I connected my iMac's headphone jack to my home stereo for better audio. Of course, that mutes the iMac's speakers and if I forget to turn on my stereo, I won't hear alert beeps when I click on something that won't work. I don't want to necessarily listen through my stereo system all the time; only when watching DVDs or music videos on youtube, etc.
Is there a program that adds a visual indicator to the Mac's alert beeps? I imagine there must be something for hearing impaired users.
Open Universal Access preferences. In the VoiceOver panel click on the Options button. From the left sidebar click on Visuals. Not sure to what degree this meets your needs, but it's what is available.