DIY Fix for SWAN HiVi M200MKIII Sound Issues

If you're interested in DIY speakers, this article is worth checking out.

How to fix the muffled, weak sound of the SWAN HiVi M200MKIII speakers?

First, let's troubleshoot the issue. Start by removing the back cover—you'll find the amplifier equipped with four TDA7294 ICs. These ICs have solid performance, so the problem may lie in the design of the preamp circuit.

To address this, you can bypass the preamp circuit and send the audio signal directly to the amplifier.

Important note: If you don't have a suitable 10mm socket to remove the components, avoid pulling the preamp board by its wires, as this could damage all three potentiometers beyond repair.

Next, you can remove the amplifier ICs for the two tweeters (see diagram below). Afterward, connect a 3.3uF crossover capacitor in series with the positive terminal of the tweeters.

If you don't have a suitable volume potentiometer on hand, you can temporarily skip installing it and send the audio signal directly to the amplifier for testing. (Make sure to connect the audio source before powering on the system.)

After testing, you'll notice the sound becomes expansive, clear, and vibrant!

Finally, use the built-in "DTS Audio Control" software in Windows 10 to adjust the graphic equalizer. Lowering the 4kHz slider slightly will restore the original sound profile of the speakers.

And there you have it—problem solved!