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Recorder & Player

Recorder Player

Overview

A simple audio recording and playback tool. It allows you to play test signals (such as sweeps or noise) to input into a circuit, or record output results and save them to files. It supports loading common audio files such as WAV, MP3, FLAC, and OGG.

☕ Coffee Break: Why is "Recording" necessary for measurement?

Why is there a "recording (recorder)" function when we are using a measurement tool? It's because sound problems don't always happen politely when we expect them to!

For example, suppose you have a problem where "a mysterious 'pop!' noise occasionally comes from the amplifier." Staring closely at the oscilloscope screen for hours waiting for that split-second "pop!" is exhausting, right? You might miss it the moment you blink.

That's when this recorder comes in handy! By just recording the sound of the suspicious machine, you can slowly play back the exact part where the "pop!" happened later, or zoom in on that waveform to your heart's content with another tool to "find the culprit." The recording function is a very reassuring presence, much like a "security camera for sound" installed in your laboratory!

Operations

Playback

Load and play files.

  • Load File: Opens an audio file.
    • Sampling Rate Conversion: If the file's sample rate differs from the application's operating rate (e.g., opening a 44.1kHz file while the app is set to 48kHz), you will be asked whether to automatically resample it. Usually, loading it as-is is fine.
    • Limit: There is a file size limit of 500 million total samples (approx. 1 hour 26 mins for 48kHz Stereo). Files exceeding this limit cannot be loaded.
  • Play / Stop: Starts and stops playback.
  • Loop: When checked, the file will repeat from the beginning after reaching the end. Useful for continuously outputting test signals.

  • Player Progress: A seekable slider indicating the current playback position. You can click or drag to seek to a specific position.

  • Output Mode

    • Stereo: Outputs the file's L/R channels as-is.
    • Left / Right: Outputs only the specified single channel.
    • Mono: If the file is stereo, it mixes the left and right channels to mono and outputs the same sound from both output channels.

  • Playback Gain: Adjusts playback volume digitally (-60dB to +12dB).

Recording

Records input signals to memory and exports them as files.

  • Record / Stop Recording: Starts and stops recording.
  • Save Recording: Saves recorded data to a file. This can only be pressed when recording is stopped. Saving is performed in the background with a progress dialog, preventing the interface from freezing even with large files.

  • Input Mode

    • Stereo: Records both L/R channels.
    • Left / Right: Records only the specified single channel.

  • Recorded Info: Displays the current recording duration in seconds.

Usage Examples

Using as a Signal Source

Prepare a WAV file containing pink noise or a sine sweep, play it with this tool, and observe it with a measurement instrument (such as a Spectrum Analyzer).

  1. Load a test signal file using Load File in the Playback section.
  2. Check Loop if you want to output the signal continuously.
  3. Press Play to start playback.
  4. Open another widget (such as the Spectrum Analyzer) and verify that the input signal is being received correctly.
  5. By switching the Output Mode, you can send a signal only to the left channel to measure crosstalk (leakage into the right channel), for example.

Capturing Abnormalities

If a circuit is producing abnormal sounds, you can record them to keep as evidence or for detailed analysis later.

  1. Verify the input settings in the Recording section.
  2. Press the Record button and reproduce the situation where the abnormal sound occurs.
  3. Once enough data is recorded, press Stop Recording.
  4. Press Save Recording and save it with a name like evidence.wav.
  5. The saved file can later be loaded and played back in this tool or opened in waveform editing software.