HOW TO PREPARE AUDIO FOR VINYL?

Preparing audio for a vinyl record is not as complex as it sounds (translation from french in progress) 

Toute l'information sonore est contenue dans deux sillons: un pour la face A, un pour la face B. Rien de plus. Chaque fréquence est représentée par un mouvement plus ou moins ample que va faire le diamant de lecture lorsque le disque tournera sur la platine: les basses occupent beaucoup de place, tandis que les aigus créent des mouvements très fins jusqu'à plus de 20kHz. Toutes sont ainsi représentées: au sein d'une ligne de basse qui ondule lentement, la caisse claire ou les voix, vont appliquer de plus petites excursions que le diamant de lecture va s'efforcer de suivre.

Toutes les cellules phono n'ont pas la même habileté à suivre tous les détails. Les cellules très haut de gamme - et très chères - vont le faire parfaitement bien, tandis que la grande majorité des cellules vont "traquer" le sillon un peu moins précisément.

Le travail de mastering et avant cela celui du mix, est de maximiser le rendu de lecture avec n'importe quelle cellule.


Si le mix est destiné à plusieurs supports (CD, streaming, vinyle...) il n'est pas nécessaire d'en faire un dédié au vinyle, c'est l'étape de mastering qui se chargera de le rendre compatible. Quelques particularités dont tout de même à prendre en considération, et si vous les intégrez au mix, le mastering sera d'autant plus performant.


TIME IS THE KEY

C'est la première des contraintes à considérer. Les disques de 12, 10 ou 7" vont déterminer la durée qui va pouvoi etre reproduire. Voir les FAQS for playtimes, depending on the size chosen. Basically, it will be necessary to sacrifice volume and / or sound quality for longer times.

ABOUT THE BASS 

If the first discs appeared in the 1950s were not very heavy in the low-end, it is almost impossible to imagine a song today without it. And that's good, because vinyl is able to reproduce very deep and powerful bass. But as these physically occupy a lot of space, if their frequency is too low (less than 40Hz), they will force the stylus to make large movements, risking to get it out of the groove, and preventing reading, by jumping, or by failing to read the other frequencies correctly, causing distortions, or "tracking" errors.

Disque vinyle avec des basses
sillon de disque vinyle avec des basses profondes

A stereo that is too wide will further increase the space required to cut them, and will decrease the time available on each side. By tightening the stereo only for these frequencies, we will be able to burn more, with better rendering. Below 300 Hz, we prefer mono, below 150 Hz, it is essential.

So that your songs are rich in bass, be sure to tighten them well, to filter almost everything that is before 40 Hz, and to pay attention to phase problems.


WHAT ABOUT THE TREBLES?

The medium and treble are very well reproduced on disc, it is in this frequency band that expresses the warmth of the vinyl, the listening comfort. The only thing to remember is that their best reproduction is at the beginning of the disc, where the speed of playback is the higher. Prefer for the last, quieter songs, a little less strong, rather than the "in your face" which will prefer the beginnings of face.

ABOUT THE PHASE

Another important feature is that of the phase. What happens when two signals are "out of phase"? The result becomes weaker, until the extreme case where the signals can cancel each other out. This results in a groove by its narrowing, even its disappearance. It is therefore impossible to cut signals out of phase. The problem is particularly important at the bottom of the spectrum, where phase shifts can drastically reduce the depth of the groove, and again pose tracking problems.
So be careful on your kick, bass, or any other instrument that tickles the bottom of the spectrum, to respect the phase alignment.

BE VIGILANT WITH SIBILANTS

The RIAA transformation which is applied in a standard way on all vinyl records & which will be "decoded" by your phono preamp during playback, sometimes over-represents the sibilants which can appear aggressive. Be sure to process your voice tracks and overheads well, the deesser must accompany you. If it is still possible to treat this problem during mastering, it is preferable to anticipate it in the mix, in order to apply surgical treatment on the only tracks that are problematic. Once the mix is made, the deesser will necessarily affect the rest of the sound content.

BE CAREFUL WITH THE DISTORTION

Pour la même raison que les sibilantes, les distorsions seront souvent accentuées une fois le son mis sur vinyle. Si celles-ci ne sont pas souhaitées, veillez à les contrôler avant l'étape de mastering. Si elles font partie de l'intention artistique, elles seront encore meilleures!

WHICH HEADROOM FOR YOUR MIXES?

For the mastering  to be effective, the peaks must be between -6 and -3 dbFS. Beyond that, the dynamic reserve is weak. The use of a limiter to lower the level of a loud mix to -3dBFS is not recommended: it does not give any additional dynamics, and does not allow effective mastering. For 7 "discs it is preferable not to exceed -4dbFS.
It is important to respect this dynamic reserve, otherwise the mastering engineer will not be able to optimize the audio content correctly. It can be counterproductive, including for the final level of your songs, to mix them louder than -3 dbFS.


ABOUT THE RMS LEVEL

This one has little importance, since it will not be the same once on vinyl. The recording time will determine the final level: the shorter it is, the louder the disc will sound. If you followed the advice below, the engineer who will be responsible for cutting your lacquer can cut it louder than if the stereo in the bass is wide, there is a lot of sibilance. When viewed under a microscope, overlapping grooves create tracking problems and jumps. To cut at a high level, you must reduce the duration of the recording (eg the Maxi 45T). There will then be enough room for the strongest modulations to be transcribed.

For a 12" 45RPM maxi, the available space is the same as for an LP, for often two or three titles. This allows to soften the constraints of volumes or stereo, at the cost of less time available on the cake ( 7-9 minutes vs 19-22 minutes).

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