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December 28, 2020 / consort3

Recasting Thiele-Small

Speakerlab started as a speaker kit maker from Seattle in the early 70s and are still going. They wrote an excellent booklet on speaker design here:

nghttp://dave.spalla.com/wp-content/uploads/2014/12/SpeakerlabDesignGuide_1983.pdf

I could not resist tweaking the bass boost circuit given in the booklet because the op-amp has to drive low resistance values. I divided the capacitors by 3 and multiplied the resistors by 3. So C2/3 are 0.22u R2 is 3.3k R3 is 150k R9 is a 220 ohm pot and R6 is a 2.2k. The opamp should be a TL072.

Their founder also wrote a paper re-casting the Thiele-Small parameters which I discovered here:

Snyder_DesignOfVentedLoudspeakerSystem_nVasQts2

More on the technique:

http://www.mfr-eng.com/articles/rpp/

Paul Carmody has wriiten a piece on how to design speakers which is worth a read:

https://www.sites.google.com/site/undefinition/diy-speaker-faqs/simulated-measurements

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