Effects
Effects are used in many modern day recordings to add excitement, dimension and personality to a song. Without effects, it would be hard to achieve the sound of today.
Effect processors are everywhere in music production and can take the form of plug-ins, rack mounted gear, Stomp boxers for guitars, and are even built into samplers and synthesisers. Although there are many opportunities to use effects, people new to mixing (and recording) often shy away from them because they lack knowledge of how they work.
An effects processor takes the input of a sound and alters it using various operations to make the sound more sonically interesting. The results of these alterations can be used by themselves or combined with the original source to produce the final output.
Most effects processors have a mix control that alters the amount of effect being used. A mix of 50% would mean the signal would be half processed and half unaffected. Processed signals are said to be wet whereas unprocessed signals are said to be dry.
Effects are sometimes used on a single input source or recorded part. The effect is inserted between the signal source and its destination. This type of effect connection is called an INSERT. In contract, it is possible to apply a little of the same effect to several channels at once. This type of effect connection is called a SEND. A mixer control, know as ‘effect send’ determines how much of each channel is sent to the effect processor.
Reverb
Reverberation describes the pattern of echoes and reflections that occur when a sound is heard in a space, for example, in a concert hall. The subtle echoes and reflections help the brain to perceive the size and shape of an acoustic space. Every space has different reverb characteristics.
The reverb unit should not be taken for granted as it is required in a mix to create space, a sense of stereo width or a front to back perspective.
A reverb processor adds an artificial reverberant sound for a wide range of pre-chosen acoustic environments. Some common presets found on a reverb unit include room, hall and cathedral.
Reverbs offer numerous settings and parameters with the main one being the decay time - the time it takes for the reverb to die away. Other common parameters include choosing the size and brightness of the location/sound.
More advanced units offer control over even more parameters, such as reflection density and pre-delay between the sound and the reverb that follows.
Adding reverb tends to push a sound to the back of a mix, making it seem more distant and behind other instruments. Many engineers use reverb to make a sound bigger and ‘lusher’. Lots ofmodern day recordings use a touch of reverb on vocals and other instruments to add excitement.
Note: Be careful not to over use reverb as it can make a sound muddy and too distant.
Common Controls Summary:Algorithms - The algorithm control determines the preset reverb algorithms e.g. Hall, room etc. Size - The size control adjusts the artificial room size giving a different tonal characteristic. Decay - The decay control determines how long the reverb lasts. Shorter decays give the impression of greater acoustic absorbency where as longer decays have the opposite effect. Damp - The damp control determines if the higher frequency content is dampened. Dampening the high frequencies can help to free up mix room and promote a warmer sound. Dry/Wet - The dry/wet control adjusts the balance between the unprocessed audio signal (dry) and the delay effect (wet). |
Reverb Tips
Reverb is used to add aural space to an instrument or sound. The following tips provide a good starting point to begin experimenting with reverb:-
- Short reverbs with a decay less than 500 milliseconds help fatten up an instrument. Long reverbs with a decay of more than 500 milliseconds will make an instrument float and push the sound back from the listener
- Reverb can smear the stereo placement of an instrument in the mix. To keep a specific stereo position of a sound, use a mono reverb panned to the same position as the dry (unprocessed) signal.
- A bright, medium decayed reverb can make vocals sound excellent, helping them sit well with the rest of the mix. Beware not to add too much, as the sound will become sibilant or lost in the mix.
- Adding EQ to the reverb signal can help create some sonic layering i.e. each instrument has its own ambient environment. The idea is to create individual sonic atmospheres that do not clash with each other:-
- To brighten up a sound, add more high frequency content.
- To help a sound blend into a mix remove the high frequencies
- If an instrument sounds muddy, remove some low frequency content.
- If the space is empty, add some low frequency content to help fill the space.
- For long decays it is better to use brighter reverbs
- For short decays it is better to use ‘duller’ reverbs
- Use long decayed reverbs on a couple of major elements in the track to help tie the sound together.
- Try and time reverb units to the tempo of the track to make it more distinct. For example, on a snare hit the decay diminishes just before the next hit.
- A very short amount of reverb on a sound can give it a sense of ‘air’.
- Short amounts of reverb can give an aggressive, fatter sound on a snare drum.
Delay
Delay is one of the most common effects used in audio production today and put simply is a form of echo. A delay processor sends the input signal to the output at a later time that is set by the delay time. This can be milliseconds or many seconds. The signal is combined with the original in an amount set by the mix control. The number of delay repeats is determined by a feedback control - the more feedback the more repeats.
Any delay under 10-20ms is inaudibly separate from the original signal. Beyond 20ms ones ear begins to think of the 2 signals as different sounds.
There are many varieties of delay including mono, stereo, multitap and slap back.
Most delay processors allow the signal to be delayed as a rhythmic time value, such as quarter notes. This type of delay is most common in modern day music and can form an integral part of the music’s rhythm.
Common Controls Summary:Delay Time – The delay control determines the delay time in note value steps (based on the tempo and the Step Length parameter) or in milliseconds, depending on the setting of the unit switch. Unit Switch – The unit switch determines whether the delay is tempo-based ('Steps' mode) or a free time delay (MS' mode). Step Length – The step length determines whether the 'steps' mode reacts in sixteenth notes (1/16) or an eighth triplet note (1/8T). Feedback – The feedback control determines the number of delay repeats. Pan – The pan control pans the delay effect to the left or to the right. Dry/Wet - Adjust the balance between the unprocessed audio signal (dry) and the delay effect (wet) |
Delay Tips
- Delay decay under 50 milliseconds will create an acoustic space around the sound.
- Delays timed with the songs tempo help add depth and rhythm to a song.
- To create a stereo effect, use a delay of about 12ms and pan both the dry signal and the processed delayed signal hard left and hard right.
- If a mix sounds muddy because of too much reverb, add some timed delay instead.
Chorus / Flange
Chorus adds depth, richness and harmonic structure to a sound by mimicking the effect of two or more sounds playing at the same time.
When the effect is produced successfully the sound has a rich, shimmering quality which would be absent if the sound came from a single source. The effect is more apparent when listening to sounds which sustain for longer periods of time.
The chorus effect processor works by delaying the input signal by about 15 milliseconds and mixing it back into the original signal. The delayed signal is then slightly detuned in pitch from the other which is controlled via the modulation rate and depth controls. A low modulation rate and depth adds a subtle change comparable to an ensemble. Add more depth (pitch shifting) and the chorus becomes more aggressive creating a warbling sound. Chorus is most effective in thickening pad parts or string ensemble sounds but is also effective on vocals and guitars.
Flanging is similar to chorus in that it occurs when two identical signals are mixed together. One signal is time-delayed by a small and gradually changing amount.
The modulation produces a swept 'comb filter' effect; peaks and notches are produced in the resultant frequency spectrum, related to each other in a linear harmonic series. Varying the time delay causes these to sweep up and down the frequency spectrum. Part of the output signal is usually fed back to the input (a 're-circulating delay line'), producing a resonance effect which further enhances the intensity of the peaks and troughs. Flanging works best on harmonically rich sounds such as bright string pads, although it can also be used on drums and cymbals.
Common Controls SummaryDelay – The delay control determines the delay time used to create the chorus/flanger effect. Usually, flanger-type effects use short delay times while chorus-type effects use medium to long delays. Feedback – The feedback control determines the amount of effect signal fed back to the input, which in turn affects the intensity and character of the effect. Turning it extreme left or right produces different flanger effects with a distinct resonance, while keeping it centred produces a more gentle chorus effect. LFO Rate - The LFO Rate determines the frequency of the LFO modulating the delay time. The higher the value, the faster the sound will oscillate. LFO Sync - The LFO sync control allows for the LFO to be synchronised to the songs tempo, in one of 16 possible time divisions. LFO Freq. Mod - The LFO Freq. Mod control determines the depth of the LFO modulation, i.e. by how much the frequency parameter should be modulated. At zero the effect is static |
Phaser
The phaser is an effects processor used to create a classic sweeping ‘phaser’ sound suitable for pads and guitars, but can be used for more extreme effects too.
Phaser effect units work by creating a complex frequency response containing many regularly-spaced "notches" in an incoming signal and combining it with a copy of itself out of phase. The positions of the notches are modulated over time by the use of a low frequency oscillator.
The phasing effect is a kind of hollow "whooshing" sound reminiscent of a flying jet airplane.
A stereo phaser uses two identical signals modulated for the left and right channels with one usually being a quarter-wave out of phase.
The phaser is best used as an insert effect.
Phasers are mostly found as plugins on sequencing software and as a part of a monolithic rack mount sound effect unit.
Common Controls SummaryFrequency - The frequency control sets the frequency of the first notch. Adjusting this will move the other notches correspondingly. This is the parameter modulated by the LFO to create phaser sweeps. Split - The split control adjusts the distance between the notches in the frequency range, thereby changing the character of the effect. Width – The width control determines the width of the notches. Raising the width deepens the effect and makes the sound more hollow and thin. LFO Rate – The LFO rate control determines the speed of the LFO modulating the frequency parameter. LFO Sync- The LFO sync control allows for the LFO to be synchronised to the songs tempo, in one of 16 possible time divisions. LFO Freq. Mod - The LFO Freq. Mod control determines the depth of the LFO modulation, i.e. by how much the frequency parameter should be modulated. At zero the effect is static Feedback – The feedback control alters the tone of the effect. For a more prominent sound turn the feedback up |
Other common effects
There are several other effects that are found on DAWS or within a studio environment. Listed below are some of the most common:-
Vibrato
Vibrato is a form of pitch modulation performed by an LFO (low frequency oscillator). It is mainly used on sustained sounds to create a wobbling type effect.
Pitch Shifters
Pitch shifters change the pitch of an original audio signal, usually by up to an octave in either direction. Short pitch shifts can be used to fatten up a sound. This is done by add the untreated sound to two pitch-shifted versions that are a few cent apart. Large pitch shifts on the other hand, can be used to create parallel harmonies.
Another use for pitch shifting is to correct out of tune notes.
Distortion
Distortion is an effects processor used to make a sound seem like it is being over-driven. Distortion can be used for varies situations and sound enhancements.
Exciters
Exciters are a type of effect processor that enhances key parts of the audio spectrum by adding sheen, sparkle and power to a sound. They can be added to individual instruments or to an entire mix.
The technology used varies from each unit with some being simply preset equalizers, others generate harmonics based on a target signal.
Tremolo
Tremolo is used to modulate the amplitude of the sound, and is often used to give a rhythmic quality to a part. Tremolo is controlled via a LFO (low frequency oscillator).
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3.26 Copyright (C) 2008 Compojoom.com / Copyright (C) 2007 Alain Georgette / Copyright (C) 2006 Frantisek Hliva. All rights reserved."
Last Updated ( Monday, 14 July 2008 13:33 )
