Mic Vs Instrument Vs Speaker Vs Line Level: What’s The Difference?

In order to successfully record sound, it must be converted into electrical signals. These signals will have a standard voltage, and this voltage is used to give a reference point for equipment, so you can make sure that the equipment is getting the input voltage it requires. There are four levels which are being handled: mic, instrument, line, and speaker levels.

The difference between mic and line inputs is that mic level voltage is extremely low. It is the weakest level, and will need a preamplifier to get it up to the line level. The microphone works by converting sound vibrations (e.g. the voice of a singer or speaker) into voltage, but this voltage isn’t strong enough to be used with other recording equipment.

Instrument level voltage is the next lowest, although it contains the greatest variation in voltage. Obviously, different types of instruments will produce different voltages, but again, these voltages are not up to the line level and will not produce good quality sound. You will still need a preamplifier to bring the voltage up to the line level, or else you will encounter the same problems as with the microphone.

Line Level Definition:

Line level refers to the voltage which an audio signal must have. As mentioned, the standards differ for professional and consumer equipment, but consumer voltages are set at -10dBV (decibel volts), and professional voltages are set at +4dBu (decibel unloaded).

Speaker Level:

Speaker levels are post amplification and are much higher voltages which should only be transferred via speaker cables.

So, to plug equipment into any device which requires a line level, you must bring the voltage up to the standard line level if you want to produce good quality sound. Similarly, if you are plugging into a device which only requires microphone level, you can’t use line levels or you will end up with distorted sound.

Once you have reached the line level and the standard voltage required, you can look at amplifying the sound to run it through a speaker or set of headphones. The resulting level will drive the speaker and produce quality sound. Understanding the steps you need to take and how to bring instrument and mic levels up to the line level will help you produce quality, professional-sounding audio at home.