Now, let’s have a brief walk through the electronic stuffing of the Revolution 7.1.
In fact, the revolution wouldn’t happen, if it were not for a long-time relationship between M-Audio and VIA. They struck up their friendship with the launch of the Delta Pro audio card family (based on the multi-channel ICE 1712 Envy24 audio controller). Last year VIA came up with improved versions of the controller, ICE 1724 Envy24 (the first variant, Envy24HT, is for PCI audio cards and the second, Envy24PT, for integration onto mainboards). The new chip differs very slightly from its predecessor (the newcomer acquires eight-channel systems support and 192kHz/24bit operating mode) and inherits all of its best qualities. You may recall that many professional sound cards were also based on ICE 1712. The Delta Pro series turned out a definite success, so M-Audio was willing to use the new Envy24HT chip in its future products. That’s how the revolution was born, and it was officially launched in December 2002.
The heart of Revolution 7.1 - VIA ICE1724HT audio controller
Like its predecessor, ICE 1724 supports 3D-sound standards: A3D, EAX and Sensaura. Unfortunately, notwithstanding its quality technical characteristics, the chip has only 16 hardware DirectSound 3D channels. This could be explained by the fact that the chip was developed not for games, but for professional work. A comparison of ICE 1712 and ICE 1724 brings no surprises: they look much the same. Seems like VIA was running the horse (that is, its newly-acquired ICEnsemble division) to launch Envy24HT as fast as possible to peg its presence in the sound card market.
The audio controller supports an analog joystick port, but this function is missing in Revolution. Anyway, nearly all game manipulators today use the USB interface for connection with the computer.
Converters are most important units of any sound card. They are responsible for quality of the sound outputted to speaker systems and received from an audio source. M-Audio chose to use high-quality DACs and ADCs from Asahi Kasei in its Revolution.
Two DACs support the analog outputs. They are six-channel AKM AK4355 and stereophonic AKM AK4381. Both have multi-bit architecture, work in a wide dynamic range with a low level of out-of-band noise. Besides, the converters are equipped with differential filters on switched capacitors (they are shown on the outputs in the flow-chart, marked as SCF – Switched-Capacitor Filter). So, there is no need for external stopping capacitors. The converters can work in 192kHz/24bit mode, which is ideal for a variety of tasks, including DVD-Audio playback. The codecs feature an independent digital per-channel volume control system with 256 discrete steps. The volume level is varied linearly in the range from 0dB to -48dB with 0.5dB increment.
6-channel AKM AK4355 DAC
- Sample rate: from 8 to 192kHz, 24bit;
- THD+N: -90dB;
- Dynamic range: 106dB.