Spice model for headphones and cables?
Jul 10, 2004 at 2:23 PM Thread Starter Post #1 of 6

DCameronMauch

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Has anyone ever seen any spice models for headphones? Maybe even cables?

I have some HD600s with 25ft Cardas cables. I would love to have or make a spice model for this combo. So I can put something into my simulations a little more accurate than just a simple 300 ohm resistor. I want to see how the complex reactance influences circuit performance. Some of the circuits I am playing with are so high speed, and prone to oscillation, that it may look stable with a straight resistor as the load, but may in fact become unstable with a realistic load.

If there is a fairly simple way to make the model based on measurements? I have at my disposal a high quality dmm, 20MHz oscope, signal generator, and obviously a computer. Perhaps something using Right Mark Audio Analyzer? I would even be willing to pick up some inexpensive gear to get the job done.
 
Jul 13, 2004 at 2:46 PM Post #3 of 6
I am curious why it is that everytime I try to bring up a discussion of a more advanced topic, no one seems interested. Clearly this forum isn't the place for such discussions. So, where would be? I haven't seen any advanced topics on headwize either. I am suprised no one in the forum wants to go beyond basic theory and subjective opamp comparisons.
 
Jul 13, 2004 at 3:23 PM Post #4 of 6
I will have ago at responding
tongue.gif

The usual practice for modeling speakers is to create an electrical
analogue using inductors capacitors and resistors.
To produce a truly detailed model of a particular phone would be a pretty complex procedure,when one considers the influence of all the components
within it , not forgetting the interaction with ones head.
Though I guess it would be possible to produce a simple model by plotting impedance
curves/ resonance frequencies.

As for existing models, no doubt manufacturers do have their own, but I would very much doubt they would make them freely available to anyone
who asked.

If you wish to research this subject further there is a fine book covering the above topics.
The headphone section should prove educational .

The book is:

Loudspeaker and headphone handbook, by John Borwick , published by
Focal Press .

http://books.elsevier.com/us//focalb...ity=focalbooks


Cheers


Setmenu
 
Jul 13, 2004 at 4:39 PM Post #5 of 6
a lumped lcr model of the cable should be good to a few MHz, for greater high frequency accuracy multiple lcr sections can be used

since capacitive load is usually the worst case for amplifier stability, simply lumping all Cload at the amplifier output is the most conservative test

single driver dynamic headphones have much smaller impedance curve variation than multi driver loudspeakers with (poorly designed) complex crossovers so there is actually little to be gained in terms of simulation accuracy – I think I remember my HD600’s I/V only varied ~20-30 degrees at driver resonance
 

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