Audio Mixing in Pro Tools on the Surface Pro 3 Tablet
When my manager asked me to write a piece about pro audio mixing on a tablet, my curiosity was definitely piqued. The thought of resorting to a tablet-specific prosumer DAW, sacrificing a professional feature set, and forgoing the use of my favorite plug-ins, was a challenge I was ready to take on. As he told me more about the assignment, it became apparent that I wouldn't be writing about pro audio mixing on just any tablet, I'd be writing about a tablet with a 2.3 GHz dual-core i7 processor, an optional keyboard, and an electronic pen that runs the desktop version of Windows 8 Professional—namely, the Surface Pro 3.
Naturally, my first thoughts were "Hmm... I wonder if I can I get Pro Tools running on this thing?” and “…what about my Waves plug-ins?" Considering that I had access to the Surface Pro Type Cover detachable keyboard for punching-in shortcuts, and that the tablet features a full-size USB 3.0 port for my iLok, I saw no reason that it wouldn't be feasible. Inspired, I took to the Avid site to do some research and found that although the Surface Pro 3 isn't technically an "Avid-qualified computer" its specifications exceed those of some of the recommended laptops. Now encouraged, I downloaded installers for PT10, as well as the Waves Mercury bundle, and started getting down to business.
Both installs went smoothly, with no anomalies to speak of. So, I plugged my Pro Tools iLok into the USB 3.0 socket, double-clicked the familiar purple and silver icon, and was greeted by the good ol' "unable to locate hardware" error. Ah yes, I love that one. Don't we all? After a minute or two of head scratching, I remembered that I had forgotten a key step: the ASIO driver. If you've ever tried to get PT working on a Windows machine, you've probably figured out that it won't work with your native audio driver, as say, it would on a Mac using Core Audio. Luckily, there is an excellent free and widely used ASIO driver called ASIO4ALL that I was able to download and install on the Surface Pro 3 in a matter of seconds. Once I did that, Pro Tools loaded right up.
Curious to see how well (or how poorly) the Surface Pro 3 handled Pro Tools and its stock plug-ins, I proceeded to load up the demo session, a catchy Brit-rock inspired pop tune called "Turn Me Off" by the Oakland, CA, rock outfit Audrye Sessions. The mix consisted of 37 audio tracks, tons of sub-mixes and parallel buses, 2 virtual instruments, and quite a bit of processing using Avid plug-ins, such as Channel Strip, D-Verb, AIR Verb, Boom, Structure Free, and others.
To my delight, the Surface Pro 3 was able to play back the 44.1-kHz session without a hitch with the Pro Tools playback engine set to 3 of 4 virtual cores used, CPU limit at 99%, ignore errors not checked, delay compensation set to maximum, and sample hardware buffer size set to 512. For readers who may not know, hardware buffer is a setting in the Pro Tools playback engine that effectively balances system latency with the amount of time the computer allows itself to process audio. So, the lower the H/W buffer, the more responsive the system is, but the more strain there is on the computer to keep up. For mixing in general, it's usually recommended to raise the buffer size to allow the computer more time for effects processing. However, I wanted to see how well the Surface Pro 3 performed under more strenuous, lower-latency conditions, so for testing purposes I bumped the H/W buffer down to 128. Surprisingly, it still performed extremely well, with no overload errors and the CPU running at about 37 - 38%. At an even lower 64 sample buffer, it ran between 41 - 45% CPU usage, but at this setting Pro Tools was giving me some intermittent -9128 CPU overload messages. So, I turned the buffer back up to 128 samples and left it there for the balance of my test.
The mix already had a bit of volume automation on the lead vocal track, but I was excited to try adding some of my own automation using the included Surface Pen, which seemed like it would be a natural marriage. I picked one of the more leady guitar parts and drew some gradual panning movement as the hook section progressed, using the pen. In freehand mode with the pencil tool selected, drawing volume breakpoints on the touchscreen with the Surface Pen proved to be a fun, efficient and accurate method for creating automation. Furthermore, I found that using the pen to draw boosts, notches, and roll-offs in the paragraphic EQ section of the Channel Strip plug-in was also quite useful and cool. Since the faders show up a bit small on the Surface Pro 3 touchscreen, it was tricky using my fingertips to manipulate track volume in the Pro Tools mix window. Using the pen to do this was a much smoother experience, allowing me to make far more accurate and precise adjustments.
At this point, I was pretty impressed with the Surface Pro 3, but I was anxious to try out some of my go-to Waves plug-ins, so as to create a more realistic mix scenario, and to put the device to the test using some effects that are a bit more demanding in terms of processing power. First, I added the Waves V-Comp to the vocal group to level it out a bit, and also created an instance of the IR1 convolution reverb (full-power version, not efficient) on a separate bus and sent the vocals to it for more ambience. I followed the reverb with the 6-band Renaissance EQ to cut some of the low end, and also applied the MaxxBass plug-in to the DI bass guitar to give it more girth. The Surface Pro 3 handled all of the processing without a problem, with no adjustments to the playback engine needed.
Before printing, I decided to add a quick mastering chain to the mix bus just for fun, starting with the stock Avid Trim plug-in, followed by the Waves C4 multiband compressor and then the L2 Ultramaximizer peak limiter. The L2 and the C4 are two of the more CPU-demanding Waves plug-ins, in my experience, and I was pleased to find that the Surface Pro 3 was able to print the mix without any issues whatsoever.
The Surface Pro 3 is the first tablet to come along that one could even consider calling a "legit" pro audio mixing and editing solution, if for no other reason, because of its laptop-strength processing power. In addition, its ability to perform well at lower hardware buffer settings makes it a viable piece for MIDI production work and maybe even audio recording, two processes in which low latency is crucial. While the Surface Pro Type Cover keyboard is on the small side and will take some getting used to in terms of ergonomics, it does make Pro Tools shortcuts and traditional mouse navigation possible, which are essential for audio editing and other tasks. Even though its relevance is somewhat limited in the Pro Tools environment, the Surface Pen did have some useful applications that I mentioned above, such as making adjustments to track volume in the mix screen, as well as drawing automation and EQ curves. I also wanted to note that in order to authorize Pro Tools and Waves at the same time, I needed to use a USB hub. I wouldn’t call this a deal-breaker, but a second full-size USB port would have been nice. Overall, I was definitely impressed with the Surface Pro 3 and feel that it may represent a big step in truly bridging the gap between the mobile computing and pro audio worlds.