We thought it might be useful to put together a quick and simple, straightforward mastering checklist for anyone lathe cutting without much prior mastering experience. Not all of these steps are always necessary, it really depends on the audio but here’s a brief rundown in no particular order:
Phase
Make sure your audio is in phase, especially in the low end. Out of phase audio causes the cutterhead drivers on a stereo head to work against each other, best case you get a weak, hollow sound, worst case it can pull the stylus up out of the groove entirely. A great free tool for checking this is Voxengo Correlometer, which shows you phase correlation by frequency rather than simply the overall spectrum.
De-essing
Sibilance and harsh upper mid frequencies can cause distortion. We often find vocal issues sitting around 9-10kHz, which tends to get missed when people only treat the 5-7kHz range. For anyone wanting more info on de-essing, see our older blog post here.
Elliptical Filter (Mono Bass)
Making your low end mono is often overused, it’s really only needed if there are actual phase problems. That said, if you do use it, the low end may be easier to cut... For more info on this, see our blog post here
High Pass Filter
A HPF is useful for cleaning up low end rumble and noise that isn’t needed and could cause issues. Just be careful with the slope, you don’t want to cut off actual bass notes. For example, a track with D as a sub bass will have fundamental frequency at 36.7Hz.
Midrange
Something that often gets overlooked is the midrange. Around 2kHz is a common trouble spot for distortion, vocals, snare cracks, guitars, all sorts. Pay attention to this area, and if needed, dynamic EQ can work well for taming it.
Limiting
Only use brickwall limiting if it’s absolutely essential. Heavy limiting can cause groove distortion, when you’re squashing transients and reducing dynamics, you’re creating denser waveforms that are harder to cut cleanly, this often shows up as distortion on playback. Heavily limited material often needs to be cut quieter to account for the groove distortion, so you end up with a quieter record anyway.
We’ve kept this brief and just a simple check list, but if you’ve got any questions always feel free to get in touch. Also, if you have problematic audio and can't work it out, feel free to send it over, we are always happy to look over audio stuff for people.