Right, the cutter is a "V" with straight sides. The various stylus shapes are all attempts to find the best compromise for tracing this groove. A "V" identical to the cutter head won't be best because if it is even slightly off in VTA it will miss a huge amount of detail. But even if VTA is perfect then it will be dragging along the whole groove wall, sapping drive from dynamics, and any dirt at all anywhere along the groove will be tracked, exaggerating noise and wear.
All the different stylus profiles are trying to avoid these problems. Sometimes you might have one that is shaped and sized to run deeper down in the groove where it might avoid wear from larger ones. But this is a side effect not a goal and not likely to work anyway. Just as likely there is crud down there as the deepest crevice is always hardest to clean. Yet another example of forest for the trees.
The real advantage in terms of noise is greater vibration control. The biggest contributor to this is simply to reduce moving mass. This is the real reason the expensive MC are better than the cheaper ones and MM. This is why Soundsmith with their MI designs are so good. This is why Strain Gauge reigns supreme. The lower the moving mass the less whipping around in the groove, the better the tracing and the lower the noise. Far bigger factor than stylus shape.
In any event there is simply no way to separate the two. A phono cartridge is quiet, or not. Tracks well, or not. Sounds good, or not. Whatever it does is the sum of all the various parts involved.
All the different stylus profiles are trying to avoid these problems. Sometimes you might have one that is shaped and sized to run deeper down in the groove where it might avoid wear from larger ones. But this is a side effect not a goal and not likely to work anyway. Just as likely there is crud down there as the deepest crevice is always hardest to clean. Yet another example of forest for the trees.
The real advantage in terms of noise is greater vibration control. The biggest contributor to this is simply to reduce moving mass. This is the real reason the expensive MC are better than the cheaper ones and MM. This is why Soundsmith with their MI designs are so good. This is why Strain Gauge reigns supreme. The lower the moving mass the less whipping around in the groove, the better the tracing and the lower the noise. Far bigger factor than stylus shape.
In any event there is simply no way to separate the two. A phono cartridge is quiet, or not. Tracks well, or not. Sounds good, or not. Whatever it does is the sum of all the various parts involved.