Calculating Thiele-Small parameters? - Home Theater Forum and Systems - HomeTheaterShack.com

Old 03-14-16, 06:20 PM Thread Starter
Shackster

Join Date: Oct 2014
Location: Denver
Posts: 14
My System
Calculating Thiele-Small parameters?

Are there any tutorials available for using the Thiele-Small parameter calculator? A search of this thread for Thiele-Small' and 'Thiele' brings no results for instruction, just issues with the calculator.

Lots of between the lines questions to be answered. Example: I see the diagram in the help file, but what is a "non-inductive" sense resistor? What kind should I buy? Tips for set up? Weighting? Multi-meter? How do I know I got good results, etc.
There seems to be a lot more that goes into it than just plugging some wires into a driver and pressing calculate.
oatmeal769 is offline

Old 03-15-16, 09:20 AM
HTS Moderator
Reviewer

Wayne Myers

Join Date: Jun 2012
Location: Lincoln, NE
Posts: 4,609
Re: Calculating Thiele-Small parameters?

Non-inductive resistors are constructed in such a way that there is no inductance (carbon composition, not wirewound or metal film) or wirewound but with the winding direction changing halfway through so the inductance cancels out. Even metal film resistors are often trimmed to the desired value by cutting a spiral in the film, forming an inductive coil. A straight piece of wire has a tiny amount of inductance, but it is the larger amounts we are concerned about, like with wirewound construction.

I just purchased some non-inductive resistors from Mouser for impedance measurements, I think they were \$3 or \$4 each. My whole order with two of each value came to just under \$30.

1 kOhm, 5 W, 1%, wirewound, non-inductive, axial lead, through-hole
71-NS5-1K Mouser #
NS0051K000FB12 Dale-Vishay #

2. for speakers
100 Ohm, 5 W, 1%, wirewound, non-inductive, axial lead, through-hole
71-NS5-100 Mouser #
NS005100R0FB12 Dale-Vishay #

3. for cables
10 Ohm, 5 W, 1%, wirewound, non-inductive, axial lead, through-hole
71-NS5-10 Mouser #
NS00510R00FB12 Dale-Vishay #
AudiocRaver is offline
Old 03-15-16, 09:27 AM Thread Starter
Shackster

Join Date: Oct 2014
Location: Denver
Posts: 14
My System
Re: Calculating Thiele-Small parameters?

Sweet, thank you!
Have you used the tool and done any calculations yet?
oatmeal769 is offline
Old 03-15-16, 09:28 AM
HTS Moderator
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Wayne Myers

Join Date: Jun 2012
Location: Lincoln, NE
Posts: 4,609
Re: Calculating Thiele-Small parameters?

Quote:
oatmeal769 wrote: View Post
Sweet, thank you!
Have you used the tool and done any calculations yet?
I have not, hope to do some impedance measurements in the next day or two, will post my results and experience.
AudiocRaver is offline
Old 03-15-16, 09:36 AM Thread Starter
Shackster

Join Date: Oct 2014
Location: Denver
Posts: 14
My System
Re: Calculating Thiele-Small parameters?

Please do. It seems there may be a lot of distance between the instructions, and practical experience.
oatmeal769 is offline

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