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Browse Prior Art Database

Business Quality Audio from Printed Circuit Board Mounted Speaker

IP.com Disclosure Number: IPCOM000114415D
Original Publication Date: 1994-Dec-01
Included in the Prior Art Database: 2005-Mar-28
Document File: 2 page(s) / 39K

Publishing Venue

IBM

Related People

Bass Sr, RH: AUTHOR [+4]

Abstract

Described is a means of significantly increasing the audio output levels from small direct board mount speakers.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 100% of the total text.

Business Quality Audio from Printed Circuit Board Mounted Speaker

      Described is a means of significantly increasing the audio
output levels from small direct board mount speakers.

      Small loud speakers designed to be direct mounted to printed
circuit boards suffer from relatively low sound output levels due to
destructive interference.  These speakers incorporate standoffs into
the frame structure such that the cone assembly is held above the
board so that only the stand offs and lead wires contact molten
solder during processing (A in the Figure).  This construction
produces a gap between the cone assembly and board such that the
speaker is "free mounted" with sound from both surfaces of the cone
able to interact to produce "bucking" or destructive interferences,
with attendant reduction in audio output levels.

      A plastic ring of such height as to just fit between the cone
assembly and the circuit board (B in the Figure) is added and holes
are made in the board beneath the cone (C in the Figure) to produce a
simple "finite baffle" enclosure.

      This mounting system significantly increases the low frequency
effectiveness and overall audio output levels of the speaker.  This
enhancement is such that those sounds of the business environment,
such as touch tone dialing and dial tones are easily heard from
printed circuit board mounted speakers when placed in machine such as
personal computers.