37.5 DS - Double Speed

When activating the Double Speed mode the Fireface 800 operates at double sample rate. The internal clock 44.1 kHz turns to 88.2 kHz, 48 kHz to 96 kHz. The internal resolution is still 24 bit.

Sample rates above 48 kHz were not always taken for granted, and are still not widely used because of the CD format (44.1 kHz) dominating everything. Before 1998 there were no re- ceiver/transmitter circuits available that could receive or transmit more than 48 kHz. Therefore a work-around was used: instead of two channels, one AES line only carries one channel, whose odd and even samples are being distributed to the former left and right channels. By this, you get the double amount of data, i. e. also double sample rate. Of course in order to transmit a stereo signal two AES/EBU ports are necessary then.

This transmission mode is called Double Wire in the professional studio world, and is also known as S/MUX (Sample Multiplexing) in connection with the ADAT format.

Not before February 1998, Crystal shipped the first 'single wire' receiver/transmitters that could also work with double sample rate. It was then possible to transmit two channels of 96 kHz data via one AES/EBU port.

But Double Wire is still far from being dead. On one hand, there are still many devices which can't handle more than 48 kHz, e. g. digital tape recorders. But also other common interfaces like ADAT or TDIF are still using this technique.

Because the ADAT interface does not allow for sampling frequencies above 48 kHz (a limitation of the interface hardware), the Fireface 800 automatically uses Sample Multiplexing in DS mode. One channel's data is distributed to two channels according to the following table:

Analog In

1

2

3

4

5

6

7

8

DS Signal

1/2

3/4

5/6

7/8

1/2

3/4

5/6

7/8

Port

ADAT1

ADAT1

ADAT1

ADAT1

ADAT2

ADAT2

ADAT2

ADAT2

As the transmission of double rate signals is done at standard sample rate (Single Speed), the ADAT outputs still deliver 44.1 kHz or 48 kHz.

37.6 QS – Quad Speed

Due to the small number of available devices that use sample rates up to 192 kHz, but even more due to a missing real world application (CD...), Quad Speed has had no broad success so far. An implementation of the ADAT format as double S/MUX results in only two channels per optical output. There are few devices using this method.

The Fireface 800 can not provide ADAT at 192 kHz, because this would equal a channel count of 64 (10+2+2+2 x 4, see chapter 37.4, Number of Channels and Bus load). The Fireface is internally limited to 48 channels.

The SPDIF (AES) output of the Fireface 800 provides 192 kHz as Single Wire only.

User's Guide Fireface 800 © RME

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Intel Fireface 800 manual DS Double Speed, QS Quad Speed, Analog DS Signal Port
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Fireface 800 specifications

The Intel Fireface 800 is a powerful audio interface celebrated for its high-performance capabilities and versatility in both studio and live settings. Designed to cater to the needs of musicians, producers, and sound engineers, it stands out with its rich feature set and reliable technology.

One of the defining features of the Fireface 800 is its support for an impressive 26 input and 28 output channels. This extensive I/O configuration facilitates seamless integration with a wide variety of audio production setups, allowing users to record multiple instruments simultaneously or create complex routing scenarios. The unit also boasts top-notch analog and digital converters, ensuring pristine sound quality with a dynamic range that captures the nuances of any audio source.

In terms of connectivity, the Fireface 800 is equipped with both FireWire and USB ports, making it compatible with a range of computers and devices. The device utilizes the FireWire 800 protocol, which delivers higher data transfer rates compared to its predecessor. This efficient transfer capability is crucial for maintaining audio fidelity and reducing latency, making it an ideal choice for real-time monitoring and recording.

The Fireface 800 also features standalone operation capabilities, functioning independently of a computer when needed. This is particularly useful for live performances, where reliability and reduced setup complexity are essential. Users can easily connect microphones, instruments, and other equipment directly to the Fireface 800, making it a versatile tool for a variety of scenarios.

With its low-latency driver technology, the Fireface 800 ensures smooth performance even when handling demanding audio tasks. Its advanced ADAT and S/PDIF digital inputs and outputs provide further flexibility for connecting other gear, such as additional preamps and effects processors.

Another noteworthy characteristic of the Fireface 800 is its robust build quality. Designed for regular use in professional environments, the unit features a rugged metal chassis that can withstand the rigors of transport and daily use. This ensures longevity and consistent performance for audio professionals who depend on reliable equipment day in and day out.

In summary, the Intel Fireface 800 is a versatile and powerful audio interface that caters to a wide spectrum of audio production needs. With its extensive I/O capabilities, high-quality converters, reliable connectivity options, and robust design, it continues to be a popular choice among audio professionals striving for excellence in their work.
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