Echo: You may sometimes hear an echo in your recording. These noises are difficult to filter out in post-production. This is usually caused by the layout of the recording room you are in. If the room is large or has little material furniture, the speech sound is reflected by the smooth surfaces and an echo is created (illustration: poor recording situation).

To minimize echo, it is often sufficient to find a room with furniture that is covered with fabric, such as a sofa, curtains, a bed or similar. These objects absorb the sound (illustration: favorable recording situation). In addition, it would also work if you stretched a blanket behind the microphone or positioned the microphone in front of the open closet so that the spoken sound cannot be reflected by the bare wall behind the microphone.

Background noise: This category includes all noises that you have become accustomed to in your environment but only become aware of when listening to the recording. These noises include, for example, car noise, vibrating cell phones, rattling chains, etc. (Figure: Sources of noise at the recording location). The first step is to become aware of these noises with the help of a test recording and to consider where the source of the noise is coming from and then switch it off.

Some sources, such as a vibrating cell phone or a rattling chain, can be specifically switched off by attentively searching for the sources of interference.

Recorded rustling: In this case, the source of the noise may be a device that generates such a noise. For example, this could be the fan of a PC or the ventilator that is running during the recording (illustration: Sources of noise at the recording location). In both cases, it is advisable to increase the distance between the microphone and the noise source.

For PCs with a built-in microphone, you can use an existing headset or smartphone, for example, to increase the distance to the PC. It may be a good idea to get to the bottom of the cause of the loud fan. Sometimes it helps to close some programs or position the laptop slightly higher so that it gets more air.

Technically induced rustling: Noise can be caused internally by a microphone that is set too sensitively or by defective microphone connections.

Please note the volume settings of the microphone. If these are too high, turn them down. If the noise is caused by a faulty microphone connection, it is worth checking this connection for a loose connection. As a rule of thumb, the more connectors there are between the microphone and the recording device, the more the audio quality will suffer.

Overdriving: If the recorded sound sounds a little "scratchy", this may be due to an overmodulated recording. This means that the recorded signal was too loud for the recording and some frequencies were cut off during the recording process.

You can find out how to avoid such sources of interference in the tab: "Correct leveling".

The best position is shown in the following illustration.

Holding the microphone

Holding the microphone in place leads to noise and an inconsistent microphone distance (figure: Unfavorable microphone fixation). This noise can also be heard on the recording.
To avoid such noise, it is advisable to fix the microphone to a stand or microphone arm.

Lowering the head

By lowering the head, the vocal sound is not optimally transmitted to the microphone (illustration: unfavorable head position).

Incorrect microphone position

If the microphone is not positioned at the same height as the mouth, the voice sound will not be optimally captured on the recording (illustration: unfavorable microphone position).

No pop protection

If there is no pop protection, the air flow, which occurs particularly with sounds such as "p/b, k/g, t/d", can be perceived in the audio recording as noise ("popping") (figure: Missing pop protection).

In the graphic you can see the level indicator of the recording volume from the program Audacity.

The recording volume is indicated by a colored bar that fills this scale. If the bar is close to the 0 dB. limit or is colored red, then the recording source is too loud. The recording is therefore overmodulated and can no longer be played back accurately and sounds scratchy/crackling when played back.

It is also possible that the recording volume is too low and may be at -48 dB. In this case, the recording would be too quiet and, depending on the quality of the recording technology, amplifying the recording would be accompanied by noise.

To avoid these extremes, the microphone level should be set optimally. For voice recordings, it is sufficient if the microphone level is mainly between -12 and -6 dB. Finding the right microphone sensitivity is called "leveling".