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MOTU 828 Firewire Audio Interface Is Now ExpandableCapable of up to 126 channels. (October 02, 2001)
"As the first and still only FireWire audio interface on the market, our 828 has been one of our most popular products ever," said MOTU's Director of Marketing, Jim Cooper. "In fact, 828 users like it so much, the first question they usually ask is: 'can I connect more 828s?' With today's free driver update, the answer is definitely yes," he added.
Each MOTU 828 interface delivers 18 simultaneous channels of 24-bit, 44.1 or 48 kHz digital audio input to - and output from - the computer: 8 balanced quarter-inch TRS analog with 2 mic preamps, 8 ADAT optical and 2 RCA S/PDIF. After downloading and installing the new Version 2 driver, users can connect up to four 828s to their computer's FireWire port(s) using standard cables and a third-party FireWire hub for a maximum of 72 simultaneous channels of input and output (32 channels of analog with 8 mic preamps, 32 channels of ADAT optical and 8 channels RCA S/PDIF). Sample-accurate synchronization is maintained across all interfaces.
Further expansion is also possible via multiple FireWire busses. With four 828s connected to the computer's FireWire port (the built-in bus), a second FireWire bus can be added to the computer via third-party expansion products in the form of a PCI or CardBus card. Bench tests performed in MOTU's quality assurance labs have shown that FireWire adapter cards typically support up to three additional 828s, allowing users to connect seven 828s to a single computer (126 channels of simultaneous I/O). Tests beyond this point are not yet conclusive, but further expansion via a third FireWire bus is theoretically possible.
For Power Macintosh models with two FireWire ports, they share the same FireWire bus. To add a second bus, a PCI FireWire adapter is required.
The maximum of four 828 interfaces per FireWire bus is due to a combination of factors: bandwidth (the amount of raw audio data on the FireWire bus) and the nature of the OHCI (Open Host Controller Interface) compliant FireWire chipsets used in most of today's Power Macs. The OHCI specification requires the FireWire controller chipset to support at least four isochronous streams of data in each direction (in and out), and most chipsets currently in use support only four streams (one for each 828). Some newer Macintosh models, however, are equipped with FireWire controllers that support more than four streams. If a user with one of these newer CPUs disables the ADAT optical ports on each 828, it is theoretically possible they could operate five - or perhaps even six 828s on the built-in Fire bus running analog and RCA S/PDIF only. Users with an interest in this much FireWire I/O can refer to MOTU¹s on-line tech support database for further information as it becomes available:
Regardless of how many 828s are connected, it is important to note that all input and output channels are individually accessible and always available to the host computer's audio software. They are not merged together at any time in the signal flow to and from the computer. For example, on a computer equipped with seven 828s, the host software would have access to 126 channels of audio input and output.
MOTU 828 expansion is supported on all G4 PowerMacs equipped with an AGP graphics card slot and all FireWire-equipped Macintosh laptops, including the G3 Pismo, G3 iBook and G4 Titanium models. 'Blue and White' G3 PowerMacs, as well as the original 'Yikes' G4 desktop, do not support multiple 828s connected to their built-in FireWire ports due to the PCI-Lynx chip sets used in these models (although they do support a single 828 or multiple 828s with a FireWire adapter card). The MOTU 828 Version 2.0 driver requires MacOS 8.6 or 9.X. FireWire Enabler 2.4 or higher is also required. Multiple 828s can be used with Digital Performer, AudioDesk (the included workstation software) and all ASIO-compatible audio software programs.
The MOTU 828 Version 2.0 Macintosh driver can be downloaded now from www.motu.com.
The MOTU 828 also ships with a WDM FireWire driver for compatibility with Windows 98SE, ME, 2000 and XP. The 828 WDM driver will soon be updated to support multiple 828s connected to a Windows PC. This Windows WDM driver update is expected to ship Q4 of 2001.
MOTU (www.motu.com) is a leading developer of music and audio recording technology for personal computers.
Related Keywords:MOTU, Audio Interface, 828, Macintosh, Jim Cooper, FireWire bus, developer of music, recording
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