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Posted by on Jan 21, 2013 | 1 comment

Transient Enhancement With Explosions

Article By: Frank Bry

Snow Explosion Composite Image

Transient enhancement plug-ins are wonderful tools to have in a sound designer’s arsenal. They can be used to soften a sound or to make it balls to the wall, hard hitting intense. Explosion sounds really benefit from this type of process. If you have recorded explosions, you may already have discovered that live is much better than tape, or should I say “BWAV file.” The human body feels the concussion wave from a powerful blast as well as hearing it. The sound still feels massive even when wearing hearing protection . In the video you will see the snow lift off the ground a little bit, and it’s especially noticeable in slow motion. When you load the raw sound files into your DAW to listen to them they seem a little limp (no pun intended). So, bring on the transient enhancement!

Recording Explosions
This leads me to the next area of this article which is recording the sounds. This article will serve a dual purpose in a way. I was going to write a separate article comparing the new Rycote ORTF mount for one of my Sennheiser MKH-8040ST microphone sets and a standard XY mount for my other MKH-8040ST. At the end of the article, I will get into this more. (Note: this article is not a product review even though it might sound like it at times. I will just share my thoughts with you on each plug-in used in this demonstration.)

The sounds I recorded for this demonstration were done in my front yard here on the ranch on a very cold day; it was just under 20°F with very little wind. I hauled my gear out the door and set up in my driveway which is currently surrounded by tall snow banks. I used two SD-702 recorders synced together and set them up 25 meters away from the explosive targets. I would shoot from this position with a .22 caliber rifle. The microphones were about half way between me and the doomed snow bank. Explosions in a snowy, winter environment are actually perfect candidates for this kind of transient process because most of the initial intense mid and high frequency energy is instantly absorbed by the soft blanket of powder snow. This makes the sound more like deep pop. Even with all the natural sound absorption there is still a great deal of sound during the first few hundred milliseconds – we just need to bring it out.

Pre-Enhancement
The Sennheiser MKH-8040 microphones record way beyond 20k, and they also record a fair amount of sub-sonic information too. To see how much and at what frequencies this very low end energy is, I turn to Waves H-EQ. This plug-in has nothing to do with transient enhancement, but it does effect how the transient plug-in reacts to the explosion especially when pitched down. I love this plug-in since I can see what’s going on with level and frequency at the same time and adjust accordingly with the various EQ emulations and parameters. As you can see in the H-EQ screenshot, there is quite a bit of sub-sonic energy between 10 and 20Hz. I added a slight roll-off at 16Hz and a slight bump in the upper range. There is also a decent spike at 100Hz, but I will leave that alone because when the explosion is pitched down an octave it becomes 50Hz and that might work in our favor.

Waves H-EQ

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