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Genex Audio GX9048 Multitrack Recorder

The early to mid '90s brought about the first widespread use of the rewritable/quick access magneto optical disc in the audio industry. Sony produced the PCM 9000, which recorded two tracks on a proprietary MO disc with great success.

The early to mid ’90s brought about the first widespread use of the rewritable/quick access magneto optical disc in the audio industry. Sony produced the PCM 9000, which recorded two tracks on a proprietary MO disc with great success.
Product PointsApplications: Studio, post production

Key Features: 48-track; hard disk; multiple media/removable drives; 24-bit/192 kHz; basic editing software; DSD/SACD-compatible

Price: Starts at $19,000

Contact: Genex Audio at 310-828-6667, Web Site.
Genex emerged shortly thereafter with the GX8000, an eight-track magneto optical disc-based recorder that used standard computer MO discs (cheaper!), and allowed digital multitrack recording with quick access at a time when hard drives were physically very large, very expensive but lacking storage capacity. Genex later developed an eight-track model, GX8500, and more recently the GX9000 Eight-Channel System to record onto any SCSI device at high sample rates in PCM and in DSD – Direct Stream Digital, a single-bit sigma-delta conversion at 2.8 MHz.

With all the latest hard disk recorders to emerge in the last few years, we are provided with the usual options – various digital formats, sample rate, editing functionality, standard file format, etc. Basic quality of sound is sometimes overlooked as many people assume that all “digital recorders are created equally.” Internal analog converters must be carefully auditioned as required, and the digital in and out must be tested for transparency when considering any audio storage medium. It is also important to consider the ability to record both PCM and DSD, depending on the requirements of the project. The Genex GX9048 promises to be an all-in recorder with few limitations.


The newest Genex is the GX9048 48-track recorder, capable of sample rates from 32 kHz up to 192 kHz at 24 bits PCM, and also DSD. Timecode (internal or external), video sync, word clock I/O are all standard issue. The unit records to hard drive, MO disc or DVD-RAM but for multitrack recording, the hard drive is really the default storage medium. The unit reviewed was fitted with a Kingston-type bay for SCSI hard drive recording, with an expansion SCSI chain on the back of the unit for additional drives, AIT tape drive for backup, etc.

It is possible to record 48 channels of audio to a single SCSI hard drive, running DSD or PCM up to 2fs/96 kHz. At 4fs/192 kHz, it is still possible to record 48 channels, but two hard drives are required to run simultaneously.

It should be noted that many other hard disk recorders on the market will lose tracks as the sample rate increases, i.e. a 24-track recorder at 48 kHz might become a 12-track at 96 kHz, and only a six-track recorder at 192 kHz – not the GX9048. The record modes include the following three options: expansion disk mode, where files can be recorded continuously across two drives for greater capacity (i.e. longer record time); insurance disk mode mandates that audio is recorded to a hard drive while simultaneously writing an MO disc or DVD-RAM in case the internal buffer becomes too full (the disc is then updated from the hard drive at the end of the recording pass).

The third option is mirror mode, which records the same information to two drives at once, creating a live backup of the audio – a great time saver. The hard drives can be formatted as Genex (proprietary) or FAT32, the latter allowing file sharing with other FAT32 PC-based systems such as the Merging Technologies Pyramix, etc. In FAT32 mode, the project file format is a standard AES31 style “ADL,” or audio decision list. In PCM mode the GX9048 records standard-format WAV files, and either AES31DSD or DSD IFF in DSD mode. Recorded files are opened for playback by selecting the ADL file to be accessed, at which time all of the associated audio files are opened onto their corresponding tracks.

The machine automatically names each recorded file, and creates a new file folder every time the machine is stopped and started in insert mode. This can be somewhat cumbersome, and may require some housekeeping of ADL file names during recording. If file sharing is not an issue, the Genex disk format can be used, which is much simpler in terms of record, locate, and playback operation since it treats the hard drive like a linear reel of tape. Depending on the requirements of the user, the GX9048 can be fitted with AES, SDIF, MADI, or analog I/O. This particular review unit was fitted with three eight-channel DSD I/O cards (Channels 1-24) and three eight-channel analog I/O cards (Channels 25-48). The DSD cards can read either AES-format for PCM recording or SDIF for DSD recording, and the analog cards can record DSD or PCM.

In Use

The setup menu on the machine face is similar to the Genex GX8500 and GX9000 in terms of navigation, using the jog wheel and value up/down and enter buttons. Genex provides software to run the machine from a PC (laptop) via USB port, and it can run with a modified GXR48 remote via nine-pin D-sub connector. In fact, due to space limitations on the front panel, the only way to arm the tracks for recording is through the use of a laptop or the remote (the recorder manual carries no mention of the laptop operation or remote option). Much of the setup can be accomplished with the laptop, such as time code rate, drive format, audio format, opening ADL files, but for some reason the date and time update function doesn’t seem to take unless entered directly on the face of the machine. The laptop can be also used to rename recorded ADLs, which greatly aids in file management. Punch recording is possible during playback, with rehearsal and auto punch modes as options.

Edit software currently exists in a Beta version, which can do basic editing tasks (crossfades, etc.) but it is not planned to include any mixing desk or plug-ins. The software will be able to create waveforms in the same format as Pyramix so that the hard drives could be moved from one format to the other without spending time drawing waveforms before working. The official release version of the editing software should be out this April.

The A/D converters were auditioned against several other popular DSD and PCM 192 kHz converters, and the Genex GX9048 did very well. The 192 kHz PCM option sounded very true to the original source, in fact one of the four engineers that listened heard no difference between the two. In DSD mode the converters were slightly colored, but in a positive way, which I find typical of the one-bit system. It translates as a high-frequency presence lift or sparkle, although it is fairly subtle. Both DSD and 4fs/192 kHz PCM had a stable image, solid center, good high frequency extension, and very satisfying low frequency response.

Our most recent project using the GX9048 was a remix of a Mahavishnu Orchestra live concert from the early 1970s. Source was an eight-track, 1-inch non-Dolby tape at 15 ips. The thought was to transfer to a multitrack DSD platform with timecode so that the mix could be automated, and so that the source tapes would be played back only once during the transfer rather than over and over during mixing. Once the file system of ADLs had been sorted out, the operation of transferring the two analog reels went quite smoothly. The assistant on the mix date was quickly familiarized with GX9048’s operation, and his prior knowledge of the model GX8500 made for a quick introduction. The Genex GX9048 then ran smoothly for two days of mixing without a hitch, happily chasing timecode from the mixing console transport panel. In my opinion, the source material was slightly enhanced by going on and off the DSD recorder – just a little extra sense of air in the top end.


The GX9048 is already a very capable multitrack hard disk recorder and, in the true spirit of Genex, it is still evolving. The option of either using the very high-quality Genex A/D converters or outboard units with slightly different characteristics makes the unit very flexible in the field or at the studio. Running 48 tracks of DSD or 192 kHz/24-bit was heretofore considered a science experiment at best – at this point I think we’re OK to remove the lab coat and safety goggles, and get to work.