AUDIO LEVELS | Zoom H4N | Mixer | Input / Output

In this post i will write my basic understanding of Audio Levels and the links that helps me to understand what is happening.

You have 3 sources of audio signals. Each signals have different voltage. Without entering in science...

Mic signal - Needs less voltage.
Line signal - Needs more voltage.
Speakers signal - Needs way more voltage.

So, ultra-simplifying. 

If you have your recorder like the Zoom H4N you have your XLR Inputs (Microphone) and your Line inputs. If you want to plug your H4N from an speaker output, you will need to reduce the level of the audio signal. (note we are talking of the level, the signal, the voltage, not of the volume when you are monitoring the audio). So you will need something like the Shure A15LA.

Below comes from here

Yes, here's a video showing that happening with the H4n
https://vimeo.com/38171316

Which is why you need an attenuator of some kind to prevent it. Other recorders allow for a line-in.
This explains what is happening to the voltage difference between line & mic

http://geoffthegreygeek.com/audio-levels/



More answers...

What's the difference between mic and line level audio? ... Both mic and line level audio refer to the voltage level of an audio signal. Wired and wireless microphones are typically connected to mic-level inputs, while most other audio devices — such as mixers and outputs of mic preamps — use line level.

Phantom power is used with condenser microphones. ... Phantom power is a DC voltage (usually 12-48 volts) used to power the electronics of a condenser microphone. For some (non-electret) condensers it may also be used to provide the polarizing voltage for the element itself

Put simply, condenser microphones have active electronics that need an external power source, while dynamic mics are passive and therefore do not need phantom power. Because of the way condenser mics work, their output is very high impedance, and therefore requires a powered circuit to reduce that impedance.

Mic Level. Mic level is the voltage of signal generated by a microphone. This is the lowest, or weakest, level signal of the four and requires a preamplifier to bring it up to line level.