Thiele Small Parameters vs. Real World.

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Afaik the Thiele Small parameters define the speaker`s "behaviour" at the resonance frequency only. These are so called small signal parameters.

Now how is the behaviour of the speaker at high power levels compared to low/small signal levels?
Which parameters are likely to shift and in which direction?

Has anyone any experience or insight into the matter?
 
Now how is the behaviour of the speaker at high power levels compared to low/small signal levels? Which parameters are likely to shift and in which direction?

Has anyone any experience or insight into the matter?

All of the basic parameters (Vas, Qes, Qms, Fs) will shift as the cone changes position, and Re will shift (increase as power input increases) . As to how much they shift (within the driver's linear range of operation) will depend on the driver's design.

Having said that, I've gotten into the practice of doing dynamic linearity tests on my builds - basically testing how they perform with short sine sweeps at different levels, up to the point that distortion reaches 10% in the passband. Even the cheap Dayton PA310 holds up quite well, with any significant non-linear changes having more to do with the box design than the driver.
 
Thanks for the answers so far.


True, my real world is about there
@ global, I've just realised this is in the subwoofer forum, does your question specifically relate to subwoofers?

Speakers in general but with main emphasis on subs.


@globalplayer
Take a look into what Klippel published - he has a lot of research and work done on the behaviour of transducers @high power. Lots to read up there :)

Thanks for the hint. Will do. Funny name, btw :).


I've gotten into the practice of doing dynamic linearity tests on my builds - basically testing how they perform with short sine sweeps at different levels, up to the point that distortion reaches 10% in the passband.

Good idea. I might have to do the same or something similar.
 
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Physical parameters are larger, yes.
Non-linearities depend on construction for the most part, I think.
But yes, the higher moving mass will have it`s disadvantages compared to a smaller driver.
The "heavy" cone needs to be accelerated and "stopped".
Smaller parts probably can be constructed for linearity more easily.
 
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