Instruction manual/user manual for FOSTEX speaker components, including technical specifications and characteristics. Brand: FOSTEX Models: FT17H, FE83, FE103, FE164, FE204 FW100 Technical specifications and connection methods for speaker components Characteristic tables: Details such as frequency response, impedance, sensitivity, and FOSTEX's general catalog. The "FE204" purchased in the early 1990s is still active as a second speaker. (Removed and listed on February 19, 2026) The bass reflex and standard enclosure for this 204 is 36 liters, but the enclosure I had was 28 liters. The dimensions of the duct can be determined from the "Helmholtz" formula. The duct's resonant frequency was adjusted to be approximately 1.5 times the speaker's lowest resonant frequency, 45Hz x 1.5 = 65Hz, by reviewing the duct length and area (duct volume). Furthermore, the result calculated from the standard enclosure's duct dimensions was also 65Hz, so this frequency range is appropriate. If you try to achieve a lower frequency than this, it will result in inaudible bass. To maximize the speaker's characteristics, it is necessary to readjust the duct using the "Helmholtz" formula, rather than simply using a readily available bass reflex enclosure as is. The FT17 tweeter was used in a 2-way system with a Pioneer full-range speaker, with a simple low-frequency cut using a single capacitor in the network for frequencies below 15KHz. The technical specification sheet was included with the speaker purchase and is the original document, not a copy. Thank you for looking. Price reduced from 640 yen to 560 yen. Thank you for your consideration.