This is an AutoHotKey (AHK) script that makes a sound when your throttle axis reaches a user set detent positions in it's axis. This requires you to be able to use a Throttle macro editor to send keystrokes to AutoHotKey.
If you have a script/macro editor with your Throttle Software, and you can send a keystroke when your throttle moves to specific positions on the axis, then you can set this up to give you an 'audio' indication of hitting a Throttle Detent.
I have a Saitek x55 HOTAS. Using the Saitek Macro Editor, I set bands on the Throttle axis at 80% rpm and 100% rpm(full military power) to send keys to AutoHotKey and make a sound. In this way, I can know where Cruise speed is, and also a warning before I go into Full Afterburner.
Download and install AUTOHOTKEY!!
Learn the basics on how to use it.
Then, try this AHK Script.