M571 On Board Sound

M571 On Board Sound Driver Installation

Having trouble with your M571 On Board Sound drivers? Here is Brad’s solution for getting your M571 Sound working correctly:

A PCI sound card is a preferable solution but the on-board sound is ok for casual stuff. The following link is for the 0n-board sound drivers you should use for win-98SE:


Unzip the files into c:\

Put your PCI video card in PCI-1, and the modem in PCI-2 or 4.

Now disable the on-board sound in the BIOS. Re-start Windows and run the uninstdrv.exe utility in the driver package to uninstall the drivers. Now go into the device manager and remove all traces of the on-board sound devices. Reboot to let Windows clean up the registry and make sure Windows doesn't find it again.

Now enable the on-board sound in the BIOS again, and let windows re-start. When it finds the on-board sound and asks for the drivers, point windoze to C:\ and it should find the cmi8330.INF file. Let it proceed and that should fix it.

M571 Microphone Volume Workaround

This information was contributed by Brad from the EYO Tech Forum. It contains his solution to the low mic gain of the M571 on board sound capability. In Brad's words:

Anyone who has tried to use a standard computer microphone with a M571's on-board sound knows there is a problem. The volume is far too low, virtually unusable. In fact, the gain is about 10db low by measurement. Granted, many M571 users upgrade to a PCI sound card but more casual users often can't justify the added expense. This piece explains the problem and offers an inexpensive, proven solution.

The "soundpro" chip used in a M571 is a C-Media CMI8330. The chip and Windows drivers contain support for a "mic boost" feature, but it isn't available and never appears in the Windows volume control or C-Media Audio Rack Mixer Panel. I believe the problem is the way the chip was integrated into the motherboard, which prevents or "locks out" its availability.

The solution is to use a preamplifier to make up for the 10db gain shortfall. A simple, inexpensive, and effective solution that I have implemented in several M571 based systems with excellent results is to construct a simple two transistor preamplifier using a commercially available kit (DIY Kit 98) which can be ordered on-line from:


For those who want to build their own from scratch, the schematic diagram and parts list are contained in a PDF file at:



Optional resistor R9 must be installed to provide the power for the microphone that would normally come from the motherboard or sound card. This 10K resistor is included in the kit.

The preamp provides 23 db of gain. This is perfect for driving the Line Input but is too high for the Mic Input and will cause distortion. Changing the value of R6 from 100 ohms to a value between 300 and 500 ohms will bring the gain down to a more appropriate level. 500 ohms has proven optimal for most desktop computer microphones I have used and/or tested.

For those building this preamp from scratch, the specified transistors may prove hard to find so generic substitue transistors may be used instead. A NTE123 can be substituted for the BC548, and a NTE159 can be substituted for the BC558. If either or both are substituted, the resulting gain may be different and the value of R6 may need to be changed accordingly.

Use shielded cable between the preamp output and M571 Input. The center conductor must be connected to the tip of a miniature stereo plug that is to be connected to the M571's Mic Input. Motherboard Jumper JP9 must not be installed.

If your microphone has unshielded cable, you may find it necessary to replace it with shielded cable to eliminate hum and other unwanted electrical interference.

The preamp may be constructed as an external battery powered unit, in which case a small plastic box is adequate. The preamp draws 1 or 2 milliamps from a 9 volt battery, thus providing long life, but a ON/OFF switch should still be provided.

The preamp may also be built into the computer. In this case it should be built in a small metal box and electrically bonded to the case to shield it from digital interference. It may be powered by a 9 volt battery or from a 12 volt line from the power supply.

This solution provides excellent audio quality. When recording to a .wav file, I suggest using a 22050 Khz or higher sample rate. I've used it for internet voice chat using Paltalk with very good results.



This page was last modified on 28 August 2002