minimum requirements:
Linux 64bit on AMD64 compatibles with Alsa audio, X11 and OpenGL (Mint, Ubuntu, Debian, Manjaro, ..)
for extended analysis outside the HiFi range, a 24bit/192kHz Soundcard is recommended.

configuration:
on exit, .myriaconf.txt with editable input devices is created.
available devices can be listed with arecord -l
only 24bit HW can be addressed directly, others will be only available under "default"

antenna for DX?
the common Realtek ALC887 (24bit/192Sps) audio Codec allows
source impedances up to 40KOhm on the ADC (mic input).
a cable to a metal Doorframe or Radiator is sufficient to see
50KW Time signal stations 500 miles away.
preamplifiers and tuned Antennas are recommended for weak Signals.

16bit USB Audio Dongles often need much lower impendance sources,
its not possible to receive weak Signals without LF preamplifiers.

change color of the spectrum
via colorcode in myriaconf.txt, or direct with 1,2,3 and q,w,e

playback of a 192ksps audiofile is cutoff at 22kHz
some distributions are capped at 22kHz audio for playback.
for audiophiles, specific HiFi/ HiEnd tests or other interests, those settings can be changed.
this is for Mint/Ubuntu with Pulseaudio. other distros might work different.
do this on your own risk! - audio hardware is usually only designed for 20Hz - 20kHz.
it is not advised to use this configuration permanently.

cat /proc/asound/card0/pcm0p/sub0/hw_params usually shows "rate 44100"
nano /etc/pulse/daemon.conf remove the ";" in front of "; default-sample-rate = 192000"
pulseaudio -k && sudo alsa force-reload to restart the driver and sound subsystem
cat /proc/asound/card0/pcm0p/sub0/hw_params will show "rate 192000" now

play software generated 96kHz_sine.wav (192kSps, 0 - 96kHz sweep, 16bit, 10 seconds, low volume)
set myriacat to linear mode (music button off), 192k, L+R, and realtime.
best viewed with initial window-size (1024 pixel) and 2*zoom factor (2048 FFT size).

its generally not useful to use this settings.
myriacat talks directly to the low level alsa hardware interface and can use
192kSps from the HW input anytime, regardless of pulseaudio-configurations.

logarithmic audio view:
essential precision tool for recording, mixing and mastering
real time monitoring for video streaming, live events and recording Studios
audio FX visualizer for DJ's and Professional Audio Engineering
visual feedback for vocalists and content creators
evaluate harmonics, frequency response curves, acoustic characteristics measurements
instrument tuning, note training, vocal aid
lossy compression quality analysis
hydroacoustics, whalesounds, aquatic studies and marine sound visualization

linear view:
pixelexact linear visualization of analog signals for scientific research
ham radio, panadapter, ripple control, DCF77, smartmeter
naval/submarine communications, alpha navigation, aviation beacons
wideband and narrowband sonogram, passive sonar, signal hunting
radio astronomy, SID monitor, lightning detector, whistlers, spherics
seismic logging, schumann resonances
forensic analysis, pattern detection
bioresonance feedback

upper sideband demodulator:
downconvert and listen to selected bandwidths from 270 millihertz to full 96kHz
LF continuous wave and communications receiver
VLF SDR, Grimeton Radio SAQ receiver
ultrasonic, infrasound, sonar and sonography converter
bat detector

oscilloscope
check for signal integrity and continuity
catch clipping, offset and distortions

vectorscope, goniometer
polar view of stereo image width and position

phase correlation meter
mono compatibility of the stereo signal

cepstrum:
inspection of motors and gearboxes,
acoustic signature vessel identification,
DEMON (Detection of Envelope Modulation on Noise),
speaker detection

v1.2
extended long time measurements up to >100 Years
reversed average selector
updated colors
minimal visual changes
enforce max screensize of 4096*2048

v1.1
adapt main spectrum shading to new mesa driver specification
change goniometer presentation to fix software rendering bug
convert ruler seconds to timestamp
update font spacing
adjusted colors
tested on:
Mint cinnamon 18.3 - 20.1,
Ubuntu Gnome 20.10,
Debian KDE Plasma 10.7.0 and
Manjaro xfce 20.2.1

v1.0
first public release