The Talking Machine Forum — For All Antique Phonographs & Recordings

In addition to the excellent "in print" books suggested, there are several books available online, many downloadable in PDF format or "flip viewing" at the internet archive ( https://archive.org/ ).

If you want a comprehensive book about the state of "contemporary" gramophones covering the technology of acoustic as well as electrically amplified equipment--as it was in 1929--you might find this of interest:
Some sections, describing the principles of sound reproduction, designing an exponential horn, etc., are VERY technical.

OrthoFan

i read the on line internet book but the other books are pricey !1

Go to bed, tiny child.