Pro Tools/24 sounds like a hit; Expandable digital workstation has great 24-bit audio

MacWeek, Feb 16, 1998 by Steven Roback

Pro Tools/24

A new 24-bit standard seems imminent for digital audio recording, and Digidesign's new Pro Tools/24 is poised to take full advantage. Replacing the 16-bit Pro Tools III PCI as Digidesign's top-of-the-line digital audio workstation, the Mac-only PT|24 features 24-bit hardware and enhanced Pro Tools 4.1 software.

The $7,995 PT|24 core system includes a new d24 I/O audio interface card, a DSP Farm card and Pro Tools 4.1 software. The d24 provides up to 32 tracks of simultaneous 24-bit or 16-bit recording and playback, depending on your system.

Unlike the Pro Tools III Disk I/O card, the d24 has no fragile SCSI port; instead, the system uses the Mac's SCSI bus. For optimal 24-bit performance you'll need a Fast and Wide Ultra SCSI-3 hard drive connected to the Mac's internal Fast SCSI-2 bus or a SCSI accelerator card connected to an external Fast SCSI-2 hard drive. Except for Apple's G3 minitowers, PT|24 does not support SCSI accelerator cards on three-slot Macs.

The DSP Farm card -- the same found in Pro Tools III PCI -- contains four Motorola DSP chips that efficiently allocate signal processing to real-time TDM (time division multiplexing) DSP plug-ins. Even so, signal processing tends to max out rather quickly.

You can expand signal processing by installing additional DSP Farm cards into your Mac's open PCI slots or an expansion chassis. But at $2,495 per additional Farm card, signal processing can get expensive fast. If you already own some good outboard gear, an alternative is to create an external effects loop using Pro Tools' hardware I/O capability and use some of your existing effects.

You'll also need an audio interface with 24-bit analog-to-digital converters. While other excellent stand-alone converters exist, such as Apogee Electronics Corp.'s $5,995 AD-8000, the new Digidesign 888|24 Audio Interface (which is not included in the core system) sounds extremely good and is a fair deal at $3,495.

The 888|24 has eight balanced analog I/Os (XLR) with 24-bit analog-to-digital and 20-bit digital-to-analog conversion, with sample rates of 48 kHz and 44.1 kHz. You also get four stereo 24-bit digital I/Os (XLR). Depending on your needs, you can use the 888|24 as a stand-alone 24-bit A/D or 20-bit D/A converter, or as a 16-bit A/D converter with Pro Tools III PCI.

Modular expandability is one of Pro Tools' best features. You can start with the core system and add DSP Farm cards and 888|24 I/Os as needed, up to 72 channels of I/O; or choose the $5,995 Pro Tools/24 Expansion Kit, which includes an additional d24 and DSP Farm card for up to 64 tracks. Strong third-party support for TDM and AudioSuite plug-ins also gives you many DSP options.

On to the software

Pro Tools 4.1 offers versatile recording, editing and mixing features with a sensible interface that closely models a recording studio. The new release adds full support for 24-bit audio and Mackie Designs Inc.'s HUI Controller, which uses MIDI to provide a tactile mixing interface.

DSP enhancements include improved TDM equalization plug-ins and an automated TDM plug-in Bypass button. AudioSuite plug-ins (destructive effects) now include one-band and four-band EQs.

Pro Tools 4.1 also fully supports the Digidesign Universal Slave Driver, which combines into one unit the sync functions of Digidesign's SMPTE Slave Driver and Video Slave Driver.

For our tests we connected an 888|24 I/O to a PT|24 core system on a Power Mac 9600/350. Using a SCSI accelerator card we achieved 24 tracks of 24-bit audio as expected. Recording with PT|24 was a pleasure; despite some coloration, the sound was startlingly big and clean.

While things can get cramped on a 17-inch monitor, the ability to quickly expand or collapse sections of the Edit and Mix windows helps. The Edit window has easy-to-use selection tools and Track and Group display lists. With five views per track you can zoom in fast to sample accuracy.

The Mix window is laid out like an actual mixing console, with five auxiliary sends and five inserts per channel. We had no problems using real-time TDM plug-ins, although our single DSP Farm card quickly maxed out, forcing us to create external analog effects loops. Still, we found many uses for TDM plug-ins, especially the included Procrastinator delay and the $995 Digidesign Intelligent Noise Reduction plug-in; Digidesign's $495 D-Verb reverb plug-in sounded tinny. The included Reverse and Pitch Shift AudioSuite plug-ins were handy, and mix automation was flawless.

We encountered no bugs or crashes in our tests. For us, the most frustrating aspect of the system was the lack of support for Digidesign's ADAT Interface, which left us staring blankly at our two ADAT XTs. (However, Digidesign's new $1,195 ADAT Bridge I/O, which supports 16 channels through two eight-track ADATs, will ship in March.) For others, Digidesign's customer support may be the most frustrating. While we had no problems, we've read many reports from unhappy users.

Conclusions

While some great pieces of 24-bit audio gear exist, none merges the essential elements of a pro recording studio into an expandable digital audio workstation as completely as PT|24. The system sounds remarkably good and is fast and easy to use.