While it’s easy to get intoxicated by this brave new world, there are still problems that hinder even some of the fastest machines. Anyone who’s used a DAW will likely have encountered glitches, clicks, and digital pops, as well as other problems like overheating and latency.
To obtain maximum performance, pros often dedicate a computer to audio only (and never, ever connect it to the Internet). It’s a fine solution, but many folks have to buy the best computer they can afford, use it for everything, then hope for the best when it comes to recording. While I’m a fan of the “fingers crossed” approach, there are still some basic steps we can take to counteract the most common DAW problems. Before proceeding, though, I’d like to thank Des McKinney, a Toronto-based engineer/producer, musician, and the man behind the excellent home recording blog www.hometracked.com, who contributed numerous tips and techniques used in this article.
DON’T BE LATE!
Latency is the delay, caused by signal conversion and processing, between playing something into your DAW and hearing it come out of your monitors or headphones. Some level of latency is inevitable, but anything more than a few milliseconds is potentially noticeable and can throw a real monkey wrench into the works — especially with playback, overdubs, and intensive recording. To minimize your overall latency:
- Update your audio interface drivers, whether ASIO, Core Audio, or WDM. Improved drivers may not lower latency per se, but instead, provide more efficient operation that allows for lower latencies.
- Choose the correct audio buffer size. Giving the DAW more time to process audio (Figure 1) stops pops and clicks, but increases latency — so find the “sweet spot.” Be realistic, though: There’s a tradeoff between latency and CPU usage, so you may need to concede some latency to get acceptable performance from the rest of your system.
- Reduce background interference. A friend was vexed that his new, costly PC seemed to be underperforming. Then I found out he was running five other applications simultaneously, and even chatting on MSN messenger while trying to record! While most of us wouldn’t dream of doing this, it illustrates a point: What is your DAW running as you record, mix, and master? Running one LAN (or DSL) connection can cause the same CPU hit as running two average plug-ins. Find out what’s going on when you record, as some arcane background activity can push an already stressed DAW to the limit; to do this with Windows XP, right-click on the Taskbar and call up the Task Manager. This shows all programs that are running. If there’s something you don’t need (“ComputerCheckup.exe,” anyone?), right-click on its name and select “End Process.”
- Disable any wireless connections. Right-click on My Computer > Properties > Hardware tab, and select Device Manager. Identify and disable all wireless connections except for ones involved in recording (e.g., Frontier Design Tranzport). As Des says, “Should your DAW be connected to the Internet anyway?”
- If your machine was ever connected to the net, scan for viruses, spyware, and Trojans. These can cause major slowdowns if present. Then, as you’re no longer connected to the net (right?), shut down any software that scans for viruses, spyware, or Trojans. These are constantly working your hard drive and degrading performance.
- Disconnect unneeded peripherals. You probably don’t need a web cam running in the background.
- Manually switch off any background activity. This includes automatic backup utilities like System Restore, scheduled updates, and Ethernet or Bluetooth networks.
- Use an AGP graphics card. If you’re stuck with a PCI card, try different resolutions, color depths, and hardware acceleration rates. You may encounter audio clicks when running at full acceleration.
- Freeze soft synths. Software synths take a lot of CPU power, so use your host software’s freeze function to “disconnect” them from your CPU.
TO PLUG-IN OR NOT TO PLUG-IN?
Plug-ins and soft synths are some of the most powerful tools in any DAW arsenal, but they take a toll on the CPU. Limit their usage until mixing, at which point you can increase latency; latency is most problematic when recording, because a few milliseconds of delay can be disconcerting. While mixing, though, a few milliseconds of delay when moving a fader is no big deal, and higher latencies leave more resources for plug-ins and soft synths. It’s good to minimize plug-in use anyway while recording; faulty plug-ins are some of the biggest culprits in generating pops when laying down tracks. If problems persist, disable them all, and go through the plug-ins one by one until you find the guilty party. Then, check for any updates.
Also, be ruthless: How many plug-ins and synths do you actually need? For best results, use mono and simplified versions of plug-ins where appropriate. Waves plug-ins, for example, come in stereo and mono versions, and the equalizers have 2-, 4-, and 8- band versions. Using an 8-band stereo equalizer on a mono kick drum track that needs a single EQ cut is wasteful. Also, use sends and buses where possible to share a plug-in among multiple tracks, rather than inserting the same plug-in on multiple tracks. Lazy overuse of plug-ins could affect both DAW performance and your artistic vision, making your computer slow and your tracks flabby.
FEELING HOT, HOT, HOT
Laptop recording is great in theory, but an older laptop might not have the requisite power for music; and while newer ones have become sleeker, slimmer beasts, this crams their components into even tinier spaces. The result can be overheating, so make sure the all-important ventilation slots are unobstructed, and the fan is free of dust or dirt. There are software-based ways to combat overheating (other than using minimal CPU power) like smcFanControl for Mac or Speedfan for PC (www.almico.com/speedfan.php). These allow you to monitor a laptop’s temperature and adjust fan settings accordingly. Floating the laptop base so there’s an air gap underneath it, using something like the Griffin technology Elevator (www.griffintechnology.com), is a good idea; some thriftier DAW users glue pencil erasers to the laptop’s corners. Finally, when propping a laptop on your lap, make sure your legs don’t block any of the vents — and never put a laptop on a rug or other soft surface.
A ground loop is electrical interference, typically hum, that occurs when one piece of gear can “see” two paths to ground. For example, suppose an amp that draws a fair amount of current sees ground through the third pin on its AC cord but also through the ground shield of a cable connecting to a sensitive piece of gear, like a mic preamp. If a voltage differential exists between these two paths, some signal might be induced into the mic preamp’s ground, and amplified to an audible level.
One potential solution is to plug all your sensitive gear into a single, properly rated AC outlet to minimize voltage differences. If that’s not possible, at least try to use fewer power outlets, or connect everything to a single power source (via extension cords and power bars) so that they share a common ground. Don’t think that two sockets in the same room are necessarily running on the same circuit; this often isn’t the case.
As we are dealing with electricity, be cautious. Avoid the temptation to break off the ground pin from a three-conductor AC cable, as the ground provides a needed safety feature should a malfunction occur that makes the gear’s chassis go “live.”
If the buzzing persists, isolate the equipment that’s causing the noise. Disconnect everything, then reconnect the components one at a time until the noise re-appears. The last piece added is usually the one causing the problem. Try moving its power lead to another outlet.
RF interference is another potential source of buzzings. One of the most common reasons for picking up RF is oxidization on cable connections. Slight corrosion can actually create small crystals on the cable, turning your jack into a primitive — but functional — crystal radio. Plug and unplug connectors repeatedly to reduce corrosion, and use products like Caig’s DeoxIT.
MAKE THE CONNECTION
Unbalanced connections could be another factor in adding noise or interference. Common sense dictates using the shortest cables possible, whether balanced or unbalanced; and don’t drape them over devices like transformers. Balanced connections are more costly, so if you’re on a budget, put them where they matter: mics and other low-level signals. A hot synth output going through a few feet of cable to a mixer will likely not cause problems. But if you can afford balanced lines, go for it — that’s one less thing to worry about.
Still living with the hum from hell? Try DI boxes, which can help eliminate ground loops, give you a balanced input, and cut down on noise. For ground loops that occur between a keyboard and a mixer or DAW interface, try running the keyboard first through a DI box with ground-lift switch. Costs vary dramatically; a Behringer D120 will set you back about $30, whereas something robust like the BSS AR-133 retails for around $150. Radial Engineering makes a wide range of direct boxes, from “plain vanilla” types to models with routing and re-amping options (Figure 2). But if you find that you need to add lots of DI boxes, do the math: You may be better off getting one really high quality DI for when it’s needed, and putting the rest of your money into a new mixer with balanced inputs and a few quality XLR leads.
FIREWIRE: “X,” THE UNKNOWN
An increasing number of DAW users are forsaking traditional PCI-based cards and using FireWire or USB interfaces (even though cards offer a slight advantage in terms of speed). But FireWire doesn’t always work perfectly; check out any recording forums, and you’ll find a plethora of posts from people having problems with FireWire audio devices. Often this has to do with pilot error, but occasionally there are mysterious, intractable problems that no user or company can figure out. In fact, just because a FireWire device works without issues on the majority of systems doesn’t mean it will work on yours. So, following are some tips to promote cordial relations with FireWire.
- Follow installation instructions to the letter. Sometimes you need to install the software first, and sometimes you need to connect the device first.
- Connect FireWire devices while the computer and device are powered-down. In theory, you should be able to hot-swap FireWire devices; in practice, this isn’t always true, with potentially disastrous results (e.g., a fried motherboard).
- Power-up the FireWire device before turning on your computer.
- Use an external AC adapter instead of bus power.
- Check the manufacturer’s website for recommended FireWire chip sets for a particular device. TI (Texas Instruments) is generally recommended, NEC usually is not.
- Avoid using combo FireWire/USB cards. Don’t say you weren’t warned.
- Mac owners, upgrade to OS X 10.4.10.
- If you own a PPC Mac, check out the power user software tips in last month’s issue for details on using the CHUD utility. If you own an Intel Mac running an earlier version of OS X, try prayer.
- Dedicate a FireWire port to audio devices, and don’t run other devices on the same port.
- Take forum posts about “This interface works perfectly” or “This interface is a piece of garbage” with a grain of salt. An interface can work perfectly on one computer yet not work on a seemingly identical computer. Try before you buy, or buy from a vendor with a liberal return policy.
- Use a high-quality cable. If the cable got crushed or stepped on, it might not work.
- If all else fails, there’s always USB 2.0.
Finally, if you do encounter problems, don’t bang your head against the wall trying to troubleshoot without first checking the website of the device’s manufacturer. There may be known issues that can be fixed with a simple driver download, or by disabling a conflicting device.