Maxing Out Your Computer
The holidays are here, and I'm in the spirit of buying toys. Like many musicians, I tend to spend my dough on new toys for the studio. This year, many of these seem to be things you can't physically pick up and play with. Even though they come in a box and you might be able to wrap them, they're really just lines of computer code, in the form of plug-ins and Pro Tools-compatible software instruments — but they're really cool nonetheless!
This month and next month, I'm going to talk about ways to max out the performance of your computer so it can handle all the new toys — plug-ins, soft synths, and soft samplers — that I hope you're lucky enough to get this year.
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Whether you're using a LE or TDM system, the processing power of your computer is a key performance factor when creating Pro Tools sessions with large track counts, or a high number of plug-in instantiations and software synth/sampler instruments. This is an even greater issue in host-based LE systems, because there are processing power trade-offs. Your host computer has a finite amount of processing resources available, and those resources can be allocated for different tasks at different times. If the computer needs more resources for one task, it will reduce the available resources in another area. For example, a computer might play back 32 tracks at once with no problem, but only allow a few plug-ins. In contrast, if you submix or delete some of the tracks, you'll probably be able to add more plug-ins. So how do you allocate your computer's resources to achieve the best performance?
First, you need to understand what's going on under the hood of your computer. The main access point for these controls is found in the Hardware Setups window (PT 5.x) or Playback Engine window (PT 6.x). Let's talk about the meaning of several terms that have to do with the performance of your computer, and how they relate to the parameters in the appropriate Pro Tools windows.
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Playback Engine Window (PT 6.x) |
CPU usage limit: The CPU usage limit is the amount of your computer's total processing power assigned to Pro Tools. If you assign 80% of your computer's power to Pro Tools, 20% is left for other applications, including your operating system. You can assign up to 85% to Pro Tools for single-processor computers. Anything beyond that would seriously slow down your user interface, or even prevent your operating system from running. On multiprocessor computers, you can choose the 99% CPU usage limit, which dedicates one entire processor to Pro Tools.
Hardware buffer size: The hardware buffer size is the amount of audio data (in samples) that the CPU grabs and processes at one time before it spits the data back out for monitoring or recording. Large buffer sizes give your computer more time to process audio data, but also increase the amount of latency (the lag time between the system's request for data and when it actually arrives) and cause slower user-interface responsiveness. Small buffer sizes decrease latency, but don't allow the use of as many plug-ins. Small hardware buffer sizes are more useful for recording sessions (less latency, less plug-ins) and large buffer sizes are more useful for mixing sessions (more latency, but more plug-ins).
DAE playback buffer: This is based on the amount of RAM used to buffer your computer's hard drive. The RAM temporarily stores audio data coming from and to the drive. The buffer refers to the time between when the input signal is received at the PCI card (or USB/FireWire port) and when the hard drive records it. The higher the buffer setting, the more time there is between when the signal is received and recorded. As an example, consider a portable CD player. If you bump the player and the CD skips, you may not hear the skip because a few seconds of the music is held in the CD player's RAM buffer. Fragmented (and FireWire) hard drives benefit most from higher DAE playback buffer settings.
Pro Tools RAM: As with any other application, allocating more RAM to the Pro Tools application increases the efficiency of the application. Windows XP and Mac OS X do this automatically, but you must manually change the RAM allocation on a Macintosh with OS 9. One direct benefit of increasing the RAM allocation to Pro Tools is that it will cache more waveform overviews. That is, the additional RAM helps the computer display the most current waveform overviews with all of the proper edits, automation, etc.
Maximizing Your System's Performance
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most obvious and powerful way to improve the performance of Pro
Tools on your computer is to increase the CPU Usage Limit. Simply
choose Hardware from the Setups menu and max out the percentage
on the CPU Usage Limit pulldown menu.
The Hardware Buffer Size setting determines the amount of monitoring latency you experience when playing back or recording tracks. With high latency, you may experience noticeable delays in audio signals. When recording you'll usually want a lower setting (128 or 256 samples) to keep latency to a minimum. However, during a mix session, you may want to increase the buffer to 512 or 1024 samples when latency isn't a factor and you want to max out the track count and use more plug-ins. I've found that 256 samples is a good all-purpose setting, but I definitely switch between buffer sizes depending on the circumstances. The DAE playback buffer size determines the amount of memory allocated within the Digidesign Audio Engine (DAE) to manage disk buffers. A smaller buffer size might improve the speed of playback/record initiation if you're experiencing lag time when you press Record or Play, but it might also make it more difficult for slow hard drives to play or record tracks reliably. A larger buffer size might improve the performance of a session with a great number of edits — however, large buffer sizes tend to increase the time lag before playback or record initiates. Digidesign recommends a value of two, which seems to work fine for me in most cases. To change the DAE Playback Buffer setting, choose Playback Engine from the Setups window.If
you want to monitor your system's performance, choose Show System
Usage from the Windows menu, as in Figure A. Sometimes, if you're
right at the limit of your computer's processing power, you may
get an error message saying that you're running out of CPU power
at a particular point, and playback/recording will stop. Watch
the CPU load level and find the point where it peaks in your
session, then see if you can reduce the number of edits or automation
density there. For more info on techniques like this, join me
here next month and also check out my book, Producing in the Home Studio with Pro Tools. |
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Choosing 99% as the CPU Usage Limit allocates one entire processor to Pro Tools. |
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Lower Hardware Buffer Sizes are best for recording with lower latency |
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Figure A The System Usage window shows you how hard your computer is working to run Pro Tools at any given time |
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With a little knowledge of how your computer interacts with Pro Tools, you can tweak your computer and maximize its performance. Join me next month for more performance-enhancing techniques and concepts that apply to both TDM and LE systems. See you soon. Peace.
Like what you see in this column? Check out my book Producing in the Home Studio with Pro Tools (2nd Edition). You can buy it online right here through Digidesign's website, or visit www.protoolsbook.com. Interested in personal instruction on Pro Tools from yours truly? Visit www.berkleemusic.com and learn about several amazing Pro Tools learning experiences available online though Berklee College of Music. Wanna see my studio and hear some samples of my work? Visit www.undergroundsun.com.
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