Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!accuvax.nwu.edu!nucsrl!telecom-request From: Julian Macassey Newsgroups: comp.dcom.telecom Subject: Re: Telecom Peeves Message-ID: <10280@accuvax.nwu.edu> Date: 31 Jul 90 15:16:30 GMT Sender: news@accuvax.nwu.edu Organization: The Hole in the Wall Hollywood California U.S.A. Lines: 60 Approved: Telecom@eecs.nwu.edu X-Submissions-To: telecom@eecs.nwu.edu X-Administrivia-To: telecom-request@eecs.nwu.edu X-Telecom-Digest: Volume 10, Issue 532, Message 8 of 10 In article <10245@accuvax.nwu.edu>, rmadison@euler.berkeley.edu (Linc Madison) writes: > In article <9974@accuvax.nwu.edu> sys0001%dircon@ukc.ac.uk writes: > X-Telecom-Digest: Volume 10, Issue 502, Message 10 of 15 > >One thing that drives me up the wall is when the person on the other > >end of the phone holds the handset so the microphone part is under > >their chin instead of in front of their mouth. > >I've seen many people doing this (when I've been in their office and > >they've taken a call). Don't they realise that they should speak > >directly into the mouthpiece for the best transmission? > No, in fact, the best (cleanest) transmission is achieved by placing > the mouthpiece directly in front of your CHIN, slightly *below* your > mouth. The reason is that by doing so you eliminate the very annoying > excessive pickup of certain sounds like "s" and "p". The effect is > even more pronounced with your average garden-variety microphone used, > for example, in a high school auditorium. Well, believe it or not, the first poster is right about telephones. Yet, the second poster is right about using PA or recording mics with dynamic, electret or condenser elements, talking directly into the element will cause popping and essing. Telephone microphones of "transmitters" in telco-speak are designed to be talked into. This is true with both U.S. (Bell) and CCITT (E.U.) standards. For best results, when on the phone talk into the microphone. A telephone handset is tested on a device called an artificial head. The transducer in the artificial head is set up at a specified distance from the mouthpiece and aimed directly at it. In fact the dimensions of Bell and CCITT handsets are carefully spelt out, I can't find all these docs right now, so most of this stuff is from memory. Most of these test devices are built by Bruel & Kjaer a Danish company. There are normally two types of transmitters used in handsets, carbon and electret. One notable exception is the GNT F78 Danish phone which has a dynamic element. The carbon element has a threshold effect which means the sensitivity drops off rapidly as the sound source moves away from it. This is useful for attenuating room noise, but as the first poster notes, it also means that if you don't speak into the transmitter the voice will be weak and indistinct. Electret transmitters are more sensitive so are more likely to pickup snide comments from bystanders in the background, so the "It's your boring mother" type asides can be clearly heard. A well designed handset using an electret will be well enough damped to avoid essing if spoken into directly. So please speak into the mouthpiece, that's where the element is. Julian Macassey, n6are julian@bongo.info.com ucla-an!denwa!bongo!julian N6ARE@K6IYK (Packet Radio) n6are.ampr.org [44.16.0.81] voice (213) 653-4495