Table of Contents

TABLE OF CONTENTS
Important Safety Instructions and Compliance Notices..v Safety symbols used in this product.... v Please follow these precautions when using this product:.. v Instructions de Scurit Importantes....vii Symboles utiliss dans ce produit....vii Beim Benutzen dieses Produktes beachten Sie bitte die folgenden Sicherheitshinweise:.viii Information to the User for Class A Digital Device (FCC Part 15, Class A).. ix Notices Regarding Laser Devices..... ix CE Declaration of Conformity.... x Introduction And Setup... 1 1.1 MasterLink Highlights.... 1 1.2 Unpacking and Inspection.... 1 1.3 AC Power Hookup..... 2 1.4 Line Conditioners and Protectors... 2 1.5 About Audio Cables..... 3 Once Around the ML-9600.... 5 2.1 The Front Panel.... 5 2.2 The Rear Panel..... 5 2.3 The Front Panel Display.... 6 HD Mode Operation.... 7 3.1 HD or CD Mode?..... 7 3.2 HD Recording Settings.... 7 3.2a Input Source.... 7 3.2b Sample Rate..... 8 3.2c Word Length.... 8 Working With Playlists....9 4.1 Selecting a Playlist.... 9 4.2 Naming a Playlist..... 9 4.3 Auditioning a Playlist.... 10 4.4 Editing A Playlist.... 10 4.4a Empty Playlists.... 10 4.4b Recording a Track.... 11 4.4c The Display.... 11 4.5 Playlist Edit Mode Pages.... 12 4.5a Track Start Time.... 12 4.5b Track End Time.... 13 4.5c Track Length..... 13 4.5d Track Fades.... 14 4.5e Track Level Adjustment.... 15 4.6 Additional Playlist Edit Functions.... 16 4.6a Editing Track Names.... 16 4.6b Adding Additional Tracks.... 16 4.6c Deleting Tracks.... 16 4.6d Changing Track Order.... 17 4.7 Tracks vs. Audio Files.... 17 4.7a Audio File Names.... 18 4.7b Inserting Audio Files Into Playlists... 18 4.7c Deleting Audio Files.... 19 4.7d Audio File Parameters vs. Track Parameters... 20 4.8 Editing a Track..... 20 4.8a Track Crop Feature.... 20 4.8b Track Start/Track End... 20 4.8c Scrubbing the Head and Tail.... 21 4.8d The Crop..... 21
ALESIS ML-9600 REFERENCE MANUAL
Table Of Contents Digital Signal Processing.... 23 5.1 Overview.....23 5.2 Signal Flow.....24 5.3 Applying DSP To A Track....25 5.4 DSP Block Detail.....25 5.4a DSP1:Compressor....25 5.4b DSP2:Parametric EQ....27 5.4c DSP3:Look-Ahead Peak Limiter....28 5.4d DSP4:Normalizer....29 Creating A CD.... 31 6.1 CD Recording Settings.....31 6.1a Advantages of CD24....31 6.2 Creating a CD.....31 6.3 The Recording Process.....32 6.3a Rendering.....32 6.3b Initializing....33 6.3c Recording.....33 6.3d Finalizing.....35 6.4 CD24 Disc Specifics.....35 CD Mode Operation.... 37 7.1 CD Playback.....37 7.1a Playing a Red Book CD....37 7.1b Playing a CD24 CD....37 7.2 Copying tracks from CD to Hard Drive....37 Utility Functions.... 39 8.1 Util1: MeterMode....39 8.2 Util2: File Sort.....39 8.3 Util3: HD Format.....40 8.4 Util4: Software Version....40 Specifications.... 41 ADC......41 DAC......41 Sample Rates Supported....41 Word Lengths Supported....41 Analog I/O.....41 Digital I/O.....41 Unit Dimensions.....41

Saftey Notices

IMPORTANT SAFETY INSTRUCTIONS AND COMPLIANCE NOTICES
SAFETY SYMBOLS USED IN THIS PRODUCT
This symbol alerts the user that there are important operating and maintenance instructions in the literature accompanying this unit.
This symbol warns the user of uninsulated voltage within the unit that can cause dangerous electric shocks.
PLEASE FOLLOW THESE PRECAUTIONS WHEN USING THIS PRODUCT:

Read these instructions.

2. Keep these instructions. 3. Heed all warnings. 4. Follow all instructions. 5. Do not use this apparatus near water. 6. Clean only with a damp cloth. Do not spray any liquid cleaner onto the faceplate, as this may damage the front panel controls or cause a dangerous condition. 7. Do not block any of the ventilation openings. Install in accordance with the manufacturer's instructions. 8. Do not install near any heat sources such as radiators, heat registers, stoves, or other apparatus (including amplifiers) that produce heat. (more on next page)

Saftey Notice

9. Do not defeat the safety purpose of the polarized or grounding-type plug. A polarized plug has two blades with one wider than the other. A grounding-type plug has two blades and a third grounding prong. The wide blade or the third prong are provided for your safety. When the provided plug does not fit into your outlet, consult an electrician for replacement of the obsolete outlet.

3.2B SAMPLE RATE

Four sample rates are available: 44.1kHz, 48kHz, 88.2kHz, and 96kHz. Pressing the SAMPLE RATE button on the front panel will toggle between these four rates. Sample rates are not user adjustable when in digital input mode; the sample rate will automatically be set to the rate of the incoming digital data.

3.2C WORD LENGTH

Three word lengths are available: 16-bit, 20-bit, and 24-bit. Pressing the WORD LENGTH button on the front panel will toggle between these three word lengths. Word lengths are userselectable when in digital input mode; note that it is therefore possible to select a shorter word length than is being received at the digital input, resulting in truncated data.

Chapter 4

WORKING WITH PLAYLISTS
When you are in "HD" mode, you will be working with Playlists. Playlists are the basic structures in which Tracks are organized before creating CDs, and are therefore one of the most crucial parts of the operation of the ML-9600 to understand. Playlists are simple in concept they are lists of the songs that you want to have on your CD. Within a playlist, you choose the order in which you want your songs to appear on the final CD, the amount of time between songs, the relative volume of the songs, and the type of signal processing applied to each song. You can think of a selected playlist as a "virtual CD"; that is, in playlist select mode the playlist should act as a compact disc would, except that its data is coming off of the internal hard disk.

4.1 SELECTING A PLAYLIST

The ML-9600 has sixteen independent playlists, each containing up to 99 Tracks. There is an additional "special" playlist located after Playlist 16 that is reserved for rendered CD images; see Chapter 6: Creating A CD for more information about this special playlist. To select a playlist, press the PLAYLIST SELECT button on the front panel underneath the main display. The words Playlist XX will be displayed on the first line of the display, where "XX" will be a number between 01 and 16. The cursor will be under the XX, and pressing the UP/YES button will increment through the playlists, while pressing DOWN/NO will decrement through the playlists. Figure 4.1.1 shows a sample playlist select display.
Figure 4.1.1 Sample Playlist Select Display This particular playlist is named "PList 01" (the default playlist name for Playlist 1), and has only one Track in it, indicated by the "01 Tks" in the lower right hand side of the display.

4.2 NAMING A PLAYLIST

Once a playlist has been selected, you may wish to change its name. Pressing CURSOR RIGHT will move the cursor to the first character of the name of the playlist. Once the cursor is in the name field, pressing UP/YES or DOWN/NO will scroll though a set of alphanumeric characters for each of the eight characters of the playlists name. Exit the name field by pressing CURSOR LEFT until the cursor is once again under the playlist number.

4.5D TRACK FADES

The ML-9600 gives the user the ability to easily create fade-ins and fade-outs on Tracks. Both functions are accessed by moving the cursor to the Playlist Edit Page Field and pressing the UP/YES or DOWN/NO buttons until the characters "FdIn" or "Fout" are displayed. Figures 4.5.4 and 4.5.5 illustrate how the display will look when indicating Track fades.
Figure 4.5.4 Track Fade-In Display.
Figure 4.5.5 Track Fade-Out Display. The "FdIn" or "FOut" in the display indicates that you are on either the Track fade-in or Track fade-out page. To the right of "FdIn" or "FOut" is a number that indicates the length of the fade, adjustable in 10mS increments. Moving the cursor under the "ones" place and pressing the UP/YES or DOWN/NO will increment the value in 1 second increments, while moving the cursor under the "hundredths" place and pressing the UP/YES or DOWN/NO will increment the value in 10 millisecond increments. TIP: Pressing UP/YES and DOWN/NO simultaneously while in the fade length field will reset the fade length to zero seconds. A fade's maximum time is limited to the length of the Track, or to 99.99 seconds, whichever is smaller. If both fade-in and fade are used on the same Track, the total fade time (fade-in + fade- out) can not exceed the length of the Track. If, for instance, you have a Track that is 2 minutes long (120 seconds) and you have entered a fade-out time of 30 seconds, you can not set your fade in time to any greater than 90 seconds. To the right of the fade length value is the fade shape indicator. Changing this parameter will affect the way that the fade sounds as it is being performed. This value can be changed between LIN(linear fade), LG1(Normal Log), and LG2(inverse log). Figure 4.5.6 illustrates the fade shapes.
Figure 4.5.6 Fade Shapes Performing a fade-in or fade-out on a Track is as simple as deciding on a length and shape for the fade. For example, If Track 1 ends at 0:02:00.00 and you select a 10 second LINear fade-out, Track 1 will begin to fade out at 0:01:50.00 and continue to fade linearly until 0:02:00.00, at which point it will be completely faded out.

4.5E TRACK LEVEL ADJUSTMENT
In Playlist Edit mode, it is possible to change the gain of a Track once it has been recorded to the hard disk. Gain adjustments are non-destructive edits and can be changed at any time. To adjust the gain on a pre-recorded Track, press PLAYLIST SELECT to choose the SKIP and appropriate playlist, then press PLAYLIST EDIT to edit the playlist. Press to choose the Track whose gain you wish to adjust. Move the cursor to the gain SKIP field, and press UP/YES or DOWN/NO to increment or decrement the gain of the Track. Pressing DOWN/NO when the gain setting is already at 0.0dB will begin to attenuate the Track, and a minus sign will be displayed before the gain digits. Track gain is adjustable in 0.1dB increments from 9.9dB to +9.9dB, after which it is adjustable in 1dB increments to +/18dB. TIP: Pressing UP/YES and DOWN/NO simultaneously while in the Track gain field will reset the Track gain to 0dB.
4.6 ADDITIONAL PLAYLIST EDIT FUNCTIONS

4.6A EDITING TRACK NAMES

Editing a Tracks name is similar to editing a Playlists name; move the cursor to the Track Name field and use the UP/YES and DOWN/NO keys to scroll through the alphanumeric character set for each of the Track names eight characters. The character set includes A-Z, a-z, 0-9, and <space>. TIP: Pressing UP/YES and DOWN/NO simultaneously while in the Track name field will cause the currently edited character to become a <space>. NOTE: When creating a CD24 disc, any lower-case letters will be automatically changed to upper-case on the CD. This is due to a limitation of the ISO-9660 specification that the discs adhere to. Similarly, spaces in names are automatically converted to underscores. For more information on CD24, see Chapter 6: Creating A CD.
4.6B ADDING ADDITIONAL TRACKS
Additional Tracks can be added to the playlist by pressing the NEW TRACK button. Figure 4.6.1 shows the New Track display.
Figure 4.6.1 New Track Display. As you can see, this display is exactly like the display shown when editing a new playlist; only the default name of the Track and the Track Number have been changed. Each time a new Track is created, the default name will be Song XX, where XX indicates the number of the Track in the playlist.

4.6C DELETING TRACKS

To delete a Track from a playlist, you must currently have that Track selected in the display. Pressing the DEL TRACK button will cause a confirm delete page to be displayed, as shown in Figure 4.6.2:

Figure 4.6.2 Delete Track Confirmation where "Song 01" is the name of the Track to be deleted. Pressing UP/YES will remove that Track from the playlist, moving the next Track in the playlist in its place. Pressing DOWN/NO will cancel the operation and return the unit to its previous state. NOTE: Deleting a Track from a playlist does not delete the audio samples from the hard disk. The audio remains on the disk in an "Audio File"; see section 4.7 for more details. 16 ALESIS ML-9600 REFERENCE MANUAL
4.6D CHANGING TRACK ORDER
Once multiple Tracks have been recorded into a playlist, it may be desirable to re-order the Tracks. This is accomplished very easily by the use of the TRACK MOVE button. First, use the SKIP buttons to select the Track you want to move. Pressing TRACK MOVE will bring up the Track Move display, as illustrated in Figure 4.6.3.
Figure 4.6.3 Track Move Display In this display, the second line of the 2X16 display changes to show "Move (source track) > (destination track)". The cursor will be under the destination Track, and the source Track will be the number of the Track you have currently selected. Pressing the UP/YES and DOWN/NO keys will scroll through the possible destination Track numbers. Once the destination Track number has been selected, pressing TRACK MOVE again will cause the display to prompt "Are You Sure?". Pressing UP/YES will complete the move, while pressing DOWN/NO will cancel the operation and return the unit to its previous state.
4.7 TRACKS VS. AUDIO FILES
The ML-9600 organizes audio data into two types: Tracks and Audio Files. An Audio File is audio that has been recorded to the hard disk; it is stored as a unique "file" on the disk. A Track is a "placeholder" in a playlist that "points" to an audio file. All Tracks have corresponding Audio Files. All Audio Files do not necessarily have corresponding Tracks; it is possible to have an Audio file on the hard disk but not have its audio incorporated by a Track in a playlist. All audio recorded to the hard disk is initially recorded as a new Track in a playlist, but may later be removed from the playlist and may only exist as a Audio File on the hard disk. Audio Files are listed at the "bottom" of every playlist, and are visually distinguished from Tracks by the lack of a Track number, and by the words "audio file" in the second line of the alphanumeric display. Audio Files do not have playlist Start or End times associated with them. Audio Files can only be accessed from within Playlist Edit mode. Audio Files are viewed by button until the last Track in a playlist is reached. One more press of pressing the SKIP button will show the first Audio File, as illustrated in Figure 4.7.1. the SKIP

Figure 4.7.1 Audio File Display
Chapter 4 The display shows the name of the Audio File and its length (in minutes and seconds) on the first line of the 2X16 alphanumeric display. The words "(audio file)" and the write protect status are indicated on the second line of the alphanumeric display. The only editable parameters in this page are the Audio File name and the Audio File write protect status. The cursor defaults to the first character of the name when this page is selected, and using the UP/YES, DOWN/NO, CURSOR LEFT and CURSOR RIGHT keys you can change the name of the Audio file, limited to 8 characters. Moving the cursor under the "U" character and pressing UP/YES and DOWN/NO will change the "write protect" status of the Audio File; U stands for Unprotected, and P stands for Protected. When an Audio File is write protected it may neither be recorded over nor cropped. Changing this parameter in an Audio File will automatically update all Tracks that point to it.

4.7A AUDIO FILE NAMES

Track names are saved with the Audio File; you cannot have two Tracks with two different names that point to the same Audio File. In addition, if you edit the name of a Track in one playlist, any other instances of that Track in other playlists as well as the Audio File associated with that Track will have their names changed to reflect the edit.
4.7B INSERTING AUDIO FILES INTO PLAYLISTS
Audio Files can be inserted into playlists using the TRACK MOVE button. First select the playlist in which you want to insert the Audio File. Next, choose the Audio File you wish to move into the playlist, and press TRACK MOVE. Figure 4.7.2 shows the Audio File move screen.
Figure 4.7.2 Audio File Move Screen Choose the destination Track and press TRACK MOVE causing the display to prompt "Are You Sure?". Pressing UP/YES will complete the move, any other key will cancel the move.
4.7C DELETING AUDIO FILES
To delete an Audio File from the hard drive, you must currently have that Audio File selected until you are past the last Track in the playlist). Pressing the in the display (press SKIP DELETE TRACK button will force the unit to check all 16 playlists for instances of the current Audio File. If the Audio File is used in any playlist, this error will be displayed temporarily:
Figure 4.7.3 Audio File In Use Warning where, in this case, Playlist 01 is the first playlist to include the current Audio File. In order to permanently delete an Audio file from the hard disk, there must be no playlists in which the Audio File is used. If there are no playlists using the current Audio File, this warning will be displayed:
Figure 4.7.4 Delete Audio File Confirmation where Song 01 is the name of the Audio File to be deleted. Pressing DOWN/NO will cancel the operation and return the unit to its previous state. Pressing UP/YES will cause a confirm delete page to be displayed, as shown in Figure 4.7.5:

Pressing TRACK START or TRACK END once will "pre-roll" the start or end of the selected Track. When you press and release TRACK START, the Track will play from its beginning and will play for five seconds, while pressing and releasing TRACK END will begin playing five seconds before the end of the Track and will stop once the end of the Track is reached. The reason this functionality is important is that you will be changing the "start pointer" and "end pointer" of your song, and will want to preview those points before you crop.
4.8C SCRUBBING THE HEAD AND TAIL
In order to move the "start pointer" and "end pointer", you must press and hold TRACK SCAN and SCAN buttons to "scrub" the audio START or TRACK END and use the back and forth. This process is much like "rocking the reels" on an analog tape machine; the SCAN and SCAN buttons, difference here is that you are doing it digitally. Using the SCAN or move the "start pointer" or "end pointer" to the desired location, then release SCAN. Once you think you have the pointers in the correct position, you may preview the points by pressing the TRACK START and TRACK END buttons (explained above).

4.8D THE CROP

NOTE: If the Track is write protected, cropping of the Track is not permitted. When the start and end pointers have been set to your satisfaction, press both TRACK START and TRACK END simultaneously to crop the Track. The display will prompt you with the message:
Figure 4.8.1 Track Crop Confirmation Pressing DOWN/NO will exit, display "Track crop canceled", and return to the Track edit display; note that the start and end pointers will still be at their new positions. Pressing UP/YES will complete the Track crop operation. The display will temporarily indicate:
Figure 4.8.3 Track Crop Complete Screen and will then return to the Track edit display.

Chapter 5

DIGITAL SIGNAL PROCESSING

5.1 OVERVIEW

The ML-9600 has a very powerful built-in Digital Signal Processor that can, if desired, make changes to your music after it has been recorded. These changes are usually made to balance the frequency content (Equalization) of a song, or to "smooth out" very dynamic music (Compression and Peak Limiting), or to maximize the signal so that it uses up all of the dynamic range available (Normalizing). The ML-9600 can perform any or all of these signal processing functions to your music. The TRACK DSP button allows you to choose different processing algorithms for your music. Pressing the TRACK DSP button cycles through the four algorithms listed below: Screen Name DSP1: Cmpress DSP2:EQ DSP3: Limiter DSP4: Normliz DSP Function Compressor Parametric Equalizer Look-ahead Peak Limiter Normalizer Comments Single-band, threshold, ratio, makeup gain, attack, release, key select, soft/hard knee, RMS or peak detect 3-band, fully parametric EQ. +/-18dB boost/cut, 2020KHz frequency range, adjustable Q, high/low shelving Output level, Limit threshold, release. Current gain multiplier Table 5.1.1 DSP Overview Table All DSP in the ML-9600 is applied in real-time, allowing you to make changes to the DSP without affecting the original audio recorded to disk. DSP is applied when either a Red Book or CD24 CD is created, so the resulting tracks on the CDs will have DSP permanently applied; however, this will not change the Audio Files on the hard disk. DSP is applied on a Track-by-Track basis. This means that you can have Tracks that point to the same Audio File in multiple playlists (or multiple Tracks in the same playlist) and apply different DSP to each Track. For instance, if you wanted to create a CD containing the same song with three different types of equalization, you could accomplish that by creating three Tracks that pointed to the same Audio File (by using Audio File move) and EQ them differently.

5.4 DSP BLOCK DETAIL

5.4A DSP1:COMPRESSOR
The Compressor in the ML-9600 is a "single-band" compressor, meaning that all frequencies of the audio are processed with the same parameters. This is in contrast to a "multi-band" compressor, which processes different frequency bands with different parameters. A detailed look at each of the parameters is presented below. Threshold The threshold control of the compressor determines at what level (relative to full-scale or 0dBFS) the compressor begins to affect the audio. Any audio that falls below the threshold is not compressed; any audio whose level exceeds the threshold is compressed according to the compressor's other parameters. The ML-9600 has a threshold range of 0dBFS to 65dBFS, adjustable in 0.5dB increments. Ratio The ratio parameter determines the ratio of input level to output level of the compressed audio. If the ratio is set to 20:1, a 20dB increase in input level to the compressor will result in only a 1dB increase in output level. Typically, ratios under 10:1 are considered "compression" style ratios, while ratios over 10:1 are considered "limiter" style thresholds. The ML-9600 has a ratio range of 1.000:1 to 20.00:1. Make-up Gain
Chapter 5 Make-up gain is applied after the compressor to "make up" the level lost during the compression process. The ML-9600 has a make-up gain range of 0.0dB to +65.0dB, adjustable in 0.5dB increments. Attack The attack time of the compressor determines how long the compressor takes to begin to take effect after audio rises above the threshold. Longer attack times allow for more of the audio's natural attack envelope to be heard, and shorter attack times impose more of the compressor's characteristics on the audio's attack envelope. The ML-9600 has an attack range of 0 microseconds to 9.9 seconds. Release The release time of the compressor determines how long the compressor takes to stop compressing the audio after it has dropped below the threshold. Shorter release times cause the compressor to try to follow the audio envelope closely, sometimes causing a "pumping" or "breathing" effect. Longer release times tend to smooth out the compression effect. The ML9600 has a release range of 0 microseconds to 9.9 seconds. Key The key parameter controls what channel the compressor is using to control the compression effect. Usually, for stereo music, this is a summation of both channels, but can be either left only or right only. Knee The knee setting changes the way that the compression effect behaves around the threshold. A "hard" knee begins to apply gain reduction (according to the ratio amount) at exactly the threshold value. A "soft" knee begins to apply gain reduction before the threshold, but at a very slight ratio value. As the input level increases, the ratio gets larger until, at some level above the threshold, the applied ratio is equal to the ratio parameter. The ML-9600 has 5 different knee choices: Hard, Soft1, Soft2, Soft3 and Soft4. These knees are shown in Figure 5.4.1.

5.4C DSP3:LOOK-AHEAD PEAK LIMITER
The Look-Ahead Peak Limiter is designed to give you the ability to limit the highest peaks in a Track and simultaneously bring up the gain of the Track in order to maximize its level before creating a CD. This allows you to "squeeze" that extra couple of decibels out of the dynamic range, without squashing your audio by hard compression or traditional limiting. The limiter in the ML-9600 is very different than a traditional limiter, which is typically thought of as a compressor with a high ratio setting. By virtue of all-digital processing, the limiter is able to "look ahead" in time to see audio level peaks. This allows the limiter to begin smoothly reducing the gain of the audio so that when the peak does occur, it is limited to the desired value. In essence, the limiter becomes a "perfect" limiter or one capable of attaining an infinity-to-one gain reduction ratio. Another difference from a traditional limiter is that the "make-up" gain is automatically applied as a function of the threshold level. This allows the limiter to act as a "maximizer", enabling you to bring your Tracks very close to the maximum level allowed without clipping. The final difference in this limiter is that the final output level can be fixed as a function of full-scale; i.e. the limiter has infinity-to-one compression ratio with an extra gain stage at its output. This allows you to decide what the peak output value of the audio will be (-0.2dBFS, for instance). The Look-ahead peak limiter is perhaps best thought of as three discrete gain blocks: The first gain block is dynamically adjusted so that its output level never exceeds the threshold level (the "perfect" limiter). The second gain block adds make-up gain to the signal equal and opposite to the threshold value (a threshold value of 10dBFS would have 10dB of make-up gain applied). The third gain block is a "scaling" gain block; it allows you to select the exact maximum output level (as a function of full-scale). If this gain block were not there, the automatic make-up gain would cause all signals that reached the threshold to equal 0dBFS. There are only three parameters in the limiter DSP block, so it is extremely easy to set up and use. A detailed look at each of the parameters follows. Threshold The Threshold parameter of the limiter sets the maximum output level from the first gain stage. No gain reduction is applied as the signal level approaches the threshold, but once it does, the limiter holds the output of that stage to the threshold value. Make-up gain is applied to the audio after it has been limited to the threshold value, so if audio is playing while the threshold parameter is adjusted downward, the output audio will appear to get louder. The threshold parameter is adjustable from 0dBFS to 65dBFS in 0.5dB increments. Output Level The Output Level parameter sets the absolute maximum output level from the limiter, as a function of full-scale. A value of 0.25dB will limit the output audio to no greater than 0.25dBFS, regardless of input level or threshold setting. The output level parameter is adjustable from 0dBFS to 65dBFS in 0.25dB increments. Release The release parameter functions exactly like its counterpart in the compressor; it controls how long gain reduction is applied to the audio after the input signal drops below the threshold. Release is adjustable from 0 microseconds to 9.9 seconds.

5.4D DSP4:NORMALIZER

A Normalizer's function is to scan a Track for the highest peak value, determine the ratio between that peak value and full-scale, and multiply the Track by that ratio so that the highest peak value of the Track is equal to full-scale. The major improvement in this normalizer over others is that the gain multiplication is performed in real time, instead of rendering the normalized file back to disk. This allows renormalizing if changes to the Track Gain, Compression, EQ, Limiting and Track Fade blocks occur after the first pass of normalization. The normalizer does not have any parameters per se, other than the current gain multiplier (which is not user set, but is determined from the Track). In order to normalize a Track, move the cursor under the "Current" field, and press the UP/YES button. The screen will prompt "Calc Track? Y/N", and if you press the UP/YES button again, the normalizer will scan through the Track, find the appropriate gain multiplier, and set the current multiply value accordingly. The normalizer will also turn its On/Off parameter to On, if it was not on previously. In order to disable the normalization, move the cursor to the On/Off field and press the DOWN/NO button to turn the normalizer off.

Chapter 6

CREATING A CD
6.1 CD RECORDING SETTINGS
Once a playlist has been assembled, creating a Compact Disc is a very simple operation. The first step in the process is deciding on which format of disc to create. There are two types of Compact Discs that the ML-9600 can create: Red Book CDs and CD24 CDs. Red Book CDs (or CD-DA discs, as they are sometimes referred to) are audio Compact Discs that conform to the Sony/Philips Red Book specification. Almost all commercial audio Compact Discs available today are "Red Book" CDs, and every standard Compact Disc player in the world will play Red Book-compliant CDs. Red Book CDs have a sample rate of 44.1kHz, and word lengths of 16-bits. In order for the ML-9600 to create a Red Book-compliant CD, the CD FORMAT switch (under the CD tray door) must be set to Red Book. Because Red Book CDs are limited to 16-bit, 44.1kHz recording, and the ML-9600 allows up to 24-bit, 96kHz recording to the hard disk, Tracks with sample rates higher than 44.1kHz or word lengths longer than 16-bits will be automatically sample-rate converted and/or noiseshaped down to 16-bit, 44.1kHz files when the CD is created. This will not affect data on the hard disk, which will remain unchanged at its original sample rate and word length. CD24 CDs are special Compact Discs capable of containing and playing back audio files that have resolutions greater than 16-bit, 44.1kHz. Alesis has combined two non-proprietary standards ISO-9660 CD-ROM disc format with AIFF sound files with proprietary information to create the CD24 standard. CD24 discs can be read by Windows, Macintosh, and UNIX operating systems, and AIFF (Audio Interchange File Format) files are recognizable by nearly every audio editing program available on either platform. In addition, the ML-9600 will recognize CD24 discs and play them as if they were standard CDs, but at the audio files' original sample rate and word length.

6.1A ADVANTAGES OF CD24

Allows low-cost, random access storage, playback, and delivery of high-resolution audio files. Allows inexpensive backup of audio recorded to the internal hard disk. Allows easy transfer of files to computer-based editing and mastering systems
In order for the ML-9600 to create a CD24 Compact Disc, the CD FORMAT switch (under the CD tray door) must be set to CD24.

6.2 CREATING A CD

Once a playlist has been recorded and edited, creating a CD is a simple task. First, make sure that you are in HD mode (using the HD/CD LEDs), and make sure the playlist you have currently selected is the one from which you wish to create a CD. This can be checked by pressing the PLAYLIST SELECT button and observing the playlist number and/or the playlist name. The next step to creating your CD is to choose which type of CD you wish to create; either Red Book or CD24. This can be changed by pressing the CD FORMAT button.
Chapter 6 Third, press the CREATE CD button. Several things happen at this time; the MasterLink checks the playlist to insure that all Tracks are greater than 5 seconds in length (a Red Book limitation), and that there are no "empty" Tracks (achieved by creating a new Track and not recording audio into that Track). Depending on the type of CD you have chosen to create, the display will then prompt with a "confirmation" page, shown in Figure 6.2.1 for a Red Book creation.
Figure 6.2.1 Create CD Confirmation Pressing DOWN/NO while this screen is displayed will cancel the operation and return you to the previous mode of operation. Pressing UP/YES while this screen is displayed will begin the CD creation process. If there is no blank CD in the drive, the CD tray will eject and the display will prompt you to insert a blank CD, as in Figure 6.2.2.
Figure 6.2.2 Insert Blank CD-R Screen Once a blank CD is inserted into the drive and the tray is closed, the unit will scan the disc to verify that a recordable disc is present. Once the disc has been verified as a recordable CD-R and its length has been determined, the MasterLink will verify that the playlist will fit on the CD-R that you have inserted. If the playlist is too large to fit on the CD, the display will prompt with a "Playlist too large" message and abort the CD creation process. If the playlist checks out, the recording process will begin.
6.3 THE RECORDING PROCESS
There are three stages of the CD recording process, which apply both to Red Book and CD24 creation: initialization, recording, and finalizing. An additional "rendering" stage may apply to Red Book CD creation.

6.3A RENDERING

When a playlist has Tracks in it that require DSP during Red Book CD creation, it is first necessary to "render" the playlist to the hard disk. This means that the DSP is applied and the audio is re-recorded to a special area on the disk set aside for this process. This DSP can include any or all of the user-adjustable DSP (fades, EQ, limiting, compression, etc.) or sample rate conversion/noise shaping that automatically occurs when a Red Book CD is created from a playlist that has Tracks at other than 44.1kHz/16-bit resolution. The amount of DSP applied dictates how quickly a Track can be rendered; with the maximum amount of DSP applied, Tracks are rendered in near real-time. 32 ALESIS ML-9600 REFERENCE MANUAL

16-, 20-, and 24-bit

ANALOG I/O

44.1kHz/48kHz Sampling Frequencies: Frequency Response: 20Hz 20kHz +0dB, -0.3dB THD+N : <0.002% @1kHz, -1dBFS Signal-to-Noise Ratio: 113dB, A-weighted 88.2kHz/96kHz Sampling Frequencies: Frequency Response: 20Hz 40kHz +0dB, -0.5dB THD+N : <0.002% @1kHz, -1dBFS Signal-to-Noise Ratio: 113dB, A-weighted

DIGITAL I/O

Supported protocols: IEC 958 Type I, Balanced (AES/EBU) and Coaxial

UNIT DIMENSIONS

Height Width: Depth Weight: 3.5"/2U 88mm 17" 432mm 11" 279mm 13.55 lb. 6.2 kg

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Product Review

Alesis ML-9600 Mastering Recorder
Reviewed by Charles Hansen
Alesis, 12555 Jefferson Boulevard, Suite 285, Los Angeles, CA 90066; www. alesis.com (see web site for dealer network map), E-mail info@alesis.com, (310) 821-5000, Fax (310) 306-2650, price $1000, dimensions (WHD): 19 3.(483mm 88mm 279mm), weight: 16.55 lb (6.2kg), warranty: 1 year, parts and labor. The Alesis MasterLink ML-9600 is a high-resolution two-track hard disk mixing and mastering recorder. It can record from analog, or AES/EBU (XLR) and S/PDIF (coax) digital inputs, or from its internal optical drive, all to its internal hard drive. Data sample rates available are 44.1kHz, 48kHz, 88.2kHz, and 96kHz, with word lengths of 16, 20, or 24 bits. From the audio files stored on the hard drive, you can burn CDs using standard Red Book (16-bit/44.1kHz), or high-resolution CD24 formats up to 24-bit, 96kHz. You can choose any combination of digital resolutions (16-, 20-, and 24-bit) and sample rates (44.1, 48, 88.2, and 96kHz) with full Audio Interchange File Format (AIFF) compatibility. You can assign audio files to any of 16 playlists, which can each store up to 99 tracks. You can store any mix of sample rate and word length files in a playlist. Once on the hard drive, you can edit your recording and apply finishing toolssuch as high-resolution parametric EQ compression, limiting, and normalizing using the onboard digital signal processing (DSP). You have total control of fade-ins, fade-outs, track gain, start points, track cropping, and track split and join. Then you can burn the finished recording to standard data CD-R in either industry-standard Red Book or the high-resolution CD24 format. CD24 is accepted by many DVD-Audio mastering facilities. You can also load either Red Book CDs or CD24 files onto the
PHOTO 1: ML-9600 front view.
PHOTO 2: ML-9600 rear view.
hard drive from the CD-RW drive. The operating software is stored in flash RAM. You can download software upgrades via Internet, burn them to a CD-R on your computer, and load the new software via the ML-9600 CDRW drive. However, a new software installation will reformat your hard drive, so you should back up all your playlists and audio files. This particular unit had software version 1.24. The latest version is 1.25, which adds support for another Sony CD-RW drive and support for hard drives larger than 30GB, even though the ML-9600 will not recognize more than 30GB at this time. The 49-page reference manual is thorough and well written, with individual chapters covering playlists, DSP, the recording process, and CD player mode.

INSIDE THE ML-9600

The ML-9600 is constructed of heavy gauge steel, with provisions for rack mounting. The rack ears are furwww.audioXpress.com
nished with the unit and fasten to each side with three screws. Various areas of the chassis have vents to enhance cooling. Four large rubber feet support the chassis. Photo 1 shows the front panel. The CD-RW drive tray is at the top left. Just below it are the remote control IR receiver window and the power switch. Next come the CD format button (High Definition or CD) and the group of record mode buttons that select sample rate, input source, and word length. The Create CD button is just to the right of the record mode group. The vacuum fluorescent digital display is to the right of the CD-RW tray. Four cursor buttons are located below it in an oval grouping. To the right of the cursor buttons are the five Playlist select, Track, and DSP buttons. Just below are another group of five Playlist Edit buttons and the Utility button. The latter controls meter mode, loop mode, playlist backup and restore, Red Book start and end time offsets, file sorting,

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hard drive format, and allows you to access system information (software versions and drive information). The hard disk transport controls are arranged in a stack at the right of the display. Play/Pause are incorporated in one switch, and the Record button is to its right. The final front panel controls are the HD/CD mode button, and a headphone volume control and stereo phone jack. The ML-9600 acts as a conventional CD player in CD mode. The display format changes and the recording functions are locked out. In HD mode, the recording functions are enabled. The rear panel (Photo 2) has an IEC power receptacle on the right. The third pin of the AC receptacle is connected to the chassis. Both balanced XLR and unbalanced phono jacks are provided on the right side of the rear panel. They are grouped as analog inputs, analog outputs, and digital inputs and outputs. Photo 3 shows the ML-9600 from the front with the cover removed. This particular unit has a Sony ATAPI CD-RW optical drive, and a Maxtor IDE 20GB hard drive that allows storage of up to 30 hours of CD Red Book audio. In the 24/96k high-resolution format, you can store up to 9.4 hours of CD24 format audio on the hard drive. The display and user interface board occupies the entire length of the front of the unit, incorporating a cutout for the CD-RW optical drive. The hard disk drive is located below the CD-RW. The ML-9600 uses a computer-like switching power supply, located on the left rear of the chassis. The CD-RW and hard drive receive the usual +5V and +12V power. The long PC board at the rear of the chassis handles audio processing, connecting to the two drives with the usual IDE ribbon connectors. The XLRs are mounted on a smaller board that connects to the main board via pin and socket connectors.
sion, is handled by eight NE5532 dual low-noise op amps. An AKM AK5393 enhanced dual bit 108kHz 24-bit 128 oversampling ADC with integral antialiasing filter immediately converts all analog input to the selected sample rate and word length. Analog output is processed at the same selected sample rate and word length by an AKM AD4393 96kHz 24-
bit 128 oversampling DAC. This chip also provides digital de-emphasis for the 44.1kHz and 48kHz sample rates. Both the ADC and DAC utilize differential analog signals. The analog output is buffered by another 5532 and sent to the front panel stereo headphone jack. The balanced outputs are 75, while the unbalanced outputs are 150.

PHOTO 3: ML-9600 interior view.

TOPOLOGY

A schematic was not furnished with the unit, but a $50 CD-ROM service manual is available from the Alesis Parts Dept., (310) 821-5000. Analog audio input/output, including the balanced-to-unbalanced signal conver-
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The digital inputs accept standard AES/EBU (balanced XLR) and S/PDIF (unbalanced coax) formats and are processed by a Cirrus Logic CS8414 96kHz digital audio receiver chip. Opti-
FIGURE 1: DSP block diagram.
cal formats are not supported. A Cirrus Logic CS8404A 96kHz digital audio interface transmitter drives the digital output jacks through 75 interface transformers. Digital signal processing is provided by an Analog Devices ADSP-21065L SharcTM 32-bit DSP chip. Two 1M 16 SDRAM chips proA-2282-1 vide support memory. The flash memory chip is a socketed Alesis-labeled device. Photo 4 shows the neat layout of the main multi-layer PC board and the DSP chip.

USING THE ML-9600

FIGURE 2: Frequency response.

A-2282-2

The ML-9600 is furnished with a full-fea-
TABLE 1 MEASURED PERFORMANCE
PARAMETER Freq Response (44.1/48kHz): Freq Response (88.2/96kHz): Total Harmonic Distortion: IMD CCIF (19+20kHz): Signal to Noise Ratio: Maximum Output, Balanced: Maximum Output, Unbalanced: Maximum Output, Headphone: Analog Input Impedance: Analog Output Impedance: Power Requirements: MANUFACTURERS RATING 20Hz20kHz, +0/0.3dB 20Hz40kHz, +0/0.5dB <0.002%, 1kHz, 1dBFS N/S 113dB, A-weighted +19dBu=0dBFS +5dBV=0dBFS 15k balanced 10k unbalanced 75 balanced 150 unbalanced 40W maximum MEASURED RESULTS 20Hz-20kHz,+0/0.1dB 20Hz-40kHz, +0/0.2dB 0.0025%, 1kHz, 1dBFS 89dB (0.0035%) <100dB ref 2V RMS, A-wtd 6.92V RMS (+19dBu) 1.78V RMS (+5dBV) 5V RMS (10k), 1.6V RMS (32) 30k balanced 10k unbalanced 76 balanced 128 unbalanced 68 headphone
PHOTO 4: DSP Chip on main PC board.
ture remote control, but is very easy to operate from the front panel controls. In CD mode, the recording capability is locked out and Red Book 16-bit/44.1kHz is automatically selected. The ML-9600 has some operational limitations when used as a CD player. There is no numeric keypad on the remote, so you cannot program individual tracks. You must use the skip buttons to go sequentially from track to track, and you cant program a series of individual tracks for playback. You dont have the usual track time and total time displays unless you change the default display mode. Keep in mind that this is a mastering recorder, not a consumer CD player. You can move CD tracks onto the hard drive, then produce up to 16 playlists of up to 99 tracks each in any order you prefer. You can then use the ML-9600 as an audio jukebox if you wish. The ML-9600 does not record on CD-R to any of the DVD-Audio formats, but the CD24 high-definition AIFF format is recognized by most DVD mastering facilities. When using the analog inputs, you can select any sample rate and word length you desire. The balanced inputs are rated for +4dBu nominal, with 15dB headroom (+19dBu maximum). The unbalanced inputs are the consumer 10dBV nominal with the same 15dB headroom, or +4dBV maximum. The analog outputs have the same dB ranges. There are no provisions for analog input level control on the ML-9600. You need to limit the analog maximum peaks by means of external audio equipment. The analog inputs are converted to the selected digital format, and the internal hard drive records this digital data, which is also re-converted to analog and sent to the analog output jacks in real time. This allows you to monitor the audio the way it will sound when played back from the hard drive. In fact, you can connect the ML-9600 into the same tape loop that you would connect a cassette tape deck, easily integrating it into most audio systems. If you intend to burn standard Red Book CDs from your analog source, the manual suggests recording files in 24-bit 88.2kHz format for hard drive

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storage. This allows the cleanest sample rate conversion to 16-bit 44.1kHz of all the high-definition formats, using a proprietary high-quality dithering algorithm. For digital input, the ML-9600 accepts any valid AES/EBU or S/PDIF data input and automatically switches to external clock mode. You can use either the balanced or the unbalanced digital input, but not both. The ML-9600 will output digital audio data at the clock speed determined by the connected source. This means you could conceivably play 44.1kHz recorded audio at 48kHz (if a DAT was connected, for instance), which would make the audio pitch too high. You cannot, however, record a Red Book CD placed in the internal CD drive to hard disk at any higher sample rate in an attempt to upsample the audio. Editing features are extensive. Since editing is destructive (the original audio file is overwritten), it is best to back up the file before editing.

FUNCTIONS

You can rename any playlist (up to eleven characters) and/or rename any track (up to eight characters). The default format is Playlist XX and Song XXX. You must use the cursor keys to scroll up and down through an alphanumeric character set and change one character at a time. Tedious work! (You may recall how difficult it was to come up with unique 8-character filenames when DOS was the only PC operating system.) You can take each track and crop the head and/or tail to eliminate noise or unwanted audio. The ML-9600 can play five seconds forward or backward at a very slow speed (like rocking the reels on an analog tape deck). This allows you to precisely place new start and end points on the track. You can record one long analog performance, then divide the single track into separate tracks using the Track Split feature. You can construct a single track from different performance takes by dividing a number of tracks at precise points into segments. You can combine the segment elements in a playlist and audition them (they will play back seamlessly). Then you can paste the elements into a single new
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track using Track Join if you are satisfied with the edit. The audio output is never muted during any mode of playback or edit. The DSP section of the ML-9600 is non-destructive. It operates on the audio file data read from the hard drive without altering it ( Fig. 1). You can apply track gain, compression, high-resolution 3-band fully-parametric EQ, limiting, fade-ins, fade-outs, and gain normalizing using the onboard digital signal processing (DSP). The compressor is very versatile adjustable threshold, ratio to 20:1, make-up gain up to 65dB, attack and release time to 9.9sec, and five choices of knee behavior at the threshold. The three EQ bands are each adjustable over 2022kHz, 18dB, with variable Q. The limiter is a 65dB range look-ahead peak limiter that prevents you from exceeding the maximum input limit, thereby avoiding the associated digital clipping. The fades
have two logarithmic and one linear shape. You can copy and paste any DSP parameter of the current track to any other track. If you really muck up the sound, you can reset the DSP to the default values and start over. If you are satisfied with the DSP results, you can render the settings to an audio file. This is a destructive process (overwriting the original track) so the usual backup recommendations apply. You can also apply DSP to only certain portions of your recording using the Track Split and Track Join features. One interesting feature is Normalizing, which allows you to scan a track for the highest peak value, determine the ratio between the peak and fullscale, and multiply the gain so the highest peak value of the track is equal to 0dBFS. The normalizer is applied to the hard disk data in real time. The CD burning process occurs at a rate between 2 and 4.5. The ML-9600
ignores any remote-control input during the CD burning process. This allows the full digital resources to be devoted to recording. A full 650MB Red Book CD-R will record in about 19 minutes, while a full CD24 CD-R takes 36 minutes. There is little incentive to use 20-bit word lengths for CD24. The CD24 AIFF file format orders 20-bit audio samples as 24-bit, so the maximum record time is the same for any given sample rate. You can record 29.6 minutes of 16-bit 96kHz data or 19.7 minutes of 20-bit or 24-bit 96kHz data on a 650MB CD-R. However, the hard drive stores 20-bit data in true 20-bit fashion, so 20-bit files give you more hard disk recording time than will 24-bit. The ML-9600 supports 700MB CD-R (80 minutes), but not all CD players will read them. MP3 is not an option.

LISTENING TEST

My first test was a listening audition of
FIGURE 3: THD+N vs. frequency.

A-2282-3

FIGURE 5: Spectrum of 50Hz sine wave.

A-2282-5

FIGURE 4: THD+N vs. output voltage.

A-2282-4

FIGURE 6: Spectrum of 1kHz sine wave.

A-2282-6

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the ML-9600 as a CD player compared to my modified Rotel 970BX CD player (aX 2/03, p. 26). The ML-9600 is an entirely satisfactory CD player (ignoring the lack of a numeric keypad on the remote and the limited digital display). It has very solid bass performance and a pleasing midrange. Only at the highest frequencies did I find it lacking compared to the Rotel. While the highs are just a bit rolled off, they also have a noticeable edginess to them, almost imparting a sibilance on percussions such as chimes and triangles. The sound stage is also a bit more forward and not as spacious as the Rotel. These characteristics may improve with operating hours, as was my experience with the Rotel when it was new. And the ML-9600 is visually entertaining, with its dancing VU level meter bars. The first recordings I made were direct digital copies from CD to the ML9600 hard disk, using the CD-RW tray. This is a reasonably fast process, running at 4 rate. You first select a CD track you want to copy, then select the destination track in the playlist. The Track Move button starts the track copy process. Be careful to select a new track in the playlist each time, so you dont overwrite the previously recorded track. You can also move an entire CD to a playlist with the Move CD feature. Next, I made a digital duplicate of the same CD tracks using a 75 S/PDIF coax connection between the Rotel CD player and the ML-9600. I listened to the playback from the ML9600 hard drive in comparison to the Rotel. The same listening comments apply to these two digital copy methods as they did for the original CD played directly on the ML-9600. As you would expect, there were no audible missteps in either digital copy process. I have a few LPs for which I also have duplicate commercial CD versions. The best test of the ML-9600s analog-digital-analog prowess is to record the analog LP files to the ML9600 hard drive in nine of the twelve sample rate/word length combinations (I skipped 48kHz) and see how they sound as compared with the analog LP. I used shorter clips of what I consid-

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BK-16 Kit
Madisound is pleased to offer the BK-16 folded horn kit.

F O S T E X

We have chosen the Fostex FF165K 6.5" full range for use in the BK-16 cabinet. The FF165K has a Kenaf fiber cone, inverted foam surround and aluminum dust cap. The FF165K is run full range with a frequency response out to 15kHz. The T90A super tweeter has been added to cover the upper frequencies. The T90A is a top-mount horn tweeter with an Alnico magnet. The tweeter is rolled off on the low end with a Fostex Tin & Copper foil capacitor. The system frequency response is 55Hz to 35kHz at 95dB. The BK-16 cabinet is made from Baltic Birch plywood and is sold flat, unassembled, unsanded and unfinished. Cabinet dimensions are 9.75" W x 14.75" D x 29" T. The kit includes: Pair of Cabinets - Flat Pair of FF165K - full range Pair of T90A - horn tweeter Pair of DB-Cup - Input cup Pair of Crossovers Nordost 2-Flat wire for tweeter Instructions Kit Price: $635.00 /pair Parts without cabinets: $439.00 /pair Cabinets only: $98.00 each
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ered to be key segments on the LPs, to allow faster reviews of the different data rate combinations. I also went through the illogical step of connecting the analog output of my Rotel CD player to the ML-9600 analog input, and copying the analog audio to the hard disk in digital form (Would that be DAD on the old CD labeling standard?). I made the recordings at 16/44.1kHz and 24/96kHz. I copied all these various audio files, from both the analog and digital sources, to a single ML-9600 playlist, which I then auditioned in great detail. First, I believe the digital sweet spot for analog LP copies lies at 20bit/88.2kHz and above. The Red Book rate 16/44.1kHz copies are the least satisfying, while both the 24/88.2kHz and 24/96kHz copies come close (but not quite equal to) the LP playback itself. I also think that sample rate is more important than word length. The 16/96kHz copies were more interesting than the 24/44.1kHz copies. I think this is because the standard 0dBFS output level is identical in both formats at 2V RMS.
20-bit and 24-bit content extends the response further down into the noise floor rather than providing more headroom. Even if a CD player could play back 24-bits of resolution, it would likely exceed the noise floor of the analog playback circuitry. A higher sample rate, however, extends the nonlinear and nonharmonic products of the steep output filters beyond where they might have audible consequences. This appears to be the case with the ML-9600. When I recorded the CD player analog output to the ML-9600 at 16/44.1kHz, there was some obvious degradation of the audio as compared with the original CD. The highs were rolled off, drier sounding, and less involving. The 24/96 recording of the Rotel analog output was more faithful to the original CD. Finally, I burned the entire playlist I produced in the previous steps to Red Book CD-R for playback on my Rotel CD player. After you press the Create CD button, the ML-9600 will first determine that the CD-R you want to use is recordable, then makes sure the playlist will fit on the disk. Then the CD-RW drive goes through an initializing period where it does self-calibration and processes the table of contents (TOC) from the playlist. The next step involves a rendering A-2282-7 process whereby the selected DSP is apFIGURE 7: Undithered 1kHz sine wave at 90.31dBFS. plied and the audio is re-recorded to a special area of the hard drive set aside for this process. If you elect to burn a standard Red Book CD, the appropriate sample rate conversion and/or noise shaping is applied to all tracks other than those that already exist in 16/44.1kHz A-2282-8 format. The high sample rate and long FIGURE 8: Wideband spectrum of 1kHz sine wave at 90.31dBFS. word length files take

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a fair amount of time to render. My 41:27long playlist took 20 minutes to render and 10 minutes to burn to CD-R. If your playlist consists of only Red Book CD tracks without any DSP, the rendering process is not required. Finally, I set about listening to the finalized CD-R on the Rotel CD player. The three analog LP 44.1kHz recordings at the three different bit rates all sounded the same. Perhaps the ML9600 rendering process, when faced with any 44.1kHz sample rate audio file, merely truncates any extra bits. Some of the LP songs I recorded to CD-R were not quite as good as some of the commercial CDs, while others were noticeably better. What surprised me was the high maximum recording level used on some CDs in comparison to the same songs on LP. I was fairly conservative during the analog recording, rarely exceeding +2dB (unbalanced inputs), while the CDs spent a lot of time near 0dB, with lots of hits on the MAX point on the level indicator. Compared with the LP, there sometimes appeared to be more compression used in the transfer from master tape to CD. The dynamic range of my LP recording was limited by the LP surface noise, while the dynamic range of some of the commercial re-releases on CD were intentionally compressed more than I thought was necessary. Im not sure whythe master tapes are a known entity in terms of dynamic range. Howev-
er, the commercial CDs that seemed to preserve the original LP dynamic range were nicely done indeed. As with any recording process, the care given in preparation and attention to detail pays off at the end.
pedance measured 10k (DC resistance), while the balanced analog XLR inputs measured 30k at 1kHz and appeared to be capacitively coupled. Pin 2 of the XLR jack is hot. The unbalanced analog

MEASUREMENTS

I operated the ML9600 for one hour with a loud music CD before making any tests. I performed many tests using the CBS Labs CD-1 and Pierre Verany test CDs (both available from Old Colony Sound Lab). I used my distortion test set sine-wave oscillator for tests where a variable signal level was required or test CD digital data was not available. I did not evaluate the ML9600 digital outputs. Table 1 summarizes the measured performance and the manufacturers specifications. The unbalanced analog input im-

FIGURE 9: 1kHz sine-wave residual distortion.

A-2282-9

A-2282-10
FIGURE 10: Spectrum of 19kHz + 20kHz intermodulation.
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output impedance at 1kHz was 128, increasing to 135 at 20Hz and 20kHz. The balanced analog output measured 76, and balance between the two channels was perfect. The headphone jack output impedance measured 68. All analog outputs had normal polarity, a positive-going pulse producing a positive-going analog output (XLR pin 2 hot). The analog outputs are muted by a relay when power is off, and during some phases of operation. The DAC frequency response for the
ML-9600 was ruler-flat from 17Hz to the point where the digital output filters for each sample rate sharply rolled off the response (Fig. 2). The 0dBFS indicated unbalanced analog output was 1.78V RMS at 1kHz, or about 1dB below the CD Red Book standard of 2V RMS. The balanced output at 0dBFS was 6.92V RMS, reflecting the difference between the pro audio dBu and the consumer dBV standards. The 1dB level display indicator came on at 1.76V RMS and 6.85V RMS, respective-
ly. I also measured the frequency response of the headphone output, which is the curved line at both ends of the graph, measured with a 0dBFS analog input signal and the input sample rate set to 96kHz. Crosstalk between channels out to 16kHz was excellent and below the noise floor of my test equipment. Likewise, the signal-noise ratio was greater than 100dB referred to the Red Book 2V RMS with A-weighting. THD+N vs. frequency at both the

A-2282-11

A-2282-12
FIGURE 11: 16-bit 44.1kHz square-wave response at 1kHz.
FIGURE 12: 24-bit 96kHz square-wave response at 1kHz.

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standard Red Book format, and the maximum 24-bit 96kHz format are shown in Fig. 3. I recorded the 24-bit 96kHz tones onto the ML-9600 hard drive from the oscillator in my distortion test set. I engaged my distortion test set 22kHz 4-pole low-pass filter to remove out-of-band noise. I did not attempt to measure THD+N beyond 20kHz for the 96kHz data due to the lack of a suitable LP filter in the test set. The upper curve is the distortion from the headphone jack with Red Book format data (10k load). At the lower frequencies the distortion is at or near the measurement floor of my distortion test set. Figure 4 shows the THD+N vs. output voltage using the CBS test disk. The bottom trace is the unbalanced line output, the middle trace is the headphone output (both at 10k load), and the top trace is the headphone output with a 32 load. There is no clipping evident because of the CD test signal source. You can, however, drive the ML-9600 into clipping from the analog inputs. When I overdrove the unbalanced analog input, the distortion went straight up just above the point where the +4dBV level indication occurred. It does not sound pleasant! An analog input signal of 1.78V RMS produced an identical analog output level, showing excellent analogdigital-analog conversion performance. The headphone output at the maximum volume control setting (10k load) was 5V RMS. The spectrum of a 50Hz sine wave at 0dBFS is shown in Fig. 5, from DC to 1.3kHz. The calculated THD+N based on the first five harmonics is 0.0022%, with no significant harmonics and only low-level noise artifacts. The measured THD+N is 0.0027%. I repeated the spectrum analysis at 1kHz 0dBFS, as shown in Fig. 6, where THD+N also measured 0.0027%. Figure 7 shows the reproduction of an undithered 16-bit/44.1kHz 1kHz sine wave at 90.31dBFS. At this level the signal consists of 1 bit of data, producing two different voltage levels that are symmetrical about the horizontal axis (time). These discrete voltage steps are not totally obvious, due to out-of-band high-frequency noise
(see the next graph). The spectrum analysis of Fig. 8 represents the undithered Red Book 1kHz sine wave at 90.31 dBFS from DC to 84kHz. The reason for this graph is that I wanted to determine whether the switching power supply in the ML-9600 was introducing any high-frequency noise. You can see switching powersupply components at about 38kHz and 76kHz. I used the 90.31dBFS signal to keep the analog output from muting. The noise is below 80dB and is probably of no real significance, even while using the 96kHz sample rate mode. The distortion residual waveform for a 1kHz sine wave at 0dBFS is shown in Fig. 9. The upper waveform is the analog output signal, and the lower waveform is the monitor output (after the THD test set notch filter), not to scale. This distortion residual signal shows a low level of third harmonic overlaid with noise. THD+N at this test point is 0.0027%. Figure 10 shows the spectrum response to equal level of 19kHz and 20kHz signals, each at 6dBFS, from

DC to 20.8kHz. The 1kHz intermodulation difference product measures 89dB, while the 18kHz and 21kHz products are virtually nonexistent. I viewed the response of the ML-9600 to 1kHz square wave test frequencies. The 16-bit 44.1kHz square wave in Fig. 11 is from the CBS test disk. The 24-bit 96kHz square wave in Fig. 12 was one I recorded from my function generator at 2.5Vpp. Both show the characteristic Gibbs Phenomenon ringing associated with the limited bandwidth produced by the digital filters. The 24-bit waveform is a better representation of the original square wave. The ML-9600 ignored defects on the Pierre Verany Test CD# 2 out to track 30. At track 31 (1mm defect), the unit put out a series of audible clicks at each pass through the defect. The unit easily met the Red Book requirement of 0.2mm max. I am very impressed with the ML9600. Not only is the digital recording capability first-rate, but also the moving parts (the ones most likely to wear out) are easily obtainable computer hardware.
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