Clarify what changed in the sound

Loudness, pitch and repetition can respond differently. A stronger low-frequency pulse is not the same observation as a new narrow tone. Identify the power measurement boundary and actual machine state, because an output reading may not describe generator loading during a transition. A phone recording with automatic gain cannot reliably quantify a loudness change without a suitable measurement approach.

Use matched conditions to narrow mechanisms

Similar speed with different recorded loading can be more informative than comparing two unrelated days, but the available data may not contain a valid match. A change could involve torque transmission, an electromagnetic excitation or another component responding to operating state. SKF supports combining several diagnostic views; it does not authorize identifying a damaged part from one acoustic correlation. Keep alternative explanations explicit when wind or speed remains confounded.

If noise changes with output while speed and wind remain poorly known, the evidence cannot isolate loading. The correct next step may be analysis of already available state information, rather than commissioning a component replacement based on a relationship the records have not established.

Choose a targeted follow-up

Ask which physical inspection or qualified analysis would distinguish the remaining possibilities and whether the actual instructions impose a restriction. Do not change electrical loading or disconnect equipment to reproduce the noise. The result should state what the evidence supports, not simply attach a component name to a load-dependent sound. No MARSTON electromagnetic-noise characteristic, acceptable tone or test procedure is established here.