The 'fix it in post' mentality may work for video, but sound is hard to salvage in the edit. From background noise to inaudible productions shot on cheap cameras, the number of casualties in audio post's emergency rooms is on the up. Andy Stout asked four audio specialists about aurally injured shows they've helped to resuscitate.
The "fix it in post" mentality may work for video, but sound is hard to salvage in the edit. From background noise to inaudible productions shot on cheap cameras, the number of casualties in audio post's emergency rooms is on the up. Andy Stout asked four audio specialists about aurally injured shows they've helped to resuscitate.

Case Study One: lack of resolution

ER: Resolution Post. Genre: Reality TV. Doctor on duty: Dan Gable, joint managing director and dubbing mixer

The casualty

A sound epidemic has broken out in reality TV - symptoms vary from poor quality sound to recordings which are just too clean and out of keeping with the show itself.

The diagnosis

"People doing observational docs work with stripped down crews and there's a trade-off between access and quality that comes out in the dubbing suite," says Gable, who's recently worked on Wife Swapand Faking Itamong a host of other OB docs. The absence of a sound recordist [ recordist absentia] is a notable symptom, but patients present other indicators depending on how long the infection has lasted. Advanced cases include problems with hidden cameras, poor quality radio mics and simple kit failure.

The prognosis

"A lot of the dubbing mixer's job nowadays is in restoring the sound and a lot of time we can perform miracles," says Gable.

The procedure

De-noising and de-hissing are the main processes for Gable, often using Pro-Tools plug-ins, while the predictable cracks and popples introduced by radio mic interference also need dealing with. The irony is that Gable has recently had to "re-noise" certain sequences. "People have become used to bad quality audio and, as a result, I've done dubs where I've introduced noise because they sound a little too clean and not very believable," he says. "If you've got an interview where one bit sounds bad and two bits sound all right, you get the bad section sounding as good as possible and then match the other ones down. Consistency is very important and if you're intercutting bits of audio you have to go to the lowest common denominator."

At the very, very worst case, if the images are compelling enough and the audio just isn't there, there's only one option. "You can do anything apart from where you can't hear what they're saying," says Gable. "We've had hidden camera stuff, where you've got a camera at one end of the room and a person at the other, where it's just had to be subtitled. Funnily enough, as soon as you get the clue from the subtitles, normally you can then hear what they're saying."

Case Study Two: car trouble

ER: The Audio Suite. Genre: Car magazines. Doctor on duty: Neil Hillman, The Audio Suite managing director

The casualty

Not so much a case for A&E, but of long-term outpatient care. Hillman looks after the audio post on Five's Fifth Gear. As such, he faces a tricky balancing act. On the one hand, engine noise can drown out the presenters. On the other: "The engine noise is part of the viewing experience and there are a lot of people watching who want to hear it."

The diagnosis

Radio mics and car engines do not happy bedfellows make, it's as simple as that.

The prognosis

Fairly good. Fifth Gearhas a highly professional team and sound recordists who set the levels as well as they are able before the presenters tootle off in the cars for a couple of hours. That means problems are kept to a minimum. Ideally, whenever using radio mics you'd also have a boom mic pointing away from the speaker to open the sound up and give you something to dip into when the radio mic gives way. However, that's not much of an option given the nature of the show and the environment which the presenters work in, so cleaning it up in post afterwards is usually the order of the day.

The procedure

"A tiny little radio mic capsule is never going to capture the human voice as well as a 416 or a conventional shotgun mic," says Hillman. "Some people's voices sound great via radio mic, with other people you can't get any body or warmth into them. So you spend a lot of time trying to tweak some presence into it. We also look at who the presenter is. Vicky [Butler-Henderson] has a higher voice and is easier to punch through as she has a more middle frequency heavy voice then the other two."

It doesn't always work, though. "In the last episode we had Jason Plato driving the new BMW over to Europe. Driving along he said: 'I'm doing 80mph on the autobahn, I'm comfortable, it's quiet and I'm doing fine.' Of course, the omni-directional radio mic doesn't work in the same way that ears work, so the radio mic is hearing the road noise, the wind noise and the engine noise which sweeps across the whole vocal spectrum and you could hardly hear him. In the end we just couldn't use it."

Case Study Three: natural disasters

ER: BBC Post Production [Bristol]. Genre: natural history. Doctor on duty: Martyn Harries, dubbing mixer

The casualty

Magnificent footage of quarter of a million reindeer on the move in Lapland with no sound.

The diagnosis

"Natural history is predominantly shot mute unless you've got a presenter there and producers working in this genre are not used to taking a sound crew with them or used to bringing sound back from a location," explains Martyn Harries.

He recalls a circumstance where one producer had been out filming Laplanders herding 250,000 reindeer: "You can hear the reindeers' tendons clicking as they run. He came back saying the noise of 1 million tendons clicking across the landscape was incredible. We said: 'Great, have you got the sound?' He said: 'No, I left the mic in the hotel that day'."

The prognosis

Nothing that can be done for this patient. However, a public health education programme is recommended to ensure that such easily avoidable yet potentially fatal cases don't occur in the future.

The procedure

The dubbing mixers needed to recreate a totally different soundtrack. There are some circumstances when it's worth recreating sounds from scratch or trawling through sound libraries to find a decent basis to start from, and others when it's more appropriate to give up and slap some music and a voiceover on a sequence. One million reindeer tendons popping all at once fall into the latter camp.

"Natural history producers need the discipline to be able capture some sound," warns Harries. Of course, the opposite situation - too much sound or sound in the wrong place - also occurs in natural history with alarming regularity.

"You can't get rid of cicadas - they're the noisiest things on the planet and they stop and start suddenly," says Harries. "If you dubbed everything in a rainforest, you'd barely be able to hear the presenter. Wind in trees too can sound like seawash and is a devil to get rid of because it's never constant. Sometimes you get very loud birdsong that just cuts off, so then you have to plaster birds on the audio or it sounds odd. The main problem we have is creating perspective. If you've got a birdcall that was recorded from half a mile away, inevitably the shot you've got is one where the bird fills the screen."

Case Study Four: driller killer

ER: Alchemy. Genre: commercials. Doctor on duty: Tim Lofts, senior sound designer.

The casualty

Out of 130 shoots for a massive Sensodyne ad campaign a good proportion had significant problems with the audio track. While symptoms varied, the chief culprit was unacceptable levels of background noise from the dentist's drill.

The diagnosis

Recordist absentia, basically. The commercials were shot on MiniDV in dental surgeries around the world and were designed to have a rough and ready feel. However, the lack of a sound recordist on the shoots meant that some elemental mistakes were made.

"If they'd taken a soundman on the shoot they could have avoided problems like putting the mics near fluorescent lighting and picking up the buzz," says Lofts. He adds: "A few weeks ago they even shot one with the suction pump still running in the background, so there was this noise all over the tape."

The prognosis

While the sheer volume of material shot for this commercial meant that some sequences could be jettisoned, usually it was the tape the client liked the best that had something wrong with the sound. "There was one which was so bad they thought they might have to fly back out to China to reshoot it," says Lofts. "But I said let's give it a go as we've got some Cedar audio restoration software here."

The procedure

Cedar is a small company based in Cambridgeshire and its software is to audio crash resuscitation what penicillin must have been to the medical establishment in the 1940s. "It allows you to clean up audio that's previously been uncleanable," says Lofts. "Basically, you feed it a sample of the sound you're trying to get rid of, it takes that footprint, analyses the entire track, recognises the sound pattern and then simply removes it. It takes a bit longer than normal because it's not automatic; it's more of an art than a science and you have to experiment a bit to get the best results."

He adds that you can spend anywhere from a couple of minutes to 40 minutes trying to edit out one sound, which might not seem like a long time, but if the booking's only an hour long, then time is money.

Tips for producers

There is a wonderful legend regarding the Queen having Heathrow close one of its runways one year so that she could record her Christmas Speech at Windsor without 747s flying over and ruining the take. However, if you are not a constitutional monarch with the power to do such things, here are some top tips to keep you out of the hands of the Audio Emergency Room.

· Don't always assume audio problems can be fixed in the dub. You can manage a lot of things, true, but it can't be done quickly and it can't be done cheaply.

· Distortion on radio mics is a huge problem, especially when it comes to speech. It's notoriously difficult to get the levels right using DV cameras, so ideally you want to set the levels 10db down to give yourself plenty of headroom, as 10db can be boosted pretty much silently in a dubbing suite. Once speech is distorted it's usually unsalvageable.

· You may have an outboard mic plugged into a camera, but are you recording it? The best way to test which mic you are actually listening to is to scratch the windshield with your finger. That way you can be positive which one you are recording.

· If you've gone to too high a level on a DigiBeta or a DV, the D to A converters on the DigiBeta can introduce distortion, so it's always an idea to go digitally out of the deck and not overload the converters in the deck itself.

· Don't shoot in noisy environments. Switching mobile phones off is a good tip rather than just silencing them, as the RF interference can affect the sound when you're using radio mics.

· Pay attention to environments. If someone is recounting a heartfelt story then traffic and noise in the background can ruin the drama of it, whereas at other times it will hardly be noticed.

· Make sure the equipment is working properly. Make sure the leads are fine and connected properly, the batteries are charged up, and you've done a test on the radio mics.

· If you're doing any blue-screen or green-screen work, try to do it in a fairly dead room. Echoey rooms when the eye can't see why the echo's there sound appalling.

· Make sure the appropriate people are miced up. It sounds obvious, but if you've got two mics and three people, it's easy to re-record the questions afterwards, so give the mics to the interviewees.

· If possible, use a sound recordist. When you're up against it, a recordist will get you something usable, while a researcher who's done a half-day audio course probably won't. You can cut around bad camerawork, you can't very easily cut around bad sound.