Update: 01/09/24
Since publishing this blog, a new EQ plugin has been released by a manufacturer we highly respect, Toneboosters. Their new plugin, "Equalizer Pro," is priced at €59, significantly lower than the €170 cost of the FabFilter Pro-Q. After testing the EQ Match feature of the new Toneboosters plugin, we are extremely impressed. If you're on a budget, this alternative is definitely worth considering. We will be using this plugin from now on for this take in our studio. Read the original and full blog post below.
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As always, we have been actively providing support to cutters, with a recurring issue being the quality of their cuts, particularly when using the stock Vinyl Recorder setup. This is due to the Main Unit being inefficient using just a 3 band EQ to connect the heads response, when in reality it needs around 10 bands.
We consistently advise replacing all stock electronics, mapping the frequency response of your cutterhead, and using corrective EQ to flatten its natural curve while accounting for resonances. This approach ensures professional, flat cuts and maximises the system's potential. The VR is an amazing machine is used correctly, capable of great cuts.
For disc cutting, a professional setup typically adheres to the industry-standard RIAA specifications, which involves using an inverse RIAA curve before the cutterhead and the RIAA curve in the phono stage during playback. However, because Vinyl Recorder setups utilise tweeters instead of transducers in the cutterhead, the standard RIAA curve is not sufficient.
Another important factor to consider is the type of diamond used. A longer diamond, typically included with the machine, will produce more high-end frequencies, while a shorter diamond from other manufacturers will produce less. Both types are effective, but your final EQ curve will be tailored to the specific diamond type you are using.
Here’s a guide to doing it yourself. We will write this in a way that works with any Vinyl Recorder setup, no matter how your audio is routed. If you're unsure about the process, we also offer this as a service. Take your time, proceed methodically, and familiarise yourself with the intricacies of your machine.
Note: These instructions apply to all dynamic cutterheads, we just specialise in support for the VR so using it as our example.
Step 1: Make Sure Playback is Calibrated.
This step is critically important: you must ensure that playback is calibrated to the 0dB reference level using a professional test record. Do not use the stock test record that comes with the machine, as it is inaccurate. We recommend using the Ortofon Test Record. If calibration proves impossible due to the stock level meter having glued knobs, making it difficult to balance the left and right channels correctly, you may need to use an RCA attenuator or replace the level meter.
Step 2: Cut Audio Without EQ.
First, ensure you have appropriate audio for this task, which involves both program material and pink noise. The program material should be audio that is specifically mastered for vinyl and has a well-balanced frequency spectrum. This is crucial, as the quality and characteristics of the audio will directly impact the accuracy of the final EQ curve. The pink noise is simply used as a final reference to double check it is sitting well overall.
The next part will be cutting a disc, this has to be carried out with caution, if you accidentally send too much audio you could blow your fuses and damage your cutterhead.
First you need to route your audio directly to the cutter amp, bypassing the Main Unit. To do this, unplug the audio inputs from the Main Unit and connect them to the cutter amp. The Main Unit's output, which previously connected to the cutter amp, is no longer needed and should be disconnected.
You are now ready to cut the audio. Start with your volume right down sending no signal at all, start to cut at 45rpm and monitor with your tonearm, then slowly raise the volume until cutting at +2dBu. This volume level is crucial, which is why accurate playback calibration is essential. Cutting at around +2dBu without corrective EQ will get the cutter head to exhibit its distortion profile and reveal its natural and mechanical resonances. We want to stress, this needs to be carried out carefully, exactly as we described and calibration MUST be right, if you calibrate with a stock VR test record you may easily blow your cutterhead.
Step 3: Record Audio
Next, record the audio back into your DAW as a 32-bit or 24-bit WAV/AIFF file. Keep in mind that the playback stylus can slightly influence the overall sound. If you don’t have access to a high-end stylus, we recommend using a widely-used model like the Ortofon 2M or Concorde series, as these are common and provide reliable performance. If you have access to the frequency response specifications of your playback stylus, you can use this information to adjust your final EQ, but it is not essential. The audio will sound muddy with a distinct lack of high end, this is normal.
Step 4: Make Your Custom EQ
For this process, we recommend using an EQ with a robust Match EQ function, unlimited bands, and various band shapes. We use FabFilter Pro-Q, which provides all the necessary features.
Start by aligning your recording with the original audio in your DAW so you can A/B compare them side by side. Ensure both files play interchangeably and have matched volume levels. Since your recording might have little high-end information, adjust the low end by ear to balance it with the original, so both tracks' low ends are at similar volumes.
Next, use the Match EQ function with the original file as the reference. Create a 1-minute loop to ensure both files play identical audio into the analyser, then match the EQ.
Before cutting a new disc, apply the EQ to the original audio. To prevent digital clipping due to the EQ's high-end boost, normalise your audio to -23 LUFS. Apply this normalisation to all audio files to keep them at a consistent volume level that avoids overloading the plugin but is still capable of cutting up to +12dBu on playback.
For example, if you're working with a vinyl-mastered album, normalise the loudest track to -23 LUFS, then adjust the gain of all other tracks to the same amount. This will maintain the album’s intended overall volume and sound integrity.
Step 5: Check and Adjust Your EQ
Cut the audio and pink noise through the new EQ. Record these, then perform another EQ match in a new instance of your EQ plugin. Adjust as needed until the A/B comparison between your cut and the original file is as close as possible. If your original audio is mastered well and suitable for the task, along with the cutting volume being right to expose the heads resonances, it should be pretty much perfect.
Step 6: Done!
You should now have well-balanced cuts that significantly enhance your system's performance. If you are apprehensive to do this yourself, we offer this service through our store.
For an example of a cut on one of our VR heads compared to its original file, visit: Dropbox Link