If you are having problems with audibility of audio in a classroom setting, for example if speech sounds muffled and unintelligible, there are steps you can take to improve this.
By default, the Zoom will utilise noise suppression, but these filters can interfere with the audio and even cut it out completely if it goes below a certain level. For situations where we need the full range of audio captured by the microphone, follow these steps:
First, open up Audio Settings in Zoom. You can do this in two ways – either from the Zoom app, or from a Zoom meeting window.

From the Zoom app, click on your profile picture and select ‘Settings’.

Or, from a Zoom meeting in progress, select Audio Settings from the Mic icon.

Then, from the Settings window, select: Audio
Next, in the Audio Profile section, select Original sound for musicians with the following options:

You can now close the Audio Setting window. Be aware that the noise suppression has not yet been turned off – we have simply added a toggle button to be able to do this.
This toggle button is displayed at the top left of your Zoom meeting screen, as shown below:

Click on where it says: Original sound for musicians , to toggle it to: On.
The message should appear informing you that ‘Noise suppression is disabled’ (see below)

Please note. While this setting will increase intelligibility of speech, it will result in more background noise, such as air conditioning and fans. For less extreme noise suppression you can experiment with the Low-High settings in the Audio Profile.