Classic Restorations

Setting Up a NuBus Power Mac as a Digital Recording Studio

- 2006.05.08

This "hopelessly outdated" Power Mac system can become a digital audio workstation with all the capabilities most basic users require.

The Digidesign AudioMedia II NuBus card (also see Integrating Vintage Macs into a Home Studio) is still a fine-sounding piece of equipment after all these years. Yes, a TASCAM DA-30 DAT player sounds better. Yes, several midrange and high-end 24-bit/96 kHz interfaces sound better. But those all cost a lot more than the venerable AMII goes for these days (about US$25 on eBay), and CDs produced in the 80s and early 90s using this card don't sound any more dated today than they did 15 years ago.

For someone with the bug for vintage Macs and the desire to record audio, a workstation built around the AudioMedia II can be a great, inexpensive choice. Today, we'll convert an unloved Power Macintosh 8100 into a powerful and versatile tool to capture, manipulate, and prepare music.

The Requisite Hardware

We've already decided on a DigiDesign AudioMedia II NuBus sound card. Any of the other DigiDesign ProTools NuBus interfaces would also work, but setting them up could be more complicated.

AudioMedia II provides stereo input and output of sound in 16-bit depth at 44.1 kHz (CD) and 48 kHz (DAT) sampling rates.

Digital (coax S/PDIF) and analog (dual RCA jacks) input are separate and cannot be used at the same time. The digital and analog outputs are both active at all times and output the same sound.

This card has a built-in Motorola DSP (Digital Signal Processor) chip that we'll be almost completely ignoring - because our Power Mac is faster and more capable. We'll be using the AudioMedia II, because of its great signal/noise ratio and extremely high quality analog-digital converters.

Now that we've chosen a NuBus card, we need a powerful NuBus Macintosh for it to live in. Any of the Power Macintosh 7100 or 8100 models make a good choice. Word on the street suggests that some may be better than others: 80 MHz machines are preferred for their 40 MHz bus speed, and second-wave models (8100/100, 8100/110, 7100/80, and Radius System 81/110) come with an improved ROM SIMM.

If you have several NuBus Power Macs to choose from, by all means pick the best one or even mix-n-match. Upgrade the ROM SIMM or overclock the bus if you're able. But if you're stuck with the Mac you've got, don't despair. These differences aren't important unless you're tweaking for ultimate performance.

It's important to have a separate physical hard drive to hold the audio data, and the speed of this drive is very important. I use and recommend a hard drive with a spindle speed of 10,000 RPM. Any reasonably modern 10K SCSI drive will be more than fast enough, so choose whichever one you like. In a pinch, a 7200 RPM disk made in the last five years or so will probably be okay as well.

eBay is a great place to look for deals on used high-performance drives, as is the local computer "buy, sell, and trade" shop.

Whichever drive you choose, make sure it has a 68-pin SCSI connector; 80-pin drives will be cheaper, but you'll have to use a potentially expensive and unreliable adapter.

Your boot drive (the one with the System Folder) isn't speed-critical; anything reliable is okay to boot from.

Enough RAM is very important. While you might be able to eke out a few recordings with very little memory, RAM is cheap and not worth struggling over. Try to get a few 32 MB SIMMs - or at least a bunch of 16 MB ones. You'll thank yourself later.

Optional Cards You'll Want

A G3 upgrade card isn't really necessary to do 16 tracks on an 8100, but once you've tried one, you'll never go without. The general feeling of system responsiveness is dramatically improved, and you'll have access to many more realtime effects. The stock CPU might lumber along with a filter or two, but even a slow G3 will handle 16 tracks along with a dozen or more effects and still have room to breathe.

Fortissimo G3 Warning

Prices for Sonnet Technologies G3 upgrades are very low on eBay right now, and the cards themselves are plentiful. An important caveat to watch for is the Fortissimo bus-doubling magic technology used in 400 MHz and faster Sonnet cards. Numerous users have reported gross incompatibilities between Fortissimo technology and DigiDesign NuBus cards. For safety, stick with the 300 MHz and slower Sonnet cards or the excellent NewerTech MaxPowr upgrades. Sonnet briefly offered a G4 upgrade for NuBus Macs, but I have never been able to test one in a digital audio editing rig.

A NuBus Fast/Wide SCSI card, such as the FWB JackHammer or ATTO SiliconExpress IV, can improve the speed and responsiveness while editing.

Am I saying that a high-performance modern hard drive is essential but a SCSI accelerator is optional? Yes, I am. When playing back many tracks of audio, the raw MB/s transfer speed isn't very critical, but the speed at which the drive can seek a particular track is. In this application, hooking a modern 10,000 RPM hard drive to your Mac's slow internal SCSI bus makes sense.

While adding a SCSI accelerator can't improve a drive's access time, it can increase megabytes per second. With my 10,000 RPM hard drive attached to the 8100's internal bus, I can do 16 tracks, but there's a buffering delay of about 1.5 seconds between pressing play and hearing sound.

When I attach the same drive to the JackHammer NuBus card, that delay drops to about one-half second. The speed of disk-based effects plugins is almost doubled, too. Adding a SCSI accelerator improves the responsiveness of your system, but it's not strictly necessary.

A high-end NuBus video card is often one of the first upgrades to any vintage system. I don't recommend it for digital audio. Here's why: When using the AudioMedia II NuBus card - and especially in conjunction with a NuBus SCSI accelerator - the NuBus' limited bandwidth is already getting hammered. Adding a NuBus video card only increases the burden, and we're not doing anything graphically intensive that requires a fancy video card.

If you really need high resolution, PDS video pass-thru adapters come with most G3 upgrades and let you keep your HPV card. If 832 x 624 is good enough for you (it is for me), I recommend using the built-in video of the 7100 or 8100.

In back-to-back testing using motherboard video and a Radius PrecisionColor Pro 8XJ NuBus card, I found the motherboard to have a very slight advantage when doing multitrack audio. Not only does it help save a little NuBus bandwidth, it also frees a precious slot. How else can an AMII, JackHammer, and SampleCell all fit inside an 8100?

More Expansion!

A SCSI CD-R or CD-RW drive will fit nicely in the Mac's internal CD-ROM bay and take the place of the original 2x read-only drive the 7100 or 8100 came with. Speeds available from older 50-pin SCSI CD recorders are not amazing by today's standards; they top out at about 6x.

When mastering audio CDs to send for production, it's best to burn at the slowest possible speed to minimize the chance for subtle, distorting errors. Many newer drives can't go slower than 8x or 12x, so that old "awfully slow" drive might actually be better, since it will probably be able to burn at a poky but accurate 1x speed. Your patience will be rewarded.

A MIDI interface, such as the Midiman Mini-MacMan or MOTU MIDI TimePiece, can bring a greater degree of freedom to your music-making than hard drive recording alone offers. Nearly any music imaginable can be input on a MIDI keyboard and played back through a choice of thousands of synthesized instruments. From bongos to violins or even a nine-foot Steinway, many instruments you don't own have their sounds on tap in sample libraries.

As a first step, your MIDI keyboard probably has a few hundred instruments built-in, and several of these can be played back simultaneously when the keyboard is under MIDI control from the Macintosh. Even more flexibility is available from rack mounted synthesizers or the DigiDesign SampleCell II NuBus card, which can be used to make an instrument from any sound clip you can record!

Make sure to reserve two spare audio tracks for all the synth instruments in the final mixdown; they're generating their sounds independently from the Macintosh and will need to be patched in at the end. I believe this inconvenience is a small price to pay for the flexibility of synthesizers and the joyous frugality of using a vintage Mac workstation.

A small mixing board makes a great jumping-on point for sound going to the AudioMedia II. Choosing one with built-in preamplifiers and phantom power will allow use of any microphone you can find. Having direct control over the sound before it enters the Mac also makes getting those levels "just right" so much easier. With an appropriate mixer in-between, you can plug an electric guitar or Rhodes piano right into the Mac and rock out or access that Hammond organ for your easy listening pleasure!

That's All for Now

Including my footnotes, I can feel 2,000 words coming up fast, and we haven't even discussed software yet! There's lots of vintage software available that's great for this Power Mac 7100 or 8100 with Mac OS 7.6.1. Some of it is commercial software that you'll need to find used, but there's enough in the free-and-clear to put together a working studio.

If you're using a PCI Power Mac with Mac OS 8.6 or newer, your freeware choices are even broader.

Be sure to come back next time, when I'll touch on some of the best free choices for both older and newer vintage systems, as well as some reasonably priced commercial offerings.

Until then, may the sun shine positively on your vintage Mac workstation! LEM

1. When these machines premiered much fuss was made about the 7100/66 and its lackluster NuBus performance. Apparently, the NuBus controller chip wants the system bus speed to be an even multiple of the NuBus speed. Since 33 doesn't divide nicely by 10, the NuBus controller supposedly doesn't work efficiently and performance suffers.

Also, when installing a G3 upgrade the bus speed is multiplied to find the G3 speed, so an upgraded 7100/80 is faster than an upgraded 8100/100. The daring may try overclocking the 7100/66, 8100/100 and 8100/110 models to gain the benefits of the 40 MHz bus.

2. In response to my previous column about RAID performance on NuBus Macs, reader Alex Timbol wrote me about this improved ROM SIMM. A bug in the first ROM causes NuBus performance to be degraded; the bug was fixed in the later ROM. I happen to have one ROM of each version, so I tested them back to-back in my G3-upgraded 8100/80.

Megabytes per Second benchmarks on a JackHammer-connected drive showed no improvement, but other tests had better results. With the old ROM my 8100 would crash after about 15 minutes of playing 24 looped tracks in Deck. With the newer ROM, it's played for hours without a hitch - a difference that means a lot.

Each version can be most easily identified by the copyright date printed directly on the black computer chips themselves. The older ROM version will say "(C) 1983-93 APPLE" while the newer version reads "(C) 1983-94 APPLE".

3. If you have used a NuBus G4 upgrade for music or audio work, please email me and tell me about the experience.

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