6/07/2008

Simple Crossover Example





















This is crossover of vifa P17W00 and use D27TG45 which very flat response. Do It youself.

6/05/2008

Calculate Baffle Diffraction Loss

Calculate Baffle Diffraction Loss. A full range speaker finds itself radiating into half space at the upper frequencies but radiating into full space at lower frequencies.As a result, there is a gradual shift of -6dB from the highs to the lows.

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Calculate Baffle Diffraction Loss

Loudspeaker History

Loudspeaker History
1874: Ernst W. Siemens applies for a U.S. patent for what he describes as a “dynamic,” or moving-coil, transducer. Siemens takes a circular coil of wire and supports it so it moves axially in a magnetic field. His patent is applied for as a “magneto-electric apparatus.” Oddly, his design isn’t used for anything audible. 1876: Alexander Graham Bell patents the telephone. Siemens works on a nonmagnetic parchment diaphragm to act as the audible radiator for his moving-coil transducer and patents his technology one year later.
It’s mostly used in phonograph players in the acoustic era. His cone is attached to flaring “morning glory”-shaped horns. 1911: Edwin S. Pridham and Peter L. Jensen invent the Magnavox -- the world’s first PA system. Wilson uses this moving-coil loudspeaker in a time when most speakers are cone designs and their frequency range is limited.
1931: Bell Labs develops the first fidelity speaker. This two-way loudspeaker (called “divided range”) uses a small horn to produce frequencies in the range of 3K to 13K hertz. The 12-inch dynamic cone radiator offers a frequency range from 5K to 10K hertz. 1932: RCA releases its own dual-range speaker for theaters. It incorporates three 6-inch cone diaphragms with aluminum voice coils aimed in multiple directions for a frequency response of 125 to 8K hertz, and 10-foot-long horns capable of reproducing 40 to 125 hertz. Hence, the era of the multi-cell horn commences. Thuras theater speaker 1933 1945: Altec Lansing Corp. puts its two-way “Voice of the Theater” speaker system on the market. It offers improved horns and magnetic drivers.
1974: Universal Pictures releases Sensurround sound for its new picture, Earthquake. It enhances low-frequency enough that during the film, the whole theaters rumble with the earthquake and aftershocks.
This is done with four large, low-frequency horns installed behind each screen. Individual horns measure 8 feet long, 4 feet wide and four feet tall. One-thousand-watt amplifiers in the back corners of the theaters power two additional horns. 1982: George Lucas and his THX sound system shoot moviegoers into a new galaxy of sound with the release of Return of the Jedi. Here, a combination of speakers, crossover networks and a high standard of audio equipment and performance standards set the next level of quality.

Speaker DIY Shop on Thailand

http://advancerich.tarad.com
This web site is Korat on thailand which have many brand speaker and DIY speaker, Tube amp...etc for sell and