Stereo Flashcards
Panning
s the distribution of a sound signal into a new stereo or multi-channel sound field determined by a pan control setting. A typical physical recording console has a pan control for each incoming source channel.
Panning law
If you want the panned sound to be perceived, acoustically, as remaining at a constant volume regardless of the pan position, then the center attenuation needs to be 3dB. This is because the acoustic summation of two identical signals increases the perceived volume by 3dB. So this is the law to choose if your audience will only ever listen via stereo loudspeakers.
if you want the panned sound to be perceived as having a constant level when summed to mono, the center attenuation needs to be 6dB, because the electrical addition of two identical signals creates a new signal with an amplitude which is 6dB larger. So this is the law to choose if your audience is likely to hear a mono sum, such as when broadcast on radio or TV, or in a club, or on a mobile phone or tablet
Mono-summing and mono compatibility
panning any mono track off‑center reduces its level in the mono balance by amaximum of around 3dB when panning hard left or right. From this perspective, the only ground rule I’d apply there is to make sure that the balance continues to function correctly in mono. If your main guitar power‑riff is panned hard left, it may struggle to fulfill its musical function in mono, simply by virtue of losing alot of ground against things like the bass, kick, snare and lead vocal (which all typically reside close to thecenter).
Any stereo recording or stereo effect return in your mix may contain elements in one channel that are out of phase or polarity-inverted compared to the other channel. These can phase‑cancel when summed to mono, and although this might simply result in asubjective level drop, typically the cancellation is frequency‑selective in some way, so the tone of affected parts suffers as well. Stereo drum-overhead mics and stereo piano recordings commonly fall foul of this to some extent, on account of the widespread use of spaced‑pair recording techniques on these instruments, but almost any multi‑miked part can potentially come acropper if you pan the individual mics independently in thestereo field.
Mid-side processing
A stereo file consists of two channels: left and right. Signal that is routed simultaneously and at equal level to both channels appears as a ‘phantom’ center image, while signal that is panned unequally to the L/R channels appears to the left or right of center.
Modern digital algorithms are capable of further separating stereo content into a monophonic mid channel (sometimes called a “center” channel) and a stereo sides channel. This means that you can apply equalization, compression or other effects to the sounds in the middle independently of the sounds panned to the sides
Mixing with Mid/Side Processing
If a track has multiple guitar parts, route them through a bus, using Mid/Side processing on the guitar bus. Automate the Mid/Side tool to boost the volume of the side channel during a chorus, or other section of the track. This makes the guitars sound bigger without adjusting panning, and as a result the section sounds more impactful.
Likewise, a slight volume boost to the side channel on drum overheads can enhance the room sound, or a slight boost to the mid channel might enhance the snare drum and rack toms.
On any particular instrument recorded in stereo, a high frequency EQ boost on just the side channel makes the ‘wider’elements sound brighter. A high shelf filter works best. This helps to add clarity to a reverb, without muddying up the signal too much.
Mastering with Mid/Side Processing
If a mix sounds muddy, try reducing low frequencies in the side channel with a low shelf filter. This might be useful, for instance, to surgically EQ the mud out of hard-panned guitars while preserving the vocal and kick drum in the center of the mix.
If the mastering compressor is struggling to reduce dynamic range without a perceived narrowing or squashing of the signal, use a Mid/Side compressor to apply less compression to the side channel than the mid channel. Heavy energy in the center of a mix, where the kick, snare, bass sit, can cause a compressor to kick in, which actually squashes the wider, more ambient and spatial elements in the mix. This technique helps avoid that problem
A dry acoustic mix can be warmed up with Mid/Side reverb. Add reverb to the mid channel, but filter out some of the low end on the wet, reverberant signal to avoid muddying the kick drum and bass. On the side channel, add 2-4% more reverb than on the mid channel, with no filtering necessary.
Stereo widening
an action that basically increases the perceived width of a mixor individual instruments. Youcan use it on just about any source. However, most professional music producers agree that elements with prominent low-frequency content like kick drums and bass should be mono.This is because phase issues are most noticeable in the low-frequency domain.
