Pro Tips to Clear Corrupted Recordings.

Howdy SEA Fans, Welcome to another tiptuesday blog post tips to clear those corrupted recordings without using restoration plug-ins.

You have made a perfect take, but there is too much reverb on the recording?
The language in your video is difficult to understand because the reflections in your room are too strong?

Especially with speech and vocals, too much space can make the content difficult to understand or the vocals in the mix will not be a proper one.
Although there are special restoration tools, usually cost a lot of money.
And sometimes that’s not necessary: with the help of everyday tools of audio editings, such as equalizer and Noisegate, you can significantly improve such recordings

Remove echo and reverberation with Noisegate
As a rule, echoes or the reverberation occur after your actual signal and also have a lower level.
Exactly this circumstance can be used to improve such recordings.
We try to remove this quieter and later coming part with the help of a so-called “gate” or “Noisegate.”
So that we leave our actual signal unscathed.
We first want to find out from which level the unwanted reverberation occurs, this value is used to set a threshold below which your signal will be lowered or simply silenced.
Then the Gate closes and leaves nothing behind The goal is to set the threshold so that the reverb level is below it, to mute it automatically.
To find the right value, it is best to use a section just before and during a pause.
Depending on the room characteristics and the distance between the source and the microphone, reverberation may take only a few milliseconds.

We try to set the Threshold so that the reverberation audible during the pause is silenced.
However, you also have to make sure that the quieter portions of your recording, which you actually want to keep, are not muted as well.
To find the optimal value it requires a bit of patience and experimentation.
It is also necessary to listen to other portions again and again.

Important parameters that can be set in addition to the threshold are the Attack and Release values.
The value of the attack time determines how long the fade-out lasts from the full level to the reduction.
With the value for the release time, you can set the length that elapses from opening the gate to reaching full volume.
Longer times make the work of the gate, less noticeable. Shorter times are very effective but can be unnatural or lead to artifacts.

Many gates also include a hold function, which is usually adjustable in stages with terms such as long-mid-short.
With this value, you can prevent constant opening and close with only short signal pauses, as is often the case with speech.
This feature can be useful if your shot through the gate should sound choppy.

The equalizer as fine-tuner to reduce space effects
In particular, when shooting in smaller spaces, it is subjected to the reverberation hall effects, but also to pronounced resonances.
This can also change the timbre.
We all know the phenomenon occurring while a person is singing inside a bathroom.
But you can counter this effect with an equalizer.
We simply try to dampen or filter out the area in which these resonances occur.
While you can use the Noisegate effectively, especially in the signal pauses, the Equalizer helps even when the gate is open.

To find the annoying area, we use a parametric equalizer and our ears.
With the equalizer, you select a frequency band and set the filter mode to “Peak”. Depending on the type of equalizer you should now be able to set the value for the “quality” Q (= Quality).
This value determines the sharpness of your filter. At a low value, the filter is broad, at higher Q, the filter area becomes narrower.
Thus, one can very precisely lower or emphasize only certain areas in the sound image, while other parts remain unchanged.

In order to find the disturbing reflections, you use such a narrow filter area with strong subsidence.
Now play your take and move the area back and forth along the frequency axis.
You will quickly find an area where your unwanted resonances go back and the sound improves.
For smaller rooms, this is often between 200 and 600 Hz.

Of course, you can do the whole thing the other way around.
Set a narrow filter range and search with strong boost your sound image.
In those places where the resonances are prominent or the sound changes unpleasantly, you then make a lowering.
Have you found this area, you can still experiment with quality and intensity for the reduction. It should be ensured that the recording still sounds as natural as possible and not too thin or artificial despite filtering.
Often it can also be helpful to filter out two or more narrow areas instead of a broad reduction. Incidentally, you can also try this procedure with flutter echoes and noise.

We hope that the tips which are mentioned above have been useful for you.
As a Sound Engineer or an aspiring sound engineer, do you know any other tips on how to improve the corrupted recordings which will be helpful for others?
You are Welcome, Do write as a comment below.

Next Step

Contact Information

  • Address
    Sound Engineering Academy
    C.S. Road, Jagathy, Thycaud (PO)
    Kerala - 695014 India
  • Phone
    +91 9895745100, +91 8547464632
  • Email

You cannot copy content of this page