How to Compare Before/After EQ with Transfer Function

Step-by-Step Procedure

1. Capture the baseline measurement. Open Transfer Function mode. Play pink noise through the system at operating level. Allow 8-10 averages for a stable reading. When the magnitude trace and coherence are stable, press S to store the trace. Name it "Before EQ."
2. Note the key problems. Identify peaks, dips, and regions of poor coherence. Use the crosshair cursor to read exact frequencies and dB values. Common issues: +8 dB peak at 2.5 kHz (harshness), -12 dB dip at 160 Hz (thin bass), rising response above 4 kHz (excessive brightness).
3. Apply your EQ adjustments. Work on the system processor or mixing console. Start with the largest deviations first. Use the AI diagnostic recommendations if available — SonaVyx suggests specific frequency, gain, and Q values. Cut peaks rather than boosting dips (cutting is more phase-friendly and reduces gain before feedback).
4. Remeasure. Without moving the microphone or changing levels, start a new measurement. The live trace now shows the post-EQ response. SonaVyx overlays this against your stored "Before EQ" trace in real time.
5. Store the after trace. Press S to store the post-EQ measurement. Name it "After EQ." You now have both traces visible: before (stored color) and after (live or second stored trace).
6. Analyze the difference. The overlay shows improvement at each frequency. A flatter response with tighter deviation from your target curve means success. Check that you did not create new problems — sometimes fixing one peak reveals a previously masked issue.
7. Export the comparison. Export both traces as FRD files for your report. SonaVyx's report generator can include the before/after overlay plot with improvement metrics: overall deviation reduction, peak reduction, and flatness improvement percentage.

Tips for Effective Comparison

• Do not move the microphone. Even 10 cm of movement changes the high-frequency response due to comb filtering from reflections. Mark the mic position or use a stand.
• Keep the source level constant. If you change the pink noise level between before and after, the comparison is invalid. Use the same output level for both measurements.
• Use the same FFT size and averaging. Changing analysis parameters between measurements creates apparent differences that are not real.
• Target curves are your friend. Enable a target curve (Flat, X-Curve, or House Curve) to see how both measurements compare to your goal, not just to each other.

Common Mistakes

• Only looking at magnitude. Check phase too. Aggressive EQ (high Q, large boost) introduces phase distortion. If the phase plot shows new wraps after EQ, consider using gentler corrections.
• Chasing perfection. A ±3 dB window around your target is excellent. Trying to flatten every 1 dB bump leads to over-EQ'd, unnatural sound.
• Ignoring coherence. If coherence drops in the after measurement, something changed (mic moved, noise increased). The magnitude difference at low-coherence frequencies is not meaningful.

Tool Bridge

Open SonaVyx Transfer Function mode, store your baseline, apply EQ, and overlay the result. Use the Report Generator for a professional before/after comparison report.