Which books OR online courses are best for Audio Industry


Pl. recommend books you feel must for Loudspeaker design building Amplifier. Also about online couses for the same. here are many on acoustics but very few on Amp & loudspeakers.
ashoka
Loudspeaker Design Cookbook by Vance Dickason
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Testing Loudspeakers Book by Joseph D'Appolito
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both available at Parts Express
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Merlin Blencowe and Morgan Jones have fantastic books on amplfier design (tubes/valves).

As an introductory primer on tube amp design, you can watch the You Tube video of Roger Modjeski’s (Music Reference) 90 minute talk at the 2015 Burning Amp Festival. It’s free! Also on You Tube are videos posted by Roger himself, wherein he discusses pre-amp design.