Loud speaker system

Claim 1

A self-contained loudspeaker combination comprising a conediaphragm type woofer and a cone-diaphragm type tweeter, each cone-diaphragm carrying a voice coil operating in an annular air gap of a magnetic circuit and having a stationary mounting rim for supporting an annular hinge portion at the large cone end, the woofer being for low-frequency operation and having its large end cone diameter of at least about 8 inches, the tweeter being for higher frequency operation and having its large end cone diameter substantially less, means for supporting the tweeter in coaxial nested relation within the volume defined by the woofer cone, and a pushing self-supporting flat baffle plate of material, whose thickness is between about one-tenth and about three-fourths inch, said plate having a curved outer edge and a window therethrough to provide an inner edge, means for supporting said plate in symmetrical relation to the coincident diaphragm axes and perpendicular thereto, said plate being small enough to be supported within the large diaphragm end portion with its outer edge stopping short of the large cone rim portion by between about one-half inch to the order of about 1 inch, depending upon the woofer speaker size, the plate inner edge being dimensioned and located with reference to the tweeter diaphragm mounting rim so that an acoustically suitable peripherally continuous extended air gap is provided, said plate material having suitable acoustic properties and the plate and spacing dimensions, shape and axial location being so selected that said speaker combination, with phasing baffle plate, when mounted for normal speaker operation with a conventional baffleboard will have a desired uniform frequency response over the desired audio-frequency range and be substantially free of resonance peaks or holes having abnormal amplitudes in such range, even though the same speaker combination minus the phasing baffle plate, when tested, will have at least one resonance or anti-resonance peak of abnormally large amplitude within the audio-frequency range, said phasing baffle plate smoothing out the frequency response characteristic and improving speaker performance, the addition and mounting of said phasing baffle plate permitting engineering efforts to be directed thereon to improve frequency response whereby tooling changes for manufacturing the speaker combination proper may be substantially eliminated.