The lower-pitched C5 “rings” for about four seconds before fading to silence. The higher-pitched G7 fades faster, but if your high-frequency hearing is good it will still ring for about one second before fading to silence.
The HLAC fire alarm at 520 Hz has a sound with a dominant frequency near C5 on a piano. A common smoke alarm (3200 Hz) has a much higher-pitched sound with a single “pure” peak near G7 on a piano.
The HLAC fire alarm is pitched where our hearing is at its best. But the typical high-pitched smoke alarm is right where normal age-related hearing loss is.
If the G7 sounds to you like a high-pitched “tink” or “whack” without ringing or musical timbre, your high frequency hearing may be compromised. You really should consider the Lifetone HLAC, and possibly seeing an audiologist. (Try this free hearing test if you like)
Please think about it: What you can hear or detect when you are awake and listening for it will not necessarily wake you up from a sound sleep.
Compare the sounds of a smoke alarm and the HLAC fire alarm