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#1
Posted to rec.audio.tech
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Using low impedance mic on PC
I have a very old but apparently high quality mic, a Sony 'F-99B', just
rediscovered in my shed: 'One point stereo dynamic microphone IMP.LOW' It proved useless when I tried it on my PC, in the usual mic socket, presumably because of its low impedance. (My multimeter shows its left and right connections as about 170 ohms.) Can anyone suggest an inexpensive UK supplied mic transformer I can buy please? -- Terry, East Grinstead, UK |
#2
Posted to rec.audio.tech
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Using low impedance mic on PC
I have a very old but apparently high quality mic, a Sony 'F-99B', just
rediscovered in my shed: 'One point stereo dynamic microphone IMP.LOW' It proved useless when I tried it on my PC, in the usual mic socket, presumably because of its low impedance. (My multimeter shows its left and right connections as about 170 ohms.) Can anyone suggest an inexpensive UK supplied mic transformer I can buy please? You might want to review the discussion at http://www.audiobanter.com/showthread.php?t=118737 which captures a USENET thread from rec.audio.pro back in '09. Based on what I read here, - The F-99B is already supposed to have a "high-impedance" output (i.e. it may already have a transformer in it). You may be reading the DC resistance of the transformer coils, rather than the audio-frequency impedance of the system. - You're likely to need a separate amplifier stage to boost the signal enough to operate into a PC's "mic" input. PC inputs are usually designed to be used with active (buffered and amplified) condenser microphones, which have a relatively high voltage output (tens to hundreds of millivolts) and a fairly strong ability to drive current. If the mic and its built-in transformer (assuming it has one, as the discussion implies) won't drive the mic input successfully now, adding an additional transformer stage may not help... you'd gain voltage, at the cost of an even higher impedance, and the input impedance of the "mic" receiver stage may load down the source impedance too much. - It may not be worth the effort... several discussions of the F-99B suggest that it's not a terribly good microphone. -- Dave Platt AE6EO Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |
#4
Posted to rec.audio.tech
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Using low impedance mic on PC
Terry Pinnell wrote:
In view of your comments I'll probably not now try to use the F-99B, But that leaves me looking for some other simple solution, and I wonder if I can get some advice here please? For the narrative in my family DVDs I've been using cheapish PC microphones. These include the long stalk type that are supposed to sit on the desk but which I hold closer to my mouth, and the headphone type slung around my neck. (I don't use the earphones, which I find uncomfortable.) Ever now and then I hand over another £5-£10 for yet another. The last, bought at the weekend, is a 'tie-pin' type. Clipped to my shirt below the open collar it seems quieter and not so bright as I'd expected, so that's probably another one that will gather dust. So make the sum and figure out how much you wasted by not getting something that is designed with audio in mind rather than pc's. .... O;-) In fact quality isn't very good with any of these. It's either muddy and too quiet or loud enough but spoiled by distortion at the start of some words. So I just want to move up a bit in quality. My googling so far has left me confused, as there seem to be so many types, and a *huge* range in cost. My opinion: you need a Sennheiser MD21 and some usb preamp-soundcard thingie. Note: there are many other routes to salvation. My ideal would simply be a better quality PC mic, for plugging straight into the mic socket as at present. Do such devices exist, or is there some inherent limitation in the technology? I'd be happy to pay £20-£40 or so to get significant improvement. They have been making MD21's for 40 years and it is a very sturdy microfone, one has survived dangling in its lead after a car for a considerable stretch of city road. What about these 'USB microphones'? If I bought one of those at the budget end if their range (£30-£70?) would I be able to use it without any special software or setup? I'd check two brands, MXL and sE. I have no experience with their usb-mics, but my recollection is that both have some. A possible issue could be that such tend to do "44.1 kHz 16 bit" audio and your video application may prefer 48 kHz sample rate, but it may be a non-issue due to some "we know best brand" audio driver doing sample rate conversion. Could I continue to work in my applications without change? No, you would need to select the actually used sound source, a USB mic "is a sound card". Some applications disliked them some years ago because of only providing sound input and not output. It "should work", if it doesn't you need to have shopped somewhere that will accept a return for a full refund. For example, the drop down box in all the audio programs I've used, and my video editor, looks like this: http://dl.dropbox.com/u/4019461/RecordingSources.jpg (I use the Realtek option, as this PC came with that built into its ASUS motherboard.) With the addition of a USB mic, would that become an additional entry in the list, or what? Any practical advice (pitched to my very low level of technical savvy in this area) would be much appreciated please. Plug and pray and select input source, it may actually work out of the shrink wrap. Note2: your mileage may vary, consider yourself inspired regarding what to look into, do not consider yourself guided by the hand to the eternally best choice. Kind regards Peter Larsen |
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