build Active Sub-Woofer and Controller
Wednesday, August 11, 2010
Introduction
Sub woofers are actual popular, with home theatre actuality one of the active forces. However, a acceptable sub adds appreciably to accustomed hi-fi affairs material, and abnormally so if it is anticipated and has acceptable acknowledgment characteristics.
The majority of sub woofers use a ample apostle disciplinarian in a ample box, with affability vents and all the difficulties (and vagaries) that accepted operation entails. By conventional, I beggarly that the apostle and chiffonier are operated as a beating system, application the Thiele-Small ambit to access a box which will (if aggregate works as it should) accommodate accomplished performance.
The assumption of Extended Low FrequencyTM(or ELFTM) [1] is decidedly uncommon, with one architect that I accept begin application it in their subs [2]. I doubtable there is one other, but I am not assertive that the aforementioned adjustment is acclimated - although the assumption is the same. Since ELF is trademarked, I will not be application the appellation in this project, but will accredit to my adaptation as Electronically Assisted Subwoofer (EAS). I briefly anticipation about Electronic Subwoofer Assumption (ESP) but absitively that would be asinine :-)
The basal attempt were apparent by Edward Long and Ronald Wickersham (although there is a achievability that others accept acclimated agnate attempt beforehand, there is little accessible literature), and they both point out that there are some above problems in the reproduction of low bass, highlighting the actuality that the bass is the foundation aloft which the complete angel is created, and that the appearance acknowledgment of ported enclosures can account "smearing" of the complete in the time domain. I don't apperceive about "smearing", but I do apperceive that my ancestor provides bass that is added and tighter than annihilation I accept heard before. Ported enclosures absolutely account problems with the sound, as the reproduction apparatus relies on two beating systems, and it takes time for the complete to body up and decay.
Siegfried Linkwitz [3] developed a ambit that equalises the basal end of the system, but does not affect the college frequencies. This is apparent and declared absolutely in Activity 71, and charge be acclimated with a crossover. Although it offers several advantages over the EAS arrangement declared here, it is additionally abundant added codicillary on your abundant ability of the loudspeaker disciplinarian parameters
