Troubleshooting USB Audio Artifacts or Latency
As with any USB audio interface, there are many potential causes of symptoms like distortion, artifacts (clicks/pops/crackling), and latency. This guide provides some helpful tips to troubleshoot the issue and get you back to dj-ing!
Troubleshooting USB Audio Symptoms
The best way to troubleshoot any broad symptoms, like audio quality issues, is to first eliminate potential causes. The following approach will help better isolate the trouble:
- Make sure that you have the latest driver installed for your product. Drivers for all Numark products are available on their respective product pages on www.numark.com.
Note: Hardware drivers only need to be installed once. Repeated installation of the driver will not fix audio issues.
- Rule out general audio hardware issues first. Words like noise, hum, distortion, clicks, pops, and dropouts are very often due to simpler causes like:
- Loose or damaged cabling - Replace cables.
- Loose or damaged input/output connections - Check your playback source (ex, speakers or headphones). Test with multiple sets of speakers or headphones. Test the same speakers or headphones with another source (ex, CD/mp3 player).
- Higher noise level or signal distortion due to poor gain staging - Poor gain staging can affect both recorded/sampled signals as well as the audio playback to your speakers/headphones. Ensure you have properly gain staged your source input/output level (ex, a turntable, microphone, etc...), software input/output level, audio interface input/output level, and headphone/speaker level adjustment. This article is one of many available online that covers reference levels and proper gain staging in software recording systems.
- Troubleshoot your computer processing power, audio software settings, and audio device drivers:
- Insufficient CPU power or memory - You can encounter a variety of pops, clicks, dropouts and crashes if your project is using too many tracks and/or plugins/FX, you have other programs or background operations running (ex, virus/security scans, internet browser, etc), or you're simply running an older/weaker computer CPU that is close to or below the minimum requirements of the software. Here is a guide on Computer Optizimation that may help this to a degree. Of course, reference your software and hardware's minimum requirements individually.
- Improper or unecessarily low Buffer Size settings - Most DJ software programs will have a Buffer Size adjustment. Experiment with Buffer Size settings to troubleshoot both latency and audio artifact symptoms.
The higher this setting is, the less stress is placed upon your computer CPU - at the expense of increased delay/latency. The lower this setting is, the more stress is placed on your CPU but the lower the latency. Lower the Buffer Size to decrease latency, but remember that if you set the Buffer Size too low, you will experience a variety of pops, clicks, or distortion symptoms (when you've reached your CPU's limit). This is one of the more common causes of software audio artifacts. It is absolutely not necessary to set the Buffer Size as low as possible to achieve minimum latency, especially considering latency times less than 10ms are getting into the realm of being indistinguishable by humans. It may not be a problem when you first configure it, but once you add tracks, instruments, and effects, you will quickly encounter audio issues.
- Insufficient USB or data bandwidth - Those using their computer as the center of their studio will often have several other audio, video, MIDI, and storage devices connected at the same time. When troubleshooting, remove all other devices to better isolate the cause. If the symptoms go away, begin adding devices back in one by one to find if one device is causing a conflict or if you simply have too many devices connected.
Keep in mind that your computer and it's various ports (USB, FireWire, Thunderbolt, etc) all have their own bandwidth limits, as does the final path to your processor and memory. Most computers will have some USB ports which have a lower priority or bandwidth, particularly those mounted on the front of desktop PCs or on any keyboard/monitor mounted ports.
When using a USB hub, the bandwidth of the computer's USB port is not increased in any way. So, while your USB hub may have 8 ports, adding 8 devices to the hub will only create a data "traffic jam", so to speak, when all of this data must merge into the one actual USB port. Additionally, some USB devices will be particularly more demanding than others - including professional multi-channel USB audio interfaces, external hard drives, or video capture devices.
- Check for USB port or USB cable related issues:
- Rule out a bad USB cable - Test with a different USB cable. Do not use any USB extenders. Keep USB cable length as short as possible; 2m/6ft is recommended.
- Rule out a bad USB port - Test on multiple USB ports, with all other USB devices disconnected.
- USB 3.0 port difficulties - If you have audio issues or latency only with USB 3.0 ports (USB 2.0 ports are working) or you only have USB 3.0 ports, see this section.
- Test your audio device with another computer. This is by far the most effective way to troubleshoot a variety of issues with an audio interface or any computer peripheral. If the same symptom seems to be occurring on a multitude of computers, get all of the system information from those computers (Windows, Mac) and get in touch with the Technical Support team for some more in-depth troubleshooting.
USB 3.0 Ports and USB 2.0 Devices
Since it's inception, the USB protocol has gone through three major revisions: USB 1, USB 2.0, and USB 3.0/3.1. The USB 3.0 spec requires that it be fully backwards compatible with USB 2.0 devices. However, not all USB 3.0 ports or the computers they're connected to will achieve this USB 2.0 backwards compatibility properly. Here are some ways to identify and troubleshoot USB 3.0 related issues.
- Identify if your computer has USB 3.0 ports.
- Look at the physical USB ports on your computer. A USB 3.0 port will be marked either by a blue color on the port itself, or by markings next to the port; either "SS" (Super speed) or "3.0".
- Check the features or technical specifications for your computer.
- Check the system properties of your computer:
- For Windows computers, navigate to the Device Manager, locate the Universal Serial Bus Controllers listing at the bottom of the list, and expand it. If you see USB 3.0, XHCI, or SuperSpeed listed, you have USB 3.0 ports.
- For Macs, from the Apple menu, navigate to About this Mac > More Info > System Report. In the Hardware section, click USB. There will be a selection(s) for USB 3.0 here if you have them. There are some other troubleshooting consideration in this Apple article.
- If using Windows 7 or earlier, it is necessary to update to the latest chipset drivers for your USB 3.0 architecture. Windows 7 and earlier is not inherently compatible with USB 3.0, so drivers are required for any USB 3.0 ports on your computer. To locate the USB 3.0 chipset:
- Open the Device Manager, expand the Universal Serial Bus Controllers listing, and expand it. Locate the Host Controller and/or Root Hub listing:
Note the manufacturer of these chipsets (Intel as in the picture above), and visit their website to ensure you're updated to the latest drivers. Here are some common USB 3.0 chipset developer's websites:
- Note: If using Windows 8 or 8.1, USB 3.0 should already be supported natively. However, you may still wish to update your USB 3.0 chipset drivers using the same method above.
- One last option for Windows users, only to be done with the detailed instructions from your computer manufacturer, would be to disable the xHCI Controller in your system BIOS. This will effectively disable USB 3.0 functionality so Windows will see all ports as USB 2.0.
- Connecting your USB 2.0 device to a USB 3.0 port using a USB 2.0 Hub may be an effective workaround for any issues you've found are due solely to the USB 3.0 port.
2015 Macbook Pro USB Issues
Of special note, there is an issue with some of the 2015 Apple Macbook Pro model USB ports which may cause specific problems with USB audio devices.
Symptoms will include a sudden extreme latency (1+ seconds) after approximately 5-10 minutes of use, requiring the device to be disconnected, then reconnected to temporarily resolve.
Here are the Model Identifiers for affected Macbook Pro models:
You can find your Model Identifier by going to your Apple menu and select About This Mac > System Report. More information about various Macbook Pro models and revisions can be found here.
With these MacBook Pro models, the Kanex USB to Thunderbolt adapter linked below can be used to connect your USB audio device to a Thunderbolt port and resolve any latency or distortion issues with the USB ports.
Before considering purchasing any adapters for use with one of these affected Macbook Pro Models, be sure to run through the above troubleshooting first.
Whether you are a customer or dealer, if you already own a Numark product, or if you just have pre-sales questions, the Numark technical support team is available to help!
Visit the link below to connect with any of the following support options: online community support, phone support, email support.