Mac Pro Need to Know: audio Computing in the Post-PCI Era

Must-have information for musicians working with Mac Pro
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It’s been nearly two years since apple unleashed its cylinder-shaped Mac Pro—a new best-in-class machine. Yet there’s been virtually no attention paid to said pro-grade Mac in the pages of Keyboard. Frankly, we haven’t heard much from our readers about it. How could this be? In this extensive tech feature-meets-gear roundup, we aim to explain the problem—and the solutions.


Many professional musicians and engineers with older Mac Pros simply weren’t interested in making the switch. After all, the design is such a radical departure from the aluminum tower we’ve known since 2006. Gone are the internal hard drive bays and PCI slots many of us have relied on for connecting audio interfaces, plug-in DSP cards, and swappable hard drives.

The “late 2013 model” also ushered in a new operating system, OS 10.9, called Mavericks. A new OS can often disrupt a well-tuned ecosystem comprising digital audio workstations, third-party plug-ins, and dedicated audio hardware. This all gave music pros plenty of trepidation about making the leap. Hence, the relative radio silence from our readership.

But time has marched on, and those aging aluminum boxes at the heart of many readers’ systems are becoming increasingly obsolete. Migration is inevitable. To help make it easier, this article includes a primer on the Mac Pro’s external ports and connectors, a roundup of popular hardware options, and power-user Q&As with Doug Rogers of sound developer EastWest and film/TV composer Charlie Clouser about making the switch.

Though we mainly talk about the new Mac Pro, the advice we provide here is just as apropos if you’re considering a current iMac or Mac Mini, as both also lack internal PCIe slots and extra drive bays.


The current Mac Pro Apple’s second-generation Mac Pro offers very few internal expansion options, which is partly why music pros have been slow to switch. Instead, the MP’s rear panel (can a cylinder have a “rear”?) is neatly outfitted with a set of four USB3 ports, six Thunderbolt 2 ports, two Gigabit Ethernet ports, and a single HDMI connector. In particular, it’s important to understand what the USB and Thunderbolt ports offer and what they mean related to connecting storage devices and music hardware.

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Before diving into each connector type and communication protocol, let’s briefly talk performance. When it comes to making music with a computer, performance can be measured in a few ways, such as the number of total audio tracks that can be simultaneously recorded and played back, the number of CPUhungry plug-ins that can run at once, the amount of latency from when an audio signal enters the computer and is then output, and more.

The wonderful reality is that track count is largely a non-issue these days, thanks to improvements in storage technologies like solid-state drives (SSDs) and data transport formats such as Thunderbolt and USB3.1. Similarly, CPUs have made huge advances in the past few years to the point where all but the most power-hungry users won’t run out of resources for running soft synths. Nonetheless, that still leaves the questions: How many samplebased software instruments can be loaded and used simultaneously, and with how much latency?

For many professionals, achieving high sample and virtual instrument track counts with low latency is the ultimate goal. Getting there, however, can be tricky (and costly). For example, what storage devices and connection formats deliver the best performance? Let’s examine.

USB3. Universal Serial Bus (USB) has been around since the ’90s, and has been widely adopted by both Mac and PC developers. This is a good thing, as it means we can be reasonably sure USB isn’t going away anytime soon. And because the standard is built with backward compatibility in mind, it’s possible to integrate older USB1 and 2 devices such as MIDI keyboard controllers and hubs for software protection dongles. (While I was writing this feature I migrated most of my studio setup over to a new Mac Pro, and I had no problem connecting my Akai Advance 49 controller, Access Virus TI, and MOTU 1248 audio interface, all of which use earlier versions of USB.)

The Mac Pro’s USB 3 ports support a maximum speed of five gigabits per second (Gbps), which is plenty fast for recording multi-channel audio at 24-bit/44.1kHz to an external USB3 hard drive. However, USB 3.1, also released back in 2013 around the same time as the Mac Pro, delivers ten Gbps. (Check out “Past, Present, and Future” at left for some context concerning these specs.) So what does this mean for the Mac Pro? Maybe not much, other than it was already behind current technology when it shipped. It’s also now behind the current Thunderbolt technology, but I’m getting ahead of myself . . .

When discussing various flavors of USB (and Thunderbolt) it’s important to differentiate between the USB version and the connector type. Version refers to the speed of communication (e.g., USB2, also called “Hi-Speed,” delivers 480 Mbps). Version 1 was introduced in 1996, version 2 in 2000, and version 3 in 2008.

Connector refers to the physical shape of the plugs and receptacles. There are three standard types: A, which is commonly used to connect devices to a USB host; this is the type used on the Mac Pro; B, which is typically used to plug into a large device such as a printer or USB MIDI controller; and C, which is relatively new. USB type C (or simply USB-C) can support the current USB3.1 speed and is being hailed as the “hot new connector” by the computing industry for its small size, reversible plug orientation (similar to the iPhone’s Lightning cable) and ability to deliver more power than previous generations.

Boiling all of this down, USB on the Mac is better than it’s ever been as far as compatibility and performance. Because of USB’s backward compatibility and the fact that the Mac Pro uses type A plugs, you shouldn’t need any adapters or special cables to integrate older gear.

Thunderbolt. There’s been some comparison of Thunderbolt to FireWire. Like FireWire when it was first introduced, Thunderbolt offers faster speeds than current competing technologies such as USB, and offers some compelling features for both developers and end users. Also like FireWire, Thunderbolt has mostly been a “Mac thing,” with very little pickup from the PC world.

Because of this, FireWire is now fading and USB is still going strong. Some skeptics think Thunderbolt will follow FireWire into the tech abyss. However, recent developments may mean wider adoption by the Mac and PC markets, and therefore a more future-proof path.

Originally co-developed by Apple and Intel, Thunderbolt combined high-speed performance (up to ten Gbps) and multiple protocols, namely DisplayPort for connecting high-res monitors and PCIe (Peripheral Component Interconnect Express). PCIe is the same technology that manufacturers such as Avid, Universal Audio, Apogee, and MOTU have used in their flagship interfaces and DSP cards—cards that can’t be installed in the new Mac Pro, of course.

For many of us, this is half of the migration equation—what do you do if you have a PCIe-based music production system? The other half is, how do you incorporate hard drives that need to deliver large capacities and top speeds for sample VIs and audio recording/playback? Turns out, Thunderbolt is the best the solution to address both.

Because Thunderbolt supports PCIe, the market of Thunderbolt audio interface and expansion options has gained a lot of traction. Currently, there are dozens of native Thunderbolt interfaces available in different price ranges, even more Thunderbolt storage devices to choose from, and a small but growing number of PCIe expansion chassis, which allow you to use PCIe cards with computers that don’t have internal slots like the Mac Pro.

Like USB, Thunderbolt has gone through an evolution. At the time of its release, the Mac Pro shipped with Thunderbolt 2 ports, which was the current technology of the day. Not anymore. In fact, just as we started developing this article, Intel announced Thunderbolt 3, which doubles the speed (now up to 40 Gbps) and added support for more formats, including USB3.1.

Ultimately this is (mostly) a good thing, as it increases the odds that Thunderbolt will live a long life. However, Thunderbolt 3 uses a different connector, which may mean we need to use adapters and specialty cables if Apple decides to replace the Mac Pro’s TB2 connectors with the latest and greatest. Fortunately, Thunderbolt is backwardcompatible, so older TB-equipped devices should still work, provided you have a compatible adapter.

As mentioned before, the market for audio and storage solutions is growing. Depending on your budget, as well as your hardware installation chops (if using expansion chassis or hard drive enclosures), there are proven migration paths that you can take to make the move. The “Gods of Thunder” section (beginning on page 37) is by no means a complete list of available products, but it’s a good place to start if you’re ready to plan your next rig.


When it comes to connecting audio interfaces and storage devices via Thunderbolt or USB, there are many options to choose from. What we’ve included here was chosen based on our own experience and the recommendations made during the artist and developer interviews.


Universal Audio Apollo16 Quad ($2,999 list)

Universal Audio Apollo 16 Quad 18-in/20-out Thunderbolt 2 audio interface with 16 line-level inputs, UAD-2 Quad DSP and Realtime Analog Classics plug-in bundle. Line-level inputs can be used to return hardware synths into your DAW. Low-latency operation, plus two Thunderbolt 2 ports for daisy-chaining additional interfaces and storage devices.

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Apogee Ensemble Thunderbolt ($2,595 list)

Apogee Ensemble Thunderbolt 30-in/34-out Thunderbolt 2 audio interface with 24-bit/192kHz resolution and 32-bit playback, eight mic preamps, Soft Limit, two headphone outputs, and talkback mic. In particular, the Ensemble looks like a great all-in-one solution that delivers ultra-low latency, especially with Logic Pro X, thanks to custom PCIe drivers. We’ll be publishing a full review in an upcoming issue.

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MOTU 828x ($999 list)

MOTU 828x 28x30 Thunderbolt/USB2 audio interface with two microphone preamps, eight TRS inputs, eight TRS outputs, two XLR outputs, two banks of ADAT I/O, MIDI, Word Clock, and built-in mixer with DSP effects. Like its FireWire predecessor, the 828x is an affordable Swiss Army interface that offers good value and performance for mobile and studio applications.

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MOTU 1248 ($1,495 list)

MOTU 1248 32-in/34-out hybrid Thunderbolt/USB 2.0 audio interface with four mic pres, 8 x 12 line-level I/O, ADAT and S/PDIF digital I/O, AVB Ethernet compatibility and 48-channel DSP mixer with built-in processing and effects. The 1248 is part of MOTU’s new fleet of hybrid audio interfaces that are the first to include Audio/Video-Bridging (AVB) technology, which makes it possible to configure large-scale, flexible audio systems interconnected with inexpensive Ethernet cables and hubs. Also in this product line are the 16A (32-in/32-out with 16 x 16 line-level I/O, ADAT and S/PDIF digital I/O; $1495) and 8M (24-in/24-out with eight mic pre’s; $1495).

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Avid Pro Tools HD Native Thunderbolt with HD Omni I/O ($4,999 list)

Avid Pro Tools HD Native Thunderbolt with HD Omni I/O This bundle includes the HD Native Thunderbolt interface, which connects other Pro Tools interfaces such as the HD Omni I/O (shown) to a Thunderbolt-equipped computer. Functionally, the HD Native Thunderbolt interface acts as a bridge between existing Pro Tools HD audio interfaces, which can’t be connected directly to the computer. HD Omni I/O: two mic preamps, four-in/eight-out line, eight channels of ADAT I/O, two channels of AES/EBU, and two channels of S/PDIF.

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PreSonus Studio 192 ($1,199.95 list)

PreSonus Studio 192 If your needs dictate USB over Thunderbolt, this 26-in/32-out USB3 audio interface has eight remote-controlled Class-A mic preamps and supports USB3. Built-in DSP includes three-band EQ and dynamics. Monitor control section includes talkback mic and two headphone outputs with independent source selection.

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iConnectivity iConnect Audio 4+

iConnectivity iConnect Audio 4+ This USB 2.0 Audio Interface has four ins and six outs, with four mic/instrument preamps, 24-bit/96kHz operation, and MIDI. But the killer app here is the multi-host device ports that let you use two hosts at the same time—for example, a Mac and an iPad. Though only USB, the added iOS connectivity and low price point make this an attractive solution for those who opt for a more modest desktop machine such as an iMac or Mac Mini.

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BlackMagic MultiDock ($595 MSRP)

BlackMagic MultiDock Four-bay docking station lets you connect and hot-swap up to four SSDs or hard drives via Thunderbolt 2. Two ports for daisy-chaining. Supports 2.5“ SATA SSDs and Just a Bunch of Drives (JBOD) mode, a popular mode for hard drives configured for use with sample instruments. Other RAID configurations are also supported.

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Other World Computing ThunderBay 4 Mini ($339 list for enclosure; starting at $699 with SSDs pre-installed)

Other World Computing Thunder- Bay 4 Mini Four-bay 2.5" SSD enclosure with Thunderbolt 2 interface. Supports JBOD and other RAID configurations. OWC also makes a similar enclosure for 3.5" drives.

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Sonnet Echo Express III-D ($979 list)

Sonnet Echo Express III-D PCIe expansion chassis that supports three full-ength, full-height, single-width cards, or one double-width card plus one single-width card; Thunderbolt 2 interface supports 20 Gbps; can be upgraded to 40Gbps Thunderbolt 3 technology with a replacement interface card (not yet available). This allows you to use existing cards such as Avid’s Pro Tools HD|X series with non-PCIe-card computers.

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HighPoint RocketStor 5212 ($149 MSRP)

Two-drive bay with Thunderbolt 1; supports 3.5" and 2.5" drives, SSD and SATA, and hot-swapping. This is a very affordable way to integrate internal hard drives with the new Mac Pro. I personally use this with my Mac Mini slave machine.


EastWest virtual instruments are now available via cloud When was the last time you installed an application using physical media such as a CD-or DVDROM? Probably not recently. Thanks to blazing fast Internet speeds, developers can deliver their wares online, and most do, saving the time and expense of shipping.

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However, while it’s one thing to ask a customer to download a 2GB installer, it’s entirely another when file sizes are in excess of 40GB. Still, developers are pushing the limits—none more so than premier soundware maker East-West. Recently they introduced Composer Cloud, a subscription-based model that gives customers complete access to EastWest’s massive virtual instrument collection, including “Gold” editions of their orchestral libraries. Currently there are two plans: Student ($14.99 per month) and Complete ($29.99 per month). This effectively eliminates the cost barrier and opens up EastWest’s catalog to more new customers, who will likely need to invest in high-speed hard drives to get the most value and best performance. We caught up with EastWest founder Doug Rogers to learn more about Composer Cloud and gain a better understanding of the trends he sees among customers regarding current-generation Macs.

EastWest's Doug Rogers According to Rogers, a subscription plan such as Composer Cloud is unprecedented in our industry. “In the past, composers with limited budgets could only purchase a new product periodically,” he notes. “Now, they have access to everything we offer in Composer Cloud at an affordable monthly price. To give some perspective, at $29.99 per month, it would take 18-anda-half years to purchase everything in the current collection.”

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In response to whether Composer Cloud offers much value to existing customers, Rogers adds that “most of our customers don’t have the 50-plus products in our collection, and cherry-pick according to what they think they’ll need, missing out on some great inspirational collections in the process.

Composer Cloud gives them access to everything, and many users comment on our Facebook and Twitter pages that they’ve found so much inspiration in collections they never would’ve purchased outright.”

We learned even more from Rogers about hardware choices and trends among customers in hopes of providing you with actionable information. Here it is in Q&A format:

How many customers are Mac-based, and of those, how many have switched to the cylinder model?

We don’t collect system data from our users unless they require tech support, but with hard drive-specific format products such as Play (our virtual instrument engine) it’s pretty evenly split between Mac and PC.

Many of our Mac users have switched to the iMac with Thunderbolt because the price tag on the [Mac Pro] cylinder model is a lot more.

What are the main considerations your customers have expressed about switching to a post-PCI computer? Any trends?

In fact, we see most users getting rid of their old systems because USB2 and FireWire are too slow, performance-wise with sample-based instruments. There has been a move to the new generation of Macs, both iMac and “trashcan,” with the PCIe SSD and Thunderbolt or USB3. In particular, the Samsung 850 EVO SSD is popular [as an external drive] because of its great price, at around 50 cents per gig or less.

In our own tests we’ve found that the voice count from Play increases dramatically when using an SSD versus a spinning hard drive, and the load times are much faster. However, we don’t notice much difference in performance between hard drives connected via USB3 versus Thunderbolt 1.

What type of hard drive do you recommend? They should absolutely be using SSD on a fast connection, PCI-e being the fastest. SSDs have halved in price in the last two years, and the performance boost is worth the cost. They should also fill their computers with RAM, which is comparatively inexpensive. Both will dramatically improve performance more than paying extra for a faster CPU.


Charlie Clouser Former Nine Inch Nails member and full-time film and TV composer Charlie Clouser has been producing music with Macs for over 20 years. His scoring credits include all seven Saw films, Resident Evil: Extinction, Numb3rs, Las Vegas, and more recently Wayward Pines. We have a full interview with Charlie slated for our next issue (December 2015), but wanted to include his very useful technical advice here.

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What was your composition rig before you made the upgrade?

For about 12 years I didn’t change a single thing in my rig, except slightly upgrading the aluminum Mac Pro towers. For a long time I’ve been using two machines, one as my main writing computer, which runs Logic, and another one that runs Pro Tools. The second Mac is basically just a big multi-track recorder—everything I do in Logic gets fed into Pro Tools over ADAT light-pipe, and that’s what I deliver to the dub stage for TV and film.

For many years I’ve been using MOTU’s PCI-424 card that allowed me to connect up to four of their 24-channel interfaces. I would use one of the MOTU 2408s and one or two of their analog 24 i/o boxes to patch in synths and outboard gear. Those rigs never gave me any problems, ever.

I’ve never used FireWire interfaces. I’ve always used PCI, whether it was Pro Tools HD3 or MOTU. I went from the G4 to the G5 Macs and then later the Intel-based Macs, and along the way I had to change the different type of PCI cards, but basically my system stayed the same for almost 15 years.

When did you upgrade to the new cylinder Mac Pro and why?

I switched about nine months ago. For me, the reason to make the switch wasn’t because I was running out of CPU power—I wasn’t. It was that my whole system was made up of discontinued products. I had a pair of 12-core Mac Pros with the MOTU 2408 and ProTools HD3 TDM systems. It became too disconcerting to me that everything in my rack was discontinued. If any one thing broke or failed, then I would have to go to eBay or some other place to find refurbished and discontinued hardware. The potential for some sort of failure that would shut me down in the middle of my work became too great.

What finally pushed me over the edge was I bought a sound library that required Kontakt version 5.2, which wouldn’t install on Snow Leopard, which I was running on my old machine. So that started an avalanche.

How did you manage the upgrade?

I kept my old system “frozen” in place so I could go back to it and recall old cues if I ever needed to. Then I completely started from zero. As I said, it wasn’t that my older Macs were underpowered. With the new Mac, it’s all about everything else around it: How do I hook up external drives? FireWire? Do they even still make Charlie Clouser Firewire? Is it eSATA? I didn’t like any of these other options compared to Thunderbolt.

Part of what I liked, conceptually, about the new system was greater capacity for expansion with Thunderbolt. I get a lot more capability to daisy-chain devices, and for me it really came down to two pieces of hardware: the Blackmagic MultiDock four-bay storage rack and a 4k monitor.

I love the MultiDock because it’s so elegant. It has got no fans or moving parts, you can jam SSD drives into it like cassettes, and it hooks up via Thunderbolt so you can daisy-chain. This all started when I put some SSD drives in my old Mac Pro tower, which was a huge leap in performance. I eventually filled up the four internal drive bays on my tower, and then I added a PCIe card that let me connect two more SSDs internally. But I filled all of those up, and I still wanted more. That led me to the MultiDock.

Another big factor in my switching was display. For the longest time I’ve been using monitors that had the highest pixel density I could get. On my old rig I was using three 30-inch monitors at 2,560 x 1,600 pixels. That was fine for Logic 9, but when I tested Logic Pro X, everything felt crowded. I couldn’t zoom out enough, I couldn’t make the tracks small enough.

So I went to my local Apple store, and they had one of the new Mac Pro stations with a 4K monitor attached to it, and I launched Logic Pro X. Then I added 200 tracks to the session just to see how it would look. I was pleasantly surprised. It didn’t matter that everything was now big and chunky, for me it works on a 4K monitor. So my new system has a 32-inch 4K Samsung monitor, and it connects with a $15 cable I can get from any Apple or Best Buy store, instead of the expensive DVI-D cables I was using.

How is your new system configured?

My new setup is based on the new MOTU hybrid Thunderbolt/USB/AVB interfaces. As soon as those hit the market, I was on board. MOTU really knocked it out of the park with these. Yes, there were a few teething pains getting it all set up, and there aren’t a lot of other products that do AVB yet. But down the road, because AVB is an open standard and it’s inexpensive, I think more manufacturers will go there.

With the new MOTU interfaces, there’s so much flexibility, it’s changed the way I work. I’ve only gone as far as two interfaces, a MOTU 112d connected to my Mac Pro via Thunderbolt, and a 1248 connected to the 112d via Ethernet. I went with the 112d digital interface because I wanted to step up to using MADI instead of ADAT to go from my Logic machine to my Pro Tools machine, so now I have 64 channels back and forth instead of 24. My monitors are the Dynaudio AIR series, which connect directly to the Logic machine via AES, which I’ve done for about ten years, and now they connect directly to the 112d.

Now, using the MOTU 112d, which has 24 channels of AES, 24 channels of ADAT, and 64 channels of MADI, I can take the six channels I’m sending via MADI to Pro Tools and mirror those to my Dynaudio speakers. What’s cool with the AVB interfaces is that I can mirror outputs in a number of ways. Whatever is coming out of Logic can go to multiple destinations. It can go to MADI as well as to AES, and I can use the 1248 over AVB via Ethernet to feed a headphone amp or my guitar effects, et cetera. All of that cross patching is done in the MOTU AVB software, which you access with a web browser.

On my Pro Tools machine I went with the HD Native Thunderbolt and Avid MADI interface, so everything is very streamlined now.

Have you noticed a big difference, pro or con, with your new rig?

The new system is faster for sure, but it’s not like Logic got twice as fast or anything crazy like that. It’s just that the whole system feels much tighter overall. I have to say, now that I’ve made the switch and gotten everything up and running, going back to my old rig—which I sometimes have to do to pull up old cues—feels crude, like going back to the ’90s. The new system is so much more bad-ass.


The bar graph at bottom (courtesy of Intel) compares performance of older and newer USB and Thunderbolt protocols, including the recently announced Thunderbolt 3, which has yet to make its way into the market. Even with the now-behind-the-times Thunderbolt 2, the current gen Mac Pros offer enough bandwidth for low-latency recording and high sample VI track counts, provided you’re using a compatible audio interface and high-speed storage solution.

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In June, Intel introduced Thunderbolt 3 (connector shown here), which many tech journalists hailed as the “one connection to rule them all.” According to Intel, “Thunderbolt 3 brings Thunderbolt to USB-C at speeds up to 40 Gbps, creating one port that does it all—delivering the fastest, most versatile connection to any dock, display or data device.”

This could mean that we’ll see Apple transition their computers and tablets over to USB-C, but as of this writing we’ve only seen this on the new MacBook announced back in March. Currently the Mac Pro sports Thunderbolt 2 connectors. If Apple replaces these with USB-C/Thunderbolt 3, we’ll be living in the Age of Adapters once again. Ah, the wheels of progress keep spinning.

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