Jun 28, 2018, updated Aug 11, 2019 General

see this Digital Audio: The Line Between Audiophiles and Audiofools


Frequency Range Of Human Hearing: 20HZ - 20,000HZ

Low Frequency Range Test (10-200 Hz) High Frequency Range Test (8-22 kHz)

Noise level

See this

Painful impulse noise—Not safe for any period of time 150 dBP = fireworks at 3 feet, firecracker, shotgun 140 dBP = firearms Painful steady noise—Not safe for any period of time 130 dBA = jackhammer 120 dBA = jet plane takeoff, siren, pneumatic drill Extremely loud—Dangerous to hearing; wear earplugs or earmuffs 112 dBA = maximum output of some MP3 players, rock concert, chainsaw 106 dBA = gas leaf blower, snow blower 100 dBA = tractor, listening with earphones 94 dBA = hair dryer, kitchen blender, food processor Very loud—Dangerous to hearing; wear earplugs or earmuffs 91 dBA = subway, passing motorcycle, gas mower Moderate—Safe listening for any time period 70 dBA = group conversation, vacuum cleaner, alarm clock 60 dBA = typical conversation, dishwasher, clothes dryer 50 dBA = moderate rainfall 40 dBA = quiet room Faint—Safe listening for any time period 30 dBA = whisper, quiet library


Non Compression audio or Linear PCM has Bit Rate of 1,411 kbps.



This is good will keep the original quality of the audio.



This is bad. It will loss some quality of the audio

both Lossless and Lossy

Some audio formats feature a combination of a lossy format and a lossless correction; this allows stripping the correction to easily obtain a lossy file.



on Mac use this app Applications > Utilities > Audio MIDI Setup


brew install ffmpeg mpv youtube-dl

show information about the audio:

ffprobe file_name 2>&1
ffprobe file_name 2>&1 | sed -E -n 's/ .*bitrate: (.*)/\1/p'


lossless size

The ‘bitrate’ of the lossless compressed file, not the original material, will achieve different amounts of compression with different audio source material - some audio compresses easily and some does not, so it will vary.

Uncompressed audio from standard CD has a fixed bitrate. It is stereo (two channels), 16 bits per sample, 44,100 (44.1 kHz) samples per second.

2 x 16 x 44,100 = 1,411,200 bits per second (bps), or approximately 1411 kbps

But when compressed using FLAC or another lossless codec, the bitrate will be less.

30% compressed -> (1 - 0.30) x 1411 = 988 kbps 40% compressed -> 847 kbps 50% compressed -> 706 kbps 60% compressed -> 564 kbps 65% compressed -> 494 kbps 70% compressed -> 423 kbps