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The Lionfish plays a sonar "ping" sound from the conning tower. The sound is a kluge of a modern electronics wired into a speaker. I don't know who created/installed it. When was cleaning up the wiring (exposed 120Vac) I made a recording of the sound for backup, in case the mystery electronics dies.

While listening the recording I started to wonder if the sound was authentic. Since my only experience of subs comes from watching "run silent run deep" and "voyage to the bottom of the sea" as a kid, I decided to check out the sonar manual.

Do I have this correct ...
* Active sonar, the ping, is super-sonic, above the frequency range of human hearing (my words)
From the manual ==> Enemy echo-ranging (pinging) produces dull thuds or sometimes shrill peeps on JP.
So the men in the sub couldn't hear the enemy's sonar coming through the hull?

* The QB and JK/QC combined with their electronics translate the super-sonic sonar pings into the range of human hearing.
It looks like the frequency is mixed down to 800Hz.

The frequency search procedure (listening for the enemies pings) specifies looking from 14kHz to 32kHz.
I would guess the fleet sub's ping frequency would have be somewhere in that range. Maybe 17kHz?

The "beat frequency control" recommended setting is 800Hz, and the "peak frequency" filter's center frequency is 800hz.
I would think that means the "ping" sound in the headphones is 800Hz.

The lionfish "ping" generator's frequency is about 20% higher than 800Hz. I found a bunch of sonar sounds on the web, the closest is 12% higher than 800Hz. Maybe all the sounds are bogus, generated by Hollywood.

Anyone know where to find an actual recording of what the sonar operator heard in his headphones?

Thanx,
Drew