FAQ – NuForce Async USB Driver
Where to download NuForce Async USB drivers?
Please visit http://www.nuforce.com/hp/support/download/download.php
What is the highest sampling rate the USB Async Driver supports?
The current version of uDAC2-SE and uDAC2-SGE supports up to 24-bit, 96kHz.
Which operating system requires drivers and which one doesn’t?
Mac OSX and higher supports asynchronous USB Audio up to 96kHz and does not require drivers. With Windows PC, there is no native support for asynchronous USB Audio, thus requiring the installation of the NuForce Async USB driver.
Which versions of the Windows drivers should I used?
There is only 1 zip file to download, and it unzips into 3 separate folders: Windows 7 32-bit, Windows 7 64-bit, and Windows XP. The driver must match the operating systems’ versions. We have no plan to support Windows Vista.
What is the NuForce Async Control Panel (CPL)?
Since the audio data transfer is in asynchronous mode, the (USB) playback sampling rate is completely asynchronous from the PC’s system clock. The CPL, running in the background, handles the audio-data transmission.
Using the CPL Audio Format determines the Output Sample Rate. It can be set for any of the supported sample rates. But keep in mind that regardless of the sample rate of the files being played, the output format is always set for the selected sample rate. For example, if the file is 44.1kHz, and the CPL is set to 24-bit, 96kHz, the USB DAC upsamples the audio stream to 96kHz.
Recommendation for Windows XP
Setting to Auto allows the playback system to automatically employ the correct sample rate without engaging Upsampling. In Auto Mode, the Stream Status indicates the sample rate currently being streamed.
Recommendation for Windows 7
The Auto Mode feature is not supported since Windows 7 provides WASAPI, i.e., the equivalent of playing back the native data rate automatically.
What are the various different WDM Audio Drivers supported by Windows and how do I choose?
A simple summary:
| Directsound (DS) | ASIO | Kernal Streaming | WASAPI | |
|---|---|---|---|---|
| Windows XP | Yes | Yes | Yes | No |
| Windows 7 | Yes | No | Yes | Yes |
Almost every media player supports the Directsound driver, i.e, Windows’ default audio playback system. The DS driver goes through a software mixer that degrades the audio (admittedly, a controversial subject) as well as rescales the sample rate to a common denominator in order to facilitate the running of multiple software.
ASIO and WASAPI bypass Windows’ mixer and sample-rate converter in order to achieve a purer sound.
In theory, Kernal Streaming offers the highest quality as it operates in Bulk Transfer mode (similar to writing to a storage device), but it is experimental and is only supported by media players such as Foobar2000.
The NuForce Async driver fully supports DS, WASAPI and ASIO. The support for Kernal Streaming remains unofficial. We offer it ad hoc with limited Foobar2000 testing.
How do I use ASIO mode in Windows XP?
Just to be clear, Windows 7 does not support ASIO. To run ASIO, install ASIO4ALL, found here:
Most media players require a special ASIO plug-in to enable support for ASIO.
Once installed and activated, ASIO can be selected as the default audio driver within those supported media softwares, e.g., Foobar2000 in Windows XP showing different supported device-driver options: ASIO, Directsound, and Kernal Streaming (requiring ASIO and KS plug-ins).
How do I use WASAPI mode in Windows 7?
Some media players require a special WASAPI plug-in to enable support for WASAPI.
Once installed and activated, WASAPI can be selected as the default audio driver, i.e., Foobar2000 in Windows 7 showing different supported device driver options: Directsound and WASAPI (requiring first installing the WASAPI plug-ins).
