Fostex D-2424
Hard Disk Recorder Review
ã 2001 by Eddie Ciletti
There are several stand-alone multitrack hard disk recorders designed specifically to replace linear tape in both analog and digital forms. (Others have evolved from sampler technology.) I am considering five Manufacturers that are directly competitive — Timeline (via Tascam), Radar (via IZ), Mackie and Alesis (reorganizing after declaring chapter 11) — Fostex stands out as one company whose experience in the field spans nearly ten years —  before it was affordable and before many people considered it an acceptable concept. While you’ve been wrestling with jammed tapes and crashing computers, Fostex has been quietly perfecting their dedicated hardware. 
The Fostex D2424 ($3995) is a 24-track recorder at standard sample rates, the jump from16-bits to 24-bits reduces recording time but not the total available tracks. At doubled sample rates, the D2424 becomes an 8 track recorder at 24-bits only. All mode options are detailed in Table-1, including ample virtual tracks. There are no drive-size limitations. Essentially, a 10GB drive has room for over 72 minutes of recording in either 24-track "standard" mode or 8-track "high-resolution" mode.
Sample Rate Þ
44.1kHz
48kHz
88.2kHz
96kHz
                 
bits Þ
16
24
16
24
24
24
     
tracks Þ
24 real tracks + 32 virtual tracks
8 real tracks + 48 additional tracks
                 
Capacity

of 10GB

drive

1888

track 

minutes

1258

track 

minutes

1735

track 

minutes

1156

track 

minutes

628

track 

minutes

577

track 

minutes

             
Table-1: Sampling Rate and Bit-Depth options for the Fostex D2424. 
Approximate recording times are based on a 10GB drive.
THE CADDY
The test unit was shipped with a single 30GB drive in a removable caddy with room for a second removable drive. It is very easy to install a drive into a caddy and prepare it for recording. The machine will query the drive(s) and report their status. If blank, the options are Quick Format (really fast) or Standard Format (depending on drive size this can be an overnight hotel stay, a European meal or both!) Backup options include DVD–RAM as well as S/P DIF. On the rear there is a half-pitch (high-density) 50-pin SCSI connector that supports one drive. 
THE FACE
Drive Access is behind the removable front panel, which becomes the remote control with an optional 30-foot (max) extension cable. The High Density 15-pin D-sub looks just like a computer monitor connector. Definitely order this cable at the time of purchase. The front panel includes a fluorescent display for viewing track levels, status indicators (sample rate, chase enable, lock, etc.), error messages, plus song and track names. 
GET DOWN TO BIZ, FAST!!!
Rather than death by feature overload, let me get right to point. The Fostex D2424 wins major points for ease of use — it behaves pretty much like a tape recorder, only better and faster — being about as plug and play as you can get. Invest just a little time with the front panel and you’ll be ready to record. There is ample documentation. At 160 pages, the Reference Manual may be a bit overwhelming — with more than just a hint of Jinglish — but the Quick Operation guide is a lighter meal at 24 pages cover to cover. 
One of the idiosyncrasies of digital recording requires that the Sample Rate and Bit Depth must be chosen up front, before formatting the hard drive. After formatting, I handed the unit over to my friend Ted who transferred a CDs worth of songs — 24 tracks in one pass — from three adats, no manual, including how to label the songs. The Fostex D2424 has three pairs of optical I/O that converse in either adat lightpipe or standard stereo as S/P DIF. Analog I/O includes 24 outputs and 8 inputs — operating / reference levels and bal / unbal options are selected from the front panel. This is an extremely smart and considerate feature. 

 
 
 
 
MIDI, MMC and MTC
The songs transferred into the Fostex D2424 were then exported, eight tracks at a time, to a Soundscape HDR-1 workstation. This required an optical to TDIF interface and a MIDI cable. The D2424 slaved to the workstation better than vice versa. For this application, I was wishing for an all-optical digital patch bay — internal or external — to eliminate repeat visits to the rear panel for each group of eight tracks. Other MIDI and music-related features include Tempo Map, Time Signature and a built-in Metronome. In addition to standard time, the D2424 can also display musical time in Bars and Beats, including Offsets. 
OPTIONS: SMPTE and AES
The stock Fostex D2424 ships with RS-422 and Word I/O for. The SMPTE / EBU TimeCode option ($895 list) includes Time Code I/O via XLRs and Video reference I/O while still leaving room for the AES/EBU option ($599 list). I installed the SMPTE board with not much difficulty although it is recommended that this be done by an authorized dealer / service center. Once physically installed, the additional features were enabled. 
I took advantage of the SMPTE capabilities of both the Fostex D2424 (via XLR) and the TASCAM DA-78HR (via RCA), requiring only an XLR to RCA adapter. Considering the random access of HD versus linear access of tape, it was more practical to Slave the D2424 to the tape machine. It was here that I encountered what is perhaps the only flaw in the D2424 and that was simply the lack of "feedback" when the sample rates did not agree. 
When the HD is formatted at 44.1kHz / 16-bit and the incoming signal is 48kHz / 16-bit, the Fostex D2424 will do everything but record and tell you why. In Stop it will input a digital signal and in Chase it will attempt to sync but not lock. I can’t imagine it would be difficult to implement a warning feature for situations such as this. If it is already there, then it was not obvious enough. The solution was simply to mount a new hard drive. Since the review machine did not come with a spare caddy the process took five minutes instead of 2.5 minutes. No big whoop! Say YES to Quick Format and be back in biz. 
KITCHEN SYNC
Here are a few of the sync-related options. Press the SETUP button on the front panel to gain access to ALL features and options. The Reference Time code can be either MTC (MIDI Time Code) or LTC (the "virtual" Linear Time Code). Supported Frame Rates are 24, 25, 29.97nd, 29.97df, 30nd and 30df. 
In addition to its internal clock, the Fostex D2424 will lock to Word clock as well as a Video reference, provided the 8345 SMPTE card has been installed. There is a Sync Preset option so that the unit always boots in a predictable manner — nothing is more painful than unlocked digital clocks! There is also an RS-422 port that speaks Sony-9-pin protocol. 
LOCK AROUND THE CLOCK
When synchronizing, there are two basic options, Vari and Free. In Vari mode, the D2424 will achieve lock with the incoming Time Code by minute variations on clock speed (sample rate) to maintain frame accuracy. In Free mode, the clock reverts to internal (or Word) after Lock is achieved unless the difference between Master and Slave exceeds ten frames. Minute variations in clock speed / sample rate affects the digital outputs, making it hard for the destination device — a digital mixer, for example — to maintain clock lock. 
TWICE BAKED
Whenever synchronizing it is always good idea to confirm that a "real lock-up" actually occurred. I did this by transferring the same tracks from the DA-78HR twice — first to tracks 1-8 and then to tracks 9-16 of the Fostex D2424. During the first transfer I did not pay attention to the settings. The next day, while transferring to tracks 9-16, the machines were locked but sounded like they were a sample or two away from each other. The immediately obvious tip off was the comb filter effect when any two "identical" tracks were compared. This may have been the phase difference between the discrete Word Clock versus the "derived" adat lightpipe word clock. I could have lived with and fixed this, but chose to investigate further and try again. 
After switching to "Vari" mode, I listened during a transfer and could hear the track pairs "phasing," which was less desirable than being a sample or two delayed. Finally, I re-transferred from scratch, in "Free" mode both times. Now all tracks simply combined as if mult-ed, confirming the SYNC accuracy of both the Tascam DA-78HR and the Fostex D2424. In summary, take nothing for granted when synching any two machines. 
OUT OF BOX EXPERIENCE
The Fostex D2424 has basic digital on-board editing including cut, paste and copy. Beyond that, the company includes the versatile Hammerfall PCI card as part of the standard package. (This same card is supplied with Steinberg’s Nuendo.) It features three pairs of adat-compatible optical I/O — one I/O pair also speaks S/P DIF — plus coaxial S/P DIF and Word I/O. Their C-Console software does more than add MIDI remote control. A voice-recognition plug-in is also available for visually or physically challenged users — or any application that requires control beyond the 30-foot limitation of the remote cable. 
I tested the Fostex D2424 along with the Hammerfall PCI I/O card interfaced with Cool Edit Pro (CEP) — an affordable (about $300), intuitive workstation that is remarkably powerful. Achieving the best configuration with any NATIVE product / hardware combo can be randomly gnarly or surprisingly easy but I did eventually nail it down, importing tracks from the D2424 all at once as well as 8 tracks at a time just to confirm CEP’s ability to sync. It works. The software choice is yours. 
HOW DOES IT SOUND?
Whenever I review a digital project, invariably the question of sound quality arises. First, you should know that I like "digital" and do not expect it to be like an API console or a vacuum-tube tape recorder. I carefully choose outboard or plug-ins for "color," currently the Crane Song HEDD192 delivers vacuum tube and tape emulation better than any product I've heard so far, but that was not used on this project.

Hi-Res SESSION: Mics
The aforementioned tests used the Fostex D2424 just as a "data" recorder via its digital I/O. During the second round the D2424 travelled to LatchLake, a local studio, for a traditional session. Since hi-res can record or playback only 8 tracks at once, a quick stereo test was made using a pair of Neumann TLM 193 cardioid mics.  (They look similar to the U89.) I placed them two-feet in front of the kit just above the top rim of the kick drum.

Hi-Res SESSION: Preamp and monitoring
The mic preamp was a four-channel transformer-less Ampria model (a local company that shares its design knowledge with Great River Electronics). The preamp was connected directly to the analog inputs of the D2424. Recording at 88.2kHz, 24-bit, we monitored through the stereo analog tape returns of the Yamaha 02R via Westlake monitors and a subwoofer.

Hi-Res SESSION: Recording
The single Neumann stereo pair, in an intimate setting, also captured electric bass and guitar (through their respective amplifiers). The kick was massive on the bottom with plenty of beater. The stereo imaging was deep. I believe both the studio owner and the band were impressed, each for their own reasons. I don't think Jeff expected the mic position to generate such intimacy and space at the same time. For the band — who played quite well for their age (15~22) — it was their first official recording. I thought they did great work.

Standard SESSION: More tracks and overdubs

We then switched to "standard" mode, recording at 48kHz 24-bit as dictated by the Yamaha 02R. Starting with the same mics and configuration, a Sennheiser e609 was added to snare, an AKG D-112 on guitar amp plus a DI on bass. Recording the basic tracks went smoothly. 
OOPS: Punch-out
Everything went well EXCEPT during a "rolling" punch-out, the machine did not return to the originally recorded signal, the only flaw encountered during all of the D2424 tests. I did not try the punch-in / punch-out feature nor did I try the foot pedal "punch option." 

The D2424 firmware is only at V1.03. I am awaiting confirmation from Fostex that a newer version is available, and if so, what issues have been addressed.

WORK-A-ROUND
The punch-out bug did not stop us from recording.  My preference (and a less-distracting work-a-round) would be to record multiple takes and edit the best into a composite. Still, punching - in and out - is a standard feature for all multitrack recorders (and should be remedied in this case, sooner than later because this is otherwise a great product).
FOSTEX REPLIES:
Fostex is aware of the punch-in problem, which they claim is the result of their very efficient file management system.  They are working on a remedy.
ONE PRODUCT, MANY SOLUTIONS
I see the Fostex D2424 as a solution to many applications. As a stand-alone 24-track recorder it is simple and reliable. In high-resolution mode it does what no digital 8-track tape machine can do — 88.2kHz / 96 kHz and 24-bits. Both the D2424 and the "media" are affordable and portable enough to do exactly what we did — using it as an intermediary, transferring all 24 tracks rather than three 8-track tapes then importing to a workstation in another part of town. Had the tracks not required surgery, I would have been happy to mix directly from the D2424. 
The Fostex D2424 is equally at home in a video facility or a project studio — it’s responsive and full of features for each application. The PCI interface opens a whole world of creative editing options, interfacing the D2424 directly with your workstation reducing the "load" on NATIVE-based systems so they can start behaving a bit more like dedicated hardware. Depending on the application, the D2424 may also free up the host processor to run more plug-ins. 
THE WHEEL KEEPS ROLLIN’
The D2424 is not the first hard disk recorder from Fostex but the culmination of experiences gained from developing and supporting several previous models. Rather than make it "almost a workstation," they wisely chose not to reinvent the wheel but to use existing (editing) wheels. The D2424 is simple and easy to use stand alone or when integrated with your existing workstation. 
The time is right to combine the power of NATIVE editing and processing with the stability and versatility of a dedicated piece of hardware. The Fostex D2424 is fully functional, stable and ready now. Don’t let this stealth multi-track digital recorder slip under your radar.
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