Beeny Cliff — Deep rumbles and booms in cave, facing into cave

(There's an improved version of this at https://freesound.org/people/Philip_Goddard/sounds/836837/ )
Wonderfully deep cave rumbles and occasional booms in ideal sea conditions, with a 'clean' swell and relatively quiet sea action, from a bit down the south side of the largest alcove of Beeny Cliff, near Boscastle, Cornwall, UK, facing into one of the cave entrances.

As I proceeded with my hike from Crackington Haven towards Boscastle on 3 September 2014, I was struck by the appearance of the sea, with a modest but unusually regular and 'clean' swell, without any superficial choppiness, and I was getting to think that this might mean ideal recording conditions at Beeny Cliff's main alcove. Then, just past Rusey Cliff I thought to ask a hiker coming the other way if they'd heard any booms or rumbles at Beeny Cliff, and they said, yes indeed; it was a bit like distant thunder.

— Oh wow, I had to get my skates on, because the tide would be changing, and those wonderful sounds would presently stop! So I hurried, half-running where I sensibly could, and wasn't disappointed when I arrived.

Little did I know that I was never again going to get such ideal recording conditions there, despite many attempts to get similar recordings with the better recorder model (PCM-D100) that I got using from 2016 onwards.

This recording is one of four that I took in this session. Really it was two main recordings, one from the alcove top and one from a bit down on the south side of the alcove (and thus able to face into one of the cave entrances there). As well as those main recordings I made another, shorter, one on the alcove top, positioning the recorder so as to be very shielded indeed from the direct sound of the sea action, so that the booms and rumbles were maximally exposed.

Similarly, I made a shorter recording down the south side of the alcove (this recording). In this case it was my 'starter' down there, with the recorder somewhat exposed to the sound of the sea action, and then l was concerned that that sea sound might be too loud for listening to a long recording really for the booms and rumbles, so I stopped that recording and put the recorder on a really low tripod and positioned it so that it wouldn't be in line-of-sight of any sea action at all. That worked out surprisingly well.

Advisory

This really comes to life, and reveals masses of further detail, when listened to with high-grade headphones rather than speakers. Also, most computer sound systems would not reproduce the very low-frequency rumbles and booms correctly, if indeed at all.

This recording in progress.

Telephoto view of Beeny Cliff from Penally Hill, near Boscastle, the arrows showing the two main recording positions during this session. The one down the side of the alcove is actually out of sight because it's just over the edge, within the alcove.

Techie stuff

The recorder was Sony PCM-M10, with Røde DeadKitten furry windshield. It was placed on a Zipshot Mini tripod, which is what I'd call 'midi', intended to be partially exposed to the direct sea sound.

Post-recording processing was to apply EQ in Audacity to correct for the muffling effect of the windshield — and then more recently stereo widening / sharpening-up using the VST plugin A1 Stereo Control (200% widening).

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