Loudspeaker capture — gated, off-axis and stitched

A quasi-anechoic speaker measurement in an ordinary room. Put the speaker on a stool away from the walls, set a measurement microphone one metre away, and each sweep is gated before the first reflection arrives so the room drops out. Rotating the speaker gives the off-axis family; a near-field capture at the woofer supplies the bass the gate cannot resolve, spliced on underneath. An optional moving-microphone pass adds the in-room response at the listening position.

Each step folds away once it is done; click a heading to reopen it.

1. Microphone and output

Measurement microphone — UMIK-1/2, Dayton OmniMic/EMM-6, Behringer ECM8000 via interface, or similar Playback output — the amplifier or active speaker input

Mic channel Play through

Audio devices have not been scanned.

A USB measurement microphone is picked automatically when its name is recognised. Set its sample rate to match the output (48 kHz is the safe choice) — Chrome refuses to measure across a rate mismatch.

Microphone calibration file (UMIK .txt from miniDSP's serial-number lookup, or any frequency + dB file). It is remembered for this microphone and loaded automatically next time it is selected.

No calibration loaded

2. Speaker and room geometry

Speaker name Cabinet Microphone distance (m) Tweeter height above floor (m) Ceiling height (m) Nearest wall or large object (m) Baffle width (m, for baffle-step correction; 0 = off) Woofer effective diameter (m) Port diameter (m) Number of ports

3. Capture and gating options

Sweep duration (s) Output level (dBFS) Start frequency (Hz) End frequency (Hz) Wait before sweep (ms) On-axis repeats Gate Manual gate (ms) Splice frequency Manual splice (Hz) Splice crossfade width (octaves) Display smoothing Moving-mic noise length (s)

Apply baffle-step correction to the near-field curve

4. Measurements

Graph

Frequency rangedB span Normalise off-axis to on-axis Show the gated and near-field parts

5. Export

Load a project (.json)

The REW zip holds one file per curve: the stitched on-axis, the gated on-axis, every angle, the near-field captures and the in-room response.
The project keeps the first 100 ms of every impulse response, so gates and splices can be changed later without re-measuring. Nothing is kept in the browser between visits: export before leaving, and load the file again to continue — its captures are added to this session's.