alsa -n ebay midi usb loopback latency valaki 1.07ms avg -re merte, kicsi jitter (<0.1ms).
jack -en csak egy merest talaltam a neten, egy masik USB loopback latency ~5ms.
classikus midi billentyuzet scan jitter 1.26 ms, 5ms halott idok, vagyis nem hiszi el ha 5 ms nem rovidebb ideig van lenyomva vagy felengedve, szerializalas latency 0.832 ms (velocity) 3 byte note start/stop bit 31250 baund, vagyis ~2ms max keses.
"The pianist played the key B7 a staggering 824 times in 60 seconds – that's more than 13 hits a second"
Az usb midi atalakto loopback eseten nem mutata nagy jittert, de egy tenyleges eszkozrol erkezo jel akkar 1ms -et keshet (polling periodusok miatt, "full speed" eszkoz).
pcie midi portos eszkozok ara az egekben, lehet megeri egy pcie->pci atalakitoval egy regebbi kartyat hasznalani, mar ha valakit tenyleg erdekel a latency kulembseg.
snd-hda-intel documentacioja nem javasol 128 byte-nal kisebb adat atvitelet , ami 32 frames buffereket jelent (2x16 bit).
- device
- device next
- hang deamon
- alkalmazas
4*0.66ms ~ 2.64 ms latency kifele. (sok midnet maskep csinalva lehetne kisebb)
Ha usb-s midi billenyuk van es feltetelezzuk maga az eszkoz max 1.3 ms -et kesik (min 0.3ms ).
Az 5ms max latency egyaltalan nem rosz ertek egy PC -s midi gepen foleg ha nem szegunk ajanlott minimum atviteli szabalyokat.
Latency of an Acoustic Piano accustikus pianot itt ~5ms kesesunek mondjak.
A kalapacs keses fugg a leutes erejotel/gyorsabbodol 1~5ms , mire zongiristahoz is eljut hang tobb ido is eltelhet <10ms.
A kalapacs sebbessege 1~6 m/s , tavolsag (blow distance) ~48mm, nekem mas jon ki, de nem biztos hogy almat hasonlitok almahoz a vegen.
model: https://www.instructables.com/Grand-piano-action-model/ , ugy latom van "szabadon repules" szakasza a kalapacs mozgasnak, legalabb azt az idot lehetne latencynek tekinteny."
The free flight of the hammer ranges from almost zero at louder tones up to 20 ms at very soft keystrokes, with some outliers up to around 40 ms at the Yamaha piano"
https://www.researchgate.net/publication/7603558_Touch_and_temporal_beh…
Gyors leutes:
" At such keystrokes, the key bottom times are between 3.5 and 0.5 ms before hammer- string contact, thus a range of the order of 3 ms. "
"At that typical dynamic range, key bottom times are even more unlikely to be perceived by the pianist separately
from the sound 共hammer-string兲, since those temporal differences are there of the order of a few milliseconds. However,
the differences between key bottom and hammer-string can be up to 40 ms in extreme cases which is of the order of or just beyond just noticeable differences for perceiving two
separate events 共Askenfelt and Jansson, 1992b, p. 345兲."
"the changes in travel times due to varying intensity might not be directly relevant for the player since they are at the thresh-old of perceivability. "
hang kesleltetest midi -rol leginkabb ugy lehet merni, ha az ember egy microfont es egy kimenti speakert (microfonos fejhalgato) kozel tesz egy gombhoz,
es hangosan megnyomja mikozben rogziti a microfont, aztan siman megnezi a hangrogzito programban a ket esemeny idobeni elterest.