We handle a lot of support jobs where we notice a recurring issue: excessively wide groove spacing on fixed pitch systems like the Vinyl Recorder. This often seems to be done for aesthetic reasons, to make the audio fill the entire side of the record. However, from a technical standpoint, this approach is actually detrimental—in reality, the grooves should be spaced as tightly as possible which is crucial for maintaining audio fidelity. For anyone who may not know this or new to cutting, here is a quick breakdown of why you should avoid spreading grooves across to cover the entire side of a disc:
Fidelity and Inner Groove Distortion
One of the biggest reasons to keep groove spacing tight is to avoid unnecessary cutting in the inner radius of the disc. As the stylus moves toward the centre, several physical limitations affect playback quality:
Reduced Linear Velocity:
• At the outer edge of a 12” record, the groove speed relative to the stylus is around 50 cm/sec at 33⅓ RPM.
• Near the centre, this drops significantly (sometimes below 20 cm/sec), meaning less disc is passing under the stylus per second.
• This reduction in speed means that the same amount of audio information is being squeezed into a smaller space, leading to a loss of detail and increased distortion.
• High frequencies become more distorted due to styli tracking errors.
By keeping grooves packed closer together, you reduce how much of the disc’s inner area is used, thereby minimising these fidelity losses. For those using a Vinyl Recorder, you can always 'ride' the green groove spacing knob for louder pats of the audio.
Lower modulation depth in spaced-out grooves:
• If you spread grooves unnecessarily, the modulation depth may need to be reduced to avoid potential tracking issues.
• Shallower grooves are more susceptible to surface noise interference.
Even though some people prefer to see a “full-looking” record side, it’s purely an aesthetic choice that harms sound quality. A well-mastered and well-cut record priorities performance over appearance.
Keeping groove spacing as tight as possible on a fixed-pitch lathe is essential for maintaining fidelity, reducing distortion, minimising noise, and ensuring a more efficient use of the record’s surface. Instead of aiming for a visually “full” record, it’s best to prioritise groove density in a way that optimises sound quality while limiting the time spent in the problematic inner grooves.