Years ago Cyber Acoustics made a 5.25in-bay speaker solution called the CA-1001 that came in beige or black, but at this point it seems to be long gone. I know that there are similar solutions out there but the speaker quality is horrible. After some searching I found a pair of external USB-powered speakers that sound pretty good and are small enough to fit in a 5.25in bay. All I needed was a 5.25in bay grille or fan solution to mount the speakers to, of which there are many such products available, just remove the fans. I was also able find a USB-to-Molex power adapter on Amazon.
The speakers come with a volume controller of which I was able to carefully glue to a standard bracket that had rectangular notches pre-cut in the bracket.
I drilled a hole in the top of the bracket to run the headphone jack through and connect it to the sound card and, viola! I've got a beige 5.25in stereo speaker solution.
Note the speakers are too tall to fit in the bay facing forward so I decided to face them upward. You can also face them downward if that is preferable.
Here is the link for the speakers:
https://www.ebay.com/itm/316123295171?itmmeta … BwAAOSwuBpngRo8

Here is the link for the 5.25in beige fan bay. Just unbolt the fans and mount the speakers to it:
https://www.ebay.com/itm/235452404671?itmmeta … h8AAOSwnX5l36y6

Here is the link for the power adapter:
https://www.amazon.com/dp/B07FK7TJG1?ref=ppx_ … asin_title&th=1