The importance of sound – Part 9: How to make a (good) promotional film
The importance of sound – Part 9: How to make a (good) promotional film

The importance of sound – Part 9: How to make a (good) promotional film

This is the latest instalment in our How To Make A (Good) Promotional Film series. If you missed previous posts or want to go right back to the beginning and find out what it’s all about, click here. New instalments will be released every Friday. Click here to have them emailed straight to your inbox the moment they go live.

It wouldn’t be fair to talk about filming visuals without talking about sound too. Poor old sound, how it so often gets forgotten! But what makes a horror movie scary, or a Scandi-crime drama gripping, or the latest David Attenborough documentary somehow seem even more 3D? It’s the sound.

In promotional films and documentaries sound often takes a back seat. High-quality sound really adds production value. It makes things sharp and sexy and tangible. And beyond that, sometimes you can tell a story with sound that you can’t tell with pictures.

You might not be able to see the engine parts moving, but you can hear an engine roar.


Electric drivetrains

A key brief from our client Saietta was to continue their ‘cool and sexy’ image (maybe not their exact words but we got the gist).  Limited by time on site, we couldn’t take the easy route of filming electric vehicles zooming around a test track doing doughnuts, or an electric plane doing a flyover. It was also important to focus on the R+D (research and development) and the tech that the company specialise in, rather than the finished vehicles it’s used in.

So it was the sound, in the end, that really made the film. The shots are slick and sexy, and give you an insight into the different aspects of what goes on in their R+D facilities. But the sound of the film is what adds the drama.

Take a look and see what you think. Can you see where additional sound design has been added, and how this mixes with the soundtrack?

So how do you get good sound?

Quite simply, by having a dedicated sound recordist on site. You can get away without one, if you have a camera-person who is confident recording sound, and in some settings that might be fine. But if sound is really important to your film, then you want someone dedicated to getting that sound.

To get good sound, you want to give sound recording the same preparation time and attention that you do the camera work:

  • As well as a shot list, you can make a sound ‘shot’ list
  • At each location, make sure your sound recordist knows what they should be trying to capture
  • Check sound is ready to go before you start shooting each shot
  • Before you leave a location, make sure the sound person has everything they need
  • Do a wild track: this is where you record 60s of pure sound from each environment (without anyone talking or making other noise). This allows the editor to set the backdrop for each location and deal with noise issues. It is especially important for locations where you are recording interviews.


Why do we clap?

Clapping gives a point for the editor to sync the picture and the sound. The camera films the clap to ‘see’ the point that the noise should happen, and the microphone ‘hears’ it. When you align those two points, your sound and picture are aligned. The onboard microphone of the camera will also ‘hear’ the clap so you can align the two noise spikes.

A clapperboard is a fancy way of clapping. In addition to making a nice clear clapping sound, it gives you space to write on the scene and take numbers to make it easier for the editor to sort through. You usually only need that in shooting dramas, but it makes me feel special and important to use one anyway!


Sound and interviews

Sound is especially important when recording interviews. To be safe, you want to record two inputs of sound. As standard, that would usually be a lapel mic clipped to the interview subject’s shirt or jacket and a directional mic pointed at them. This gives you a back up if one mic picks up unwanted extra noise. The editor can also choose which channel sounds better for the editor, or blend them both.

As a side note, I prefer to go for hidden lapel mics where possible. A visible mic draws the viewer’s attention to the fact that this is being recorded, which I think breaks the immersive experience of feeling part of a real story. However, this will depend on budget, having an experienced sound recordist to attach it, and time constraints for setting up the interview.


Noise on set

One of the things we often have to contend with, especially because we’re usually on industrial sites, is extra noise on set. This can be anything from background machinery, to people talking, to a radio playing.

If you can see the source of noise in your shots (i.e. a piece of moving machinery or workers moving about) then that’s not necessarily a problem; it all fits with the content that you’re capturing. But noises that you can’t ‘see’ can really mess up an edit. You may not notice it at the time, but you don’t want to review your footage and realise that The Beach Boys are blaring out of a radio over every one of your shots.

Just like you will need to try and control lighting and action while filming, you will need to control the sound environment. Turn the radio off. Turn off air conditioning or humming machinery wherever possible. Remind everyone present that you are filming, and ask them to keep chat to a minimum.


Listen to your sound recordist

The most valuable tip I can give for getting good sound for your film is to listen to the person recording it. You may not be able to hear something, but their microphones are very sensitive. If they say a machine is too loud, or they can hear talking next door, or there’s a plane flying overhead… then pause the interview or the action and sort it out.


I talk more about sound in interviews in my next section: Part 10 – Setting up the interview


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