Dear
@J.R. Boisclair,
@Balle Clorin, and
@tony22,
You’ve drawn conclusions about test records and how they’re cut, but there are important aspects you’re missing. Let me explain:
1. Azimuth Measurements Without Lacquers
First of all, you’re measuring test records for azimuth, but you don’t have access to the lacquers of those test record. It’s impossible to evaluate cutting accuracy solely based on azimuth measurements.
@J.R. Boisclair, please don’t bring up zenith error here—I’m focusing only on azimuth because the findings others are discussing are based on that. While I agree zenith errors are more critical and related to cutting, and I know your findings are the result of meticulous work but in order to keep things simple, it’s better to focus on azimuth for now.
2. Impact of Electroplating and Pressing on Azimuth
There are several electroplating stages, and azimuth can shift between these steps because the mother, father, and stamper are all thin metal discs. These discs aren’t perfectly flat on a microscopic level—they’re like fabric with tiny imperfections after washing. Additionally, a stamper may not be perfectly mounted in the mold, and errors during flattening of stamper or pressing of record can exacerbate the issue. Pressed records may also exhibit micro-warps or larger warps caused by mishandling during pressing or insufficient cooling. Without access to the lacquers, it’s impossible to evaluate the cutting azimuth accurately or identify the provenance of problems. Impossible to decide whether it’s a cutting issue or pressing issue.
3. Channel Separation Goals
Judging azimuth based on channel separation alone misses the point. The goal isn’t achieving identical separation numbers for both channels but achieving the highest possible separation for each. For instance, 28dB L / 28dB R is worse than 26dB L / 35dB R. A discrepancy in channel separation doesn’t necessarily indicate a problem, as long as it leads to optimal azimuth alignment and minimal phase error. Different test records may show mismatched numbers, but both can still be valid as long as they point to the same or similar azimuth alignment.
4. Impact of Warped Records on Azimuth
Records, like stampers, aren’t perfectly flat. Microscopic warps affect azimuth. I’ve observed this myself—when I flatten my test records using an ORB disc flattener, I notice slight improvements in azimuth. Similarly, when I measure azimuth on a vacuum hold-down turntable, the discrepancies between test records are reduced. This confirms that a vacuum hold-down effectively flattens records.
Conclusion
Please avoid making assumptions about the cutting stage based solely on azimuth measurements, as there isn’t enough information to draw definitive conclusions. A single test record isn’t sufficient for such judgments. Any issues could stem from the cutting technician, electroplating, pressing, or a combination of these factors—we simply don’t know.
Additionally, don’t make assumptions about the azimuth of a test record unless you’re using a vacuum hold-down turntable or at least a disc flattener. Align azimuth as I’ve explained above.
If you don’t trust test records, there’s no better alternative. WallyService (cartridge evaluation), for example, does not provide true azimuth alignment. Its assumption based approach (it’s does not involve actual alignment on tonearm) ensures stylus perpendicularity in the groove—if you’re lucky enough to achieve it—and costs over $500 per cartridge. If you have an expensive cartridge Wally service can make sense but proper azimuth alignment involves aligning the coils, not the stylus.
