JACK Meterbridge is a UNIX-based meterbridge for the JACK audio system. It acts as a measurement tool that displays real-time data from connected audio devices, such as the level of input/output signals, and enables users to monitor their sound systems easily.
PPM - Peak Program Level Meters that comply with the BS 6840-10 standards. These meters are designed to indicate peak amplitude instead of Volume Units (VU) meters which are designed to indicate volume. These meters have a scale that is linear with decibels, which is correct according to the standard. However, the software developer admits that they have not used a real PPM meter, so feedback is welcome.
VU - Volume Unit Meters that conform to BS 6840-17:1991. These meters are designed to measure the "volume" of an audio signal. Although not as relevant to digital systems as PPM meters, they can be useful if interfacing with analogue tape, FM broadcast equipment, or for obtaining a general idea of signal volume. With the -r flag (set reference level), you can calibrate these meters to your DA converters with ease, and the meter is pre-adjusted to allign correctly calibrated DA converters with analogue systems.
DPM - Digital Peak Meters that comply with the IEC 268-18:1995 standards. These meters are usually found in digital consoles, HD recorders, and are the most efficient in screen real-estate and CPU use. However, they might look a bit boring, but they get the job done.
JF - "Jellyfish" Meters (aka. Goniometer) are stereo scope displays that can be used to spot phase and mono compatibility problems. These meters can display signals with stronger left or right channels, and dead mono is indicated as a vertical line. The meter below the scope display indicates the degree of stereo correlation between the channels.
SCO - Scope is a rendering of an oscilloscope display that has a basic trigger function, but has no timebase control. It renders one pixel per sample and might not be suitable for use at 96KHz.
To use JACK Meterbridge, you must first ensure that the jack library and headers are installed. You will also need the SDL version 1.2 (may work with 1.0), and SDL_image with PNG support. The software can be installed by running the following commands: ./configure, make, su -c "make install". To test your audio, use the following commands:
- To test VU meters: meterbridge -t vu alsa_pcm:capture_1 alsa_pcm:capture_2
- To test PPM meters: meterbridge -t ppm alsa_pcm:playback_1 alsa_pcm:playback_2
- To start a bridge with unconnected 4 meters: meterbridge -t ppm x x x x (or any other invalid port names).
Overall, JACK Meterbridge is an excellent software for audio monitoring, and with its various meter types, it can cater to different audio monitoring needs.
Version 0.9.2: N/A