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An Introduction to Equalization - A free download from Audio Masterclass

Equipping Your Home Recording Studio - A free download from Audio Masterclass

An Introduction to Compression: Basic Compression - A free download from Audio Masterclass

Your school grades you 0 to 100%. But what does a real-world client think of your work?

A brief introduction to reverb and effects for the home recording studio

An inside view of the weirdest recording session ever, at the BBC!

The first rule of acoustic treatment

How to make your recordings sound great in the car

Mic the speaker, or use the line output?

Can a spectrograph give you insight into EQ, or should you just listen?

"Sysmobomb" by The Engines Of Love

Can you use the classic AKG C451 on snare drum?

A microphone for the kick drum: Is the AKG D12 the only valid choice?

Why you need a DI box for your electric guitar

Description of why a DI box is necessary, and why an electric guitar cannot be plugged directly into the mixing console.

Why can't you plug an electric guitar into a mixing console input without using a DI box or preamp?

The answer is that the electric guitar (unless it has a built-in preamp)has a 'high impedance' output. This means that although the pickup can produce a reasonably strong voltage, its current drive capability is limited.

The best way to think of this is as the signal being carried by a small number of electrons. Each electron is doing its best, but there are only a few of them.

The microphone and line inputs of the mixing console are of low and medium impedance respectively. This means that they demand more current than the guitar is able to supply. The result is a weakened signal, noticeably lacking in high frequency content.

The DI (direct inject) box or preamp boosts up the current of the signal so that it is meaty enough to drive the console input.

So why can't console inputs be high impedance? The answer is that this is not optimal. A high impedance signal is prone to noise and interference. High impedance signals are only used where necessary, and for preference the cable run should be short.

By David Mellor Monday December 12, 2005