Hi All I’m recording SFX for an independent film. One of those is a plane crashing into the ground. It has to be a powerful crash. I’ve used many props for this (the jet engines are a fan pitch-shifted down and time stretched a bit) but the impact sounds tend to loose all thir power after I pitch-shift down. I’ll do some more recordings asap but to be honest I’m at a loss....what props can I use for something as massive as a plane crash? Or maybe there is a way to fix the loss of power problem I’m experiencing when pitch-shifting smaller crash and impact sounds?
Seconded on the details selling it. I had to design a bunch of train car impacts a while back and ran into similar problems with getting things to sound massive. Don't think that your pitch-shifted layers will make the entire sound - they can provide some low body, but all that high tinkly, full-res stuff is also really important.
My quick tips in addition to what's been said here:
1) Picture what's actually happening to the plane in slow motion and map it out if it will help you structure your crash. Like, maybe first there's the plane hitting water, so you need a large splash. Then there's the metal of the plane crumpling - deep metal stresses and groans, maybe some high creaks or write tensiony snaps. Glass breaks. A fuel tank explodes. Bubbles rush up as some stuff starts to sink down, etc.
2) Don't be afraid to use some distortion. Hearing a real impact like that close up would probably deafen you instantly, so go big.
3) Jump from as quiet as you possibly can to as loud as you possibly can as quickly as you possibly can. There's no better way to make something sound loud than using all the dynamic range you have and making it as transient as possible. Once that initial 'hit' is done, you can bring up a bunch of squashed/limited layers, but I wouldn't bother compressing the initial hit at all. Maybe have the first part of the impact be the bass so that people's ears get a chance to warm up a tiny bit before the real nasty hits come in though.
4) Kinda goes without saying, but try to hit the full frequency spectrum - sub basses, low groans, low mid explosions, mid creaks and tears, mid high creepy dry ice-y sort of metal sounds, high glass. That'll give you even more perceived loudness and make sure that no matter what else is going on in the mix (e.g. music), there are the necessary layers available to the mixer to make your hit sound as big as possible at that moment.
Impacts that long are kinda like doing a mini mix session - you will want to be constantly taking your audience's ears from one detail to another in very short amounts of time. So choose your details and make sure to give them space to speak, one by one.
Post up when you're done! Would love to hear it.
From my observations (since I've haven't had the opportunity to design a plane crash yet), a plane crash or other large scale impact is designed with a ton of carefully layered sounds/events. I've always liked this one. Which is less about the impact and more about the aftermath. Really nice use of metal, water in this sequence to elevate the danger.
Real world props.
I'd suggest finding a large metal dumpster or shipping container to start. They can sound huge if recorded in the right way.
It's not always necessary to pitch elements down to sound big if you record them with some proximity effect. Or the opposite, use acoustics to your advantage and record with some distance to capture some nice big reverb/slap. Contact mics are also your friend, especially with metal. And don't forget about the subwoofer, a key tool in designing these large scale events. A little 60kHz rumble can go a long way in selling size.
Have you looked at library recordings of trains (rumble, wheel screeches), or car crashes? Building demolition? Those could make for nice material as well.
I got some explosion sounds while playing with bass and reverb the distortion makes it seem more powerful I think, you can download it if you like. I don't know how the scene plays out exactly but you could also try slowly pitching up the engine sounds as it descends to add more tension and and lower other sounds with it prior to the explosion to make it seem more powerful (like this LoTR example), Greg Russell also mentions a good point (skip to 16:35) when mixing to make an impact seem more powerful.
Layer up the impact, distortion as Luca said would sound great as well as a sub bass going under it.
I thought the turbines on the plane would pitch up not down as they are working harder?
contact mics/close mic on big sheets of metal, get the creeks yourself, go to a junk yard, I'm sure they won't mind.
In crashes and such, the impact and explosions are not even close to as important as the immediate aftermath with debris and material stress! You can make the fattest, most bad-ass explosion in the world, and the audience still just think it's a pretty cool sound, but by adding collapsing metal, sprinkles of debris, bursting plastic, chattering glass and all kinds of really unhealthy sounds you sell the shit has really hit the fan in 1000Mph!
In explosions, dynamite is very often a best friend. TNT and such burns with an extremely high speed that tends to be very difficult to do something with (at least what I think right now), but dynamite has a nice and threatening release with nice low-end I've found very useful in many ways. Also, the low-end is vital for the scale, but actually not that threatening. Imho the best way to enhance the shitstorm-effect in an explosion, other than loads of debris, is to use the range around 2KHz, a very physical range for the human ear, and a very careful raise somewhere around the centered bass, with the sub-bass (not to be confused with LFE, though it will mostly come from there) as just an enhancer.
I'm not a big fan of hammock shaped EQ'ing, especially not in explosions and impacts...