Measuring Frequency Response

Use this page when you need one repeatable sweep that tells you what shape the system is making before you start changing things.

Tiny Version

Sweep the system, look at the shape, change one thing, and check again.

What Your First Graph Is For

• Repeatability first, beauty second.
• Find the obvious bump, dip, or slope before chasing tiny wiggles.
• Change one variable at a time so the next graph means something.

Mic Placement

Place the measurement microphone at the listening position, pointed the same way for each repeat sweep. The point is consistency, not chasing a magic inch on the first day.

Beginner Field Version

1. Use a calibrated measurement microphone, REW or equivalent software, and a quiet enough environment.
2. Check the noise floor first. It should sit well below the test signal.
3. Run one sweep, save it, then repeat from the same mic position.
4. If the repeats are close, begin changing one setting at a time and compare the shape.

Standards Version

1. Verify microphone and interface calibration before the sweep.
2. Use a log-swept sine with enough FFT resolution for the job.
3. Average repeated measurements when noise or environment demands it.
4. Apply windowing only when you understand what part of the response you are isolating.

Equipment

• Calibrated measurement microphone
• Audio interface or USB measurement microphone
• REW or equivalent software
• Known-clean signal path

Standards References

IEC 60268-5 remains useful for loudspeaker measurement conditions, and CEA-2010 remains useful for subwoofer output measurement. Keep those truth rails, but do not let them hide the simple repeatable path you need first.