Configuring Windows 95 for Optimum Performance
Excessive PCI Activity message
Synchronizing MME Input and/or Output Pairs
Windows 95 Drivers: MME vs. ASIO, etc.
Do not use the 1212 I/O for system sounds
1212 I/O Utility opens the card
Many seemingly innocuous features can cause problems with real-time applications. With a digital audio program, such problems can result in audio pops and clicks, or even audio dropouts. Fortunately, these problems can be avoided by careful configuration of the Windows system to ensure reliable audio performance.
Repeated re-sizing of the virtual memory swap file can cause problems with real-time processes. You can prevent this by setting the size of the swap file to a single, constant value. To do so:
1. Open Control Panel/System/System Properties/Performance/Virtual Memory.
2. Set the Max and Min sizes to the same value.
This restrains the swap file to a single size.
It's a good rule of thumb to set the swap size to match the amount of installed RAM. For instance, if you have 16 megabytes of RAM, set the Max and Min sizes to 16 megabytes as well.
The dynamic disk caching of Windows 95 can cause problems with real-time applications. When the cache grows to be very large, the task of maintaining the cache can tax the processor to the point that it can't keep up with audio processing, which leads to audio dropouts.
You can prevent this by editing SYSTEM.INI to limit the cache size to a manageable level. To do so:
1. In the Start menu, select Run.
2. Type SYSEDIT.
3. Select the SYSTEM.INI window.
4. After the section labeled [386ENH], add the following lines (keeping capitalization exactly the same): [VCACHE] MaxFileCache=4096
This will limit the maximum cache size to 4096k (4 megabytes). You can try other values, if you like, but this is a good starting place.
Write-behind caching can also cause problems with real-time processes. To disable this function:
1. Open Control Panel/System/Performance/File System/Troubleshooting.
2. Click on "Disable write-behind caching for all drives."
Windows can automatically detect the insertion of a CD-ROM into the CD-ROM drive. However, this detection can cause problems with real-time processes. To disable this function:
1. Open Control Panel/System/Device manager/CDROM. 2. Disable Auto Insertion Detect.
Background processes take up CPU horsepower, and so they can interfere with real-time processes. To see if any background processes are running (such as video panels), press CTRL-ALT-Delete.
Background virus-scanning programs, in particular, are known to cause audio dropouts. The BIOS of some motherboards also includes a virus warning feature; this should be disabled, as well.
Windows 95 caches video data to the hard drive, which diminishes real-time performance. To minimize this caching activity, we recommend installing a minimum of 2 megabytes of RAM on your video card. Increasing video RAM to 4 megabytes will help even more.
The built-in screen savers of Windows 95 may provide better performance than third-party screen savers, such as After Dark. Additionally, single-color background screens result in faster, more efficient video performance, easing the load on the system in general.
The BIOS of some motherboards includes power-management features; for reliable real-time performance, these should be disabled.
*ALL* of the above steps are recommended for all systems. In some cases, you may find the tips below to be effective, as well.
In some cases, you may be able to diminish the amount of virtual memory swapping by changing the "typical role of this computer" (in the File System screen) to Mobile or Docking system, instead of Desktop Computer.
Some graphics acceleration cards may impact performance to the extent that they interfere with audio. In this case, you can try going to the Control Panel/System/Performance/Graphics and scaling back the amount of acceleration.
The 1212 I/O card relies on being able to transfer small amounts of data across the PCI bus at regular intervals (roughly 3,000 times per second). If other devices tie up the PCI bus for extended periods of time, this can prevent the 1212 I/O from completing a transfer before the next scheduled transfer. If this happens, the audio stream will be corrupted.
The 1212 I/O attempts to detect such conditions; if it does, the "Excessive PCI Activity" warning will appear.
In our experience, most of these situations are the result of interactions with video cards that tie up the PCI bus for extended periods of time. Some possible solutions are listed below:
Try adjusting the acceleration settings of other devices on the PCI bus.
Try swapping the 1212 I/O with other PCI cards. In some instances (depending upon the PCI BIOS of your PC), placing the cards in new locations will change their assigned priorities on the PCI bus.
The default settings of older drivers for the Matrox Millennium or Mystique video cards may interfere with digital audio. An updated driver which corrects this issue is available from the manufacturer. If you prefer to keep using an older driver, you can do the following:
1. Add the following two lines to your SYSTEM.INI file:
[mga.drv] PCIChipset=1
2. Disable the Use PowerGDI acceleration feature in the Advanced Matrox setup (Control Panel->Display Properties->MGA Settings->Advanced->Performance).
If you are using another PCI video card, try installing the standard Windows 95 VGA driver. If the problem goes away, then there is an interaction with that card's video driver. If this is the case, contact the video card's manufacturer. They may have an updated driver or a switch similar to the Matrox above that addresses the problem.
Through the standard Windows 95 driver, each of the 1212 I/O's six input and output pairs appears to the system as an independent wave device. The digital audio program must start recording or playback on each of them, one at a time, which can cause small offsets between the stereo pairs.
The sync settings in the Korg 1212 I/O Wave Device Control solve this by creating groups of synchronized input and output pairs. The 1212 I/O will not start either recording or playback until all of the devices in the group have received the start command from the digital audio program.
Note that this synchronization applies only to input and output pairs on the same 1212 I/O card.
There are two options for synchronization: Auto Sync and Custom.
When Auto Sync is checked, synchronization happens automatically. Whenever you select or de-select a 1212 I/O input or output pair in your digital audio program, Auto Sync will add or delete the pair from the synchronization group.
Auto Sync should work well for most applications. If you like, however, you can disable Auto Sync, and make settings manually using the Custom Synchronization window (under the Custom button).
The Custom Synchronization window allows you to manually control the 1212 I/O's wave device synchronization, to group any desired set of inputs and outputs.
When Auto Sync is checked, the Custom button is disabled, and any previous settings in the Custom Synchronization window will be ignored.
Korg provides two drivers for use with Windows 95.
The first is a low-level driver, which talks directly to the hardware.
The second is an MME (Multimedia) driver, which makes the 1212 I/O available as multiple Wave devices, for use with any Windows Multimedia- compatible programs. The MME driver talks to the 1212 I/O card through the low-level Korg driver.
Programs which directly support the 1212 I/O - such as Cubase VST, through Steinberg's Korg 1212 ASIO driver - talk directly to the low-level Korg driver, skipping over the MME driver.
The advantage of direct support (such as through ASIO) is that it is inherently more efficient than MME drivers. This is because MME drivers introduce an additional layer into the communication between the audio software and the 1212 I/O. MME drivers also may cause a large amount of delay when monitoring record inputs through software effects.
For instance, through MME, Cubase VST's audio path looks like this:
VST -> ASIO MME driver -> Korg MME driver -> Korg low-level driver
With a direct ASIO driver for the 1212 I/O, one step is eliminated, making for greater efficiency:
VST -> ASIO 1212 I/O driver -> Korg low-level driver
So, MME drivers provide broad compatibility, while direct support (such as through Steinberg's ASIO) provides enhanced efficiency.
For information on downloading the 1212 I/O ASIO driver for Windows, see Downloading ASIO Drivers.
We recommend not using the card for system sounds when digital audio software applications are running. Some digital audio applications may want to have the card open at all times, and this will conflict with the system when it tries to open the card to play a system sound.
To avoid this, you can either turn off system sounds (while still leaving the 1212 I/O selected as the preferred audio device), or you can select another audio card for use as the preferred audio device. To simply disable system sounds, go to the Sounds Control Panel, and select "No Sounds" in the "Schemes" menu.
To set the preferred audio playback and record devices to a device other than the 1212 I/O, go to the Audio section of the Multimedia Properties Control Panel. If you do not have another audio card to use as the preferred playback and record device, you can also simply select "None."
The 1212 I/O Utility appears to the card as any other digital audio software. When the Utility is in the foreground, it opens the card, locking it out from use by other programs. If another program has opened the card, the Utility will be locked out, and will not be able to change any of the card's settings; if this happens, the Utility will display a warning message.
When using the card as a wave device, most programs only keep the card open when playing, recording, or monitoring input; when the program is stopped, it will usually release the card, freeing it for use by other applications (such as the Utility).
Some programs may keep the card open as long as they are running - regardless of whether they are playing, recording, or stopped. In this case, you may need to exit the program in order to use the Utility (or any other digital audio program).
When Windows 98 starts up the first time after the 1212 I/O has been installed in a PCI slot, the Update Device Driver Wizard may, on some computers, incorrectly identify the card as a "PLX USB Test Board." To install the correct drivers for the 1212 I.O:
1. Insert the 1212 I/O Drivers floppy disk into the computer.
2. Select the "Display a list of all drivers in a specific location" option.
3. Click Next.
4. Select "Have Disk."
The 1212 I/O's driver will appear. Select it from the list, and then allow the Wizard to finish the installation.