Reference Guide

1467
Audio hardware (sound cards) and drivers
Beginner’s guide to Cakewalk software
WDM and MME
In most situations, the newer WDM (Windows Driver Model) sound card drivers that most sound
card vendors are creating are a much better choice than the older MME (Multi-Media Extensions)
drivers. If your sound card vendor has a WDM driver, it’s usually a good idea use it. The following
table compares their characteristics:
IRQs
An IRQ (Interrupt Request) is an assigned location where the CPU expects to be interrupted by a
device when it has completed a task. There are 16 IRQs on a PC. Usually, three or four are taken by
the system, leaving 12 or 13 for other devices, like printers, USB devices, hard disks, floppy disk
drives, keyboard and sound card. Some of these devices can share an IRQ with other devices, but
for the most part this is not a good thing, and for a sound card which can use a lot of CPU power, it
can be a real problem. IRQ conflicts can cause your system to freeze or fail to boot up properly, or
the system may fail to recognize your sound card. Sometimes the problem only reveals itself when
you attempt to use the device that is sharing an IRQ.
Checking IRQ settings in Windows 98 and Windows Me
If your computer is running Windows 98 or Windows Me, use this procedure:
1. Right-click on the My Computer icon on your desktop and select Properties from the menu that
appears.
The System Properties dialog appears.
2. Click the Device Manager tab.
WDM MME
Lower latency Usually higher latency
Works with Windows 2000, ME, 98
SE, but not 98 Gold
Works with Windows 98, and ME. Some MME drivers may work with
Windows 2000.
Not every sound card vendor has
produced a WDM driver.
MME drivers are widely available.
Note: If you use two or more sound cards at the same time, and not all
of them have WDM drivers, you must force the WDM drivers to function
as MME drivers. Go to Edit > Preferences > Audio - Playback and
Recording and select MME in the Driver Mode list.
Table 254.