Studio Recording Signal Paths

Every studio will have slightly different signal chain, dependent on what equipment they have available, but there are some basic similarities between all modern set ups.

Essentially, the task of the modern studio is to convert sound vibrations into digital data which can then be manipulated within a DAW before being converted again into sound energy for playback through speakers and headphones.

The diagram below shows an example of a basic studio signal flow. Start at the acoustic guitar and work your way round to the ear…

It is important to note that not every audio interface contains a preamp; some require a separate unit.

There are a number of ways in which effects can be added to a signal path in your DAW.

In your DAW, every track will have it’s own mixer channel strip, allowing you to apply effects to just that track, rather than the whole mix. Adding an effect to an individual channel like this is known as an insert.

If, however, you want to apply one effect to multiple channels, you can do this via an aux send or by creating a subgroup. If you we’re doing this in a DAW, you could of course just apply the effect to one channel and then duplicate the settings on all other channels that you want to be effected but this uses up a lot of processing power and can overload your computer, causing you DAW to crash.

Aux sends and subgroups are very similar as they both allow you to send signals from multiple channels (known as using a bus) to one channel where an effect can be applied to them all at once.

An auxiliary send will allow the signal from your audio channels to be sent to the master channel, as usual. It will also make a copy of the signal from both audio channels, and this copy will be sent to an aux track. The affected signal from the aux track will then be combined with the original signal and sent to the master channel to produce the final stereo output.

A subgroup, on the other hand, will not make a copy of the signal from your audio channels and will reroute the outputs of the channels to the aux track. The signal will be affected by whatever effect is applied to the aux channel, the output of which will then become the input of the master channel, finally producing a stereo output.

1. Gain staging

It’s common to gain stage first so that you can control what level your signal goes in to the rest of your plugins or effects units. For more information on gain staging, please see this page on the capture of sound.

2. EQ and compression

There is much debate over which one of these effects should be first in your signal path and there is no right or wrong answer. It all depends on how your recorded signal needs to be corrected and what sound/tone you want.

Before discussing why you might order them in one way compared to another, you need to understand how compressing a signal changes not only the dynamic range but also the tone.

When you compress a signal, the loudest signal will always be the fundamental, meaning that it will compress certain frequencies more than others, normally lower frequencies, due to the rules of the harmonic series. This can result in a perceived loss of bass frequencies.

For more information on how compression affects timbre, this page from Pro Audio Files is very informative.

• EQ then compression – it can be useful to EQ before you compress because you are removing unwanted frequencies before they can be emphasised by the compressor. A disadvantage of inserting an EQ first, however, is that if you want to go back and change anything in your EQ, it will also change how the compressor works, and you will need to recalibrate it.

• Compression then EQ – the main advantage of ordering them this way is that you get more control over the tone because the compressor is not getting in the way of any changes that you make to your EQ.

• Subtractive EQ, compression, additive EQ – a common way of eliminating the problems with the other approaches is to get rid of unwanted frequencies first (subtractive EQ) so that the compressor doesn’t emphasise the unwanted frequencies, compress the signal, then apply additive EQ so that your compressor doesn’t compress the frequencies that you want to be boosted.

For more information on compression, please see this page on dynamic processing.

For more information on EQ, please see this page.

3. Creative Effects

Creative effects include chorus, flanger, phaser and tremolo. Again, there are really no rules as to where you place things in your effects chain, but the logic of having modulation effects here is that you have done the corrective work (EQ and compression) to get the right tone, and now you can add the creative element.

More information on effects can be found here.

4. Reverb

The whole purpose of reverb is to put a sound in a space. Unless you want an experimental reverb, it is common practice to put reverb at the end of your effects chain so that it is affecting all of the signal, wet (processed) and dry (original).

There are three different signal levels (referring to voltage) that you need to know:

• Mic level: A balanced audio signal that has lowest level of the three levels. Generated by microphones. A preamp is required to boost the signal to line level.

• Instrument level: An unbalanced audio signals that sits between mic and line level in terms of voltage level. Generated by instruments such as electric guitars and keyboards. Requires a preamp to be brought up to line level.

• Line level: A balanced audio signal that has the highest level of all three levels. Used to transmit analog sound between audio components.

Thunderbolt is a cable/protocol designed by Intel and Apple. The original Thunderbolt cable (versions 1 and 2) used a Mini DisplayPort connector and have a transfer speed of 20 Gbps. The more recent versions (Thunderbolt 3 and 4) use a USB C connector and have a transfer speed of 40 Gbps.