For many specialized applications, sampling at rates higher than 48 kHz is a requirement.
Some common applications for high sampling rates include:
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- acoustic test and measurement,
- sound effects recording,
- classical music recording,
- environmental recording.
The USBPre 2 operates at sampling rates up to 192 kHz. The information below describes some of the sampling rate and bit depth limitations the USBPre 2 has in different operating environments.
Stand Alone Mode
When the USBPre 2 is operating in Stand Alone mode (without being connected to a computer), it operates at the sampling rate set by its back panel hardware DIP switches. Available sampling rates include:
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- 16 kHz
- 32 kHz
- 44.1 kHz
- 48 kHz
- 88.2 kHz
- 96 kHz
- 192 kHz
The USBPre 2 in Stand alone mode always operates at 24-bits. If it is connected to an input which only accepts 16 bits, the 8 least significant bits will be ignored (truncated). When digital audio signals are used as inputs in Stand Alone mode the USBPre 2 will lock to the incoming rate and operate at that rate. There are no sampling rate converters on the USBPre 2.
Mac OS 10.5.8+
Mac OS versions 10.5.8 and greater support USB Audio Class 2.0 devices as Core Audio devices. This allows for connections at high sampling rates. USBPre 2 sampling rates supported in Mac OS 10.5.8 and greater include:
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- 8 kHz, 16- or 24-bit
- 16 kHz, 16- or 24-bit
- 24 kHz, 16- or 24-bit
- 32 kHz, 16- or 24-bit
- 44.1 kHz, 16- or 24-bit
- 48 kHz, 16- or 24-bit
- 88.2 kHz, 16- or 24-bit
- 96 kHz, 16- or 24-bit
- 176.4 kHz, 16- or 24-bit
- 192 kHz, 16- or 24-bit
Either the operating system or a software application can control the sampling rate of the USBPre 2.
Windows XP, Vista, and 7
Windows does not support USB Audio Class 2, reverting instead to USB Audio Class 1. As a class-compliant device the USBPre 2 has a maximum sampling rate of 48 kHz in Windows. Supported rates include:
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- 8 kHz, 16-bit
- 16 kHz, 16-bit
- 32 kHz, 16-bit
- 44.1 kHz, 16- or 24-bit
- 48 kHz, 16- or 24-bit
To operate with higher sampling rates in Windows, devices require a dedicated driver, such as a dedicated ASIO driver, which is available as a separate download from the Sound Devices website. Click here to read more on the USBPre 2 ASIO driver for Windows OS.
iOS
The USBPre 2 can be used as an audio device in Apple's IOS version 3.2 with an Apple iPad. With the iPad, the USBPre 2 is limited to a maximum sampling rate of 48 kHz, since IOS accepts USB Audio Class 1 devices.