H/T: Grug Brain

this collection of thoughts on sound gathered by grug sound engineer

grug sound engineer not so smart, but grug sound engineer listen country and techno many long year and learn some things although mostly still confused

grug sound engineer try collect learns into small, easily digestible and funny page, not only for you, the young grug, but also for him because as grug sound engineer get older he forget important things, like which cable red or white and which way speaker vibrate

sound is deep like bear cave and will consume young grug if he lets it. it too late for old grug, but young grug can save himself. learns from mistake of old grug after many moons listen music and dance around fire

The Eternal Enemy: Noise

apex predator of grug sound engineer is noise and distortion

noise bad
distortion bad

distortion very bad, hurt speaker and grug ears

given choice between distortion and t-rex, grug take t-rex, except when dancing around fire – then grug no care about noise if sound loud, but loud sound bad for young grug ears

noise is enemy worse than bear

once bear inside cave, hard make bear leave
so better to avoid noise with good signal chain

grug study signal processing learn to hunt and kill noise & distortion

high-fidelity mean faithful reproduction, low noise, low distortion
old grug like faithful sound so much, grug even name company faith acoustics

Signal Chain

young grug signal chain look like streamer -> DAC -> amplifier -> speakers -> room. room & speaker last in signal chain. sometimes grug think better in reverse

1. room is like cave
   • flat cave wall echo like valley. echo bad. young grug call this reverb
   • sound treatment like carpet & curtains in grug cave, less reverb
   • wise grug always face speakers down length of cave, less reverb
2. speaker turn electrical energy into acoustic energy
   • speakers have drivers – driver is just magnet attached to cone
   • magnet move when electricity go up & down, push cone back & forth
   • moving cone make sound, hit grug ear. make grug feel good, especially when dance by fire in moonlight
   • grug mount driver in speaker box to make sound louder – young grug call this resonating chamber
3. amplifier or “amp” adds strength of bison to input signal to make speaker roar like king of jungle
   • sometimes amp inside speaker. grug call this speaker active, because amp built-in
   • most speaker passive – need amp
   • most high-fidelity speakers passive – need amp
4. DAC or digital-to-analog converter decodes digital signal of ones & zeros to analog signal smooth like balding grug hairline, so amp can make smooth signal loud
   • young grug already has DAC inside TV, phone, laptop and bluetooth speaker, but not very good
   • good external DAC cost few wolf skins, but make grug close eyes when dance around fire
5. streamer download digital music from young grug internet like Spotify, TIDAL or YouTube
   • streamer send digital signal to DAC to turn ones & zeros into smooth analog signal
   • sometimes streamer have internal DAC, usually not good

grug no like vinyl because vinyl noisy. other grugs want religious war over grug say this heresy

Components

now grug discuss each component so young grug can purchase good sound for cave. young grug neighbour will love grug for bringing good sound to quiet valley!

Speakers

easy for grug to make speaker sound good in one place, at low volume
hard for grug to make speaker sound good everywhere, at high volume

loud speaker usually not very good
good speaker usually not very loud

good loud speaker cost many wolf skins – grug wife not happy

rule of thumb: young grug spend twice as many wolf skins on speakers as amp, but amp so cheap now, grug can spend 10 times more wolf skins on speakers than amp

listen close young grug, speaker have important characteristics:

• power rating measured in Watts
  • determine how big amp grug buy
  • most amp specifications from manufacturer very misleading for grug
  • grug only trust objective measurement from big brain old grugs on AudioScienceReview
• nominal impedance grug measure in ohms like buddha
  • usually 8-ohm, 6-ohm or 4-ohm.
  • impedance matter because safe for amplifier
  • most speaker 8-ohm; car speaker 4-ohm
  • nominal mean average, like grug iq, but in reality impedance change by frequency:
    • low frequency whale noise draw more current (low impedance)
    • high frequency bird noise draw less current (high impedance)
  • current is limit. power supply of amp always run out of current eventually, just like grug want rest after chase wife on savanna
• sensitivity just mean efficiency, measured in decibel (dB)
  • sensitivity mean how much loudness hit grug ear for 1 Watt of electrical power
  • more sensitivity better, so amp not work as hard as grug to sell amps for cave
  • low-sensitivity speakers (inefficient ) need bigger amp for make loud roar
  • average speaker 83dB sensitivity
  • bookshelf speaker usually 89dB sensitivity
  • for every 6dB lower speaker sensitivity, amp work twice as hard make same loudness, i.e. 83dB speaker need twice as much power as 89dB speaker for same loudness
  • professional cave club speaker very efficient @ 100dB sensitivity
• frequency response depend on drivers
  • big driver make low frequency like bison. called woofer
  • small driver make high frequency like bird. called tweeter
  • together, many drivers cover all frequency – this why grug speaker have 2 or 3 drivers
  • very hard make drivers not overlap so one frequency band too loud. grug spend many moons study cross-over circuit
  • young grug hear up to 20kHz
  • old grug only hear up to 16kHz
  • most speakers have ~50Hz–18kHz response
  • if speaker only go down to 70Hz, young grug need subwoofer to make cave thunder like herd of bison
• dispersion angle mean how wide speaker throw sound in cave so grug buy big or small couch

Amplifier

• power rating mean how much power amp send to speaker
  • rule of thumb: grug want amp twice as strong as speaker so amp can relax like sloth, not work hard like grug father in mines
  • power output depend on speaker impedance
  • amp make peak power for short burst
  • amp make less power continuous
• number of channels mean how many speaker young grug buy
  • stereo mean two channels, so two speakers
  • 5.1 surround sound mean 5 speakers, 1 subwoofer
  • surround sound only good when grug wife watch movie. more speakers make more echo in cave
  • grug think better spend wolf skins on fewer, better speaker
  • 2x40W means amp has two channels and send 40W power to each speaker
• SINAD mean signal-to-noise and distortion ratio, measured in dB
  • high SINAD means less noise, grug like high SINAD
  • good budget amp like Fosi Audio V3 has 88dB SINAD
  • very good amp has ~100dB SINAD, but more expensive than grug wife
• THD mean total harmonic distortion. it measure distortion
  • more distortion bad. grug hate distortion
  • 0.003% THD good
  • 0.0001% THD very good
  • 1% THD bad
  • 5% THD unbearable
  • distortion always go up with loudness
  • max amp power rating usually reported at 1% THD
  • when amp work hard, more distortion – this why grug want amp to relax like brontosaurus
• THD+N mean total harmonic distortion + noise, same as THD but include noise in measurement

DAC

young grug stream digital music from internet. DAC convert digital signal to analog signal so amp can make loud. DAC stand for digital-to-analog converter. also known as sound interface

• SINAD mean signal-to-noise and distortion ratio, measured in dB
  • good DAC has 116dB SINAD
  • bad DAC has ~88dB SINAD
• THD+N mean total harmonic distortion + noise, same as THD but include noise in measurement
  • 0.000146% THD+N good for DAC
• dynamic range too complicated for old grug to explain after drink many icewine over years on plains
  • 19-22 bits dynamic range good

Streamer

many young grug use bluetooth on phone for send sound to amp. this drain young grug phone battery and when grug walk outside to turn t-rex burger, sound stop. bluetooth has noise. better use WiFi streamer like old grug

streamer download music from young grug WiFi and send digital signal to DAC. streamer have remote and apply EQ

best streamer for grug made by WiiM, but big brain grug short on wolf skin can try Raspberry Pi + VolumeIO if grug like hunting without eating for week

young grug consider aspects in streamer:

• supported streaming services for young grug:
  • Spotify
  • TIDAL
  • Apple Music
  • Roon
  • etc.
• built-in DAC in streamer usually not very good:
  • WiiM Mini cheap but need good external DAC, no include remote
  • WiiM Pro streamer good, but need external DAC like S.M.S.L SU-1, no include remote
  • WiiM Pro Plus good, DAC good – almost as good as SU-1, come with remote
  • WiiM Ultra has good DAC and screen, but cost many wolf skin so only for rich old grug, come with remote
• gain control w/remote so grug can sit on couch reduce volume when grug neighbour complain
• equalizer (EQ) make frequency flat like grug forehead
  • grug wife happy when cave not boomy
• room modelling sense echoes in cave with phone, apply auto-EQ
  • room modelling aggressive like badger, but useful for find resonant frequency
  • WiiM Pro, WiiM Pro Plus & WiiM Ultra have room modelling
• AirPlay useful for magic fruit shaman – many device one ecosystem
• Bluetooth convenient but never good, old grug avoid

old grug recommend WiiM Pro streamer with S.M.S.L SU-1 DAC
but if young grug only buy one device for small cave, get WiiM Pro Plus with good built-in DAC

System Recommendation

old grug recommend best budget audiophile system in December 2024:

• WiiM Pro streamer @ R3,600
• WiiM Remote @ R500
• S.M.S.L SU-1 DAC @ R2,195
• Fosi Audio V3 (48V) @ R3,195

Total cost: R9,490.00 wolf skins.

grug even give discount for broke young grug if spend many wolf skins

old grug recommend young grug buy used luxury speaker. speaker market like lemons market, good value used.

if young grug good hunter, old grug like KEF LS50 Meta speakers cost many wolf skins
old grug also like B&W 606 and 607 speakers

Amplify Early

grug know one thing true: every part of signal chain add noise
every part that amplify, also amplify noise

now grug remember: which part amplify?
amp and preamp in DAC both amplify

grug now test young grug brain:

• should young grug set volume low on streamer and volume high on amp?
• or should young grug set volume high on streamer, low on amp?

old grug learn to amplify early: set streamer high, amp low
why? when grug amplify late, grug amplify noise most

consider: when signal quiet, amp loud, amplify hiss – many noise

this why better amplify early, add less noise so amp not work hard, amp relax like sloth on warm day

this learn also apply bluetooth speaker: young grug better off set phone volume high, speaker volume low, so amp relax

young grug wise now. if young grug smile, grug trade wolf skins for hi-fi cave. may make grug wife sad, but make grug very happy