User manual M-AUDIO PROFIRE LIGHTBRIDGE

[. . . ] 34-in/36-out FireWire Lightpipe Interface User Guide English Table of Contents English . 19 M-Audio ProFire Lightbridge User Guide | 2 Introduction hank you for purchasing M-Audio's ProFire Lightbridge interface. ProFire Lightbridge uses the ADAT optical I/O standard to bring extensive digital connectivity to your studio. With its four ADAT optical inputs, four ADAT optical outputs, S/PDIF coaxial input and output, and stereo analog outputs, ProFire Lightbridge lets you connect a variety of devices to your FireWire-equipped digital audio workstation. [. . . ] The ProFire Lightbridge interface's control panel gives you the option of enabling and disabling various digital ports. Disabling unused ports helps cut down on the processing demands placed on your computer. These options vary depending on whether you use a Mac OS X- or Windows XP-based computer: Macintosh: On OS X, all inputs and outputs can be individually enabled or disabled. Once a port is disabled, that port will not appear in any of your audio applications. Windows: On Windows XP, digital inputs can be enabled or disabled individually, while all output ports remain active. Your audio software will display all inputs and outputs regardless of each port's status, but any audio received on inactive input ports will be ignored. NOTE: This is normal behavior for this device on this platform due to the way Windows currently handles enabling and disabling of audio channels. You can conserve significant amounts of processing power by enabling and disabling digital ports wisely. For example, if you currently only own one ADAT device, disabling the unused ports allows you to free up processing power for other tasks such as running additional virtual instruments. Alternatively, when mixing a project, you might not require any inputs, but may want to run many plug-in effects. Temporarily disabling unused ports will free up your computer's processing power to help run those plug-ins. Information on configuring the interface can be found in Chapter 10. M-Audio ProFire Lightbridge User Guide | 10 The Software Control Panel A 10 fter installing the ProFire Lightbridge drivers, you can use the control panel software to configure various parameters of the interface. To access the control panel in Windows, click the red M-Audio icon in the system tray, or click Start > Control Panel and select the ProFire Lightbridge control panel icon. On the Mac, the control panel can be accessed by double-clicking the M-Audio FireWire icon in the Applications folder or by selecting the M-Audio FireWire icon in System Preferences > Other. Your DAW software may also allow you to access the control panel from within the program. Hardware Page Windows ProFire Lightbridge User Guide Macintosh | 11 Sample Rate Detected This window displays the incoming sample rate of the sync master source. This is an information-only display­the incoming sample rate must be changed through your audio software (if the sync source is set to internal), or by changing the sample rate output of the designated master device (if your sync source is set to any of the external options). Note: This window will show "mismatch" if the ProFire Lightbridge detects different sample rates on at least two of its digital input ports. It is mandatory that all incoming digital audio streams are synchronized for proper operation. See chapter 11 for more information on word clock synchronization Adat S/MUX mode The ADAT format carries eight channels of audio when operating at standard sampling rates of 44. 1 or 48kHz, or four channels when operating at high resolution sampling rates of 88. 2 or 96kHz. This high resolution mode is known as "S/MUX" and is enabled when an ADAT source toggles a special bit in its output stream. This bit tells the destination device to switch to S/MUX mode in order to receive the high resolution signal correctly. Unfortunately, some devices do not toggle the S/MUX bit and as a result, the ProFire Lightbridge may be unable to automatically detect whether the incoming signal is standard resolution or high resolution. The "Auto-Detect" and "Override" buttons allow you to resolve this issue: Auto-Detect ­ This is the default setting and should work in most cases. When this mode is selected, ProFire Lightbridge observes the S/MUX bit of an incoming signal and automatically switches between standard and high resolution modes. [. . . ] Precise, accurate timing in sending and receiving those words is critical. Each device in your interconnected digital world must share the same timing in order to communicate correctly--that is, their clocks must be synchronized. This synchronization is achieved by designating one device as the timing "master, " and all other connected devices as "slaves, " locking the slaves to the master. Only one device in the chain can be the master, and all other devices must slave to that master. [. . . ]