Category: Explosions

About six months ago I purchased a ton of fireworks. Why? Because I like blowing things up. So combine that with a recorder and you have some awesome sounds. I never got around to actually using any of them until just last week, when I decided to bring a bunch of them out to a party at my friends house, which is in the middle of nowhere.

While at the party, we found this long drainage pipe and started throwing bottle rockets down it. The sound was absolutely amazing, and I decided that I needed to record the resulting sound. So a few days later, I returned with an arsenal of rockets, firecrackers, and my favorite, mortars. Armed with a Zaxcom Deva V and a locker of mics, my goal was to record thick, epic explosion sounds.

So we went out and recorded for about 4 hours. When we were on our last mortar (we only brought about 6 – cost about $10 per charge!) I said, “hey what would happen if I put the mortar in upside-down and lit it?” So I set up everything, got the cameras ready, found a good hiding spot, then hit record.

My friend, Mark, set up his camera to take a long exposure of the whole thing. This was hit result:

Click for full resolution - picture taken by Mark Hammer
(click for larger resolution)

Epic, eh? Wait till you hear the sound! Oh, BTW – we couldn’t find even a trace of the firing tube. Completely disintegrated!

Mics that were used:

MKH60 – Stand was about 10′ from the mortar, mic was 35′ in the air, aimed straight down.
CSS-5 – about 30′ from the mortar, 5 feet off the ground
MKH50 – about 15′ from the mortar, a foot off the ground

All recorded at 192k 24b straight into a Zaxcom Deva V.

Quick disclaimer about the sound: this is an edited sound, I did a little work to beef it up, but I only used the original sound. I did not add any sweeteners whatsoever!

Please feel free to download the sound. All I ask is that if you decide to use it in anything, you just let me know so I know where it goes :-)

Also, the sounds I collected from this session will be included in my upcoming library full of impacts and explosions over at HartFX! Stay tuned!


Tim Prebble has released a new sound library through Hiss and a Roar! His 4th Library, Fireworks, is amazing! Recorded over 2 days, with 4 recordists, $600au of specially selected fireworks, a few weeks of tender love and editing, and voila! A new library is born! And it took a bit of dedication too. Here’s an excerpt from Tim’s blog on the experience:

FIREWORKS is a library I have been planning for well over a year. Here in New Zealand fireworks are only sold for one week each year (Guy Fawkes is November 5th) and most years I would buy a bunch of fireworks & record them for my library, and I noticed how often those sounds were handy for all sorts of purposes…. So in November 2009 I contacted a number of fireworks importers and asked them to hand select an arsenal for me based on sound. Six hundred dollars later I had a serious fireworks selection but summer was starting & I knew I would have to wait for winter & the fire risk to not be an issue. So I stored my potential library away & waited…

Lots of Fireworks!

Not only am I very excited about the quality of this library (24b 192k!), but I am very jealous that Tim got to shoot off that many fireworks!

Tim didn’t only record raw fireworks, but he did a lot of perspective and “prop” recording too!  Here’s a bit of what he had to say about it:

Apart from 3 big plastic bins of fireworks one of my goals with capturing the fireworks library was about context: these sounds are very useful when designing weapons and I was very interested in reinforcing this aspect by releasing fireworks in metal pipes of various sizes. Earlier in the week I visited a great junkyard and bought a number of different size pipes, from a 2m long metal drain pipe to short narrow pipes to a larger air conditioning vent; all great sources of resonance!

Go check out Tim’s blog on the experience and download a copy! There are 5 versions, ranging from $9 to $99, and a free one too! The $99 version is pretty sweet: 210 sounds, multichannel, 24bit, 192k. Great deal!

Tim Prebble – Sound Devices 722 with two Sanken CUB mics
Dave Whitehead – Sound Devices 722 with Sennhesier 8050 and DPA4006
Matt Lambourn – Sound Devices 722 with MKH816 and my MKH70
Ray Beentjes – Sound Devices 744 with quad rig: Sennheiser MKH50+30 LR and MKH816 x 2 LsRs

Check out Tim’s blog on the library here.

You can purchase and download the library here!

Last week, I wrote about the “Sound Snooper” homemade “shotgunish” microphone from an Electronics journal published in 1965. I thought it looked awesome and I wanted to know how it sounded, so I decided to make one. I did not, however, want to pony up the $200 for the aluminum piping used in the journal. At least not for the first time around. Instead, I decided to spend a mere $4.68 on PVC piping, and about $20 on epoxy. Far cry from $200. I used 1/2″ PVC instead of the 3/8″ Aluminum (couldn’t find 3/8″). I figured the difference was somewhat negligible.

So I started construction:

I played around with a few different types of glues. Found out that the 5 minute epoxy in the plunger works best. You just have to work quickly or it will set in the plunger itself! After working for a few hours on it (it was a slow process, as I could only put a few together at a time and had to let them set before I moved on), I started realizing that it was turning out a little on the large side (larger than I expected). So I started measuring some things. It was at this time that I realized that PVC pipe was measured by the inside diameter, while aluminum is measured by the outside diameter. This means that my PVC contraption would be twice the size as the aluminum one made in the journal. This would pose to be a bit of a problem because I can’t find a diaphragm that big, unless it’s dynamic, which kind of defeats the purpose of a long distance mic…

Anyways, I was to continue anyways, because I must finish what I start.

Here’s some pics of the mic coming along:

I finally finished the body, and moved on to the electronics. As I said before, there isn’t a condenser capsule big enough for this application, so that’s out of the question. The journal used a crystal mic, but the biggest one of those I could find was 2 inches, which is big enough for the one they made, but my mic was almost 6 inches in diameter. So, I went down to my local electronics surplus store and bought myself a 4.25″ dynamic driver. It was made to be a speaker, most likely the woofer driver in a small pair of speakers, but I decided to use it as my mic capsule. Unfortunately, I didn’t take a picture of it before I put everything together.

Anyways, I soldered a lead with a 1/4″ TRS connector on it to the mic capsule. I found a funnel that was about 5.24 inches in diameter, which was the biggest one I could find, and mounted my dynamic capsule in it by drilling holes in the funnel and running solid copper wire through the holes. I then cut up the diameter of the funnel every few inches so I could fit it around my mic body. I fitted everything together and manhandled some gaff tape onto it to make it stick (this wasn’t an easy process…). Everything was together, and I decided to try it out. Here’s a pic of the finished product:

So, as you can imagine, it didn’t sound terrific, being dynamic and all. My plan is to make a better one some time (hopefully soon) and order a crystal mic or something to use with it. But for now, I’m just working with what I’ve got.

Below are a few recordings I did with the mic. It sounds fairly cool, because it’s really saturated. It’s fairly directional as well, but I’m guessing if it were much more sensitive, I’d be hearing the directionality a lot more. I found that going directly into a preamp rendered a fairly high level signal, but it was very bass heavy, and didn’t have a lot of high end response. It sounded very “tubey”. I then tried it through an impedance matcher / balancing circuit. I lost a very significant amount of level, but it fixed the frequency response almost completely. It sounded almost normal.

Here’s a recording of a fire cracker with just the “Tube” mic:

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Here’s the same recording with the CSS-5 and a contact mic mixed in:

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Speaking of my contact mic (the one I made and blogged about a few weeks ago, it met its untimely doom during this recording. I decided to gaff tape it directly to the firecracker to get a cool impact sound. Granted, I knew it would break, I just didn’t know how long it would last. I reinforced the sides of the firecrackers with tape so the explosion would be directed to the ends, minimizing the impact on the mic. It lasted 4 takes. I’m proud of it. $1.00 of parts down the drain, but I made a new one, so all is good.

Here’s a pic of the dead mic:

Here’s a recording of the final moments of its life. It was a good mic. It always listened, never talked back. It has a short life, but maximized its effectiveness despite its shortcomings:

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I’ll get some more recordings up as soon as I have time to do a few. I can try to entertain requests if you’re interested, since it’s a one-off. Anywho, hopefully I’ll get around to making a new and improved version sometime soon. Wish me luck!

Mix Magazine has written an amazing article on veteran Sound Designer / Mixer Ezra Dweck, who has recently been contracted to help design an IED attack simulator for the training of US Troops. He was enlisted to capture and recreate, as acurately as possible, what it sounds like to a soldier inside a humvee to get hit by and IED. That sounds like a difficult, but incredible fun task! “Wait, you mean I get to blow stuff up, AND record it? Then you want me to play it back as loud as possible?” Sounds like a sweet gig to me :-)

The Audio Challenge
For the sound design, Dweck was tasked with coming up with as realistic a presentation of the sound inside a Humvee in patrol and combat situations as possible. The training Humvee will have five soldiers in it — four in the cramped main part of the vehicle, and one turret gunner on top partially exposed through the roof. “My initial idea was to investigate some 360-degree surround speaker systems, but they just weren’t feasible for the space inside the Humvee,” says Dweck. “I went through a lot of negotiations with the guys who are building the thing — a company called Technifex that does a lot of theme park stuff — and what I wound up with basically is 6.1, but not in a traditional layout inside the vehicle. So it’s five speakers in a normal L/C/R, Ls/Rs position, and then there’s a full-range, full-sized speaker mounted in the dash in the middle and a subwoofer in the engine bay where the engine would be. I did a bunch of research to find a full-performance, relatively small driver speaker I thought would work, and I wound up with a Meyer MM4XP for the five. It’s about the size of a 4-inch tile, but about six inches deep. They run on a 48-volt distribution system, but they’re self-powered. They’re good down to about 300 Hz, so I need the full-sized midrange speaker in the middle to kind of balance it out.

“Then on the exterior, mounted on this giant truss that the projectors are mounted on, I also have three speakers [JBL EONs] arranged left-center-right.”

Read the rest over at Mix Online

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