Snoman R. Dance Music Manual: Tools, Toys, and Techniques

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PART 1

Technology and Theory

the tonal characteristics of each perspective instrument. These signals are then

culminated together in the desk and fed into the loudspeaker monitors and/

or recorder to produce the ﬁ nished mix. As simple as this premise may be,

though, simply looking at a desk reveals that there’s actually a lot more going

on and to better understand this we need to break the desk down to each indi-

vidual input channel.

Typically, a mixing desk can offer anywhere from two input channels to over a

hundred, depending on its price. Each of these channels (referred to by engi-

neers as a ‘strip’) is designed to accept either a mono or stereo signal from

one musical source and provide some tonal editing features for that one strip.

Clearly, this means that if you have ﬁ ve external hardware instruments, each

with a mono output, you would need a desk with an absolute minimum

total of ﬁ ve ‘strips’ so that you could input each into a separate channel of the

desk. For reasons we’ll touch upon, you should always aim to have as many

channels strips in a mixer as you can afford, no matter how few instruments

you may own.

Generally speaking, the physical inputs for each channel are located at the rear

of the desk and will consist of a 1/4 ⬙ jack or XLR connection, or both. This lat-

ter conﬁ guration doesn’t mean that two inputs can be directed into the same

channel strip simultaneously; rather it allows you to choose whether that par-

ticular channel accepts a signal from a jack or an XLR connector. Most desks

will have the capacity to accept a signal of any level, whether it’s mic-level

(⫺ 60 dBu) or line level ( ⫺10 dBV or ⫹ 4 dBu) and whether the cables are

balanced or unbalanced.

Some of the older mixing desks may describe these inputs as being Low-Z or

Hi-Z but all this is describing is the input impedance of that particular channel.

If Hi-Z is used then the impedance is higher to accept unbalanced line-level

signals, while if Low-Z is used the impedance is lower to accept balanced ones.

As all mixing desks operate at line level to keep the signal to noise ratio at a min-

imum, once a signal enters the desk it is ﬁ rst directed to the pre-ampliﬁ er stage

to bring the incoming signal up to operating level of the desk. Although this pre-

amp stage isn’t particularly necessary with line-level signals as most desks use this

as their nominal operating level, it is required to bring the relatively low levels

generated by most microphones to a more respectable level for mixing. This pre-

amp will have an associated rotary gain control on the facia of the desk (often

called pots – an acronym for potentiometer) labelled ‘trim’ or ‘gain’. As its name

would suggest, this allows you to adjust the volume of the signal entering the

channels input by increasing the amount of ampliﬁ cation at the pre-amp.

To reduce the possibility of the mixer introducing noise into the channel you

should ensure that the signal entering the mixer is as high as possible rather

than input a low-level signal and boost it at pre-amp stage of the mixer. Keep

in mind that a good signal entering the mixer before the pre-amp is more likely

to remain noise-free as it passes through the rest of the mixer.

Cables, Mixing Desks and Effects Busses

CHAPTER 3

Some mixers may also offer a ‘pad’ switch at the input stage, which is used to

attenuate the incoming signal before it reaches the pre-ampliﬁ er. The amount of

attenuation applied is commonly ﬁ xed at 12 or 24 dB and is used to prevent any

hot signals entering the inputs from overdriving the desk. A typical example of

this may be where the mixer operates at the ‘semi-professional’ ⫺ 10 dBV and one

of the instruments connected to it outputs at the ‘professional’ ⫹ 4 dBu. As we’ve

previously touched upon, this would mean that the input level at the desk would

be 11.8 dB higher than the desk’s intended operational level. Obviously this will

result in distortion, but by activating the pad switch, the incoming signal could

be attenuated by 24 dB and the volume could then be made back up to unity

gain with the trim pot on that particular channel.

Busses refer to the various signal paths within a mixer that the inputted audio can travel

through.

The term Unity Gain means that one or all of the mixer channels volume faders are set

at 0 dB, the loudest signal possible before you begin to move into the mixers headroom

and possible distortion.

On top of this, some high-end mixers may also offer a phantom power switch,

a ground lift switch and/or a phase reverse switch, the functions of which are

described below:

■ Phantom power is used to supply capacitor microphones with the volt-

age they require to operate. This also means that the mixer has to use

its own ampliﬁ er to increase its signal level, and generally speaking, the

amp circuits in mixers will not be as good as those found in stand-alone

microphone pre-ampliﬁ ers.

■ A ground lift switch will only be featured on mixers that accept balanced

XLR connections, and when this is activated, it disables pin number one

on the connector from the mixer’s ground circuitry. Again, as touched

upon this will eliminate any ground hum or extraneous noises.

■ Phase reverse – sometimes marked by a small circle with a diagonal line

through it – switches the polarity of the incoming signal, which can

have a multitude of uses. Typically, they’re included on mixing desks to

prevent any recordings taken simultaneously with a number of micro-

phones from interfering with one another, since the sound of one

microphone can weaken the sound from a second microphone that’s

positioned further away. Subsequently, phase-reverse switches are only

usually found next to XLR microphone inputs since it’s easy to imple-

ment on these – the switch simply swaps over the two signal pins.

Following this input section, the signal is commonly routed through a mute

switch (allowing you to instantly mute the channel) and into the insert buss.

PART 1

Technology and Theory

These allow you to insert processors such as compressors or noise gates to clean

up or bring a signal under control before it’s routed into the EQ. On a mix-

ing desk these are the most important aspect as they allow you to modify the

tonal content of a sound for creative applications or, more commonly, so that

the timbre ﬁ ts into a mix better. As a result, when looking for a mixing desk it’s

worthwhile seeing how well equipped the EQ section is as this will give a good

impression of how useful the desk will be to you. Most cheap consumer mix-

ers will only offer a high and low EQ section, which can be used to increase or

reduce the gain at a predetermined frequency. More expensive desks will offer

sweepable EQs that allow you to select and boost any frequency you choose and

offer ﬁ lters so that you can remove all the frequencies above or below a certain

frequency. This section may also offer a pre- or post-EQ button that allows you

to re-route the signal path to bypass the EQ section (pre-EQ) and move directly

to the pre-fader buss, or move through the EQ section (post-EQ) and then into

the pre-fader buss. Obviously, this allows you to bypass the EQ section once in a

while to determine the effect that any EQ adjustments have had on a sound.

The pre-fader buss allows you to bypass the channel’s volume fader and route

the signal at its nominal volume to the auxiliary buss or go through the faders

and then to the auxiliary buss. Fundamentally, an aux buss is a way of routing

the channel’s signal to physical outputs usually labelled as ‘aux outs ’ located at

the rear of the desk. The purpose behind this is to send the channel’s signal out

to an external effect and then return the results back into the desk (we’ll look

more closely at aux and insert effects in a moment). The number of aux busses

featured on a desk varies widely from 1 to over 20, and not all desks will give

the option of pre- or post-fader aux sends and may be hardwired to pre-fader.

This means that you would have no control over the level that’s sent to the aux

buss via the channel fader; instead the aux send control would be used to con-

trol the level.

After this aux buss section, the signal is passed through onto the volume con-

trol for the channel. These can sometimes appear in the form of rotary con-

trollers on cheaper desks but generally they use faders with a 60 or 100 mm

throw.

Although these shouldn’t particularly require any real explanation, it’s

astounding how many users believe that they are used to increase the ampliﬁ -

cation of a particular channel. This isn’t the case at all, since if you look at any

desk the faders are marked 0 dB close to the top of their throw instead of at the

bottom. This means that you’re not amplifying the incoming signal by increas-

ing the fader’s position; rather you’re allowing more of the original signal travel

through the fader’s circuitry that increases the gain on that channel.

After the faders, the resulting signal then travels through the panning buss

(allowing you to pan the signal left and right) and into a subgroup buss. The

number of subgroup busses depends entirely on the price and model of mixer

but essentially these allow you to group a number of fader positions together

‘Throw ’ refers to the two extremes of a fader’s movement from minimum to maximum.

Cables, Mixing Desks and Effects Busses

CHAPTER 3

and control them all with just one fader control. A typical application of this is

if the kick, snare, claps, hi-hats and cymbals each have a channel of their own in

the mixer. By then setting each individual element to its respective volume and

required EQ (in effect mixing down the drum loop so that it sounds right) all

Input

Pad

Pre-amp

Mute

Aux bus

Pan

Subgroup

Master fader

Gain

Insert effects

Bypass EQ

Channel

fader

Effects Aux return

Post-fader aux

FIGURE 3.2

The typical structure of a mixing desk

PART 1

Technology and Theory

of these levels can be routed to a single group track whereby moving just one

subgroup fader, the volume of the entire drum sub-mix can be adjusted to suit

the rest of the mix.

Finally, these subgroup channels, if used, along with the rest of the ‘free’

faders, are combined together into the main stereo mix bus, which passes to the

main mix fader, allowing you to adjust the overall level of the mix. It’s at this

stage that things can become more complicated since the direction and options

available to this stereo buss are entirely dependent on the mixer in question.

In the majority of smaller, less expensive mixers the buss will simply pass

through a pan control and then out to the mixer’s physical outputs. Semi-

professional desks may pass through the pan control and an EQ before sending

the mix out to the main physical outputs. Professional desks may go through

panning, EQ and then split the buss into any number of other stereo busses,

allowing you to send the mix to not only the speakers but also the headphones,

another pair of monitors (situated in the recording room) and a recording

device .

Ultimately, the more EQ and routing options a desk has to offer, the more cre-

ative you can become. But, at the same time, the more features on offer, the

more expensive it will be. Naturally, most of these concerns are circumvented

with audio sequencers as they generally offer everything a professional desk does

with the only limitation being the number of physical connections dictated by

the soundcard you have ﬁ tted. Nevertheless, this doesn’t deter many from rely-

ing entirely on sequencers as any external instruments can always be recorded as

audio and placed on their own track and have software effects applied.

ROUTING EFFECTS AND PROCESSORS

Understanding the internal buss structure of a typical mixing desk (hardware or

software) is only part of the puzzle because when it comes to actually process-

ing signals, the insert/aux buss system they are transferred through will often

dictate the overall results. Any ‘external’ signal processing can be divided into

two groups: processors and effects. The difference between these two is rela-

tively simple but important to recognize.

All effects will utilize a wet/dry control (wet is the affected signal and dry is

the unaffected signal) that allows you to conﬁ gure how much of the original

signal remains unaffected and how much is affected. A typical example of

this would be for reverb whereby you don’t necessarily want to run the entire

audio through the effect otherwise it could appear swamped in decays; instead

you would want to affect the signal by a small amount only. For instance, you

may keep 75% of the original signal and apply just 25% of the reverb effect.

Conversely, all processors, such as compressors, noise gates and limiters, are

designed to work with 100% of the signal and thus have no wet/dry parameter.

This is simply because in many instances there would be little point trying to

control the dynamics of just some of the signal because the rest of it would

Cables, Mixing Desks and Effects Busses

CHAPTER 3

still retain its dynamic range. Nevertheless, due to the different nature of these

two processes, a mixing desk uses two different buss systems to access them: an

insert buss for processors and an auxiliary buss for effects. The difference and

reasons behind using these two busses will become clear as we look at both.

AUXILIARY BUSS

Nearly all mixers will feature the aux buss after the EQ rather than before since it’s

considered that effects are applied at the ﬁ nal stages of a mix to add the ﬁ nal ‘pol-

ish’. At this point, a percentage of the signal can be routed through the aux bus and

to a series of aux outs located at the back of the mixer. Each aux out is connected to

an effects unit and the signal is then returned into the desk. With the aux potenti-

ometer on the channel strip set at zero, the audio signal ignores the bus and moves

directly onto the fader. However, by gradually increasing the aux pot you can con-

trol how much of the signal is split and routed to the aux buss and onto the effect.

The more this is increased the more audio signal will be directed to the aux buss.

The aux return (the effected signal) is then returned to a separate channel on the

mixing desk, which can then be mixed with the original channel .

As you can see from the above diagram, two separate audio leads are required.

One has to carry the signal from the mixer and into the effects while the other

has to return the effect back into the desk. Additionally, the effected signal

cannot be returned into the original channel since there will still be some dry

audio at the fader; instead they are usually returned into speciﬁ c aux returns.

These signals are then bussed through the mixer into additional mixer ‘sub-

group’ channels. These are most commonly a group of volume faders or pots

(one for each return), which permit you to balance the volume of the effected

signal with the original dry channel.

Note that when accessing effects from a mixing desk, the mix control on the

effects unit should generally be set to 100% wet since you can control the

amount of wet/dry signal with the mixing desk itself.

While retuning the effected signal to its predeﬁ ned aux channel return may

seem sensible, very few artists will actually bother using the aux returns at all,

Effects unit

Inputs

Aux out

Aux return

FIGURE 3.3

An aux send conﬁ guration

PART 1

Technology and Theory

instead preferring to return the signal to a normal free mixing channel. This

opens up a whole new realm of possibilities since the returning effect has

access to the channels pre-amp, an insert, EQ, pan and volume. For example,

a returned reverb effect could be pushed into distortion by increasing the

mixers’ pre-amp, or the EQ could be used as a low- and high-frequency ﬁ lter if

the effects unit doesn’t feature them.

Another beneﬁ t of using aux sends is that each channel on the mixer will have

access to the same auxiliary busses, meaning that signals from other chan-

nels could also be sent down the same auxiliary buss to the effects unit. This

approach can be especially useful when using computer-based audio sequenc-

ers since opening multiple instances of the same effect can use up a propor-

tionate amount of the CPU. Instead, you can simply open up one effect and

send each channel to the same effect, which also saves time spent in setting

a number of effects units up, all of which share the same parameters. What’s

more, in a hardware situation, as only a portion of the signal is being sent

to the effect, there is less noise and signal degradation, and as the effects is

returned to a separate channel, you have total control over the wet and dry lev-

els through the mixer.

One ﬁ nal aspect of aux busses is that they can sometimes be conﬁ gured to

operate the aux bus either pre- or post-fader. Of the two, pre-fader is possibly

the least used since the signal is split into two before it reaches the fader. This

means that if you were to reduce the fader you would not reduce the gain of

the signal being bussed to the effect, so with every fader adjustment you would

also need to readjust the aux pot to suit. This can have its uses as it allows

you to reduce the volume of the dry signal while leaving the wet at a constant

volume, but generally post-fader is much more useful while mixing. Using

post-fader, reducing the channel’s fader will also systematically reduce the aux-

iliary send too, saving the need to continually adjust the aux buss send level

whenever you change the volume.

INSERT BUSS

Unlike aux busses, insert busses are positioned just before the EQ and are

designed for use with processors rather than with effects. This is because pro-

cessors require the entire signal and there is no point in applying compres-

sion or gating to only part of a signal! Typically, a processor takes the output

of a microphone pre-amp and feeds it directly into a compressor to prevent any

clipping. The resulting compressed signal would then be connected into the mix-

ing desk’s channel so that the signal ﬂ ows out of the microphone pre-amp into

the compressor and then ﬁ nally into the desk for mixing. This, however, is a rather

convoluted way of working because to compress the output of a synthesizer, for

example, requires that you scrabble around at the back of the rack and rewire all

the necessary connections. In addition, if the output from the synthesizer was par-

ticularly low there is no way of increasing its gain into the compressor.

Cables, Mixing Desks and Effects Busses

CHAPTER 3

This can be avoided if the mixing desk features insert points, which com-

monly appear directly after the pre-amp stage. Consequently, the mixer’s

pre-amp stage can be used to increase the signal level from the synthesizer

before it’s passed on to the insert bus. This is then passed into the external

compressor where the signal is squashed before being returned to the same

mixing channel .

On occasion compressors may be accessed through the aux send bus rather

than the insert bus. With this conﬁ guration, you can increase the overall level

of the signal by mixing the compressed with the uncompressed signal. This can

help to preserve the transients of the signal.

This is accomplished using only one physical connection – an insert cable – on

the mixing desk. Fundamentally, this is an ordinary audio cable with a T ⫹ S

(Tip–Sleeve) jack at one end and a R ⫹ S (Ring –Sleeve) jack at the other. The

tip is used to transmit the signal from the desk’s channel to the compressor

and is returned back into the same mixing channel through the ring connec-

tion of the same cable. Most mixers return this processed signal before the EQ

and volume bus, allowing shaping of the overall signal after processing.

Tonal shaping after processing won’t necessarily create any problems if the pro-

cessor happens to be a noise gate, but if it’s a compressor, it raises the issue that

if the EQ were raised after compression, the signal would be increased past the

level of the previously controlled dynamics. To understand the issue, we ﬁ rst

need to consider what would happen if the compressor was returned after the

EQ section.

To begin with, the EQ section would be used to correct the tone of the incom-

ing signal on that particular channel before it was sent to the compressor. This

compressor would then be adjusted so that it controls the dynamics of the

timbre and the subsequent EQ before the signal is returned to the desk. Due

to the nature of compression, however, the tonal content of the sound will be

modiﬁ ed, so it would need to be EQ’d again. This subsequent EQ will reintro-

duce the peaks that were previously controlled by the compressor, so the com-

pressor must be adjusted again. This would alter the tonal content, so it would

Processor

Inputs

Insert out and return

FIGURE 3.4

An insert conﬁ guration

PART 1

Technology and Theory

need EQ’ing yet again, and so on. Thus, an ever-increasing circle of EQ, com-

pression, EQ, compression must continue until the signal is overcompressed

or pushing beyond unity gain, distorting the desk. By inserting the compressor

before the EQ section, this continual circle can be avoided.

With the compressor positioned before the EQ, the issue of destroying the

previously controlled dynamics when boosting the EQ is still raised, but this

shouldn’t be the case provided the EQ is correctly used. As touched upon in

earlier chapters, it’s in our nature to perceive louder sounds to be inﬁ nitely

better than quieter, even if the louder sound is tonally worse than the quieter

one. Thus, when working with EQ it’s necessary to reduce the channel’s fader

while boosting any frequencies so that they remain at the same volume as the

un-EQ’d version. Used in this way, when bypassing the modiﬁ ed EQ to com-

pare it with the unmodiﬁ ed version, a difference in volume cannot cloud your

judgement. As a result, the signal level of the modiﬁ ed EQ is the same as the

unmodiﬁ ed version, so the dynamics from the compressor remain the same.

This approach maintains a more natural sound, so it is worth experimenting

by placing the EQ before the compressor. For example, using this conﬁ guration

the EQ could be used to create a frequency-selective compressor. In this set-up,

the loudest frequencies control the compressor’s action. By boosting quieter

frequencies so that they instead breach the compressor’s threshold it’s possible

to change the dynamic action of a drum loop or motif. In fact, it’s important

to note that the order of any processing or effects, if they’re inserted, can have a

dramatic inﬂ uence on the overall sound.

From a theoretical mixing point of view, effects should not be chained together

in series. This is because although it is perfectly feasible to route reverb, delay,

chorus, ﬂ angers and phasers into a mix as inserts, chaining effects in this way

can introduce a number of problems. If an effect is used as an insert, 100%

of the signal will be directed into the external effects unit, and because many

units are introduced with low levels of noise while also degrading the signal’s

overall quality, both of the effected signal and the noise will be returned into

the desk. What’s more, the control over the relationship between dry audio and

wet effects would be from the effects interface and, in many instances, greater

control will be required.

Many effects use a single control to adjust the balance between dry and wet

levels, so as the wet level is increased, the dry level decreases proportionally.

Equally, increasing the dry level proportionally decreases the wet level. While

this may not initially appear problematic, if you decided to thicken out a trance

lead with delay or reverb but wanted to keep the same amount of dry level in

the mix that you already have, it isn’t going to be possible. As soon as the wet-

ness factor is increased the dry level will decrease proportionally which may

result in a more wet than dry sound. This can cause the transients of each hit

to be washed over by the subsequent delays or reverb tail from the preceding

notes, reducing the impact of the sound.

Cables, Mixing Desks and Effects Busses

CHAPTER 3

Nevertheless, by using effects as inserts and chaining them together in series it’s

possible to create new effects because both dry and wet results from each pre-

ceding effect would be transformed by the ones that follow them. This opens

up a whole world of experimental and creative opportunity that could easily

digest the rest of this book, so rather than list all of the possible combinations

(as if I could) we’ll examine the reasoning behind why, theoretically at least,

some processors and effects should precede others.

Gate > Compressor > EQ > Effects

Normally, to maintain a ‘natural’ sound a gate should always appear ﬁ rst in the

line of any processor or effects since they’re used to remove unwanted noise

from the signal before it’s compressed, EQ’d or effected. While it is perfectly

feasible to place the compressor before the gate as it would make little differ-

ence to the actual sound it’s unwise to do so. This is because the compressor

reduces the dynamic range of signal and, as a gate works by monitoring the

dynamic range and removing artefacts below a certain volume, placing com-

pression ﬁ rst, the gate would be more difﬁ cult to set up and may remove some

of the signal you wish to keep. For reasons we’ve already touched upon, the EQ

should then appear after compression and the effects should follow the EQ sec-

tion as they’re usually the last aspect in the mixing chain.

Gate > Compressor > Effects > EQ

Again the beginning aspects of this arrangement will keep the signal natural

but by placing the EQ after the effects it can be used to sculpt the tonal quali-

ties produced by the effect. For example, if the effect following the compres-

sion is distortion, the compressor will even out the signal level making the

distortion effect more noticeable on the decays of notes. Additionally, since

distortion will introduce more harmonics into the signal, some of which can

be unpleasant, it can be carefully sculpted with the EQ unit to produce a more

controlled pleasing result.

Gate > Compressor > EQ > Effects > Effects

The beginning of this signal chain will produce the most natural results but the

order of the effects afterwards will determine the outcome. For instance, if you

were to place reverb before distortion, the reverb tails will be treated to distortion,

but if it were placed afterwards, the effect would not be as strong since the reverbs

tail would not be treated. Similarly, if delay were placed after distortion, the sub-

sequent delays would be of the distorted signal, while if the delay came ﬁ rst, the

distortion would be applied to the delays producing a different sound altogether. If

ﬂ anger were added to this set-up, things become even more complicated since this

effect is essentially a modulated comb ﬁ lter. By placing it after distortion the ﬂ anger

would comb ﬁ lter the distorted signal producing a rather spectacular phased effect,

yet if it were placed before, the effect would vary the intensity of the distortion.

To go further, if the ﬂ anger were placed after distortion but before reverb, the

ﬂ ange effect would contain some distorted frequencies but the reverbs tail