We've had an influx of questions recently where the main focus is cutterhead mapping. We always advise people to map their cutterhead, but there's more to it than just the mapping itself. Once you map your cutterhead's frequency response and resonances, you're building a feedforward system, and that means gain staging becomes crucial. Both your cutting and playback chains need to be properly calibrated to get consistent results.
This isn't the only way to do it, but in our experience it's the cleanest approach and the easiest to work with. It's tried and tested, we used to cut 1000 discs a month across three lathes, all operating identically, with no surprises. We knew exactly what volume we'd cut at and exactly what we'd get back. If you want us to help you set this up, this is the routing and calibration method we work from.
Playback Chain
Always calibrate your playback chain before your cutting chain. The signal path should be:
Turntable → RIAA Preamp → Level Meter → Monitoring
Calibrate your level meter to 0 VU using the 1kHz 0 VU sine wave test tone on your test record. If your level meter shows 0dB as its maximum value, ignore the markings and set 0 VU on your test record to the end of the yellow LEDs. This gives you the headroom you need to cut at proper volumes.
If your RIAA preamp has an independent volume control, make sure it isn't internally clipping before calibrating anything else. This is an easy one to overlook but it will ruin the sound and calibration if it's not right.
Monitoring sits after the level meter and you can set this up however you like. The key thing is not to change anything in the signal path before the level meter, this section must stay calibrated so you always know your real cutting volume. The level meter is the only place you take volume readings from, because it's directly representing what's being cut to disc.
Cutting Chain
Your cutting chain should be:
DAW with cutterhead EQ plugin → Audio Interface → Cutteramp → Cutterhead
This is a direct signal path, once you audio is mastered and final, you then import into a new cutting session in your DAW, the audio then gets its EQ and resonance treatment in software and goes straight to the cutterhead. Your cutterhead EQ software should always be on the master channel output, not the individual channels. For those wondering what this iEQ s, see here.
To calibrate this chain, normalise your audio in the DAW before it reaches the EQ. This ensures all audio enters the EQ at the same volume, which means you can set a consistent 0 VU point on your volume knob.
The normalisation target depends on your cutterhead. On the MC-02 we normalise to -23 LUFS, on the NC-V8 sometimes -30 LUFS. The goal is to find the sweet spot where your audio plays through cleanly and your cutterhead EQ plugin isn't internally clipping, you can check this from the meter within the EQ plugin itself. If working on a mastered album where each songs volume is set to work coherently, normalise the first song, and then adjust the gain of all other songs equally.
If you use a hardware player rather than a DAW, the same principle applies. Normalise your audio to your chosen LUFS target, render it with the cutterhead EQ applied, and play back the rendered file through your hardware player. This way the calibration is rendered into the file itself and your hardware player will perform consistently.
Cutteramp
Always run your cutteramp at full volume. The volume control in your chain is your audio interface or volume knob, not the cutteramp, the amp should always be wide open. This is why using a recommended amp matters. A QSC GX3 for example works perfectly well for most entry level lathes.
A/B audio
This system is straightforward, play audio, cut audio, play back the cut. We don't use an A/B monitoring method while cutting, for a couple of reasons.
First, with a feedforward system your audio will have the cutterhead EQ applied to it, so it won't sound anything like the original. You can route around this with additional channels, but we strongly advise against it. We've worked with many studios who've done this and all of them ended up with gain staging issues that caused problems. When we need to help troubleshoot, a clean and simple signal path is the easiest to diagnose.
Second, A/Bing while cutting isn't reliable anyway. Room noise, lathe noise, vacuum noise, and cutterhead noise all skew your perception. A quick test cut is the only reliable way to hear how something actually sounds. With a feedforward system set up exactly as described, your cutterhead will be cutting to its maximum potential every time.
Document Everything
Once you have your chain calibrated, write everything down. Your LUFS normalisation target, your interface gain setting, your volume knob position at 0 VU, all of it. Lathes get bumped, settings get changed, and if something shifts you want to be able to get straight back to where you were without starting from scratch. A simple note on your phone or a piece of paper on the wall next to the lathe is enough.
Also save your DAW session as a master cutting template once everything is dialled in. This way your EQ plugin instances, routing, and normalisation settings are all ready to go every time you start a new job. Load the template, drop your audio in, and you're working from a known calibrated starting point every single time. It sounds obvious but it's one of those things people skip and then regret when something goes wrong.
Keep it simple, keep it clean. Audio on a direct path to the cutterhead, playback chain straight and calibrated. The more routing you add, the more room there is for error, and this isn't just opinion, it's something we deal with regularly in support work with real world info. The customers who have the fewest problems are almost always the ones with the simplest signal paths. We are not saying this is the only way, but it is a way that definitely works.