Be loud! Din pasiune pentru sunet

[dre]

Imi ziceti de ce parametrii depinde group delayul: volum, damping, rezonatoare, sau de ce o fi? Se ppate modifica din constructia incintei sau depinde numai de difuzor?

[o&g]

depinde de toate cele care le-ai mentionat tu "volum, damping, rezonatoare"

depinde si de difuzor,dar se poate modifica si ajusta din constructia incintei

[Silviu]

Group delay describes how long spectrally infitesimally narrow sine burst signal takes to travel through speaker's acoustic "filter". The flatter the group delay, the better. The value itself is not a concern, other that if delay becomes too large, then it might be difficult to match the design to other speaker's which might have less group delay. Large groupdelay variations usually means large ringing when transient signals are applied to the system. Mathematically it is the derivative of negative phase versus frequency in radians/sec. So when phase changes linearly versus frequency, then the group delay has a constant value. If that seems to hard to think, think it as follows: Take a number of people, where each individual represents a particular frequency. Now, send them simultaneously running to specific target. If they all reach the target at same time, then group delay is flat. They all take same time to reach the goal. Now, if some of those are in worse shape than others, they'll arrive later than others. Now, the group delay is not constant, and different frequencies will arrive at different times. That's group delay.If you are wondering why the group delay of vented box is very different from WinISD version 0.43 and below, the reason is that it calculated it wrong. Current versions produce correct results.

Asta zice in Contents la WinIsd.
Sincer nici eu nu am inteles mai nimic.
Ceea ce stiu (si vad ca apare prin text) este ca acest group delay nu depinde de difuzor. Principalul factor este incinta. O parte din sunetul din spatele difuzorului este filtrat prin peretii incintei. Acel sunet este adus "in faza" cu unda din fata din cauza atenuarii (intarzierea data de grosimea si rigiditatea peretilor incintei). Problema e ca atenuarea duce la o intarziere a sunetului ce trece prin pereti. In cazuri extreme la subwoofere bass-reflex se poate auzi basul mult mai lung decat trebuie sau basul nu este suficient de "crispat". Motivul principal, in caz ca se intampa: materiale proaste si design prost al incintei
Pentru hi-fi este foarte important aspectul asta pentru ca nu se pot imperechea boxe de tipuri diferite bine. In cazurile respective se face analiza competa axiala pe 180 grade pentru evaluarea acestor aberatii de sunet.
Ideal ar fi ca graficul delay/frecventa sa fie cat se poate de liniar, fara varfuri "rebele".
Daca construiesti un subwoofer pt masina nu te intereseaza toate astea.