SignalScope X 12.3 for Mac was available to download from the developer's website when we last checked. We cannot confirm if there is a free download of this app available. This free Mac application was originally designed by Faber Acoustical, LLC. Please check the Mac app with an antivirus before launch as it is downloaded from the developer's website, and we cannot ensure that it is safe. The application is included in Audio & Video Tools.
From the developer:
SignalScope X offers a range of powerful measurement and analysis tools to enhance your productivity in areas such as acoustics (sound and vibration), audio, electronics, and electroacoustics. The application includes a free oscilloscope tool. The utility is designed to help you analyze signals coming from the Mac or iOS device’s current audio input device.
You may want to check out more software for Mac, such as CROSS-DJ, Radiologik DJ or AmpliTube Metal, which might be similar to SignalScope X.