RME's DIGI range of soundcards offers comprehensive cross‑platform support, high audio quality and lots of extras, such as digital format conversion.
Founded in 1996, Germany‑based RME Audio have gained an enviable reputation over the last few years, largely for their excellent Hammerfall range of soundcards (reviewed in SOS September 1999), which provide rock‑solid performance with low latency settings. This is possibly because they develop all their hardware in‑house, including lower‑level components such as the PCI and ADAT interfaces, giving them full control over every aspect of the design. Their products have also appeared in disguised form from other manufacturers such as SEKD (as the PRODIF range) and Steinberg, who currently market both a rebadged Hammerfall and DIGI 96/8 PST model.
The subject of this review is another member of the DIGI 96 range, which currently consists of five models. The basic model is the DIGI 96, featuring a single S/PDIF optical in and out; the 96/8's optical I/O is switchable between S/PDIF and eight‑channel ADAT formats, and the 96/8 PRO adds an XLR connector for AES‑EBU compatibility and a stereo analogue output. The 96/8 PST foregoes the XLR connector in favour of a stereo analogue input, while the DIGI 96/8 PAD is the model under review here. As the flagship of the range it incorporates every feature of the others in one card, giving it an S/PDIF co‑axial in and out, an optical in and out switchable between S/PDIF and eight‑channel ADAT formats, AES‑EBU in and out on XLRs, and 24‑bit/96kHz stereo analogue I/O.
The DIGI 96/8 PAD is a compact 5.5‑inch PCI card, featuring a pair of stereo quarter‑inch jacks for the analogue I/O — users will need some sort of splitter lead to separate the left and right channels for connection to other gear. Completing the backplate socket quotient are two Toslink sockets for optical duties, and a nine‑way D‑type connector for attaching the supplied adaptor lead. This is about nine inches long and carries an in‑line XLR plug and socket for AES‑EBU connection, plus a pair of in‑line phono sockets for co‑axial digital I/O. Also on the backplate is a useful red error LED that remains lit until a valid signal is detected at any one of the digital inputs.
On the card itself are various additional connectors and jumpers. There's a digital input suitable for connection to a CD‑ROM's digital output, or to synchronise another DIGI card, and a Sync output for which a suitable short cable is also supplied. A pair of jumpers lets you switch analogue input sensitivity between ‑10dBV and +4dBu: it's a shame that this can't be done by software switching, but this preset approach does tend to make for a cleaner signal path. The default 'jumper in place' settings are for the more sensitive ‑10dBV, but if your gear will provide the required +19dBu for 0dBFS, you'll get slightly lower noise levels removing them. Finally, two three‑pin connectors are also provided to connect the optional WCM (Word Clock Module).
- Analogue connectors: unbalanced quarter‑inch stereo jacks.
- Analogue inputs: two, unbalanced, nominal level +4dBu/‑10dBV (selectable using jumpers).
- Analogue outputs: two, unbalanced, nominal level +10/+4/‑2/‑8dBu (software switched).
- A‑D converters: AKM AK5383, 24‑bit, dual‑bit delta‑sigma.
- D‑A converters: Analog Devices AD1852, 24‑bit.
- Dynamic range: Input 109dBA, output 112dBA.
- Total harmonic distortion + noise: <0.001%.
- Frequency response: 5Hz to 44.8kHz, ±0.5dB, at 96kHz sample rate.
- Channel separation: >110dB.
- Digital connectors: Toslink optical, in‑line phono co‑axial, XLR AES‑EBU.
- S/PDIF jitter: <1nS in PLL mode (44.1kHz, optical in).
- ADAT jitter: <2nS in PLL mode (44.1kHz, optical in).
- Supported bit depths: 16, 20, and 24.
- Supported sample rates: 32, 44.1, 48, 64, 88.2, 96kHz, and variable (word clock).
I'm pleased to report that the DIGI 96 series not only has drivers for Windows 95/98 and NT 4.0, but also for Windows 2000, Mac OS, and even Linux, Unix, and Solaris. There have been dozens of releases for all the various platforms, each either curing bugs, improving performance, or adding new features. I downloaded the latest version 4.96 drivers for my PC running under Windows 98SE. These support any combination of DIGI 96‑series cards, as long as they are sync'ed together, either by using a common clock signal at their inputs, or by using the optional word clock module mentioned previously.
The DIGI was correctly detected without a hitch, and I was up and running within a couple of minutes, with a new shortcut and Taskbar icon, both of which launch the comprehensive Settings utility.
The Windows 95/98 drivers support MME, DirectSound, ASIO 2.0, and GSIF, as well as full multi‑client operation as long as all applications use the same audio format. You can even set up different sample rates at input and output if desired. Windows normally sees the ADAT input and output as four stereo pairs, although an eight‑channel single device is also supported. The ADAT mode is fairly transparent to use: once your software accesses more than two tracks, it switches into this automatically.
The digital I/O is very versatile, with a Mixed mode allowing you to select ADAT in and S/PDIF out or vice versa, while SyncAlign ensures that whatever you choose, all the channels remain in sample‑accurate sync with each other. Input clock can be set to Optical, Co‑axial, Internal, XLR, or Analog, or you can use the AutoSelect option to search among the digital inputs for a valid clock signal to lock onto. An Input Status window displays the current settings. Along with the error LED on the card's backplate, this makes tracking down digital problems comparatively easy, especially with helpful error messages such as 'No Lock', 'Out Of Range', 'Stereo', or 'ADAT'. I was also impressed by the attention to detail with options such as Check Input, which prevents recording if (for instance) you've selected a 44.1kHz sample rate in your software, but the detected input clock is at 48kHz.
There are three options for general monitoring: Automatic patches the input signal to the output when it's activated for recording, while Play Only prevents this causing digital howlround when patched to a digital mixing desk, and Input patches real‑time signals through to the output whenever playback isn't active. Zero‑latency monitoring is available both as Punch I/O mode when using Samplitude, and when using the ASIO 2.0 drivers in any suitable host application.
When in ADAT mode you can select which pair of channels to monitor through the D‑A converters and analogue output, while in S/PDIF mode, the analogue output defaults to channels 1 and 2. Various options such as Consumer/Professional format and Emphasis can be altered to taste on all digital outputs, and the card creates a completely new header for widest compatibility with other digital devices. The analogue output has four‑way switched attenuation, along with variable faders, so that you can adjust output level over a 72dB range. This makes it compatible with virtually all external gear, as well as handy for headphone monitoring.
Force ADAT mode lets you record or play back stereo files, but transfer them to an ADAT device. You just select which of its four pairs to use inside your software application. In conjunction with the Input monitoring mode, you can use this for real‑time S/PDIF to ADAT conversion, and the stereo input signal is then copied to all four stereo pairs at the output (sadly, this function isn't currently available in the NT or 2000 drivers). Conversely, selecting A/S Conv converts an ADAT input to S/PDIF output: you can choose which one of the ADAT stereo pairs is routed to the S/PDIF output using the Track buttons.
It can get confusing dealing with digital clocks manually, but unless you do it correctly you'll end up with skips and jumps in your audio. To make things easier, RME provide an intelligent AutoSync mode that sticks with the low‑jitter internal clock unless a valid clock is detected at the active input, when it switches over automatically. This should be a great help during 'on the fly' recordings, since you don't have to rely on the external clock being present before you start, and it also enables multiple DIGI cards to be synchronised from one input signal. However, there are some situations in which this mode can cause digital feedback, when you should switch the card to Master clock mode. A third Word Clock option is available if you've fitted the optional WCM module.
Unusually, while the A‑D converters are from AKM, and employ the AK5383 chip also found in M‑Audio's flagship Delta 1010 model, the D‑A converters are from a completely different company: the Analog Devices AD1852 chip. Listening tests against my new benchmark Echo Mia proved that these D‑A converters were well up to scratch. There were subtle differences between the two, with the Analog Devices AD1852 of the RME card having a marginally sweeter, more natural, and open sound than the AK4528 of the Mia, as well as slightly better stereo imaging. However, on some material I preferred my Mia, so it was a close‑run race.
The A‑D converters also performed well, and I measured the RMS background noise at ‑109dB in 24‑bit/44.1kHz mode — an excellent figure, and identical to that of M‑Audio's flagship Delta 1010, which uses the same converters. Doubling the bandwidth to 24‑bit/96kHz reduced this to ‑101dB, again in line with the Delta 1010, placing these two cards joint best in my table of noise results.
Four ASIO buffer sizes are available, and I managed to run Cubase VST at the lowest 256‑byte setting, giving me a very good 6mS latency with a 44.1kHz sample rate. The GSIF drivers also worked flawlessly in GigaStudio, and after a few tweaks I did get both applications running simultaneously, although RME don't recommend this. Both the DirectSound and MME drivers also worked very well, giving me 15mS glitch‑free latency with the stand‑alone version of Pro 52.
When I first received this soundcard for review, I expected it to be a good all‑rounder for those who need to record, playback, and interface with a wide variety of digital and analogue gear. I was surprised at the number of unexpected features such as S/PDIF to ADAT conversion, intelligent AutoSync and the various ways to support multiple cards, and beyond all I was impressed by the attention to detail. No stone has been left unturned in the design and execution of this RME soundcard, and I repeatedly found myself wishing that my own had features such as the informative Input and Output Status displays, and the Check Input safe mode.
I haven't come across any other soundcard quite like the DIGI 96/8 PAD for comparison, but it does seem good value at £365 considering everything on offer, and would be an ideal choice for any musician with an ADAT or DAT recorder who wants to move into computer editing. There's no built‑in DSP monitor mixer for the inputs and playback channels as on some cards, but then these other cards don't provide the versatile ADAT and S/PDIF conversion options.
For those who don't need all its facilities, the other four members of the DIGI 96 series provide different feature sets at lower prices, while those needing more analogue I/O could add external ADAT‑compatible converters. The DIGI 96 series may have been around for several years, but it's a sign that RME got it right first time that they are still selling so well. As long as they carry on making and supporting them there's no reason why this shouldn't continue.