From mjh@buttle.lcs.mit.edu Mon Jan 13 20:01 EST 1997 From: Mark Handley X-Organisation: Information Sciences Institute, USC X-Phone: +1 617 253 6011 To: Henning Schulzrinne cc: rem-conf@es.net Subject: Re: Headphone/microphone combinations? In-reply-to: Your message of "Wed, 08 Jan 1997 08:54:35 EST." <32D3A71B.7930@cs.columbia.edu> Date: Mon, 13 Jan 1997 20:00:20 -0500 Message-ID: <19631.853203620@buttle.lcs.mit.edu> Sender: mjh@buttle.lcs.mit.edu Content-Type: text X-Mozilla-Status: 0011 Content-Length: 2628 Having never been very satisfied with any of the headsets I've tried (and we had a pretty good selection at UCL), I finally resorted to building my own. My requirements were to have headphones that go over my ears rather than press on them because this puts the drivers a little further from my ears meaning load sounds hurt less (and MBone sessions often have loud sounds) and because I find them more comfortable for wearing for long periods of time. I spent some time wandering around audio shops till I found a set of headphones that were suitably comfortable without really caring too much about the quality because, lets face it, good high frequency response is actually a liability with workstations - the high frequency hiss from SparcStations on walkman type headsets always annoys me. What I got were a pair of $30 Aiwa headphones - I was prepared to spend a lot more, but these were more comfortable. I also got a tiny ( < 10mm) $2 condenser microphone from Radio Shack, assorted cables and plugs, a 10uF capacitor and a wire coathanger. Assorted soldering, bending of coathanger and insulating tape later I now have the headset I wanted. The SparcStation supplies the 5V bias voltage for the mike just perfectly. This is on an SS20 - don't know how universal it is, but I think SS10s and SS5s are the same. +------+ +---+ | |-------------- bias (+5V) ---------------------| | | | \ / | mike | || +===+ | |------||--------- output ----------------------| | 3.5mm plug | | || 10 uF |===| | | | | | |---------------- ground -----------------------| | +------+ | | +=======+ | | I have to admit I was surprised that the bias and the output were the opposite way round from what I expected. You need a good breathshield over the mike when it's only 2-3cm from your mouth, but Radio Shack sell those too. Anyway, this setup works pretty well. Total cost: about $40. See http://buttle.lcs.mit.edu/~mjh/headphones.gif for a not terribly good GIF. Mark