Gravis Ultrasound ACE

Technical details
Name: Ultrasound ACE (Audio Card Enhancer)
Company: Advanced Gravis
Chipset: Gravis GF1
Bus: ISA 16 bit
Connectors: Line-Out, Line-In
FCC-ID: HYN412-0054-AA
Manufactured: 1992

This card was inteded to as add-on sound card to an existing system that has already e.g. a Sound Blaster plugged. It has a line-in and line-out where it can be chained in the audio output. It adds complete Gravis Ultrasound functionality. The Gravis Ultrasound uses a different approach as Creatives Soundblaster Series. The GF1 is a fixed-function DSP that can play only samples from its own RAM. From there it can interpolate and mix 32 independent channels that are upsampled to the output sample rate. When using more than 14 active channels the output sample rate goes gradually down from 44100 Hz to 19293 Hz when all 32 channels play.
This design makes the card perfect for tracker style music. When software has native support it can use the card to play nearly without CPU load music. (only note changes have to be transmitted)

Gravis Ultrasound Drivers and Software

Gravis Ultrasound ACE driver CD

Wavetable Comparison Recordings