With new PCI audio I/O cards becoming available for PCI Macintoshes and newer PCs almost every month, it's good to know that those with NuBus Macintoshes aren't being totally forgotten. Mike Collins checks out the first products from Symetrix's new division,Lucid Technology.
So, it's finally happened! The very thing I've been suggesting in various articles on the subject of Macintosh MIDI + Audio software over the previous couple of years: an affordable NuBus board has finally been developed for the Mac, to provide the S/PDIF input and output that's sadly missing from older Macs.
Lucid Technology, a new division of Symetrix (see the interview with Dane Butcher of Lucid in SOS January 1997), have developed two new digital hardware products for the Macintosh, the NB24 digital I/O card for NuBus Macs and the ADA1000 20‑bit analogue‑to‑digital and digital‑to‑analogue converters — which are packaged together in a 19‑inch, 1U, rackmount unit at a budget price.
The NB24 allows S/PDIF digital audio equipment, such as DAT machines and CD players, to be used as an audio source for hard disk recording on the Mac, or the Mac to be used as a source of S/PDIF digital audio for DAT players. The NB24 is ready to handle 24‑bit audio, although Apple's Sound Manager, through which the NB24 operates, currently supports a maximum of 16‑bit audio. Future versions of Sound Manager will probably support 24 bits, so you'll be able to use 24‑bit converters and any applications that support 24 bits with the Lucid board when Sound Manager is upgraded.
Getting It All Working
The NB24 fits easily into a vacant Macintosh NuBus slot — and no further hardware configuration is necessary. You simply connect the card's input to the digital output of a DAT machine, A/D converter or CD player and connect the card's output to a DAT machine or D/A converter. Once the hardware is in place, you start up the computer, place the supplied NB24 software driver in your Mac's Extensions folder, and restart your computer. The only thing to watch out for here is that Cubase VST users should use Lucid's version 1.01CB drivers, while Deck users should use version 1.02DK.
The way that most applications make use of the NB24 is by selecting the Apple Sound Manager as the audio I/O hardware. You can then select the NB24 as the Input and Output Device from your Mac's Sound Control Panel. Sound Manager will then redirect the audio through the NB24 rather than through the computer's built‑in audio hardware. So, once your computer has rebooted, you open the Apple Sound Control Panel, select Inputs from the menu, and check that you can see the Lucid NB24 icon, as shown in Figure 1. Then you open the Outputs panel and select the 44.1kHz/16‑bit stereo options (see Figure 2) — and that's it!
The NB24's input will lock to whatever sample rate the digital input signal is running at — normally 48kHz, 44.1kHz or 32kHz — while you select the output rate using your Mac's Sound Control Panel. The supported output rates are 48kHz, 44.1kHz and 22.05kHz, and the NB24 can also lock to an external clock running from between 32kHz to 48kHz.
Compatibility
In theory, any piece of software that can use the Apple Sound Manager will work with the NB24, although in practice some software will not work properly without special drivers — such as Cubase VST and Deck, as mentioned above. The Lucid documentation also warns that you can only work with a restricted number of audio tracks using Logic Audio. Other applications that have been tested successfully by Lucid include BIAS Peak v1.x, Macromedia SoundEdit16 v2 and Deck v2.2, Infinity Looping Tools, Digidesign Session v2.0 and Pro Tools Power Mix, Opcode Audioshop and Adobe Premiere v4.0.
There are a couple of other points worth mentioning here. The NB24 will not work with software that does not allow use of, or bypasses, the Apple Sound Manager — so it won't work with Digidesign's Sound Designer II, for instance.
Also, Apple have changed the way the Sound Manager works — it is now built into Mac OS 7.6 — so the Lucid board is unlikely to work with the new version of Mac OS until new drivers have been tweaked for use with the NB24. This may also be the case with any audio software that uses the Sound Manager, so don't forget to check with your dealer before you buy if you want to work with System 7.6.
In Action
I installed the Lucid board on my Quadra 950 so that I could check it out with a range of MIDI software. I used System 7.5.1, OMS 2.3, DAE/DSI 2.95, and Sound Manager 3.2.1, with Sound Control Panel 8.0.5. I wasn't able to test the NB24 with MOTU's Digital Performer or Steinberg's Cubase Audio XT, as they only work with Digidesign's DAE (Digital Audio Engine) and hardware at present, not the Apple Sound Manager. The other Steinberg alternative, Cubase VST, only works on a Power Mac, and not with my Quadra 950. [We're also told that Cubase VST will only become compatible with the Lucid driver from version 3.5 onwards, which is currently set for late summer release — Assistant Ed].
I also had a few problems with Opcode's Studio Vision v3.0.6 — recording kept stopping of its own accord, and various glitchy, clicky sounds were superimposed on the audio I recorded — although apparently further tweaks to both Lucid's driver and Opcode's software are in the pipeline to correct these. I am happy to report that SoundEdit 16 v2 worked fine, as did BIAS Peak v1.0.
To test the quality of the A/D converters, I recorded a piece of music, using Peak, from my DAT player, connecting the analogue outputs to the analogue inputs on the ADA1000. I then recorded the same piece of music using a Digidesign 442 interface and 4‑channel card using Deck v2.5. Deck v2.5 allowed me to work with eight tracks of audio using this card, although I only used two tracks for the test.
I had to use Pro Tools with Deck, as I couldn't get Deck 2.5 to work using the supplied v1.02DK driver software — although this driver software should work with Deck v2.2. Deck v2.5 did boot up with the 1.02DK driver software installed, and even offered me 12 tracks to play with running on my Quadra 950 with an external 1Gb Fujitsu drive — but, like Studio Vision, it simply would not record more than a few seconds' worth of music successfully.
For playback, I decided to output the audio from the Mac digitally via the Digidesign 442 interface, taking a digital output from the Digidesign card into my Yamaha 02R mixer, so I could use the 02R's D/A converters. This took the Lucid and the Digidesign D/A converters out of the picture, so that I could listen for any differences in the audio quality due to the performance of the Lucid and Digidesign A/D converters. I put the stereo files of the test recordings made using the two different sets of converters into Pro Tools to audition them, swapping between the version recorded with the Lucid converters and the version recorded using the Digidesign converters. After adjusting the playback levels of each pair of tracks to match as closely as possible (within less than a dB), I focused my attention on the different instruments in the mixes, as well as the overall mixes. At first, it was quite difficult to tell them apart, and it was only after careful listening that the differences became more apparent. The Digidesign interface won out, but you would expect that of a system that cost at least four times the current price of the Lucid system! The general sound quality was smoother, the bottom end fuller, and the top end clearer. Having said this, if I stopped concentrating so hard and turned my attention even slightly away, I could quite easily forget about these differences. On balance, I preferred the Digidesign 16‑bit converters to the Lucid 20‑bit converters, but if I was on a budget, I would definitely be more than happy to use the Lucid converters. The ADA1000 D/A converters also sounded fine.
Conclusion
From my experiences, it seems that several software packages which work with the Apple Sound Manager will not work properly with the Lucid NB24 — although the forthcoming software updates and new drivers from Lucid should sort all this out fairly soon. At the time of writing, MacroMedia were still in the final testing phases with Deck 2.5 and the Lucid card, but it's almost certain that by the time you read this Lucid will have drivers for Deck which work with version 2.5 or later, and Macromedia will have completed testing of their software with the card.
On paper, the ADA1000/NB24 system offers more dynamic range and a better signal‑to‑noise ratio than the Digidesign Pro Tools system with which I compared it. Having tried both systems side by side, I did prefer the sound of the Digidesign system, but I liked the extra tracks available using the Lucid system — especially at the extremely reasonable asking price. And those on a very low budget can simply get the board and use this with a DAT machine with reasonable quality converters.
The Lucid system is a great choice for anyone using a NuBus Mac who wants to work with digital audio. It even gives you 16‑bit or up to 48kHz audio on a Mac with 8‑bit audio hardware. And the ADA1000 converters are more than good enough for all but the more demanding professional applications. All in all — great value for money!
Looking To The Future — From Nubus To PCI
Lucid Technology have designed the NB24 board for NuBus Macs first, working on the basis that there are still plenty of these models in use around the world. As most of you will be aware, all the Macs currently being produced use PCI slots, so Lucid will be following up with their PCI24 and PCI24 DSP boards over the coming months. The PCI24 board version is almost at beta‑testing stage, and this will have both S/PDIF and AES/EBU interfaces. A couple of months later, there will be a PCI24 DSP board with S/PDIF, AES/EBU and stereo analogue in and and out. This will also have DSP on board, and will be bundled with a selection of Waves plug‑ins. Featuring 6Mb of onboard RAM, this board will allow you to create effects that need a lot of RAM — reverb, filtering, and so forth. The PCI card will also have sample‑rate conversion at the input stage, so you can put 48kHz audio in and get a 44.1kHz file on disk. This will be very useful for people who have DATs recorded at 48kHz and need to get this into the Mac to burn a CD at 44.1kHz.
Any of these cards can be paired with the ADA1000 converters, making a very cost‑effective package which should appeal to the many musicians now using Macs. Ultimately, though, the PCI cards are where the main interest will be. These cards will initially only be available with Macintosh driver software, but Lucid will also be developing a PC driver so they can sell their boards into the larger PC market.
It's More Fun To Convert — The ADA1000
The ADA1000's technical specifications are quite respectable, with a signal‑to‑noise ratio of better than 95dB (A‑weighted) and a frequency response flat to within 1dB between 20Hz and 20kHz quoted for the A/D converters. At 90dB (A‑weighted), the D/A section is not quite as good on the signal‑to‑noise figure. The total harmonic distortion and noise figures are better than 90dB and better than 81dB respectively.
The front panel has three main sections, containing the input level controls, the D/A status indicator and the A/D sample rate selection. You get rotary controls for left and right analogue input levels, and a Stereo Link switch lets you use the left channel input control as a master control for both left and right input levels. An associated Signal Present LED indicates that you have an analogue audio input present. To the left of the rotary controls there is a Headroom meter. This is a row of LEDs, calibrated in 4dB steps, designed to show the amount of signal headroom available before clipping. As with all A/D converters, it is best to run the signal as high on the headroom meter as possible without hitting the clip point. To avoid overdriving the A/D converter, you should test the signal coming into the ADA1000 for the highest peaks and then adjust the input level controls so that peaks don't cause the Clip LEDs to light.
To let you verify that the connections are correct when you first hook up the ADA1000 to a digital device, there is a Signal Present LED in the D/A Status section. This indicates that there is a valid AES/EBU or S/PDIF format digital signal at the ADA1000's digital input port. Once a valid signal is present, the ADA1000's D/A circuitry automatically locks to the sample rate of the incoming digital bit stream. Four buttons at the right of the front panel let you choose between fixed sample rates of 48kHz, 44.1kHz and 32kHz, or a sample rate as determined by the sample rate coming into the digital input port.
The inputs and outputs are on the back panel, and both AES/EBU (via XLR) and S/PDIF (via phono) digital formats are supported, with a switch to let you flip between S/PDIF and AES/EBU formats. For analogue input and output, both XLR and quarter‑inch jack connectors are provided. Finally, the ADA1000 uses an external AC adapter. There's a Power Indicator LED on the front panel, although there's no on/off switch.
Pros
- At last — a digital audio input and output NuBus card for the Macintosh.
- Extremely simple to install and configure.
- The ADA1000 interface complements the board perfectly and
Cons
- Some work still needs to be done before the NB24 will work
Summary
These products deliver the goods — digital audio input and output, and support for 16‑bit audio at a range of sample rates, even on Macs that only have 8‑bit audio built‑in.