Ping....... Ping..PingPingPingPing

[Captain Birdseye]

Can someone explain to me how this sound was audible in the U-Boat?

I don't think I fully grasp Sonar, and wonder how U-Boat crews could hear the ping of the sonar inside the boat with no headphones?

[tomfon]

Hi.

I think you can find enough information here: http://uboat.net/allies/technical/asdic.htm.

There is also this mod, here: http://www.subsim.com/radioroom/down...?do=file&id=42

The latest version is called, "The Real Ping II".

[TarJak]

Pretty simple physics. SONAR uses a sound transmitted through the water to detect relfections of that sound from objects in the water.

If you are in the water when the sound is made you can hear it.

[BulSoldier]

Funny i always thought that the sonar uses freqencies(spl?) that are beyond human capabilities to hear.

[d@rk51d3]

The "ping" sound effect is more of a Hollywood stereotype. Apparently it actually sounded like pebbles dropping on the hull, or wires scraping along it.

[Jimbuna]

Originally Posted by d@rk51d3

The "ping" sound effect is more of a Hollywood stereotype. Apparently it actually sounded like pebbles dropping on the hull, or wires scraping along it.

Only when 'hitting' the submarine.

http://www.uboataces.com/ref-sonar-sounds.shtml

[Captain Birdseye]

Those sounds sure are eerie

If the Sonar was a sound wave, then how come U-Boat crews couldn't hear it pass them or come near to them? Just like they could hear an explosion or bulkheads collapsing

Is there a mod that will change the "ping" to the more realistic pebble's on hull? or can I do it myself?

[Melonfish]

i thought sonar had a hard time with solid objects in the water? isn't it the bubble of air that actually reflects the sound?
unless my physics are way off from what i remember sound can pass between water and solid object with some resistance but as soon as it hits air its like it hitting a barrier and thus gave a better return.

[TarJak]

Originally Posted by BulSoldier

Funny i always thought that the sonar uses freqencies(spl?) that are beyond human capabilities to hear.

ASDIC used frequencies between 14 and 22 kilocycles at the upper end of human hearing. Each ship using ASDIC had to use a different frequency to avoid detecting each others return signals. 20 Kilocycles is considered at the very upper limit of human hearing for signals of normal intensity (human voice spoken normally), in air but the density of water changes the upper limit somewhat along with the fact that ASDIC pings had to be reasonably loud to carry up to 2km from the transmitter and get a return signal, so those ships using 22Kilocycles would have been almost impossible to hear but those below that range were certainly audible.

Most of the recordings that exist today of ASDIC are from the operator's console aboard an escort ship fo some kind. I've not found one that was recorded aboard a WWII submarine that was being pinged but it would be interesting to hear the difference.

This excellent article covers some of the issues raised here: http://jproc.ca/sari/asd_gen.html

According to the Maritime Musem of Liverpool this is a recording of an ASDIC capable ship approaching and passing over a target: http://www.liverpoolmuseums.org.uk/m...dio/asidic.mp3

[BulSoldier]

Well another question then . DId the submarine crews had any other way to find out that they are being pinged apart from hearing the ping ?
If there are no other ways i find it rather strange why not all asdic equiped ships dont use freqencies that couldnt be heard.

[rs77]

well but in this case.. ASDIC operator wouldn't hear it too

[Letum]

Originally Posted by rs77

well but in this case.. ASDIC operator wouldn't hear it too

They couldn't hear the real ping.
As the war progressed frequencies got higher and where far beyond
human hearing.

ASDIC sets primary used visual displays to inform the operator of the
results. First needles, then CRT displays. Any audio feedback for the
operator would need a reduction in frequency several fold.

In a sub you would not hear 1940s ASDIC unless it was from very near the
sub and aimed directly at the sub. Even then, the sounds produced are
secondary sounds and not the sounds of the ping it's self.


More discussion on thios topic here:
http://www.subsim.com/radioroom/showthread.php?t=142163

[Captain Birdseye]

Hmm, it seems that UberTorpedo no longer has a link to realistic ping sounds.

As someone else said in that thread, after reading all this, I think i'll just cringe every time I hear the Hollywood ping. This has to be one of the most interesting aspects of submarine warfare. Surely a helpful modder with a simple audio program such as Audacity can knock something together for us? I'd have a go if I knew what the hell I was doing!

[ltforce]

Those sounds aren't from a WW2 escort, those are modern day submarine sounds...like a 688i, Seawolf...etc....those are definitely not from a ww2 escort.


TarJak has the correct sounds....the ones from the uboat site would be from modern day subs and in all honesty most of them sound like he made them himself...

[TarJak]

Originally Posted by BulSoldier

Well another question then . DId the submarine crews had any other way to find out that they are being pinged apart from hearing the ping ?
If there are no other ways i find it rather strange why not all asdic equiped ships dont use freqencies that couldnt be heard.

Of course the obvious answer is the rain of depth charges exploding around them. I'd say that would have been a clue.

But seriously, no way they could have known unless they heard something. Maybe if the hydrophone operator had his equipment tuned to listen to the same frequency as the ping he may have heard it, but TBH I don't even know if that was possible.

Maybe this is something the Mythbusters could do a spot on?