Use room-measurement tools

Prepare the measurement chain

Room EQ Wizard uses a logarithmic sine sweep to derive response and impulse information from the generated and captured signals. Decide what you want to investigate first: a bass problem at one seat, left-right differences, or consistency across a listening area. These questions require different comparisons, not simply more graphs.

Select the intended input and output explicitly. A calibrated USB microphone normally does not need an interface loopback calibration. An analogue microphone and interface require the applicable microphone, interface, and SPL calibration steps. REW can derive SPL from supported microphone sensitivity data, but a calibration file without recognized sensitivity information is not automatically an absolute level reference.

• Use the calibration file for the individual microphone and its orientation. Match files labelled 0 degrees or 90 degrees to the documented direction.
• Support the microphone at the intended ear position. Record its position, orientation, calibration filename, and audio-device settings.

Capture a baseline you can repeat

Start with low playback volume and use the documented level checks before a sweep. Keep comparison levels consistent and avoid input clipping. Choose a frequency range appropriate to the speaker or subwoofer. Do not raise levels to overcome a bad connection or select unusually long speaker sweeps merely because they look more thorough.

Measure left and right speakers separately before measuring the combined system, when routing permits. Give each trace a descriptive name and notes. Repeat a baseline without changing anything: unexplained differences suggest the setup needs investigation before a before-and-after claim. Save the measurement file, not only a screenshot, so analysis settings remain reviewable.

• Keep room state, volume controls, processing, and microphone position unchanged for a direct comparison.
• Note background noise, interrupted sweeps, clipping warnings, or accidental routing changes. Do not treat a suspect capture as usable evidence.

Interpret each display for its actual question

An in-room sweep includes direct sound and reflections. Its transfer function changes when the microphone or source moves. Frequency response shows level versus frequency, while decay displays show how energy persists. An impulse-response window selects which arrival times contribute to an analysis. Real-time analysis follows the ongoing signal instead of replacing every sweep-based view.

Use the same smoothing and display limits for comparisons. Smoothing can hide narrow features, while a tightly cropped vertical scale can exaggerate differences. Multiple microphone positions help reveal whether an issue belongs to one point or a wider area. After DSP equalization, do not treat a smoother response curve as proof that the room's reverberation time changed. Inspect decay separately.

• Before adjusting anything, identify whether the proposed change concerns level response, reflections, or decay.
• Re-measure after a change and inspect nearby positions. Avoid assuming one smoother curve establishes an improvement everywhere.

Hypothetical example: comparing a bass problem

Suppose a listener wants to investigate bass at a desk. Name the initial trace for the speaker, seat, and unchanged system settings. Capture another trace at the same point, then document a nearby seat position and measure again. Only after checking repeatability should the listener compare a feasible speaker-position change.

The resulting decision is conditional: a position-dependent feature prompts more placement checks, while inconsistent repeats prompt setup checks. Neither result alone diagnoses faulty hardware or justifies an equalization prescription. Keep the original captures and notes, including unsuccessful experiments. No response values or improvements are assumed in this hypothetical workflow.