Masurarea parametrilor Thiele Small

[drid]

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RCF L15/554K med-bass o incinta trapezoidale sau normala are cineva masurile

[SIG]

Intrucat titlul topicului s-a nimerit sa fie sugestiv ptr. masurarea parametrilor Thiele Small,doresc sa pun la dispozitie o lucrare de asemenea interesanta si utila celor care sunt interesati sa calculeze acesti parametrii.

Multe multumiri autorului.

Succes.

index.pdf

[SIG]

In caz ca nu cunoastem, cum putem afla cat mai lesne cu putinta cat este Xmax la un difuzor ?

Am gasit un exemplu de calcul, dar nu stiu cat ne putem increde in el. (rezultatul obtinut de autor este cu o marja de eroare foarte mica, 3%, dar poate fi intamplator):

 

Let's examine our old friend the JBL2226.

X-max is rated at 7.6mm, coil length is 19.05mm, gap height is 8.1mm

Coil overhang is (19.05 - 8.1)/2 = 5.475mm

Traditional method is to use a current probe and measure the displacement at 10% obseved THD on an O-scope.

DuMax looks for a drop in drive force of 30%, I kinda like using 10% distortion as a limit.

How can I estimate a useable X-max without special equipment?

Take the coil overhang and add the mean of 15% of the total coil length and 25% of the gap height.

15% of the coil length is 2.8575mm

25% of the gap height is 2.025mm

2.405mm is the square root of the product of those two numbers

This gives us 7.88mm added to the coil overhang

This is within 3% of the 7.6mm value on the JBL data sheet.

This is for overhung coils only(the majority in the market place).

 

Ce parere aveti?? Poate oferi acest mod de calcul un rezultat multumitor ?

Editat Noiembrie 16, 2009 de SIG