Different components of a loudspeaker circuit.

[EGregersen]

Hey guys.
I have a loudspeaker circuit that really puzzles me. I can't seem to find an explanation of the different components in a loudspeaker circuit that I've been handed. In the drawing of the circuit, the following descriptions of the different parts occurs: Le, Re, Rg, Les, Res, Rms and Ces. What are these? I am hoping for an explanation of these, and maybe even an explanation of what they physically represent in the loudspeaker.

Thanks in advance! 🙂

 

[wintermute]

le is voice coil inductance, and re is the DC resistance of the voicecoil. I'm not sure what the others are, but are probably other measurements that describe the electrical characteristics of the speaker. Have a look at Theil Small parameters, They can be used to determine how a particular driver will behave in a given box.

Tony.

 

[sreten]

Hi,

Its an equivalent circuit and some equivalents are more
useful than others : Basta! technical documentation

Here's an equivalent circuit for a raw dynamic driver. It doubles as one for a sealed (or enclosed driver) where “Rg” is speaker
cable impedance & cross-over resistance & amplifier's output impedance. For what it's worth, most people ignore “Rms”.

The magnitude of the impedance for real world driver is plotted below. The low frequency spike is modeled by the
“Ces”; “Res”; “Les” section of the circuit while the high frequency slope is the responsibility of “Le” (voice coil inductance).

The above only models the impedance of the driver, not that well regarding Le TBH.

rgds, sreten.

 

[sofaspud]

In addition to the previous replies,
I think all the nes components are "equivalent series" and Rms is actually root-mean-square. Rg I believe to be the impedance of the input signal source.

 

[sreten]

Hi,

Rms is resistance due to mechanical damping, related to Qms.
Res is resistance due to electrical damping, related to Qes.
Les models the cone mass, related to Mms.
Ces models suspension compliance, related to Cms.

rgds, sreten.

 

[Ron E]

Hey guys.
I have a loudspeaker circuit that really puzzles me. I can't seem to find an explanation of the different components in a loudspeaker circuit that I've been handed.

The best references on this are Acoustics by L.L. Beranek and Theory and Design of Loudspeaker Enclosures by J.E. Benson.

A loudspeaker (in or out of an enclosure) is a system composed of electrical, mechanical and acoustical elements that are coupled together. That simple circuit is a simplified representation of the mechanical and acoustical elements all transferred to the electrical side.