Differences between Microphone and instrument cable

Fotolia 13196802 XS1 Mic, Line and Instrument Level Whats the Difference?Mic, Line and Instrument Level – What’s the Difference?

Mic Level

When sound hits the diaphragm of a microphone very low voltage signals are produced. On a dynamic microphone these signals are typically around 1.5 millivolts. For a more sensitive microphone the voltage would be more like 70 millivolts.

These signals are weak and can be affected by electrical interference quite easily. If you plug a mic directly into an active speaker for example, you probably won’t get any sound. As this signal is so weak a pre-amp is required to boost the signal to line level. The outputs of the pre-amp can then be connected to the inputs of a mixing desk or audio interface for example.

Fotolia 5072002 XS1 Mic, Line and Instrument Level Whats the Difference?Microphone impedance affects the efficiency of how the signal is transferred to the input of the pre-amp. Mic level is -56 to -40 dbm. High quality microphones have low impedances and are best suited to low impedance inputs. Low impedance means the current is stronger therefore giving a better signal to noise ratio. Consumer microphones are often high impedance (Hi-Z) and should be connected to high impedance inputs. High impedance signals are more prone to interference and noise.

dbx db12 active di box 300x300 Mic, Line and Instrument Level Whats the Difference?Some modern condenser mics have quite a high output. When using them with a loud sound source such as drums or vocals with phantom power (+48v) enabled, they can be plugged directly into a compressor or mixing desk without the need for a pre-amp.

Line Level

Line level signals have a much higher voltage output than mic or instrument level, usually somewhere around 750 millivolts. As this signal is stronger it can be carried over a longer distance. 750 millivolts is the industry standard and allows for the interconnection of different devices from different manufacturers.

There are two types of line level:

  • consumer line level is at -10dBV
  • professional line level is at +4dBu (or dBm)

RCA (phono) connectors are usually -10dBV. XLR connectors are usually +4dBu (Mic Level). TRS quarter inch jack plugs can be either -10dBV or +4dBu

Instrument Level

Although keyboards and guitars do not output at the same level they are usally somewhere between mic and line level. To take the signal of an instrument to line level an active DI (Direct Injection or Direct Input) Box is required. To take the signal of an instrument to mic level an active or passive DI Box can be used.

DI (Direct Injection or Direct Input) Box

DI Boxes convert unbalanced high impedance signals from guitar pickups and contact microphones, into balanced low impedance signals required by mixing desks.

Cheap SPY software, hardware?

by RevengingAngel

*Need some hardware and software reccomendations.
I want to set up a camera and microphone to record a noisy neighbor who has been deliberately slamming his door in my apartment building. Camera and microphone will be mounted somewhere just outside my door. If cables are required, they'd have to be thin enough to fit between a door and a doorframe, very snug space.
The neighbor is maybe 12 feet away from my door, the hall is reasonably well-lit. Ideal situation would be to record it all with a time and date stamp, on my computer.
However, I'd like to do it all (mike, camera, software) for no more than $100. Links?

Gadgets from Hyderabad, Fin & more  — Free Press Journal
These include microphones, headphones, telephony accessories, and avionics headsets for consumer, professional, and business applications. Sennheiser was in the news recently with the launch of its PMX 95, PCX 95 and PX 95 headphones in India.

Popular Q&A

What is the difference between audio cables and instrument cables?

I'm looking at cables for my synth, and I notice that musiciansfriend.com has instrument as well as audio cables. What's the difference?

insturment cables have better shielding less chance of picking up stay signals

Related Posts