Digital and analog mixers, sound-reinforcement speakers, studio monitors, the human user interface (HUI) control surface only a handful of manufacturers

Digital and analog mixers, sound-reinforcement speakers, studio monitors, the human user interface (HUI) control surface — only a handful of manufacturers cover as many bases as Mackie Designs does. The only thing missing in its stable of products was a recorder. Enter the Mackie HDR24/96, a 24-track hard-disk recorder that supports 24-bit resolution and sampling rates as high as 96 kHz.

The HDR24/96 combines the recording ease of a tape machine with the basic editing power of a digital audio workstation (DAW). The package is filled with goodies, including various I/O and removable storage options and the ability to serve as a file transfer protocol (FTP) server for transferring files to and from computers.


The front panel of the HDR24/96 is dominated by 24 meters and track-arming buttons (see Fig. 1). To the right of the channel meters is an 8-digit location counter, a small array of status lights (indicating sampling rate, bit depth, time code, clock, and error), and a 24-by-4-pixel backlit LCD.

Directly under the LCD are four Select buttons flanked by two large arrow buttons. Those buttons and the buttons in the row beneath them are used to navigate the HDR24/96's menu system from the front panel. The bottom row of buttons (Track, Project, Backup, Disk Util, System, Digi I/O, Sync) is for choosing a menu; the Select buttons are for choosing a parameter to edit; the arrow buttons are for moving between pages; and the Increment and Decrement buttons, also in the bottom row, are for adjusting values.

Standard transport buttons (Stop, Play, FF, Rew, Record) reside at the bottom right of the front panel; record and locate functions (Locate, Store, Time Code Chase, Autotake, and so on) are handled by a final bank of buttons under track-arm buttons 16 through 24.

The front panel also includes a drive bay for removable Mackie Media drives (fast IDE drives for real-time recording), a floppy drive for installing OS updates, and the power switch.

Although the front panel has a lot of controls, Mackie did its homework to determine which functions need to be there and how they should be laid out. Front-panel operation is surprisingly intuitive, and I almost never needed to dip into the manual to find a function. Clearly, Mackie is trying to retain as much of the tape-machine paradigm as possible while striving to provide the more complex, hard-disk specific functions in a similarly straightforward presentation.

Powered by a 433 MHz Intel Celeron CPU, the HDR24/96 is stocked with 128 MB of RAM. That may not seem like much RAM for a desktop computer, but it's a healthy amount for a computer completely dedicated to music production.


A graphical user interface (GUI) is much better for exploiting DAW-style editing than the buttons-and-LCD interface. To that end, the HDR24/96's rear panel sports connections for an AT keyboard, a PS2 mouse, and an SVGA monitor (see Fig. 2). Using those devices gives you a DAW interface that duplicates all of the HDR24/96's front-panel functions while allowing other functionality, such as region and drag-and-drop editing. In general, the front panel permits recording, playback, and system configuration functions, whereas the GUI provides greater depth for those and other features that would be difficult to use with hardware alone.

The GUI software is integral to the HDR24/96's onboard operating system; you don't need external or optional software (see Fig. 3). I'm not sure why the keyboard connector is an AT type instead of PS2, but they are electrically identical, so a simple adapter (available at any computer store) will let you use your PS2 keyboard with the HDR24/96.

Mackie's recognition of the fact that the HDR24/96 is a dedicated PC doesn't end with the GUI. The rear panel contains a 100Base-T Ethernet connection, which, when connected to a Mac or PC, allows the HDR24/96 to act as an FTP server so that sound files can be transferred back and forth easily.

The Ethernet and video connections are on PCI cards mounted in two of the HDR24/96's rear-panel slots. The two other slot-mounted cards are MIDI and Sync cards. The MIDI connections are on a DB9 connector, like those found on every PC sound card, and use the standard pin out for such connectors. You can therefore use any run-of-the-mill sound-card adapter that breaks out the DB9 to standard 5-pin DIN MIDI I/O connectors. One such adapter is included with the HDR24/96.

The Sync card has BNC connectors for word clock in and out and a 75• termination button. It also contains a ¼inch phone jack for reading SMPTE time code. Two slots, marked ACC1 and ACC2, are reserved for expansion.

The keyboard and mouse connectors, along with jacks for a footswitch and the optional remote, are situated in the middle of the rear panel. The footswitch jack facilitates hands-free recording and playback and can be set up to punch in and out, start and stop the transport, or step through the locate points. Mackie's remote controllers for the HDR24/96 are the Remote24 ($299) and its bigger sibling, the Remote48 ($1,499).

Next to the cooling fan, which is fairly quiet, are three slots for I/O cards, each of which carries eight audio channels. The cards available are the PDI-8 AES/EBU ($399), AIO-8 analog I/O ($399), the DIO-8 Lightpipe/TDIF ($449), and the OPT-8 Lightpipe ($99). The converters on the AIO-8 are 24-bit with 128× oversampling. The analog and AES/EBU cards use DB25 connectors, so budget for those extra costs for cables if you're buying the cards.

Inputs on the PDI-8 offer real-time sampling-rate conversion and the ability to switch the status bit for easy data compatibility between AES/EBU (pro) and S/PDIF (consumer) devices. The DIO-8 allows conversion between ADAT and TDIF formats and includes a BNC connector for TDIF sync.

The I/O slots are hard-assigned to their corresponding tracks: the card in slot 1 accesses only tracks 1 through 8; slot 2, tracks 9 through 16; and slot 3, tracks 17 through 24. My review unit was equipped with one each of the analog, ADAT/TDIF, and AES/EBU I/O cards, in that order. Only tracks 1 through 8 could be recorded or played to and from analog. I wish I had the flexibility to map the I/O cards to any track, even if that feature were available only in the GUI. To work around it, I had to drag regions from one set of tracks to another; however, Mackie says it will implement remapping capabilities.

While I'm listing I/O gotchas, I should note that the HDR24/96 can record and play back at 96 kHz only through the AES/EBU I/O or using ADAT or TDIF signals when connected to another HDR24/96 or a device that understands the proprietary data format. Extended sampling rates aren't available with the analog I/O, but Mackie says other options for high-sampling-rate I/O are in development.

To make use of the HDR24/96's high-sampling-rate capabilities, you need external 96 kHz converters that support the AES/EBU dual-wire standard that Mackie uses. Alas, I had no such converters and was unable to try the HDR24/96's high-sampling-rate recording. However, given that the cards, not the unit itself, would not be doing the A/D/A conversion, the HDR24/96 need only handle the digital data without corrupting it, which I'm confident it can.


When you power up the HDR24/96, it loads its operating system and checks to see what storage is online. It then loads the default project, which is the last project you were working on (if available) or a new, untitled project. Configuration functions are accessed by pressing one of the menu buttons to enter a menu and then pressing a Select button to choose a parameter. If the menu contains more than four parameters, the unit prompts you to use the arrow buttons to reach them.

When you enter a menu, the Select button LED lights for each button that will access a parameter, and the parameter name appears in the bottom of the LCD. For instance, if you have a new project and want to set its sampling rate or bit depth, press the Sync button; then, press the Select button under Sample Rate (or Bit Depth, which is a page to the right) to access that parameter. As you can see from that example, the organization of the HDR24/96's menus is unconventional; I would expect those functions to reside in the System menu, though the Sync menu is not an entirely illogical choice.

Once you access the sampling-rate parameter, the LCD shows the parameter name in the top row, its value in the third row, and double arrows in the bottom row above the two left-most Select buttons (the LEDs are lit to indicate that they are active). Over the right-most Select button, the LCD shows “OK” while the LED blinks. Edit a value by pressing the Select buttons to raise or lower the value and press the OK Select button when the desired value is reached. Observant users will notice that the LEDs over the Increment and Decrement buttons are also lit when the parameter is selected; the buttons can be used instead of the Select buttons.

Using the Select buttons with the LCD arrows to edit values rather than using the arrow buttons (which are reserved for page navigation) is simple and intuitive; that method is implemented consistently throughout the system. The rest of the configuration functions follow a similar form. In the GUI, those functions are collected in the Setup window, which includes tabs to select different pages of parameters corresponding to the front panel's menus.

Once the basic configuration is done, recording is as easy as using a tape machine: press the track-arm buttons for the tracks you want to record; then, use the transport buttons to put the machine into record. All the standard tape-machine recording functions are there: All Input and Auto Input monitoring, one-button punch-in, auto punch-in and -out, loop recording, and so on. Some features, such as auto punch-in and -out and one-button punch-in, must be enabled from the GUI, though the actual record operations can be performed from the front panel.

Levels can be monitored visually on the front panel's 24-segment LED track meters or from the GUI's meters, which can be set to monitor peak values, average values, or both. The main body of the GUI is the track display, but at the top of the screen is an area that alternates between acting as the meter bridge and a tools palette. The functions are switched by clicking on a keyboard tab. To the right of the area, the GUI has onscreen transport controls and a location display.


All recording is done into a familiar data architecture: the highest level structure is the project, which contains 24 tracks. A recording pass onto a track creates a take, and some or all of a take can be designated as a region. Takes on a track that are not currently active are virtual takes. A complete configuration of regions on all the tracks is a playlist. Because playlists and regions are editing constructs and all editing is performed in the GUI, playlists and regions can only be created and managed from the GUI, whereas projects and tracks can be managed from the front panel or the GUI.

The recording media includes an internal 20 GB UDMA IDE drive and the front-panel drive bay, which holds Mackie Media removable media housings. The M-90 ($199) is a fast UDMA drive capable of real-time recording. You can purchase your own UDMA drive and a Mackie Media tray, install it, and get right to work. However, Mackie warns that not all drives are fast enough to record 24 tracks of 24-bit audio in real time. You can purchase qualified drives from Mackie, but if you choose to find your own, drives as large as 32 GB are supported. A software utility that tests the drive for its ability to perform real-time recording is onboard the HDR24/96.

In contrast, the Mackie Media Project drives ($299) are 2.2 GB ORB cartridges mounted in Mackie Media trays. They are too slow for real-time work and are solely for backing up data.

In addition to recording into a project, WAV and AIFF files from another project, or copied to the HDR24/96 using its FTP capabilities, can be imported. Importing does not reference the existing file but creates a new one, converting AIFF files to WAV and creating split stereo files from interleaved files in the process.


Once you make your recording, the usual array of playback functions is there for your listening and locating pleasure. You can set up preroll (but not postroll), locate points, and auto play (which puts the deck into play as soon as it locates) as well as loop selected portions of regions. The front panel provides four locate points only; the GUI adds another locate point and a cue list that holds as many as 100 cues. Locate points 1 and 2 hold loop points when you are loop recording or playing (other than region looping), whereas locate points 3 and 4 hold the Auto-Punch points.

Note that the HDR24/96 always plays back at a 24-bit resolution, even if you recorded at 16 bits. In addition, if you record 16-bit files and edit in the HDR24/96, the fades will be at 24-bit resolution and will not be dithered down to 16 or 20 bits if you digitally transfer from the HDR24/96 to a 16- or 20-bit system. How a given lower-resolution system will react to receiving that 24-bit data is a good question; in most cases, it will probably be truncated.

So far what you've seen is a recorder with all of the functions you expect for recording and playing. The HDR24/96's editing features, however, are what set it apart from most hard-disk recorders.


Editing on the HDR24/96 is performed exclusively in the GUI. Standard editing functions in the GUI include Cut, Copy, and Paste; region Edge editing; region nudging; discontiguous selection; dragging within and among tracks and from a Region List; scrubbing; and snapping to a grid. Most key GUI functions have keyboard equivalents, though they are not user-definable. The grid can be set to time or musical note values (for example, bar, beat, and tick).

The HDR24/96's GUI is well suited for working within a musical context. To do so, it must have a concept of tempo; you have three ways to give the HDR24/96 that information. The simplest is to set a Default Tempo (or Global Tempo) in the MIDI screen of the Setup window. The second method is to import a tempo map from a Standard MIDI File, a function also executed from the MIDI screen.

The last method is to use the Selection-to-Tempo command, which lets you define the number of beats contained in the current selection. The HDR24/96 then calculates and sets the Global Tempo. The unit's ability to import tempo maps and to define a tempo from a selection is slick. The only missing link is the ability to create a tempo map by repeatedly performing Selection-to-Tempo on different selections within a recording.

The HDR24/96 puts a 10 ms fade at the beginning and end of every region, which is convenient. The fade shape and duration can be set in the Region Editor dialog box. Similarly, whenever two regions overlap, a 10 ms crossfade is created. The Auto Xfade function, when activated, creates a crossfade over the duration of the overlapping portion between two regions.

Dragging the end of a fade-in or beginning of a fade-out changes the fade's length; dragging the other end trims the region's beginning or end and, in the process, moves the fade while maintaining its length. For crossfades, dragging the beginning or end trims the region boundary and alters the fade length. Some of that behavior is not consistent with DAWs like Digidesign's Pro Tools, but it is logical and efficient.

The fades have a few small limitations: there are only three fade shapes, and the feature that places fades at the head and tail of every region cannot be defeated. You will have to transfer tracks to a DAW for those times when extremely precise surgery is required.

One of the nicest editing features Mackie included in the HDR24/96 is a History list, a powerful system that allows for multiple undo levels. As with fades, there are areas in which a more robust implementation would be preferable, but remember that it's not a DAW but a pumped-up recorder. Having multiple undo levels at all is more than some big-time DAWs can claim.

Break-point volume automation can be constructed on a region-by-region basis, but not across an entire track. Here, I think the HDR24/96 does come up a little lacking in comparison with many popular DAWs.

Once you fully edit a track on the HDR24/96, you can bounce the whole thing to a new file with the Render Track function. That simplifies tasks like comping background vocals for a chorus or creating a percussion loop and then dropping it in on every chorus.


The HDR24/96 has plenty of clocking and sync functions. It can be clocked from an external word-clock signal, clocked internally, or locked to video black. It can be synced to SMPTE or MIDI Time Code (MTC) and can be controlled by MIDI Machine Control (MMC) commands. The HDR24/96 can generate time-code and MMC commands too.

If 24 tracks aren't enough, Mackie claims any number of HDR24/96s can be locked together with sample accuracy if you have enough connections to the same word-clock and time-code sources. As long as each HDR24/96 receives a solid word clock (which, for more than two units, means having a word-clock distribution system) and time-code signal, you can (theoretically) just keep stacking them.


Any computer system needs a method of backing up data, and the HDR24/96 has one, but it really amounts to nothing more than a copy facility. It does not offer any true computer backup amenities such as lossless data compression, incremental backup, and the ability to compare and verify written data.

One of the most interesting features Mackie included in the HDR24/96 is its ability to act as an FTP server. The HDR24/96 can function in a simple peer-to-peer network or on a hub as part of a larger network. Getting that to work is somewhat more complicated than getting MIDI to work, though some of the same basic principles of addressing are involved.

Over time, I suspect that Mackie and its users will provide a great deal of guidance on the HDR24/96's FTP capabilities. Mackie has a forum on its Web site and an HDR24/96 discussion board in Yahoo Groups, so you should have plenty of ways to get help in addition to Mackie tech support.


I threw my usual test sources at the HDR24/96: vibes, drums, synths, guitars, and vocals. Put simply, the unit sounds every bit as good as you would expect. Vibes and cymbals are a good test for converters and clocks in digital devices. Many digital devices add a piercing quality to the strong and pure yet warm sound of the vibes. However, the HDR24/96 maintained the instrument's soft edges and kept the airiness and spatial definition of the Earthworks mics and mic preamp used to record the vibes.

Cymbals quickly reveal any kind of distortion at the top end of the spectrum, because they have substantial activity in their upper partials. The HDR24/96 preserved the complex spectral activity without adding the edginess heard on many cymbal recordings.

The HDR24/96 is clean and has a pleasing sound that is not fatiguing to the ears. It captured the positive attributes of each source I tried with it.

The HDR24/96 is somewhat of a hybrid system, which is a risky strategy for Mackie to undertake. Some users will always wish the HDR24/96 were more stripped down so that it would be even simpler to operate, and others will want to see it do everything a DAW can do. Mackie has done an excellent job of riding this line, and I expect the blend to improve over time. Some functions could obviously be put only in the GUI, but many others were difficult choices. Mackie has shown with the HDR24/96 that it is capable of finding a good balance in feature placement.

Figuring out how to use most of the HDR24/96's functions from the front panel and from the GUI is easy. The biggest exception is the FTP function, not because the feature is poorly implemented but simply because setting up a network is an involved process.

The HDR24/96 comes with three manuals: a Quick Start Guide, an Editing Guide, and a Technical Reference. Between them, the unit's functions are well covered. However, none of the manuals have an index, which costs the user some time midsession when desperately trying to find all references to a particular function. I am a constant index user and a strong believer that documentation should provide quick access to information; I would have liked to see indexes and, in the electronic (Adobe Acrobat) versions of the documents, bookmarks, given that the manuals are not hefty.


The HDR24/96 can be used as a standalone for rudimentary tracking, but as a practical matter, a monitor, a keyboard, and a mouse should be thought of as necessities, not options. Once you experience the benefits of that hybrid, you'll be loath to work without them unless you're in a nonstudio situation, such as recording live.

The HDR24/96 does have a few rough edges, such as its inability to map physical inputs arbitrarily to tracks and the way that the cursor can sometimes become almost invisible against the GUI background. A few more DAW-type features would add a lot to the HDR24/96; for example, edit grouping would make it faster to cut and paste across a bunch of drum tracks.

Other wish-list items include the ability to put sampling-rate conversion with dither on outputs (even if only in the DIO-8) to transfer 24-bit, 96 kHz data to 16-bit, 44.1 or 48 kHz systems; more robust backup software; and more high-sampling-rate I/O options.

The HDR24/96 has several unused slots, and I'm guessing Mackie will put those to good use as it has in its D8B mixer. DSP cards could add some real bang to the HDR24/96 and seem a fairly obvious move, though Mackie declined to comment on the idea.


Mackie's HDR24/96 demonstrates why standalone hard-disk recorders have replaced the modular digital multitrack tape recorder in popularity. Although the HDR24/96 still has room to grow, it is mature enough to be stable and ready to use now.

The HDR24/96 sounds great, is full featured and easy to operate, and is slick in its design. It's a winner!

Larry the Oprovides music and audio services with his San Francisco — based company, Toys in the Attic, and has been a contributor toEMsince 1986.


Mackie Designs
multitrack hard-disk recorder



PROS: Well-thought-out design. Provides strong functionality and quick usability right out of the box. Good removable-media scheme. Many professional features such as sampling rate conversion on AES/EBU inputs and FTP server capability. Stable.

CONS: Weak backup feature. Cannot freely map inputs to tracks and tracks to outputs. No analog to 96 kHz I/O. FTP can be tricky to set up.


Mackie Designs
tel. (800) 898-3211 or (425) 487-4333

HDR24/96 Specifications

Tracks24Virtual Tracks192Frequency Response2 Hz-22 kHz (±0.5 dB)Adjacent-channel Crosstalk-90 dBuSample Recording Resolution24-bit linearInternal Processing Resolution24-bitClock Reference Sourcesinternal; external; word clockTime-code Types/RatesMTC; SMPTE/24; 25; 29.97 drop, nondrop; 30 drop, nondropDimensions4U × 13.25"Weight35 lb.

HDR24/96 Optional I/O Specifications

Analog I/O8 channels on each board (44.1, 48 kHz sampling rates only)AES/EBU I/O8 channels on each boardTDIF I/O8 channels on each boardADAT I/O8 channels on each boardSampling Rate44.1, 48, 96 kHzAnalog I/O Level+4 dBuHeadroom+22 dBuTotal Harmonic Distortion (A/D/A)0.00001%Dynamic Range106 dB (analog); 144 dB (digital)