Living in Europe, this has been bothering me too. Yet today, I have finally found a workaround! It may seem a bit complicated but it WORKS and I made it as easy for you as possible
1) You need to download and install
Free Alarm Clock. Run it and be sure to enable "Run at Windows startup" in the Options menu (should be on by default, but anyway...).
2) Locate the program's folder (probably "Program Files\FreeAlarmClock") and extract
this sound into it (click "Download file -> Download slowly"). It's a split second of a brown noise set to very low volume, so it's barely audible (as the name suggests ) but it should still be recognized by your speakers when played. In case it's not (unlikely, but can happen), I also provided two slightly louder versions of the sound you can try out (unzip the sound from a ZIP file named +3db or +6db - this is to maintain the sound name which must be "Barely Audible.mp3" for the alarm set (as follows) to work) - you will find it in your "FreeAlarmClock\Sounds" folder).
3) In FreeAlarmClock, click "File -> Load from file" and use
this file (click "Download slowly" again). It's a set of 720 "alarms" that are run each day (which has 1440 minutes), resulting in the sound above being played every 2 minutes. It's almost unnoticable (unless you set really high volume) but it does it's job of preventing the speakers from going to standby
4) Finally (unless you want the alarm bubble to pop up in your system tray every 2 minutes )
turn off all notifications for FreeAlarmClock - just set it to "Hide icons and notifications".
That's it! Hope you found this useful. And feel free to let me know if any of the links is down - I'll gladly reupload it for you.
Someone might say it's a bit overkill as it requires you to have an app running in the background, but it's free, quite light on system resources (doesn't affect CPU usage and uses only 5-10 MB of physical memory (RAM) on my machine) and once set and configured to run at system startup, it's a complete solve-and-forget solution