Method for producing speaker construction

Abstract

An inexpensive minimum component loudspeaker which dispenses with the need for either a spider or top plate, consisting of a back plate having a centrally disposed hollow post, an annular permanent magnet mounted on the back plate and closely adjacent the post, and a basket having a central portion lying flat against the permanent magnet and including a central opening concentric with the post and a folded back annular flange which lies flatly against the base of the basket to form a double layer of metallic material disposed closely adjacent the confronting surface of the post to form an air gap. The additional metallic material channels the magnetic lines so that there is a maximum concentration of gauss lines within the air gap. A single piece combination cone and dust cover having mounted thereto a bobbin with coils to form a voice coil is precisely located in relation to the air gap by means of a collapsible shim gauge. The shim gauge has locating fingers which extend through the central opening of the post and precisely locate the voice coil in relation to the air gap. After the described location is effected, the outer periphery of the cone is adhesively joined to the major diameter end of the basket by means of a heat polymerized adhesive, following which the gauge is removed and the voice coil is permanently and reliably located in an accurately defined position. A series of openings are disposed about the basket to provide free venting of air and thereby prevent distortion during operation.