USB

Overview

The term "USB" is used to describe a form of general purpose serial computer interface standard; the Universal Serial Bus.

Related Topics

USB setup (contains setup information previously found on this USB page)

AES

S-PDIF

Digital interconnect

PCM

Basics

The USB standard was conceived as a low-cost multipurpose solution for connecting computer peripheral devices such as the keyboard and mouse. Other applications include connections for printers, external hard drives, digital cameras, network adapters, and digital audio devices. Click here for more detailed information on USB

Audio Applications of USB

General

Lavry USB audio connections receive and transmit PCM digital audio signals. When the computer plays back a digital audio file in a different format, it is converted to PCM format prior to USB output. One example would be the playback of MP3 files in a media player, or in iTunes. In most cases, audio input devices are shown as a “microphone” in the operating system control panels, regardless of whether they are indeed a microphone or line level audio device. In a similar manner, audio output devices are shown as a “speaker” in the operating system control panels, regardless of whether they are a speaker or line level audio device.

Lavry

All current Lavry products with USB connectivity utilize the “Native” USB audio drivers of the computer’s Operating System (OS). This effectively makes Lavry converters “plug & play” with some settings required for optimum results. For specific information on USB connection and settings, see USB setup. For additional information, please refer to the product manual, documents listed under the Downloads tab of the product page on the Lavry website, and the product page of the Lavry Wiki.

The Lavry AD11 and DA11 are USB 1.1 compatible.

USB Standards and Audio Specifications

The USB 1.0 Class 1 standard allows for 24 bit/96 kHz maximum resolution for input and output of digital audio. All operating systems (Win, OSX, and Linux) support USB Audio Class 1 natively, which means when using audio devices which utilize these native drivers, it is not necessary to install drivers before using the device. All support 2 channel audio with 24 bit words and 96 kHz sample rate. The Lavry AD11 and DA11 are this class of device.

USB 2.0 is downwardly compatible with class 1 and supports 32 bit and all common sample rates > 96 kHz. With the data rate of High Speed (40 X Full speed), recording 60 channels using 24 bits at 96 kHz is possible.

From mid-2010 on USB audio class 2 drivers are available in OSX 10.6.4 and Linux. Both support sample rates up to 384 kHz.

Microsoft® OS did not support USB Audio Class 2 prior to Windows10. If you have an audio device which supports sample frequencies higher than 96kHz and are running an OS prior to Windows10; you will probably need a third party USB class 2 driver for proper operation at SR’s above 96kHz

USB Setup tips

Please see USB setup for detailed setup information for Lavry products.

Changes to the OS

OS manufacturers periodically update or release new versions of their software, which can result in changes to the operation of the USB audio. Because the AD11 and DA11 are Class 1 Compliant audio devices, changes to the OS normally do not affect them in the manner third party drivers are affected.

However, it is possible that third party drivers which are installed when the update happens could be affected and this could in turn affect the operation of the Lavry unit if these drivers replaced the original OS USB audio drivers.