Audio Test Lab
Build a signal. See what comes back.
Audio input
Microphone off · audio stays on this device
Connection & measurement quality
Connect an input to inspect the actual channel count, sample rate and browser processing.
Use a stereo audio interface for simultaneous reference and measurement inputs. Input audio is never routed to the speakers. Changing input or FFT settings resets averaging. Transfer-function estimates always use at least eight averages, even when the spectrum is set to Fast. Overlapped windows are correlated.
Add / edit Generator B Stopped
Phase adjustment is applied by delaying Generator B by the equivalent fraction of one cycle. It is most meaningful when both generators are at the same frequency.
Frequency library
Crossover pair buttons load the two generators on either side of the crossover point so you can compare response quickly.
Up to 32 tones. The sum is peak-normalized before master gain.
Edit sequence
Each line: tone, noise, sweep, voice or silence; frequency/color; seconds; output. Example: tone,1000,3,left. Sweep uses start:end. Up to 20 steps, maximum 120 seconds.
No sequence playing. Outputs can be mixed intentionally; Stop All stops every source.
While playing, color changes switch live. Use Apply band for filter changes.
Select a color, then Start Noise. While playing, colors switch immediately. Band changes use Apply band settings.
Anti-phase sends the same sine wave to both channels with one channel inverted 180°. On correctly wired stereo playback, the image should become diffuse and cancel strongly when summed to mono.
Ready
Input analyzer
Inspect the captured signal, separate from the generated output.
Connect an input to start. Levels shown in dBFS; not calibrated SPL.
How to read this view
Spectrum displays window-corrected FFT bin amplitudes in dBFS. Noise levels depend on FFT resolution. The spectrogram shows frequency over time; the waveform shows sample amplitude. Saved traces overlay spectrum only. Freeze pauses the plot, not input capture or recording.
System response
Compare two simultaneous inputs from one audio interface.
Set up reference & measurement
Feed the source signal into your system and interface Reference input. Connect a measurement microphone or system return to the Measurement input on the same interface. Use broadband noise for a full response; a single tone cannot describe the full frequency range.
Requires two captured channels. No simulated reference is substituted.
Waiting for reference and measurement signals.
Verify your interface with a direct loopback before interpreting acoustic results. Acoustics and Level have their own setup and confidence checks. This browser lab is not a certified measurement instrument.
Room & impulse analysis
Inspect a real impulse response or deconvolve a paired reference/return recording.
Capture reference and return
Use two inputs from the same interface: reference on Input 1, return/microphone on Input 2. Connect input first. Capture starts before a 2-second logarithmic sweep; 3 seconds of decay follow. Independent sources are stopped before capture. Keep amplifier and microphone gains fixed.
Import an IR WAV, or connect two inputs and capture. Processing stays on this device.
Move the cursor or touch the graph for a time/value readout.
Decay fits are withheld when available decay range, fit linearity or recording length is insufficient. These estimates are not certified room-acoustic measurements.
Level monitor
Digital levels until you establish and confirm a calibration for this device and channel.
Uncalibrated · values are dBFS, not SPL.
Calibrate with an acoustic calibrator
Fit a known acoustic calibrator to the microphone. Select Z weighting and the correct input. Let it stabilize, then capture its known SPL. Device, channel or capture-processing changes invalidate calibration. Hardware gain changes cannot be detected by a browser: confirm gain before applying a profile.
Move the cursor or touch for a time/value readout.
Frequency weighting is evaluated from windowed block power; Fast/Slow are block-updated time averages. This browser monitor is not a certified sound-level meter. Gaps, clipping and active browser processing are reported.
Analyzer controls & correction
No frequency correction loaded. Absolute SPL calibration is separate.
Two inputs required
Response traces & phase tools
No saved responses.
Delay compensation aligns captured sample windows before the FFT. The delay finder searches a rolling reference/measurement history. Each saved response retains its routing, delay and confidence data.
Noise timing & stereo
Apply band restarts with these settings. Gate on = 0 gives continuous noise. Match periodic length to the analyzer FFT for repeatable bin excitation.
Sweep steps & repeat
Start greater than End sweeps downward. Duration is per pass, including all step dwell times. Hold and Resume preserve the current pass.
Link generators & polarity
Linking changes frequency. Use Start A + B together for repeatable phase; delay and polarity remain separate controls.
Named projects
Device profiles & playback device
Profiles include device identity, channel, capture settings, frequency correction and any established level calibration.
Uses system output unless browser output selection is available.