Sound Mixing Techniques for Games and Multimedia PDF

4 - Sound Mixing Sound Design - Games and Multimedia Miguel Negrão ©2023 CC BY-NC-ND 4.0 An example of mixing a track: https://www.youtube.com/watch?v=fGSTEBwxSbo  Initially sounds were recorded directly onto a medium capable of storing a single channel of audio. Later it...

4 - Sound Mixing Sound Design - Games and Multimedia Miguel Negrão ©2023 CC BY-NC-ND 4.0 An example of mixing a track: https://www.youtube.com/watch?v=fGSTEBwxSbo  Initially sounds were recorded directly onto a medium capable of storing a single channel of audio. Later it became possible to mix sounds recorded or created in different moments.  This made possible creating sound compositions for fixed media, be it for music, film, etc. Sound mixing is also done at live performances.  Mixing can also be done algorithmically as with computer games and computer based sound art.  Until recently mixing was mostly done with physical mixing consoles or mixers. Since computers with digital to analogue converters became available it is also possible to mix using computer software. When creating a sound fragment for fixed media (music production, film audio post-production, computer game sound design) multitrack recording is used. With multitrack recording and mixing it is possible to: record sounds to different tracks; record multiple sounds simultaneously (a band, film location recording); apply different effects to each track; mix all the tracks; save the final result to an audio file.  Currently almost all multitrack recording is done using computers. Using computers allows for non-linear editing.  Mixing usually takes place in a studio using loudspeakers or monitors.  Near-field monitors are placed closer to the mixing engineer.  Headphones are also used. Good headphones can function as a magnifying glass for sounds. Mixers Example: Midas Verona Mixer (analog) A mixer combines a number of input channels into a number of output channels in realtime. gain effects volume (fader) Main Master auxiliar Auxiliar Master 1 Group Master 1 gain effects volume (fader) auxiliar gain effects volume (fader) auxiliar  It also allows the individual application of audio effects (eq, compression, etc) to each channel. Can be analog or digital.  Analog Some sound engineers prefer the "analog sound" (e.g. My Bloody Valentine, M.B.V.; Slipknot, Slipknot) One physical control per controllable parameter.  Digital Can save presets, can change configuration with the press of a button. Automation Lighter/smaller Some can use plugins (VST, etc). Touch screens can make some things easier (others harder). Initially they didn't have as many physical controls as analog mixers, and hence were more cumbersome to use.  Digital - control surface When recording it's possible to not have a mixer and do everything in the computer. Physical controls are provided using a control surface. Sections of a mixer  Example: Midas Verona each vertical segment is called a "channel strip" Mono Input Channels  Mono input channels | v Stereo Input Channels Stereo input channels | v  groups - auxes - masters - matrices - talk buss - solo control - Output Section automutes - Output Section | v Channel strip The audio enters in one of the physical inputs. it is processed (EQ, compression, etc). It is sent to several possible signal paths or buses (Master, Groups, Aux). gain effects volume (fader) Main Master auxiliar Auxiliar Master 1 Group Master 1 gain effects volume (fader) Mono Channels inse rt one insert point on a single TRS jack socket. one direct output on a single impedance balanced quarter-inch jack socket one line in quarter-inch TRS balanced jack socket 51 one mic XLR female d ire c t o ut line in line le ft L (ste re o o nly) line in rig ht line in PUSH m ic  48v -15 phantom power p o we r pa d + 30 + 45 Microphone preamplifier gain + 15 + 60 m ic g a in phase invert m ic O ins Gain: the amount of amplification or attenuation that a system applies to an incoming signal. Usually measured in dBs. Unity gain no amplification (0 dB) Amplification gain has positive value in dB (e.g. 10dB) Attenuation gain has negative value in dB (e.g -6dB) Some mixers also allow gain attenuation for line level inputs, beside the gain control for the microphone input.  60 160 hi-p a ss 20 400 -15 + 15 5k 10k tre b le 2k 20k -15 1k + 15 3k Parametric equalizer hi-mid 400 8k 300 1k lo -mid 100 2k -15 + 15 50 100 b a ss 20 200 -15 + 15 a ux p re eq eq o ff on  EQs can be Fixed: control boost/cut Semi-parametric: control boost/cut and frequency Parametric: control boost/cut, frequency and bandwidth/Q Some mixers (e.g. SSL) also have per- channel compression.  0 +6 0 Auxiliary Sends (Aux Send) a ux 2 +6 0 Allows the creation of additional mixes. +6 0 - live monitoring on stage for performing musicians. +6 0 +6 - send to global effects unit (e.g. reverb). - Alternative mix for recording. 0 +6 0 +6 Can be pre or post fader. 0 +6  Pre-fader example: monitoring for musicians on stage. gain effects volume (fader) Main bus auxiliar auxiliar bus Post-fader - send to FX  Example: send to effects unit. gain effects volume (fader) Main bus auxiliar auxiliar bus  Example: send to effects unit Return using another input channel gain effects volume (fader) Main bus auxiliar auxiliar bus external effect unit gain effects volume (fader) Main bus  Example: send to effects unit Return using another auxiliary return gain effects volume (fader) Main bus auxiliar auxiliar bus external effect unit aux return Main bus Aux return is a special input channel which usually doesn't have many controls, usually just a volume knob. Channel strip Group assignment Panning Mute Solo Meter Fader  Groups can send to different outputs such as other loudspeakers. E.g. surround setups or loudspeaker orchestras. The group bus can be sent to the master bus, in this case the groups are used to create submixes. For instance put 8 channels for a drumkit in a group, then use a single fader to control the drums. Solo - play only this track (and other tracks with solo activated). Mute - don't play this track. Panning - move the sound in the stereo field (left - center - right). Stereo track - balance - knob in center position will have 0 dB of gain for both channels and will attenuate one channel as the control is turned, leaving the other channel at 0 dB. Meter - shows the level of the signal. Some mixers only have clipping indicator.  groups - auxes - masters - matrices - talk buss - solo control - Output Section automutes -  a ux 1 0 MUTE SOLO + 10 Auxiliar outputs g ro up a ux a ux c /o p re g ro up 1 g ro up p re to m tx fa d e m o no ste re o c l r pa n m a ste r s is MUTE g ro up 1 SOLO 10 5 0 5 Group Outputs 10 15 20 30 40  ma ste r me te rs + 21 + 21 + 21 + 18 + 18 + 18 + 15 + 15 + 15 + 12 + 12 + 12 +9 +9 +9 +6 +6 +6 +3 +3 +3 0 0 0 -3 -3 -3 -6 -6 -6 -9 -9 -9 -12 -12 -12 -15 -15 -15 -18 -18 -18 -21 -21 -21 -24 -24 -24 le ft m o no rig ht so lo me te rs le ft p fl rig ht + 21 + 21 + 21 + 18 + 18 + 18 + 15 + 15 + 15 + 12 + 12 + 12 +9 +9 +9 +6 +6 +6 +3 +3 +3 0 0 0 -3 -3 -3 -6 -6 -6 -9 -9 -9 -12 -12 -12 -15 -15 -15 -18 -18 -18 -21 -21 -21 -24 -24 -24 150 500 0 50 5k + 10 fre q ta p e 0 m o no + 10 g e ne ra to r ste re o SOLO on 3 1 2 NEUTRIK + 15 + 60 ta lk Master Outputs ta lk on m ic ma ste r ta lk e xte rna l so lo in pla c e g ro up s 1 1-2 a uto 3-4 2 5-6 mute 7-8 m o no ste re o 3 a ux m a trix ma ste rs 4 p fl SOLO m o nito r p ho ne s lo c a l 0 0 + 10 + 10 MUTE MUTE ste re o p re to m o no inse rt MUTE MUTE MUTE le ft rig ht mo no SOLO SOLO ste re o m o no 10 10 5 5 0 0 5 5 10 10 15 15 20 20 30 30 40 40 Master vs Auxiliary Send vs Groups Group bus - Can be used as another separate bus which outputs to other loudspeakers or devices. Main bus - usually goes to the main loudspeakers. Auxiliary bus - different from groups because you can do a different mix using the knobs. Master vs Auxiliary Send vs Groups Groups as additional outputs. gain effects volume (fader) Main Master auxiliar Auxiliar Master 1 Group Master 1 gain effects volume (fader) auxiliar gain effects volume (fader) auxiliar Master vs Auxiliary Send vs Groups Groups as submixes. gain effects volume (fader) Main Master auxiliar Auxiliar Master 1 Group Master 1 gain effects volume (fader) auxiliar gain effects volume (fader) auxiliar Physical connections  Physical connections Transmitting an electrical signal requires two separate conductors. The signal is the voltage difference between the two elements. To transmit two signals only 3 conductors are needed as one can be shared.  Jack TS (tip 3, sleeve 1) Normal mono signals TRS (tip 3, ring 2, sleeve 1) Balanced signals or stereo signals  XLR Used for: Balanced signals Phantom power  Balanced signals External Noise balanced output balanced input + RCA Insert cable  Insert Compressor gain effects volume (fader) Main bus auxiliar auxiliar bus Physical inputs Mono Channels inse rt one insert point on a single TRS jack socket. one direct output on a single impedance balanced quarter-inch jack socket one line in quarter-inch TRS balanced jack socket 51 one mic XLR female d ire c t o ut line in line le ft L (ste re o o nly) line in rig ht line in PUSH m ic Stereo Channel Input inse rt one insert point on a single TRS jack socket; two quarter-inch TRS balanced line in jack socket inputs; one mic XLR female. 51 d ire c t o ut line in line le ft L (ste re o o nly) line in rig ht line in PUSH m ic Physical outputs Master Outputs inse rt inse rt inse rt MR MC ML Output Source Connector Master L Left Buss XLR Male (Bal) ta p e ta lk ta lk o ut Master C Mono Buss XLR Male (Bal) PUSH in in Master R Right Buss XLR Male (Bal) R L Monitor L AFL Solo L Buss XLR Male (Bal) o ut PFL Out PFL Solo Buss XLR Male (Bal) m o nito r p fl o ut m o nito r R L Monitor R AFL Solo R Buss XLR Male (Bal) Tape Out L Master Left RCA Phono Tape Out R Master Right RCA Phono Talk Out Talk Buss XLR Male (Bal) m a ste r m a ste r m a ste r R C L Aux Outputs a ux o ut a ux o ut a ux o ut a ux o ut a ux o ut a ux o ut a ux o ut a ux o ut 8 7 6 5 4 3 2 1 Group Output inse rt inse rt G2 G1 m a trix d ire c t 1 in 1 a ux o ut a ux o ut Group Insert 2 1 Group Output g ro up g ro up 2 1 Levels  Levels Input Signal Microphone weak smartphone weak/medium professional audio weak/medium headphones medium amplifier output very strong  Levels - units used dBV: dBu: where. -> dBV compares with a signal which measures 1V RMS such as a 1V DC signal.  Levels Type Level Consumer line level (e.g. smartphone) -10 dBV (~ -7.7 dBu) Professional line level (e.g. mixer) +4 dBu microphone dBu  Gain staging The final level is determined by Preamplifier gain Channel fader Master fader What values to choose for each one ? Preamplifier gain too low, faders will be too high, not enough space to maneuver. Preamplifier gain too high, danger of distortion or clipping. Approaches Set preamplifier gain just somewhat below clipping level. Use faders to create the mix.  Set faders at unity gain. Use preamplifier gain to create initial mix. Correct mix with small movement of faders. Control Room, Headphones, PFL, AFL, Solo Usually besides the main, groups and auxiliary outputs there are also control room or PFL and headphone outputs.  PFL - Pre-fader listen gain EQ volume (fader) Main bus main speakers/broadcast/recordin PFL bus (mono) monitor speakers meter After pressing PFL button on input channel: gain EQ volume (fader) Main bus main speakers/broadcast/recordin PFL bus (mono) monitor speakers meter usually the fader should be all the way down (-∞ dB) the ensure the track doesn't go into the main bus.  PFL Once a track has PFL pressed, meter and control room are disconnected from main bus and connected to that track. Used for: Checking level of input on the main meter. Listening to a single input on headphones or on the "control room" loudspeakers.  Solo gain EQ volume (fader) Main bus gain EQ volume (fader) Main bus main speakers/broadcast/recordin gain EQ volume (fader) Main bus gain EQ volume (fader) Main bus gain EQ volume (fader) Main bus main speakers/broadcast/recordin Solo On gain EQ volume (fader) Main bus  Talkback Allow communication with the musicians on stage (live) or in the recording room (studio). A low quality microphone on the mixer. A button to activate the microphone signal. It's possible to choose where the talk bus is routed to (main, aux, all). Matrix mixer d ire c t m o no Matrix 3 Matrix 2 Matrix 4 Matrix 1 Group 1 Group 2 Group 3 Group 4 Automation: record the movement of faders. Control the level of multiple tracks simultaneously Approaches VCA Groups: add the dB value of one fader to a group of other faders. moving fader automation: have one fader control a group of other faders, maitaining the relative levels. Groups Metering - volume unit (VU) meter Similar to perceived loudness. 0 -5 -10 -15 -20 -25 -30 -36 1 2  Metering - Peak meter Displays instantaneous level.  e q ua lise r line in inse rt d ire c t o ut p fl m e te r hi-p a ss -15 + 15 filte r -15 + 15 -15 + 15 -15 + 15 18 bass lo-mid hi-mid treble 60 160 12 50 100 300 1k 1k 3k 5k 10k + 30 + 45 p ha nto m eq 0 20 400 on -18 48v hi-pass 20 200 100 2k 400 8k 2k 20k m ic O/ inse rt + 15 + 60 p ha se m ic g a in p o we r re ve rse -15 se nd -15 m ic - re turn pa d d ire c t o p tio n 0 a ux p re 1 b us a ux p re a ux 8 a ux 7 MUTE eq p re p re a ux 1 o ff +6 a ux p o st 1 b us 0 a ux p re 2 b us a ux 7&8 p re o p tio n a ux 2 p re e q +6 a ux p o st 2 b us 0 a ux p re 3 b us a ux 3 +6 a ux p o st 3 b us 0 a ux p re 4 b us a ux 4 +6 a ux p o st 4 b us 0 a ux p re 5 b us a ux 5 +6 a ux p o st 5 b us Block diagram 0 a ux p re 6 b us a ux 6 10 +6 a ux p o st 6 b us 0 a ux 7 5 a ux 7 b us +6 m a ste r p o st e q 0 + 10d B s is ste re o a ux 8 0 a ux 8 b us p a n in ste re o m o d e m o no L +6 c m ute 1 5 le ft b us a uto m ute 1 b us m ute 2 10 a uto m ute 2 b us l pa n r R m o no b us m ute 3 15 L c a uto m ute 3 b us 20 rig ht b us C m ute 4 30 a uto m ute 4 b us g ro up s g rp 1 g rp 3 g rp 5 g rp 7 pa n R pa n 40 so lo in p la c e b us so lo lo g ic p a n in sis m o d e so lo o n b us g ro up 7 b us g ro up 5 b us g ro up 3 b us g ro up 1 b us g rp 2 g rp 4 g rp 6 g rp 8 SOLO g ro up 8 b us g ro up 6 b us VERONA MONO INPUTMODULE g ro up 4 b us BLOC K DIAGRAM g ro up 2 b us le ft so lo b us rig ht so lo b us p fl b us Mixer examples DJ mixer (Numark) Digital live mixer (Digidesign Venue S6L) Compact mixer (Behringer Xenyx 1202) Studio mixer (Neve VR Legend 72 ch) -- Control Surface for Digital Audio Workstation (Digidesign ICON D- Command)  Study resources Digital Sound and Music - Mixing - chapter 7 (free, pdf in moodle)  Study resources (Extra) Portuguese: "Introdução à Engenharia de Som"; Nuno Fonseca; FCA; 2012 - Capítulo 3 - Mesa de Mistura English: "Modern Recording Techniques"; David Miles Huber, Robert E. Runstein; Focal Press; 8th edition; 2013 - Chapter 14 - The Art and Technology of Mixing