PC Magazine has a review on the Hercules Muse Pocket USB external sound module. The unit offers paltry sound output, with noise troubles at -32dB and a problem switching from 5.1 mode to stereo ...

We don't recommend going this low, unless your onboard audio is shot. Creative Labs has its Sound Blaster Omni, which is a USB sound module with built-in volume control.

It's newest product, the Xonar U7 MKII, is a compact USB sound card with a built-in headphone amplifier. The Xonar U7 MKII is mostly intended for laptops, though it can be used with desktops as well.

Aside from their charging port, Apple has made some other small changes to the new USB-C AirPods Pro 2. Does that change their sound at all?

The $99 3D Sound One Module fastens to your over-the-ear headphones using a black rubber band and connects to your iPhone, iPad, or PC using Bluetooth.