Audacity Equalization Effect Plugin Basics
Always set Audacity to make a copy to work with while leaving the original file untouched. Being neurotic, I make copies of the original audio files and save them in a different folder (not in the Audacity folder) or upload them to Google Drive, or one of the other safe storage areas. Use File>Save>backup to save a super file of your current results and continue on editing the original from there.
Some expert suggest you use compression before equalization. I would remove high end, low end and subsonic noise first using EQ, or filter, then compress, then EQ.
If you start reading about audio mastering by industry professionals you will go mad from the volume of information and conflicting ideas. There is no such thing as perfection at our level, You can make a mediocre recording sound pretty darn good and no one will notice it’s not perfect.
Using that happy paradigm:
An Equalizer allows us to raise or lower the gain (audio loudness level) of a range of frequencies above and below the frequency we select without changing the loudness of everything.. You are adjusting a range. The numbers that run across the bottom of the Equalizer show the frequencies low to high going left to right. Usually. High frequencies correspond to high pitch sounds and low frequencies to low pitch sounds.
When you move a slider up or down for a particular frequency you are basically raising or lowering the volume for just a small range of frequencies with the one you selected at the center is the most changed. Usually.
When we adjust the volume of audio we are raising or lowering all frequencies equally. Approximately.
- Frequency. This sets the center of the range of frequencies we want adjusted.
- Gain. This determines the amount of change. Positive numbers boost the gain in that range of frequencies, while negative numbers reduce the gain in that range. What the sliders change, boosts+ or reduces-. Shown on the left of the equalizer vertically in Db. (Decibels)
- Q/Width. This determines the width of the range of frequencies we want to adjust. Higher numbers create narrow ranges. When adjusting values for a voice, the default setting of 2 is good.
Caution. Yes another one: when you move the sliders up to boost a frequency range you can easily amplify the gain to the point of clipping. The equalizer doesn’t care.
If your sliders are set to amplify any frequencies, especially the lower frequencies (normally the loudest), then first use the Normalize effect set at -3 dB or lower. If you find that your EQ settings have caused clipping, you can Edit>Undo and apply normalization before reapplying your EQ settings.
You can see clipping in your recorded file View>Show Clipping
There is a Clipfix plugin but best is to normalize the overall level as described above. Most of the time repairs are not as good as good editing. Note that clipping can occur while recording, so watch your gain and levels during a session.
Sample EQ Settings
We're going to use graphic mode:
- Men: Add 3-5 dB around 180 – 200 Hz. for warmth
- All: Add 3-5 dB around 315 Hz.for warmth
- Men: Add 4-6 dB around 3,000 Hz clarity
- Women: Add 4-6 dB around 4,000 Hz clarity
Reduce low-frequency if the voice sounds “rumbly” and muffled.
Reduce highest frequencies and lowest to reduce noise if necessary, but watch out for creating a sound that's artificial. Go easy.
Drop gain around 80-130 Hz can to clean things up
Noise is not a single frequency. Noise spans the entire range of human hearing. This means that you can’t use a simple EQ to remove noise, unless it is a very deep rumble or high hiss. Instead, you use the noise reduction plugin.It may be tempting to try to reduce AC mains hum with EQ but those sounds have harmonics which are tough to get without damaging the quality.
Other Tips
1. Use a High Pass Filter or EQ setting to Cut Everything Below 80Hz
Dropping the lowest freq slider is pretty close to a high pass
Try this for a quick improvement on any voice over.Anything below this frequency will be low end rumble and noise. Remove it, and it will instantly clean up your voice over.
Try going even higher, especially on a female voice. If your voice recording is sounding a bit too bass heavy, cutting everything below 100Hz will really help with intelligibility.
2. Cut 100-300 Hz to Add Clarity
Similar to the last tip, cutting the bass will improve clarity. On the other hand, if the voice sounds a bit thin, try boosting somewhere in this frequency range.
3. Cut 300-400 Hz if the Voice Sounds ‘Muddy’
This is a problematic frequency range for most recordings—particularly in music. If the voice sounds a too muddy, try cutting somewhere around this area.
4. A Wide Boost Between 2-6 kHz Can Improve Clarity
If cutting some of the bass around 100-300Hz doesn’t add enough clarity, try a gentle boost across this frequency range.
Be careful of exaggerating the S sounds of the voice though, which leads me on to…
5. Cut Around 3-5 kHz if the Voice Sounds too Sibilant
Be wary of this frequency range when boosting. Boosting too much at these frequencies can make the voice sound highly sibilant and add too much sizzle.
Hey Generally if a male voice is sibilant it will tend to be in
the 3-5k Hz range. If a female voice is sibilant it will tend to be in
the 5-8k Hz range
if the quiet parts are difficult to understand, you can apply an EQ
boost in the 2-5k Hz range after the compressor to aid diction.
Subsonic Noise
Subsonic or low-band noise can enter your recorded audio through physical vibrations during the recording or noise from HVAC, fans etc.
Frequencies below 20 Hz are "subsonic" because the human ear is unable to perceive it as recognisable sound. First remove any DC offset in the recording using the Normalization plugin.
To remove subsonics from your track you may filter it with:
- Audacity's built in Equalizer under the Effect menu
- Audacity's built-in High Pass Filter under the same menu - set the cut-off frequency to around 25 Hz. You can repeat this same effect a couple of times if a sharper cut-off slope is desired.
- This Nyquist plug-in subsonic
After removing subsonic noise re-normalize your audio. It will be louder with more definition in the bass.
