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Re: inherently critically damped

155.218.56.95

Posted by Mart on May 4, 1999 at 00:35:37

In Reply to: Re: inherently critically damped posted by hZ on May 3, 1999 at 23:34:35:

a driver can be accurately aproximated by:

 +---)()()()(--+
 |    |
 |    | 
0---+---/\/\/\/---+---/\/\/\/\---)()()()(---0
 |    |
 |    |
 +-----| |-----+

However, the left half approximates the speaker's LF near fs. Thus, we can shorten it to:

  Re  Le
0---/\/\/\/\---)()()()(---0 

where "Re" & "Le" are among the common Thiel-Small parameters of the speaker:
Le : voice-coil inductance in Henries
Re : DC resistance

This is the Zobel circuit:

  Rz  Cz
0---/\/\/\/\---| |---0 

When the 2 are wired in parallel the effective impedence is purely resistive at the higher frequencies.

The preceeding post was talking about a resonant reactance current between the cap & choke. The frequency {fe} is defined as:
2*Pi*fe == 1/Sqrt[Le*Cz]

However, in a LRC circuit the damping factor (del) is:

+---/\/\/\/\---+
|    |
|    |
|   -----
|
|   -----
|    |
|    |
+---)()()()(---+

del == R*Sqrt[C/L]/2

In our case
R = 2*Re
L = Le
C = Cz = Le/Re^2

thus
del == 2*Re*Sqrt[Le/(Re^2*Le)]/2 == 1

If del is less than one the circuit rings, above one the circuit is slow & makes the sound dull.

If you need more info, it's time to grab a basic electronics book.

This post is made possible by the generous support of people like you and our sponsors:

Sonic Craft

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