Capacitor/Condenser Microphones

[Jim Thompson]

Didn't some old capacitor/condenser microphones use RF oscillation?

I seem to vaguely recall such schemes, but my surfing has come up
nought.

Does anyone have some links?

Thanks!

...Jim Thompson

 

[Don Pearce]

Didn't some old capacitor/condenser microphones use RF oscillation?

I seem to vaguely recall such schemes, but my surfing has come up
nought.

Does anyone have some links?

Thanks!

...Jim Thompson

Sennheiser make RF-based microphones. The MKH range is what you want.

d
Pearce Consulting
http://www.pearce.uk.com

 

[ChrisGibboGibson]

Didn't some old capacitor/condenser microphones use RF oscillation?

I seem to vaguely recall such schemes, but my surfing has come up
nought.

Does anyone have some links?

Sennheiser used RF biasing for some of their condenser mics. Don't know of any
others who did it though. How do I know? Because if the screening was anything
but perfect they, used to beat with harmonics of the bias oscillators in tape
recorders and make a right noise.

No links but you know where to look now.

Gibbo

 

[Richard Crowley]

"Jim Thompson" wrote ...

Didn't some old capacitor/condenser microphones use RF oscillation?

I seem to vaguely recall such schemes, but my surfing has come up
nought.

Yes, I seem to recall that some early designs used RF, but likely
nothing in the last 50 years.

Does anyone have some links?

There are some microphone historians that may know over
on
I once thought about making a "direct digital" mic by using
a condenser mic capsule in an RF oscillator circuit and a
high-speed freq counter to generate the digital samples.

 

[ChrisGibboGibson]

"Jim Thompson" wrote ...

Yes, I seem to recall that some early designs used RF, but likely
nothing in the last 50 years.

I'm *pretty* sure they still make them. Mainly because they sound great.

Gibbo

 

[Richard Crowley]

Didn't some old capacitor/condenser microphones use RF oscillation?

I seem to vaguely recall such schemes, but my surfing has come up
nought.

Does anyone have some links?

http://www.sennheiser.se/filer/sennheiser/RF_Microphones.pdf

I got lots of hits on Google with: rf condenser -interference -wireless
(because many sites mention "RF interference" and/or wireless mics)

(If my previous posting didn't get cancelled properly, ignore it!)

 

[Joerg]

Hi Richard,

(If my previous posting didn't get cancelled properly, ignore it!)

How can you cancel a post to an unmoderated newsgroup? Just curious.

Regards, Joerg

 

[Richard Crowley]

How can you cancel a post to an unmoderated newsgroup? Just curious.

Canceling a message (only your own, of course!) is a
fundamental part of Usenet and the NNTP protocol.

How it is implemented is dependent on which news-reader
application you are using. I use MS Outlook Express and the
function is found in the menu bar under "Message". In the
drop-down menu is a selection for "Cancel Message"

Note, however, that because of the speed of the modern
internet infrastructure, your Usenet message may have
already been forwarded to hundreds (thousands?) of news
servers and may have already be read/downloaded by
thousands of readers before the cancel message can go
out and do its thing. Usenet was a "store-n-forward" or
a kind of "peer-to-peer" sharing protocol long before
Napster, et. al. came along. Because of that, cancelling
a message is a rather unreliable exercise.

 

[Rich The Philosophizer]

...

Canceling a message (only your own, of course!) is a
fundamental part of Usenet and the NNTP protocol.

How it is implemented is dependent on which news-reader
application you are using. I use MS Outlook Express and the
function is found in the menu bar under "Message". In the
drop-down menu is a selection for "Cancel Message"

Note, however, that because of the speed of the modern
internet infrastructure, your Usenet message may have
already been forwarded to hundreds (thousands?) of news
servers and may have already be read/downloaded by
thousands of readers before the cancel message can go
out and do its thing. Usenet was a "store-n-forward" or
a kind of "peer-to-peer" sharing protocol long before
Napster, et. al. came along. Because of that, cancelling
a message is a rather unreliable exercise.

OK, lessee-

 

[Guy Macon]

How can you cancel a post to an unmoderated newsgroup? Just curious.

Send a post using this syntax:

(start)

Newsgroups: sci.electronics.design,sci.electronics.misc
Subject: cmsg cancel <[email protected]>
Message-ID: <[email protected]>
Control: cancel <[email protected]>
References: <[email protected]>
Supersedes: <[email protected]>
X-Cancelled-By: [email protected]
Approved: [email protected]
Sender: [email protected]
From: [email protected]
X-No-Archive: Yes

cancel <[email protected]>

(end)

****************************************************

Here is a template, ready for you to enter your info:

Newsgroups:
Subject: cmsg cancel <>
Message-ID: <cancel.>
Control: cancel <>
References: <>
Supersedes: <>
X-Cancelled-By:
Approved:
Sender:
From:
X-No-Archive: Yes

cancel <>

 

[Richard Crowley]

OK, lessee-

I saw it at 2:07pm PST. My newsreader says that you
posted your message at 2:02 But the timestamps are
not particularly reliable, either IME.

 

[BFoelsch]

I have used quite a few old condenser mikes, but I think the only OLD ones
that used an RF oscillator/detector/discriminator were the Stevens Tru-Sonic
units, about 1949-1950.
The most popular of the line was the Stevens C-2S, which was used with the
OD-4 oscillator demodulator unit.

Kind of a counter-intuitive setup, the OD-4 contained a crystal oscillator,
and the microphone head contained the capacity element and a small inductor.
The oscillator ran of course at a fixed frequency, but the microphone proper
was part of a discriminator circuit. Microphones were tremendous, sound
wise, but a real pain otherwise. Because everything was tuned, the mike and
the O/D unit needed matching serial numbers, and cable damage was generally
catastrophic, as the cable capacitance was part of the discriminator
circuit.

I don't have a link, but I do have a schematic and specs here.

Other than that, I don't know of any other mikes that used RF. By far the
vast majority just used a DC polarized capacitor element with an amplifier
in the mike head.

 

[ChrisGibboGibson]

Send a post using this syntax:

(start)

Newsgroups: sci.electronics.design,sci.electronics.misc
Subject: cmsg cancel <[email protected]>
Message-ID: <[email protected]>
Control: cancel <[email protected]>
References: <[email protected]>
Supersedes: <[email protected]>
X-Cancelled-By: [email protected]
Approved: [email protected]
Sender: [email protected]
From: [email protected]
X-No-Archive: Yes

cancel <[email protected]>

(end)

****************************************************

Here is a template, ready for you to enter your info:

Newsgroups:
Subject: cmsg cancel <>
Message-ID: <cancel.>
Control: cancel <>
References: <>
Supersedes: <>
X-Cancelled-By:
Approved:
Sender:
From:
X-No-Archive: Yes

cancel <>

Or just click the cancel button on the newsreader.

In both cases hope no one read it first, which they will have done.

Gibbo

 

[Tim Wescott]

Didn't some old capacitor/condenser microphones use RF oscillation?

I seem to vaguely recall such schemes, but my surfing has come up
nought.

Does anyone have some links?

Thanks!

...Jim Thompson

Whuffo you doing this?

If it's of interest QST ran a couple of articles a while back on home
brewing your own condenser mics, but they use HV DC and FET preamps to
extract the signal. Pretty clever -- the author was claiming high audio
quality from aluminum foil and other household items, but then it always
sounds better when you do it yourself...

 

[Jim Thompson]

Whuffo you doing this?

If it's of interest QST ran a couple of articles a while back on home
brewing your own condenser mics, but they use HV DC and FET preamps to
extract the signal. Pretty clever -- the author was claiming high audio
quality from aluminum foil and other household items, but then it always
sounds better when you do it yourself...

Think micro-microphones ;-)

...Jim Thompson

 

[Tim Williams]

OK, lessee-

Not only that but most servers don't honor the cancellation either,
something known as Dave the Resurrector I recall...

Tim

 

[Frank Bemelman]

Or just click the cancel button on the newsreader.

Which only works on your own messages. You can also cancel
others messages, but it is a bit more work. Typically the work
of automated cancel-bots. I have once written one (revartson)
for a dutch newsgroup, with permission of 99% of the group.
Dangerous tool.

In both cases hope no one read it first, which they will have done.

Yes, you need to be quick

 

[ChrisGibboGibson]

Which only works on your own messages. You can also cancel
others messages, but it is a bit more work. Typically the work
of automated cancel-bots. I have once written one (revartson)
for a dutch newsgroup, with permission of 99% of the group.
Dangerous tool.


Yes, you need to be quick

You can cancel others' messages?

I vote you for group moderator.

Gibbo

 

[Frank Bemelman]

You can cancel others' messages?

Yes, no problem.

I vote you for group moderator.

Thanks for the compliment but no thanks. I prefer all the
shit that comes with the package. Personal kill-files are
more than adequate. The Breitbart index is useless for
cancel bots. Nocem is better, but still useless, imo.
Freedom of speach is more important, even if someone replies
to all postings with 'do you want fries with that'.

 

[Rich The Philosophizer]

...

I saw it at 2:07pm PST. My newsreader says that you
posted your message at 2:02 But the timestamps are
not particularly reliable, either IME.

Fascinating!

I clicked cancel about four seconds after I clicked "send"!

Well, maybe ten.

The thread isn't up at google yet, but it's only been a few
minutes.

Cheers!
Rich