The present invention relates to speakers and in particular to speakers of the moving coil type of relatively small diameter for use in stereo headsets and the like.
Heretofore it has been common practice to construct the diaphragm assembly for a moving coil type of headset speaker of three discrete parts. These parts comprise a low frequency diaphragm a high frequency dome and a voice coil form about which the voice coil is wound. The three parts were cemented together to form the completed diaphragm assembly. In this prior art type of construction, two distinct gluing operations were required. That is, the high frequency dome was separated from the voice coil form by adhesive and the low frequency diaphragm was also separated from the voice coil form by an adhesive layer.
It is common knowledge that in a mechanical acoustic driving system, such as a loudspeaker, a phase shift occurs at each change in the density of the material from which the driver is formed. This phase shift results is distortions at specific frequencies.
It is also well known that it is desirable to keep the vibrating system (i.e., the diaphragm-dome assembly) as light-weight as possible in order to achieve the lowest possible free field resonance frequency. With conventional headset two inch speakers now available, this frequency is approximately 450 Hz.