Knowledgebase: GS Series > GS-R24
GS-R24. Multitrack Recording: Maximizing Performance. PC tuning
Posted by Nicola Beretta, Last modified by on 25 February 2011 02:29 PM

Multitrack recording and playback is not an easy task even for modern computers and laptops.
We recommend that you check your system’s specs and optimize your setup in advance.
Top-spec desktop workstations are often the way to go for professional, reliable, high channel count audio recording and playback.
The following best practices should help to improve your overall I/O capability, get better audio performance
and make sure that your computer is capable of streaming audio data to and from the FireWire bus.

Ensure your ‘Allen & Heath FireWire’ driver is up to date.
Please note that ‘Allen & Heath FireWire’ is compatible with both GS-R24 and ZED-R16 and supersedes any previous ZED-R driver.

Poor audio performance is mainly caused by the configuration of the computer, by what other applications are running at the time,
and lastly by the worst-case DPC latency.  Please note that this is not the latency of the audio data transfer: the DPC latency is the timing delay
imposed on certain instructions used by your computer to process data.  Because ‘Allen & Heath FireWire’ is a kernel-based driver, some device drivers,
including network and video adapters, can hold the CPU for a long time, with spikes of several milliseconds, causing dropouts on playback and recording.

‘Allen & Heath FireWire’ control panel (Windows version only) includes a DPC Latency Checker Tool.
This allows the deferred procedure call delays to be measured and recorded.
Additional information is provided in the control panel user guide.

Safe Operation Modes may be recommended if high DPC timings are measured.
The Operation Mode enforces buffer levels which help prevent performance-related dropouts.
The higher the Mode number, the less chance of audio artefacts, with the sacrifice of increased system latency.

When spikes of several milliseconds occur in Normal mode with low buffer sizes,
then audio dropout could almost definitely happen resulting in clicks at the very least,
and interruptions in the audio software application.

If you experience such an issue, make sure that you have installed the latest version of each driver.
You can try disabling one device at a time in Device Manager and see if one in particular is causing the issue.

Certain nVidia drivers have been found to cause intermittent DPC latency spikes.
If this applies to you try updating, disabling or uninstalling the video adapter driver.
Your Windows standard VGA driver might be capable to work at your desired resolution if you don't need 3D acceleration.

By shift-clicking the icon in the Devices area of the ‘Allen & Heath FireWire’ control panel the Event Log is brought up in a window.
This displays status information and changes recorded since the control panel was launched,
so it can keep a record of events or device issues over a period of time if the control panel is left running.

Dropouts usually cause the device to loose lock of the two receiver data streams, resulting in a ‘Device rx lock changed’ event in the log.
Reliable performance can be verified by launching an audio application and leaving it to run whilst monitoring the Event Log window in the control panel.

You should also launch the Scan Tool in the ‘Allen & Heath FireWire’ control panel System tab.
This will interrogate your computer's FireWire 1394 OHCI controller and determine its compatibility with the GS-R24 or ZED-R16.

The above diagnostic tools provide a way to check your computer system’s capability for streaming audio data to and from the FireWire device.
They won’t tell you exactly what the causes are but allow comparisons to be made when changes or improvements are made to the system.

As a further advice:

- Disable the advanced visual effects in Windows.
- Disable Windows Firewall and any installed antivirus or firewall software.
- Disable your screensaver and any power management setting.
- Quit any unnecessary applications or services you may have running. It is always advisable either to run as few simultaneous applications as possible,
  or to have a completely separate dedicated machine for recording.
- When possible, direct recording data to a non-system, separate, fast hard drive, either internal or external.

We hope this helps.




keywords: Zedr-16 zedr16 gsr24 gsr-24