When sourcing a vibration analyzer, you must prioritize the Frequency Range (bandwidth) to ensure it covers the operating speeds of your machinery, typically from 2 Hz to 20 kHz. Look for a high FFT Resolution (lines of resolution), ideally 6,400 lines or higher, to distinguish between closely spaced vibration frequencies. Additionally, verify the Number of Channels; while single-channel units are portable, dual or four-channel analyzers allow for phase analysis and cross-channel measurements, which are critical for diagnosing structural resonance and misalignment.