OASYS PCI and USB Devices
OASYS PCI Website
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OASYS PCI and USB
devices
On almost all computers, USB signals ultimately travel across the PCI bus - even though USB has its own separate connectors, and even if the USB support is built onto the motherboard, without using a separate PCI card.
Because of USB's high bandwidth, USB MIDI interfaces and other full-speed USB devices can make large demands on the PCI bus. In some cases, especially on computers running Windows 95/98/ME, this may cause problems with PCI audio hardware, such as distortion and audio breakups. These problems can be avoided by choosing the right kind of USB MIDI interface, and also by proper system configuration.
MIDI Interfaces: choose "Interrupt Mode" instead of "Bulk Mode"
USB MIDI interfaces may use two basic types of drivers: "Interrupt Mode" and "Bulk Mode." "Interrupt Mode" is used by most high-end MIDI interfaces; it should offer greater timing reliability, and also should not cause any problems with PCI audio hardware.
"Bulk Mode," on the other hand, is used by some USB MIDI interfaces, and can cause problems with PCI audio hardware. These problems can sometimes be alleviated by careful system configuration (under Windows 95/98/ME), but it is best to avoid having the problems in the first place!
Therefore, before purchasing a USB MIDI interface, we recommend making sure that its drivers use "Interrupt Mode," and not "Bulk Mode." If you already have a "Bulk Mode" interface, see the recommendations below for system configuration tips to optimize PCI performance:
Optimizing MacOS for audio and MIDI
Optimizing Windows For Audio and MIDI (especially the sections PCI slots with shared resources, SoundBlaster Live, and Set Sound Scheme to None)
Copyright 1999-2002 Korg Inc. FAQ Version: 8/19/02