Hours 33 – 37: IR Recording Part 2 – Disused Quarry

Hello friends! I’m back again, this time writing up some more IR recordings from earlier in the week.

For this IR recording session, I walked down to an old disused quarry, which is on the outskirts of my city. It’s a pretty huge space and it’s very impressive to walk around. It looks ace and I was aware that it had a huge cliff face, which I thought would probably give some cool reverb responses. I wasn’t wrong.


It made for a fantastic IR recording location, and produced that typical ‘slapback’ type of sound when excited with a balloon. It’d be a perfect location to record guns i’d imagine, although it’s technically public land (so probably not). I did however rock up with my usual recording setup, a matched pair of 414’s in the mid/side configuration (on a stereo bar) going into the sound devices 633, and monitored with a pair of KRK headphones. The sound was good, a nice stereo spread (much like the IR’s from my last post) and it captured a nice sonic picture of the space. It was a windy day, and being so wide and flat, there was a lot of wind battering the mics. I did use the dead kittens again, but unfortunately there was still some problems with low end wind interference, which I think was to be expected. I’m thinking about building some kind of homemade blimp to use over the stereo bar – hopefully something that means I can still use the large diaphragm condensers.

Annoyingly I had trouble with the mid/side – for the first time, actually. Usually i’ve been quite diligent with checking that the mics are in the correct polar patterns, but stupidly this time that thought passed me by. I realised half way through the session that the front facing mic was on figure-8, and the mic on the side was in cardioid. It was very annoying – I quickly changed them to the correct setup, and retraced my steps to the cool sounding places, and re-recorded the balloon pop.

The recordings themselves are good, despite the noise. I’ve experimented a little with them as IR’s, and the results are, well, interesting. Essentially, unlike reverb, the large open space has created almost a delay effect. This sounds very cool when lit up with a balloon (or a gunshot, for example), but when applied to anything else, it just creates a quieter duplicate seconds after the transient. This will be a cool IR to play with in some scenarios – and definitely a great sound design tool – but I don’t think it’ll work perfectly with all sounds. When I release the IR library hopefully some other people may find some cool uses for them.


I began facing the cliff-face, and popping the balloons from various distances. I found that the closer to the cliff-face itself, the less the slapback effect occurred in the sound. Below is a recording from this position, with the balloon roughly 5 meters from the wall – quite close. As you can hear, it’s very punchy and very tight. This’d be a perfect IR to liven up some exterior player or weapon foley, for example, when used subtly. Again, as with the previous IR recordings, this was captured without a limiter – so the sample recording is loud. Please be aware of this when listening. Its also worth mentioning that I haven’t done any processing other than the mid/side encoding – and the wind and low end noise will be taken out when the IR is properly edited.

Next I moved in a little further, and into a section that was indented slightly. This, again, created more of a tight decay, much like the first example. Annoyingly the ground all around this area was very boggy, and some parts were almost swamp-like. I guess there’s probably not a lot of drainage on such a flat plane of land.


I think this’d be a great tight reverb to use to excite any outdoor sounds, without the fear of drowning them in an artificially huge sounding IR. At this point there were a couple of guys who turned up behind me, on quadbikes, and were riding around the quarry. They didn’t interfere with me at all, other than their engines being in the background of my recording. I was actually very tempted to ask them if I could record their quadbikes’ engines, but I decided against it. At any rate, some kind of low EQ work would be good to take out the rumble of the engines – but this’ll be done when I come to edit the IR’s properly. Again, this is a loud recording.

And lastly, I managed to capture the ‘slapback’ delay thing as I moved into a more rounded area, which had cliffs on both sides.


I’m pretty impressed with how these turned out. You can hear the solid slapback delay, and I think the mid/side captured it very well. Irritatingly however, on the second pop, there was a large group of birds at the top of the cliffs to one side: while they did fly away when I actually popped the balloon, they did chirp a bit during the actual transient, so hopefully that will be something I can look at when editing. As you can hear, traffic had picked up a bit, as it was about 5pm: this will also be taken out during the editing process. As usual, all of these samples are raw from the recorder.

So that’s the lot for the meantime! i’m planning to do some more cool IR recording sessions in the near future, stay tuned for that.

Thanks for reading!



Hours 33 – 37: IR Recording Part 2 – Disused Quarry

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