The infamous startup tone that the Mac is known for when you turn it on isn't just a sound, but is actually a very important part of your Mac's boot up process.
Unless your volume is turned all the way down, not hearing your startup tone at the time you power on your Mac may indicate a problem with your machine. Additionally, unusual startup tone sequences are also indicative of a problem with your Mac and will require troubleshooting to resolve.
In this piece, we'll attempt to outline what all the different scenarios of the Mac startup sounds mean to give you better understanding of what to do should you ever end up in a situation where your Mac's startup tone doesn't sound right.