tapes by copying all eight tracks to another LX20 (or ADAT-compatible machine) via the digital bus. Alesis urges you to back up whenever you have material you don’t want to lose. This is not yet a perfect world. Synchronizing two machines together via the 9-pin sync bus allows for making sample-accurate copies, referred to the internal time code. This is the preferred way to make copies.
Chapter 10 - Multiple LX20/ADAT Operation put the new tape into the master, the damaged tape in the slave, and copy from the slave to the master. M AKING A 16-BIT COPY FROM A 20-BIT MASTER With over 100,000 ADAT 16-bit Type I machines in use, you may need to trade tapes with someone who owns an older machine. You can still record with your LX20 in 20bit Type II mode, and make Type I-compatible “clones.” You can also use an older Type I machine as a slave to an LX20.
Applications - Chapter 11 DIGITAL CLOCK CONSIDERATIONS Switching between the LX20’s two internal clock sample rates (48 kHz and 44.1 kHz) changes the reference used for computing tape location. Therefore, the same tape location will appear to have two different time addresses depending on the selected sample rate. Since the LX20 cannot detect an external clock’s sample rate, you need to choose the reference base the LX20 should use to calculate tape position while syncing to a digital clock.
Chapter 10 - Multiple LX20/ADAT Operation INPUT MONITORING The ADAT LX20 monitors the input signals through the A/D and D/A converters at all times. This lets you hear eactly what the audio will sound like when it’s played back from tape. However, there’s a minuscule delay as the digital audio passes through the converters’ buffers.
Applications - Chapter 11 Here are some possible solutions: • Use a phase switch on your mixer (if your mixing board provides this) to invert the phase of a “problem track” to compensate. • Wire your patchbay to reverse the input and output polarity of the LX20s in the system, but use standard cables on the ADATs in the system. This is recommended only for studios where master tapes will be exchanged between units or sent out of house.
Chapter 11 - Applications CHAPTER 1 1 A PPLICATIONS O VERVIEW This chapter describes some typical LX20 applications. These are overviews that do not include step-by-step instructions. Therefore, you may need to refer to other sections of this manual for details on how to set up the LX20 for a particular application. COMBINED M ULTITRACK/MIXDOWN D ECK The LX20 can serve as a combination 6-track multitrack recorder and 2-track mixdown deck.
Applications - Chapter 11 Example: Suppose a guitar lick is too loud in the mix. Rewind to before the offending lick, reduce only the guitar level at the mixer, then press Play. Punch in at the point where you want the lower guitar level. Punch out at the end of the loud guitar lick to return to the previous volume level. Note that unlike analog recording, there is no punch-out gap where silence occurs; punch-out is immediate.
Chapter 11 - Applications LIBRARIES AND ARCHIVES The LX20 is superb for archiving purposes, such as speeches and broadcasts, stereo mixes or libraries of stereo samples. The LX20 can record over eight hours of mono material by recording approx. 60 minutes on each track (using ST-180 tape). Over four hours of stereo mixes or samples can be recorded by mixing down to four sets of stereo pairs (1/2, 3/4, 5/6, and 7/8).
Applications - Chapter 11 Doing a premix of virtual tracks to two or more tape tracks can solve these and other problems. Many times this premix will have that kind of special energy that exists only during the early process of constructing a song, and will be preferable to a more laboriously-done premix during the final mixing stage. Besides, if you need to change the premix later, no problem: resync the sequencer to tape, and re-record the premix. There are other reasons to record virtual tracks.
Chapter 11 - Applications To set up a system for MMC control, first lock the sequencer to the LX20’s time code; the transport commands you issue from the sequencer act like a remote control. Here’s the basic hookup: • • • • Make sure your sequencer is receiving MTC from the LX20.
Applications - Chapter 11 TYPICAL APPLICATIONS Over 100 manufacturers support the ADAT Optical Interface. Compatible products include computer interfaces (such as the Alesis ADAT-PCR), signal processors, keyboards (Korg Trinity, Alesis QS Series), data translators, and more. (In fact, for digital audio transfer Silicon Graphics now includes the ADAT Optical Interface as an option for lower-end machines, and makes it a standard feature for higherend computers.
Chapter 11 - Applications A REAL -WORLD EXAMPLE Suppose you did a great tape on your ADAT at home, and now want to edit it in a hard disk recording setup at a commercial studio. You then want to transfer the hard disk material over to a different digital tape format, which happens to be the digital tape recorder used by a musical collaborator, who will then mix this down using a digital mixer while adding more tracks.
Applications - Chapter 11 PRE-MASTERING WITH THE LX20 Mastering has typically been the weak link in the project studio. Sure, you can mix down to DAT—but how about assembling those mixes into a smooth, wellintegrated recording? The following summarizes how to do pre-mastering with a DAT, hard disk editing program with digital audio interface capable of “talking to” the DAT, and an LX20. You shouldn’t have trouble modifying this procedure to fit your specific setup; it’s the principles that count.
Appendix A - Digital Recording Concepts APPENDIX A DIGITAL R ECORDING C ONCEPTS ANALOG RECORDING BASICS Digital recording works very differently from analog recording. With analog recording, tape containing millions of tiny magnetizable particles move past a record head. The magnetic field around this head fluctuates according to the audio signal present at the tape recorder’s input.
Digital Recording Concepts - Appendix A Analog Signal Digital Signal A/D These numbers, which represent coded audio, are then converted into an audio signal that can be recorded on tape. Fortunately, recording a number on tape doesn’t degrade the signal. During playback, a digital-to-analog (D/A) converter reads the numbers from tape and outputs a corresponding level. This creates a “stairstep” reconstruction of the original signal, which is close to (but not exactly) the same as the original signal.
Appendix A - Digital Recording Concepts W HY S-VHS? S-VHS recording technology offers more than enough bandwidth to record eight tracks of digital audio. S-VHS tapes are built to higher standards than standard VHS tapes, and can take the tape shuttling required by professional audio applications. S-VHS tape cassettes are also inexpensive compared to reel-to-reel tape, readily available, compact, and easy to transport and store.
Troubleshooting - Appendix B APPENDIX B T ROUBLESHOOTING RE-INITIALIZING: TRY THIS FIRST If your unit behaves erratically or “freezes,” do not assume you need to clean the heads or perform any type of servicing. This situation can sometimes occur due to line voltage spikes, temporary brownouts, and other problems related to AC power. To fix the problem: • Eject the Tape. • Power down the unit, then power it back up again. Many times this is all you need to do.
Appendix B - Troubleshooting TROUBLESHOOTING INDEX If you experience problems while operating the LX20, please use the following table to locate possible causes and solutions before contacting Alesis customer service for assistance. Symptom The display does not light when the POWER switch is turned on. FORMAT indicator flashes. The record-enabled tracks’ meters do not indicate input levels. Can’t change the sample rate/clock source. Pressing AUTO REC displays “invALid”. AUTO RETURN indicator flashes.
Troubleshooting - Appendix B ERROR RATE DISPLAY The TIME counter has a secondary mode which, when selected, will display only the minutes and seconds of the tape position, and the error rate while the transport is engaged in play or record. This error rate is viewed as a count of the number of sync block errors per 14 drum revolutions (every 280ms), up to a theoretical maximum of 6720 errors. Selecting this display mode during any other mode than play or record will always give a reading of “0000”.
Appendix B - Troubleshooting ADAT HEAD LIFE The expected head life for each ADAT varies according to a number of factors. Properly cared for, your heads should last for thousands of hours. If abused, they will wear out dramatically sooner. You should not subject your ADAT to environmental extremes, humidity or moisture of any kind, dust, dirt, extreme temperatures, extreme temperature fluctuations or any kind of physical abuse (drops, shocks).
Troubleshooting - Appendix B ADAT HEAD M AINTENANCE The heads of each ADAT are pre-aligned at Alesis. No user adjustment is necessary. Eventually, depending on the quality of the tapes used and the environmental conditions where the ADAT and its tapes are stored, head cleaning may become necessary. Unlike analog or even video tape recorders, the actual sound quality of an ADAT recording will not be affected until there is quite a bit of dirt on the drum and heads.
Appendix B - Troubleshooting TAPE CARE AND M AINTENANCE ADAT tapes are no different than any standard tape: they must be treated with care. Never expose ADAT tapes to temperature extremes, strong magnetic fields (such as speakers), high humidity, dust and so on. You should always practice SAFE TAPE: • At the end of every session, rewind the tape back to the leader. Stop, eject the tape, remove it from the ADAT, and place it in its protective case.
Troubleshooting - Appendix B M AINTENANCE/SERVICE CLEANING Disconnect the AC cord, then use a damp cloth to clean the LX-20’s metal and plastic surfaces. For heavy dirt, use a non-abrasive household cleaner such as Formula 409 or Fantastik. DO NOT SPRAY THE CLEANER DIRECTLY ONTO THE FRONT OF THE UNIT AS IT MAY DESTROY THE LUBRICANTS USED IN THE SWITCHES AND CONTROLS! Spray onto a cloth, then use the cloth to clean the unit. MAINTENANCE Here are some tips for preventive maintenance.
Appendix B - Troubleshooting OBTAINING REPAIR SERVICE Before contacting Alesis, check over all your connections, and make sure you’ve read the manual. Customers in the USA: If the problem persists, call Alesis USA at 1-800-5ALESIS and request the Product Support department. Please have your serial number (located on the back of the machine and starting with a “4D”) when you call.
Error Codes - Appendix C APPENDIX C ERROR CODES The following errors codes may appear from time to time in the TIME counter display. Use this reference to learn the possible cause of the error code before attempting to contact Alesis Product Support. dv Dew Sensor: The unit has been subjected to overly high humidity. Do not operate the unit. Turn on the power without installing a tape. This will allow the unit to warm up and disperse the moisture.
Appendix C - Error Codes Er 7 Clean Heads: If this error message is seen, it may indicate that the heads are in need of cleaning. See ADAT Head Maintenance for information about cleaning your heads. Er 8 Sync Lost: Error message 8 normally occurs when the tape reaches the end while formatting or recording. It is caused by the fact that the LX20 cannot read timing data from the leader. The error is caused by the unit losing sync. If the unit is being run in the slave mode check the sync cable connection.
Error Codes - Appendix C A UTOMATIC B RAKE CALIBRATION P ROCEDURE If the "CAL brAc" error message appears, the internal braking system of the LX20 may need to be adjusted. The intelligent transport software is capable of calibrating the LX20’s brakes automatically in a self-test procedure. You may perform this procedure as a regular maintenance procedure every 250 hours of head drum operation (to see the hours on your unit, hold SET LOCATE and press STOP).
Appendix C - Error Codes STEPS TO TAKE BEFORE CALLING FOR HELP If an error message is displayed or if an ADAT starts behaving strangely, it will be helpful if you can pinpoint the problem as precisely as possible. Before calling Alesis, please try the suggested tests below: ❿ ❡ ① ➃ ➄ Stop the tape playing (or recording). Does the error go away? Rewind the tape a minute or two. Press PLAY. Does the error recur? Eject the tape. Place it back in the LX20 and press PLAY.
Specifications SPECIFICATIONS Transport Recording Format: Tape Format: Heads: Approximate Recording Times: ST-60: ST-120/SE-180: ST-160/SE-240: ST-180/SE-260: Fast Wind Rate: ADAT Rotary head digital recording Type I (16-bit) and Type II (20-bit) S-VHS cartridge 4 (2 Read, 2 Write); Read before Write 22 minutes 40 minutes 54 minutes 62 minutes 40 x play speed (Threaded) Audio Number of Audio Channels: Audio Conversion: Record (A/D): Playback (D/A): Sample Rate: Vari Speed Range: Frequency Response: Dynam
Specifications Digital Inputs/Outputs Connectors: Communications Protocol: Two EIAJ fiber optical jacks (1 in, 1 out) 8-Channel Serial Communication Power Requirements: Power Consumption: Operating Temperature: Operating Humidity: 90V–250V AC, 50/60 Hz 40W 10–40° C for specified performance 80% maximum with no dew condensation for specified performance 5.25" x 19" x 8.5" (133.3 x 482 x 241mm) 16.5 lbs. (7.
Glossary G LOSSARY A A/D or Analog-to-Digital Converter The device that converts an analog audio signal to digital audio. Once encoded, all audio is stored or processed as a series of numbers rather than as the audio itself. AES/EBU Interface A two-channel, digital audio hardware/software standard.
Glossary called the Auto Return End point. The point that is returned to is called the Auto Return Start point.
Glossary B Balanced Audio Signals Signals that are carried on three-conductor cables, with two of the conductors carrying the same signal 180° out of phase and third as ground. Balanced connections usually cost more than unbalanced connections, but are less susceptible to picking up hum and interference with low-level signals. Bounce Bouncing means taking audio from one track and placing it on another.
Glossary D DAT Digital Audio Tape. This term has come to mean specific digital audio tape recorders that use cartridges smaller than those of a standard cassette, and which record two tracks of digital audio (and sometimes timecode). Digital I/O Input and output connections where signals passed from one stage to another remain in the digital domain. The XT20 has digital I/O connectors that carry digital data for all eight tracks.
Glossary L 94 ADAT LX20 Reference Manual
Glossary M MIDI Musical Instrument Digital Interface (MIDI). A protocol whereby various MIDIcompatible products can communicate various musical and non-musical messages (such as notes, controls, etc.). MMC MIDI Machine Control (MMC). A subset of MIDI messages which correspond to tape machine’s transport controls and other functions. Mute Used as a verb, to “mute a channel” means to turn off the audio for that channel. Used as a noun, “mutes” are the buttons which turn off a particular channel.
Glossary Q R Record-Ready A track mode, often called “armed.” When you want to record on a track, you “ready” or “arm” the track. When you push the record button, all tracks that are ready or armed will go into record mode. Rotary Head A type of tape head, as used in the XT20, that spins at a high rate of speed in order to create the same effect as having the tape moving by at rates not physically possible with today’s tapes and transports. S Safe A track mode.
Glossary Similar to the AES/EBU interface, but created by Sony and Philips with consumer applications in mind. The optional AI-1 from Alesis offers both the consumer S/PDIF interface and professional AES/EBU format for use with the XT20. S-VHS Acronym for Super Video Home System, an improved version of VHS with greater resolution and dubbing capabilities, as well as improved sound. T Track An area of tape on which audio is recorded. A track can be thought of as a picture of an output over time.
