Early film-sound reproduction: Manometric Flames?
Clay Leander
In a reply to someone, I began thinking about reproduction
technology. Guess loudspeakers are still the weak link
in the reproduction chain. Wondering if there are any
real improvements?
I once dug into some old SMPE (before the 'T') archives
concerning film sound reproduction systems. There was
one system that used compressed air (?!) , and another
that employed "Manometric Flames".
Any enlightenment here?
- Clayton
*****
Frank Wylie
Clay Leander <clay...@earthlink.net> wrote:
>I once dug into some old SMPE (before the 'T') archives
> and another
>that employed "Manometric Flames".
>
>Any enlightenment here?
I think this was the "singing" or "speaking arc". The dc current
going into an arc light was modulated by a either a carbon capsule
microphone or a sound track (circa 1902). It was a crude and very
limited amplifier.
.
John Garrett
In article <359512...@earthlink.net>,
Clay Leander <clay...@earthlink.net> wrote:
>one system that used compressed air (?!) , and another
>that employed "Manometric Flames".
^^^^^^^^^^^^^^^^^
Plasma?
>
John
Sandy MacRae
May I point you at a recently published article by John Aldred of AMPS on
this subject?
http://www.amps.net/newsletters/24_arc.htm
Sandy MacRae AMPS
Frank Wylie wrote in message <3595a868...@news2.infinet.com>...
>Clay Leander <clay...@earthlink.net> wrote:
>
>
>>I once dug into some old SMPE (before the 'T') archives
>> and another
>>that employed "Manometric Flames".
>>
Good4Sound
In regards to (jgarrett) and his report on how humidity can wreck havoc on the
schoeps and the cutone. I had the great oppurtunity (ha!) to experience it in
full force. Although, I wasn't lucky to have jungles for the location. I was
lucky and got stuck in a shower stall while they used a water based smoker to
steam up the mirror. I noticed later some clicking noices and we both came to
the conclusion ( the mixer and I) that our schopes was craping out.
We ended up putting it up to a 5k and letting it dry out during takes. But I
should ask what would be a better way of drying it out and would there be any
long term problems with it?
by the by.......... the schopes, IT ROCKS !!!!!!!!!!!
Rusty
boom op,
utah
Jean Casanova
Have had same problem of clicking shoeps in Haman or hot showers scenes,
only solution on these days was to have two or three mikes to alternate.
After that our shoepses came back to they normal state and condition without
any alteration in sound.
--
J. C.
Reply by removing the "nospam." from email
or click here : Jean.C...@wanadoo.fr
Senator Mike Michaels, c.a.s.
Thanks David, for being on the "group" and for the fine response. This
IS what this professional sound for film group is about, and having the
folks who make (and market) the equipment we use participate here makes
it worth the "maltise Falcons", "make money without working", "Girls,
girls, girls!" and wanna-be "wunderkinds" we also get.
I feel better, now!
David Josephson
Tomaras:
>>Why are Schoeps mics so much more prone to humidity problems than other
>>microphones? Has Schoeps decided that they would sacrifice quality in some
>>way by engineering their way around the problem?
Kludge:
>Because they are externally polarized with a fairly high polarization
>voltage. In fact, they are less prone to humidity problems than a lot
>of the externally polarized mikes (just try the Neumann MKH 84 in a
>humid place some day), but a lot more common in the film industry than
>the others.
>You can drop the polarization voltage and then you get lower output, which
>is what Beyer has done on some of their externally polarized mikes, which
>run with only around 45V on the diaphragm. This sacrifices S/N, though.
I don't think that dropping the voltage from 60 to 45 will change
anything. If there is a leakage path, you'll hear it.
This may seem heretical, but you guys really ought to know what is going
on. Fact to remember: water does not conduct electricity. However, the
slightest bit of ionic contaminant (alkali or acid) while nonconducting
in a dry state, added to water makes a nice noise generator.
What happens when you toast the mic on a 5K is that some of the water
gets driven off, maybe enough that the deposit is no longer conductive.
But it's not a permanent fix. Storing the mic in a box with little
silica gel packets is approximately useless, unless the box is sealed
and you have recently (past few days) dried out the silica gel. But
again, even if you store the mics in a vacuum, if there is some junk
that collects water, it will make noise as soon as you bring it into the
real air again.
In nearly every case I've looked at, the problem is fingerprints and
other crust on the surface of some insulator, which *then* combines with
airborne water vapor to make a conductive path.
Schoeps mics seem to be particularly susceptible because of the nature of
the connector, which must carry polarize voltage, signal, power for the
Colette electronics, and a test input. They have done the best that can
be done in the circumstances by making the surface path long (that's
what all the ridges are for in that connector). But it makes the connector
attact all kinds of junk which gets wedged down inside each time the
capsule is removed.
Recommended fix: get some fresh 91 or 99% isopropyl alcohol (don't use
denatured, or <91%) and a fairly stiff small artist's brush, like a
#1 or #2 bristle brush for oil painting (about 1/4" across). First wash
the brush out in several rinses of alcohol (pour alcohol into a dish,
wash the brush, then discard the alcohol and wipe the dish dry). Now
use fresh alcohol and the brush to scrupulously clean the white plastic
insulators on both the capsule and the preamp, and let them air dry.
DO NOT TOUCH THE PLASTIC after that. Don't ever pour anything back into
the alcohol bottle, and keep it uncapped for as little time as possible.
If this doesn't work, it's true, your best bet is to send them back to
Jerry Bruck and have them disassembled and cleaned by people who can
put them back together *and* test to see that they did it right.
--
David Josephson / Josephson Engineering / San Jose CA / da...@josephson.com
pv
To me, David Josephson's response is like a revelation. My
assumption was that the noise was a result of something
happening in or around the diaphragm. To suggest that the
problem is a result of conductivity problems in the connectors...
Well, that's never come up in any discussions I've had regarding
humidity.
I'm intrigued enough to wonder if I should clean the contacts now,
or wait untill the next humidity problem occurs, to test the
solution directly.
I've wondered about the effectiveness of the silica packets, and
more concerned about the dust they may generate inside the case.
pv
David Josephson
>To me, David Josephson's response is like a revelation. My
>assumption was that the noise was a result of something
>happening in or around the diaphragm. To suggest that the
The Schoeps design is well sealed between the diaphragm and backplate;
unless the mic has been dunked and corrosion begun there, or carelessly
disassembled by someone, that's not the problem.
>problem is a result of conductivity problems in the connectors...
>Well, that's never come up in any discussions I've had regarding
>humidity.
>I'm intrigued enough to wonder if I should clean the contacts now,
>or wait untill the next humidity problem occurs, to test the
>solution directly.
Note, it's not the contacts -- those clean themselves when mating --
but the insulators, the white or grey plastic parts that have to be
clean.
>I've wondered about the effectiveness of the silica packets, and
>more concerned about the dust they may generate inside the case.
Dust is not a problem. But silica gel packets absorb a small and
finite amount of water. They are intended for packing with a
piece of equipment at manufacture which is then *sealed* in plastic.
This makes sure that any moisture trapped in the box when it's made
is immobilized in the gel. If you cycle the gel packets (200F
oven for 3-4 hours) and then pack them with the gear in a small
airtight box, they will do some good. Otherwise they are no help.
John Garrett
David Josephson <dav...@rahul.net> wrote:
>In <911A16CA75B8626E.1FD3DD21...@library-proxy.airnews.net> "pv" <verr...@airmail.net> writes:
>
>>To me, David Josephson's response is like a revelation. My
>>assumption was that the noise was a result of something
>>happening in or around the diaphragm. To suggest that the
>
>The Schoeps design is well sealed between the diaphragm and backplate;
>unless the mic has been dunked and corrosion begun there, or carelessly
>disassembled by someone, that's not the problem.
I didn't know this. I will get more info from Jerry Bruck and post
here.
>>I've wondered about the effectiveness of the silica packets, and
>>more concerned about the dust they may generate inside the case.
>
>Dust is not a problem. But silica gel packets absorb a small and
>finite amount of water. They are intended for packing with a
>piece of equipment at manufacture which is then *sealed* in plastic.
>This makes sure that any moisture trapped in the box when it's made
>is immobilized in the gel. If you cycle the gel packets (200F
>oven for 3-4 hours) and then pack them with the gear in a small
>airtight box, they will do some good. Otherwise they are no help.
Right, which I pointed out in my original reccommendation of silica gel.
Gotta be an airtight thang. Welcome to the list, David. I believe we
spoke at AES last year, and I have sent folks your way.
G. John Garrett, cas
Good4Sound
the sound? And has anyone used those latex finger tips over the capsule? Does
this also affect the sound? I will be using it for high humidity situations.
Any ideas???????
Rusty
Senator Mike Michaels, c.a.s.
Try it, and let us know your results!
Sandy MacRae
Good4Sound wrote in message
<199807102332...@ladder03.news.aol.com>...
>Hey , has anyone used condoms over the mic? And how does it affect if at
all
>the sound? And has anyone used those latex finger tips over the capsule?
Does
>this also affect the sound? I will be using it for high humidity
situations.
>Any ideas???????
Yes - I used the aforementioned on a Sennheiser MKH405 some years ago to
attempt a recording underwater in a tank. I was surprised how LITTLE
difference it made to the sound out of water when stretched tight over the
top. The H.F. started to drop off with the second one.... BTW - The
underwater sound recording was a success and the mic came out dry! Advice -
use non-lubricated plain ended ones...
Sandy MacRae
John Garrett
"Senator Mike Michaels, c.a.s." <studi...@earthlink.net> wrote:
>Good4Sound wrote:
>
>> Hey , has anyone used condoms over the mic? And how does it affect
>> if at all
>> the sound? And has anyone used those latex finger tips over the
>> capsule? Does
>> this also affect the sound? I will be using it for high humidity
>> situations.
Yes and yes. I've used condoms over mics and dipped the bidness end
into a pool for underwater fx; its not as good as an expensive
hydrophone, but hard to tell the difference, since underwater sound is
perceived so differently. I guess you could transport your capsule in a
finger cot or condom, but if there's humidity trapped inside it won't do
you any good. I have a small watertight Pelican case that I stick mic
capsules into, with a silica gel cannister. That dries em out and keeps
em dry, until they're out in the big scary world again.
G. John Garrett, cas
Good4Sound
>Try it, & let us know your results.
Another shower scene again!!!!! And the condom seem to help.
FYI>>>>>
Make sure you put it on when you're not in the shower stall.
It gets really steamy in
there.!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Thanks you guys for all your advice.
Ms. Rusty
boom op
AFinke8
with MK41's years ago. The capsules could only take the humidity for an hour
or so. To remedy, I put them in ziplock bags of silica beads which was very
effective in removing the moisture.
Nothing I could do about the mosquitos, though.