Difference between revisions of "Electronic music - audio effects"

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m (Vocoder)
m (Compressor)
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A compressor is like someone sitting at a volume slider and shifting it down quickly where the input is loud.
 
A compressor is like someone sitting at a volume slider and shifting it down quickly where the input is loud.
...but automated, and responding pretty quickly.
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...but automated, and responding pretty quickly (this is also one way to explain some of the parmeters).
  
  
Apparently, the first compressors were for broadcasting,
 
mostly just to avoid overdriven signals that would cause distorted sound, and might even damage transmitters.
 
  
This is where the version with many knobs (threshold, ratio, attack, decay) came from, and this stuck around when adopted into music, in part because in professional recording studios, more control is never a ''bad'' thing.
 
  
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Apparently, the first compressors were for broadcasting, mostly just to avoid overdriven signals that would cause distorted sound, and might even damage transmitters.
  
Yet many musicians, particularly live, might a single-knob version, because it does its primary job decently and is simpler to control.
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This is where the version with many knobs (threshold, ratio, attack, decay) came from, and this stuck around when adopted into music, in part because in professional recording studios, more control is rarely a ''bad'' thing.
  
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Yet many musicians, particularly live, might like a few-knob or single-knob version, because it does its primary job decently and is simpler to control.
  
  
 
The louder it is, the more it tempers the loudness,  
 
The louder it is, the more it tempers the loudness,  
 
so it puts the quiet and the loud closer together.  
 
so it puts the quiet and the loud closer together.  
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'''threshold and ration''' combine to mean "a volume above the threshold will become volume/ratio above the threshold"
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: on ratio
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:: 2:1 is almost inaudble
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:: over 20:1 is almost identical to a limiter
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: on threshold
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:: so things below the threshold are not changed at all
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:: more flattening often comes down to lowering the threshold, and upping the result in the mix (to )
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:: there are a few different approaches to doing this on a mixing desk, all valid (though some more applicable to speakers and some more to music)
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Compression has varied uses.
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While the full description is more involved, the most common uses are
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: bringing up quieter things that you want more clearly in your mix
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: taking down the loudest peaks from being distracting
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This is often largely about consistency of the result.
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Note that it reduces dynamics - this can be its main upside, and its main downside.
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If it is ''fully intentional'' that your vocals, bass guitar, etc come in and out, you want little to no compression.
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'''For radio use, bloggers, streamers, or PA systems''', a compressor is useful, largely to let you worry less about quiet parts falling away.
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For example, if you put the threshold low and the ratio relatively high, you can whisper and shout on a mic -- without putting a volume dial up to bring in the whispering, or down avoid clipping on the shouting.
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(It does nothing to improve noise behaviour, in fact it's preferable to use a low noise mic.)
  
  
For example, you can whisper and shout on a mic -- without putting a volume dial up to bring in the whispering, or down avoid clipping on the shouting.
 
  
 
Note that reducing dynamics is roughly the same as bringing in softer-played notes - which often means bringing in the lower end a bit.
 
Note that reducing dynamics is roughly the same as bringing in softer-played notes - which often means bringing in the lower end a bit.
  
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So for instruments that are played at varied volume (like vocals or acoustic guitars), making it sound like it's being played more consistently, which can be particularly useful live.
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It may make the lower frequencies sound more consistent (even when it's based just on amplitide, without any EQ).
  
Similarly, some instruments can be played at varied volume, making it sound like it's being played more consistently. It may make the lower frequencies sound more consistent (even when it's based just on amplitide, without any EQ)
 
  
For example, it can get more consistent volume out of a guitar, which can be particularly useful live.
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As pedal effects, settings matter to the sound of the specific source as well - attack can choose to allow in some distortion, release can work as a sustain (though this may fight with overall compression if that's agressive) meaning a more ambient sound
  
As pedal effects, settings matter to the sound as well - attack can choose to allow in some distortion, release can work as a sustain (though this may fight with overall compression if that's agressive) meaning a more ambient sound
 
  
  
  
  
You typically don't want it applied more generally than that.  
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Say, you can apply it to a mixed song, which'll make it sound louder -- but also more muddled, bycause ''by definition'' it implies reducing dynamic range, particularly on more transient sounds.
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'''In live stage mixing''',
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it can help even out higher-dynamic instruments,
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like vocals, and acoustic guitars,
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and the fact that you can control multiple sources much more easily when they are compressed.
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Relatedly, there is ''some'' argument to having headphone/monitors towards speakers/singers hear a compressed version of what they sing may let them worry less about their dynamics, particularly if they go to low levels.
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''However'', for public speaking or loud singing, and if they're not used to this or are not aware you're doing this, they may may try to overcorrect.
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So keep this compression light unless they know you're doing it.
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'''In production mixing''', compression is more about
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* combining things with different dynamics
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: putting them at close volume ''or'' keep them at different volumes in a more controlled way
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* and the variations of in particularly vocals, usually between phrases, e.g.
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: one vocalist between phrases
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: combining two vocalists, background vocalists
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You usually don't want it applied more generally than specific instrument sources.  
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Say, you can apply it to a mixed song, which'll make it sound louder -- but also more muddled, bycause ''by definition'' it reducing dynamic range, particularly on more transient sounds.
  
 
As such, it has it uses in mixing, either to reduce the punchiness of parts of the mix that naturally have more dynamic range than others - or, if it's the same, selectively suppressing part to give other parts more focus.
 
As such, it has it uses in mixing, either to reduce the punchiness of parts of the mix that naturally have more dynamic range than others - or, if it's the same, selectively suppressing part to give other parts more focus.
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It is often used to make the less-loud parts more prominent, which can e.g. make more of a bass guitar's sustain audible and not just the picking,
 
It is often used to make the less-loud parts more prominent, which can e.g. make more of a bass guitar's sustain audible and not just the picking,
 
or it can suppress a screamy vocalist without having to turn down their regular singing.
 
or it can suppress a screamy vocalist without having to turn down their regular singing.
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Note that while a compressor will mostly change the dynamics of vocals, it also changes their tone.
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A faster attack will sound thinner, a slow attack will sound thicker.
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Which means that higher singing will sound less shrill with a slower attack, which might fit the music better.
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This can also matter to public speaking.
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As can the release, which you may want to keep lower.
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Stronger compression (ratiowis) on vocals gives a more in your face sound
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However
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: too much environment noise, non-isolated band sounds, will run into noise or messier output,
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: and consider that monitors, in live setups, may more easily lead to feedback issues if you use strong compression
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Parameters:
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Notes:
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* distorted things don't really compress, because they have a fairly constant volume - the point at which they clip.
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: so you rely more on the volume slider.
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: (you can still multi-band compressor to control tone)
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Multi-band compression
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Revision as of 15:22, 7 June 2021

The physical and human spects dealing with audio, video, and images

Vision and color perception: objectively describing color · the eyes and the brain · physics, numbers, and (non)linearity · color spaces · references, links, and unsorted stuff

Image: file formats · image processing

Video: format notes · encoding notes · On display speed


Audio physics and physiology: Basic sound physics · Human hearing, psychoacoustics · Descriptions used for sound and music

Digital sound and processing: capture, storage, reproduction · programming and codescs · some glossary · Audio and signal processing - unsorted stuff


Electronic music: Some history, ways of making noises · Gaming synth · Notes on audio latency ··· microphones · studio and stage notes · Effects ·

Music electronics: device voltage and impedance, audio and otherwise · amps and speakers · basic audio hacks · Simple ADCs and DACs · digital audio · multichannel and surround ·

Noise stuff: Stray signals and noise · sound-related noise names · electronic non-coupled noise names · electronic coupled noise · ground loop · strategies to avoid coupled noise · Sampling, reproduction, and transmission distortions · (tape) noise reduction


Unsorted: Visuals DIY · Signal analysis, modeling, processing (some audio, some more generic) · Music fingerprinting and identification

For more, see Category:Audio, video, images

Noise gate

Distortion, overdrive, fuzz, etc.

Compressor

Delays

Some relevant theory
Flanger, Chorus
Reverb
Delay
Tape delay
DIY
Repurposing a floppy drive as sampler or tape-style delay

Wah-wah

Voice box

Bit crusher

Vocoder

Autotune

Phase shifter

Pitch shifter, frequency shifter

Modulation

Modulation alters a signal waveform using a carrier waveform.


https://en.wikibooks.org/wiki/Sound_Synthesis_Theory/Modulation_Synthesis


AM

FM

Ring modulation

Phase modulation