[mcp6453[_2_]]

After 55 years in the audio business, I have encountered a strange
problem for the very first time. I set up a small mixer and two dynamic
mics for remote recording. Everything tested perfectly at home. When I
moved the setup to the remote location (an office building), there was
hum and buzz in both mics. Isolation the mics from all wall warts and
power supplies did not have an effect on the noise.

New mic cables. No change.
Different (dynamic) mics. No change.
Added dbx286s for each mic. No change.
Disconnected all external equipment from the mixer. No change.
Physically rotating the mics on the desk. Change.

At this point, I think there is a serious electrical problem in the
building. There was not much time to test, but I will be going back in
the next few days to do so. I was not able to turn off the fluorescent
lights to see if a ballast has gone nuclear.

I may take a couple of condenser mics to see if they exhibit the same
problem, but I really want to use dynamics.

Thoughts?

[Scott Dorsey]

mcp6453 wrote:
After 55 years in the audio business, I have encountered a strange
problem for the very first time. I set up a small mixer and two dynamic
mics for remote recording. Everything tested perfectly at home. When I
moved the setup to the remote location (an office building), there was
hum and buzz in both mics. Isolation the mics from all wall warts and
power supplies did not have an effect on the noise.

New mic cables. No change.
Different (dynamic) mics. No change.
Added dbx286s for each mic. No change.
Disconnected all external equipment from the mixer. No change.
Physically rotating the mics on the desk. Change.

You have a magnetic field somewhere, maybe from a large transformer nearby,
and the microphones are picking up magnetic field leakage. Moving the
location to the other side of the room might fix everything. Then again it
might not. You might also try an original Sennheiser MD421, which has a
bucking coil to reduce magnetic pickup.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[mcp6453[_2_]]

On 8/29/2018 8:21 AM, Scott Dorsey wrote:
mcp6453 wrote:
After 55 years in the audio business, I have encountered a strange
problem for the very first time. I set up a small mixer and two dynamic
mics for remote recording. Everything tested perfectly at home. When I
moved the setup to the remote location (an office building), there was
hum and buzz in both mics. Isolation the mics from all wall warts and
power supplies did not have an effect on the noise.

New mic cables. No change.
Different (dynamic) mics. No change.
Added dbx286s for each mic. No change.
Disconnected all external equipment from the mixer. No change.
Physically rotating the mics on the desk. Change.

You have a magnetic field somewhere, maybe from a large transformer nearby,
and the microphones are picking up magnetic field leakage. Moving the
location to the other side of the room might fix everything. Then again it
might not. You might also try an original Sennheiser MD421, which has a
bucking coil to reduce magnetic pickup.
--scott

Thanks, Scott. I only have one original MD421. Can you think of another
mic that would be useful to try along with the 421?

[Scott Dorsey]

mcp6453 wrote:
On 8/29/2018 8:21 AM, Scott Dorsey wrote:

You have a magnetic field somewhere, maybe from a large transformer nearby,
and the microphones are picking up magnetic field leakage. Moving the
location to the other side of the room might fix everything. Then again it
might not. You might also try an original Sennheiser MD421, which has a
bucking coil to reduce magnetic pickup.

Thanks, Scott. I only have one original MD421. Can you think of another
mic that would be useful to try along with the 421?

Some generic condenser mike without a transformer in it.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[mcp6453[_2_]]

On 8/29/2018 8:57 AM, Scott Dorsey wrote:
mcp6453 wrote:
On 8/29/2018 8:21 AM, Scott Dorsey wrote:

You have a magnetic field somewhere, maybe from a large transformer nearby,
and the microphones are picking up magnetic field leakage. Moving the
location to the other side of the room might fix everything. Then again it
might not. You might also try an original Sennheiser MD421, which has a
bucking coil to reduce magnetic pickup.

Thanks, Scott. I only have one original MD421. Can you think of another
mic that would be useful to try along with the 421?

Some generic condenser mike without a transformer in it.
--scott

I'm trying to think what I might have that's transformerless. My TLM67
doesn't have a transformer, but I only have one. (We need two matching
mics for video aesthetics.) What about the Beta 87A?

[Mike Rivers[_2_]]

On 8/29/2018 5:02 AM, mcp6453 wrote:
I set up a small mixer and two dynamic mics for remote recording.
Everything tested perfectly at home. When I moved the setup to the
remote location (an office building), there was hum and buzz in both mics.

Look outside for a nearby cell tower. A friend had a problem like that
in his studio when Verizon turned on a new transmitter in a tower to
near his place. After verifying the cause by having a Verizon tech come
out and temporarily shut off the transmitter, he managed to get them to
leave it off. You might not be that lucky.

--
"Today's production equipment is IT based and cannot be operated without
a passing knowledge of computing, although it seems that it can be
operated without a passing knowledge of audio" - John Watkinson

Drop by http://mikeriversaudio.wordpress.com now and then

[mcp6453[_2_]]

On 8/29/2018 9:19 AM, Mike Rivers wrote:
On 8/29/2018 5:02 AM, mcp6453 wrote:
I set up a small mixer and two dynamic mics for remote recording.
Everything tested perfectly at home. When I moved the setup to the
remote location (an office building), there was hum and buzz in both
mics.

Look outside for a nearby cell tower. A friend had a problem like that
in his studio when Verizon turned on a new transmitter in a tower to
near his place. After verifying the cause by having a Verizon tech come
out and temporarily shut off the transmitter, he managed to get them to
leave it off. You might not be that lucky.

I actually mentioned to the other guy that I thought there might be a
cell or microwave tower nearby causing the problem. I'm going to take a
few mics over there and do some experimenting. It has me ****ed off at
the moment.

Thankfully this session was not critical or time sensitive. With all of
the RF pollution going on in the country now, it's not a bad idea to
have a couple of mics in the kit that don't exhibit the problem. (one of
the mics was an SM58.)

[PStamler]

It sound like your problem is not RFI (Radio Frequency Interference) but EMI (Electro-Magnetic Interference) Another mic with a hum-bucking coil is the Electro-Voice RE15/RE16 (same basic capsule, but the 16 has a pop filter and a slightly brighter sound). But small transformerless condensers (like Oktava MK012s) will ignore the noise too -- why exactly do you prefer to use dynamics in this situation?

Peace,
Paul Stamler

[Bill[_20_]]

In message , mcp6453
writes
After 55 years in the audio business, I have encountered a strange
problem for the very first time. I set up a small mixer and two dynamic
mics for remote recording. Everything tested perfectly at home. When I
moved the setup to the remote location (an office building), there was
hum and buzz in both mics. Isolation the mics from all wall warts and
power supplies did not have an effect on the noise.

Some years ago, I was asked to build a small broadcast studio for a new
religious conference centre. The room they had selected looked ideal,
but during the first recce, I walked round the outside of the building
and saw that the power distribution for the whole site had its building
backing on to one wall. A subsequent test with a dynamic mic into a Uher
(remember them?) showed that hum was a real problem.

We chose a room on the other side of the site. The promotions lady was
not happy to be turned out of her nice office.
--
Bill

[mcp6453[_2_]]

On 8/29/2018 2:30 PM, PStamler wrote:
It sound like your problem is not RFI (Radio Frequency Interference) but EMI (Electro-Magnetic Interference) Another mic with a hum-bucking coil is the Electro-Voice RE15/RE16 (same basic capsule, but the 16 has a pop filter and a slightly brighter sound). But small transformerless condensers (like Oktava MK012s) will ignore the noise too -- why exactly do you prefer to use dynamics in this situation?

Peace,
Paul Stamler

I'll take the RE15 and RE18 to test. I don't have an RE16.

The recording is for spoken voice in a room with terrible acoustics.
Dynamic mics are more forgiving, in my experience. Having said that, I'm
going to try to Beta 87As just for fun.

[mcp6453[_2_]]

On 8/29/2018 2:30 PM, PStamler wrote:
It sound like your problem is not RFI (Radio Frequency Interference) but EMI (Electro-Magnetic Interference) Another mic with a hum-bucking coil is the Electro-Voice RE15/RE16 (same basic capsule, but the 16 has a pop filter and a slightly brighter sound). But small transformerless condensers (like Oktava MK012s) will ignore the noise too -- why exactly do you prefer to use dynamics in this situation?

Peace,
Paul Stamler


By the way, I agree that it's probably EMI instead of RFI. Now if I can
just find my roll of mu-metal tape, I'll wrap the bodies of the mics.
Or, maybe I can turn the room into a Faraday cage.

[geoff]

On 30/08/2018 12:45 AM, mcp6453 wrote:
On 8/29/2018 8:21 AM, Scott Dorsey wrote:
mcp6453Â* wrote:
After 55 years in the audio business, I have encountered a strange
problem for the very first time. I set up a small mixer and two dynamic
mics for remote recording. Everything tested perfectly at home. When I
moved the setup to the remote location (an office building), there was
hum and buzz in both mics. Isolation the mics from all wall warts and
power supplies did not have an effect on the noise.

New mic cables. No change.
Different (dynamic) mics. No change.
Added dbx286s for each mic. No change.
Disconnected all external equipment from the mixer. No change.
Physically rotating the mics on the desk. Change.

You have a magnetic field somewhere, maybe from a large transformer
nearby,
and the microphones are picking up magnetic field leakage.Â* Moving the
location to the other side of the room might fix everything.Â* Then
again it
might not.Â* You might also try an original Sennheiser MD421, which has a
bucking coil to reduce magnetic pickup.
--scott

Thanks, Scott. I only have one original MD421. Can you think of another
mic that would be useful to try along with the 421?

Just the one would indicate if a local strong hum field was the problem,
or not .

geoff

[PStamler]

On Wednesday, August 29, 2018 at 7:02:13 AM

An electric guitar with a single-coil pickup makes a great probe for electromagnetic hum.

And dynamic mics are no more immune to acoustically bad rooms than condenser mics.

Peace,
Paul

[geoff]

On 30/08/2018 4:31 PM, PStamler wrote:
On Wednesday, August 29, 2018 at 7:02:13 AM

An electric guitar with a single-coil pickup makes a great probe for electromagnetic hum.

And dynamic mics are no more immune to acoustically bad rooms than condenser mics.

Peace,
Paul



I guess a condenser mic may be more sensitive and pick up more of the
low-level rubbish from the room that a dynamic may miss ...

geoff

[Adrian Tuddenham[_2_]]

mcp6453 wrote:

On 8/29/2018 2:30 PM, PStamler wrote:
It sound like your problem is not RFI (Radio Frequency Interference) but
EMI (Electro-Magnetic Interference) Another mic with a hum-bucking coil
is the Electro-Voice RE15/RE16 (same basic capsule, but the 16 has a pop
filter and a slightly brighter sound). But small transformerless
condensers (like Oktava MK012s) will ignore the noise too -- why exactly
do you prefer to use dynamics in this situation?

Peace,
Paul Stamler


By the way, I agree that it's probably EMI instead of RFI. Now if I can
just find my roll of mu-metal tape, I'll wrap the bodies of the mics.
Or, maybe I can turn the room into a Faraday cage.

Use the mic as a sensor and track down the source.


--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk

[John Williamson]

On 30/08/2018 09:21, geoff wrote:

I guess a condenser mic may be more sensitive and pick up more of the
low-level rubbish from the room that a dynamic may miss ...

Not so much if it's hum originating from the magnetic field a
transformer or lighting choke gives out, unless it uses a transformer in
the circuit somewhere.

Condenser mics tend to be more sensitive to things like cellphones or
two way radios, which are not a steady hum as described. They may, if
it's really close, pick up the discharge in a fluorescent tube.


--
Tciao for Now!

John.

[geoff]

On 30/08/2018 10:57 PM, John Williamson wrote:
On 30/08/2018 09:21, geoff wrote:

I guess a condenser mic may be more sensitive and pick up more of the
low-level rubbish from the room that a dynamic may miss ...

Not so much if it's hum originating from the magnetic field a
transformer or lighting choke gives out, unless it uses a transformer in
the circuit somewhere.

Condenser mics tend to be more sensitive to things like cellphones or
two way radios, which are not a steady hum as described. They may, if
it's really close, pick up the discharge in a fluorescent tube.




Yeah, but was referring to the apparent preference for using dynamics in
the first place in that nasty room environment, apart from the hum thing.

geoff

[mcp6453[_2_]]

On 8/29/2018 2:30 PM, PStamler wrote:
It sound like your problem is not RFI (Radio Frequency Interference) but EMI (Electro-Magnetic Interference) Another mic with a hum-bucking coil is the Electro-Voice RE15/RE16 (same basic capsule, but the 16 has a pop filter and a slightly brighter sound). But small transformerless condensers (like Oktava MK012s) will ignore the noise too -- why exactly do you prefer to use dynamics in this situation?

Here's what I've found. The problem is definitely EMI. There's a cell
phone tower less than a block away. Moving the mic in the room can
exacerbate or eliminate the noise. Unfortunately there is not a
practical position that will eliminate it. So, I took an RE15, RE18,
MD421U, and Beta 87A. All of the mics eliminated the noise although
there was still a little with the 421. Since the 87As were the only ones
I had two of, I used those. They didn't sound so good for this
application and need to be replaced.

Upon further research, I discovered that the PR40 (my favorite
spoken-word mic) and the RE20/27 have humbucking coils. With God as my
witness (ala WKRP), after all this time, I never knew about the coils.
How I overlooked it escapes me. What this experience has taught me is
that it is a REALLY good idea to use mics with humbucking coils whenever
possible - particularly in unfamiliar territory. Since I almost always
use a PR40, I've avoided the problem in most cases. However, the PR40 is
very large for on-camera use, so I'm thinking about a couple of RE16s,
unless someone can suggest less expensive alternatives that also include
effective humbucking coils.

[John Williamson]

On 06/09/2018 17:36, mcp6453 wrote:
Here's what I've found. The problem is definitely EMI. There's a cell
phone tower less than a block away. Moving the mic in the room can
exacerbate or eliminate the noise. Unfortunately there is not a
practical position that will eliminate it. So, I took an RE15, RE18,
MD421U, and Beta 87A. All of the mics eliminated the noise although
there was still a little with the 421. Since the 87As were the only ones
I had two of, I used those. They didn't sound so good for this
application and need to be replaced.

If the interference is from a cell tower a block away, then it is RFI,
and can probably be stopped dead by putting ferrite beads on the mic
cables near the mic and mixer (If used). Cell interference has a
characteristic sound, and is not a hum.

EMI is much shorter range, will be a constant or intermittent hum or
buzz, and will likely be from a transformer or light fitting choke
you've not found yet. Moving the mic will show where the field is
strongest, and lead you to what needs to be turned off. Changing the
angle of the mic may help with this, as the sensitivity depends on the
relative angles of the mic and the field, though changing the mic angle
will also foul up the recording...


--
Tciao for Now!

John.

[Mike Rivers[_2_]]

On 9/6/2018 1:02 PM, John Williamson wrote:
If the interference is from a cell tower a block away, then it is RF

RFI is a special case of EMI. They're both electromagnetic radiation.
What you get from a power line or a wall wart is interference from
electromagnetic induction.

Picky, picky.

A friend of mine with this problem actually got Verizon to turn off the
transmitter on the tower that was causing the interference with his
mics, but it took a lot of complaining. Something that might help (he
got the transmitter turned off before he placed the order) is to change
out the connectors on a few mic cables with the Neutric EMI-filtered ones.

http://www.neutrik.com/en/xlr/emc-series/nc3mxx-emc



--

For a good time, call http://mikeriversaudio.wordpress.com

[mcp6453[_2_]]

On 9/6/2018 2:23 PM, Mike Rivers wrote:
On 9/6/2018 1:02 PM, John Williamson wrote:
If the interference is from a cell tower a block away, then it is RF

RFI is a special case of EMI. They're both electromagnetic radiation.
What you get from a power line or a wall wart is interference from
electromagnetic induction.

Picky, picky.

A friend of mine with this problem actually got Verizon to turn off the
transmitter on the tower that was causing the interference with his
mics, but it took a lot of complaining. Something that might help (he
got the transmitter turned off before he placed the order) is to change
out the connectors on a few mic cables with the Neutric EMI-filtered ones.

http://www.neutrik.com/en/xlr/emc-series/nc3mxx-emc

These connectors appear to be a good idea for high-frequency
interference. It would be interesting to try them. If I were on the road
a lot, I'd probably use cables with them all the time.

[[email protected]]

On Thursday, September 6, 2018 at 2:58:07 PM UTC-4, mcp6453 wrote:
On 9/6/2018 2:23 PM, Mike Rivers wrote:
On 9/6/2018 1:02 PM, John Williamson wrote:
If the interference is from a cell tower a block away, then it is RF

RFI is a special case of EMI. They're both electromagnetic radiation.
What you get from a power line or a wall wart is interference from
electromagnetic induction.

Picky, picky.

A friend of mine with this problem actually got Verizon to turn off the
transmitter on the tower that was causing the interference with his
mics, but it took a lot of complaining. Something that might help (he
got the transmitter turned off before he placed the order) is to change
out the connectors on a few mic cables with the Neutric EMI-filtered ones.

http://www.neutrik.com/en/xlr/emc-series/nc3mxx-emc

These connectors appear to be a good idea for high-frequency
interference. It would be interesting to try them. If I were on the road
a lot, I'd probably use cables with them all the time.

If we are talking about dynamic mics that have no active electronics in them, then I would doubt that the mics themselves are susceptible to the RF. A hum bucking coil should not make any difference to RF susceptibility.

However, the mics and the cable can pick up RF and feed it to the preamp which of course can be susceptible to RF.

Have you tried another preamp?

Mark

of course can p

[Ty Ford[_2_]]

On Thursday, September 6, 2018 at 1:02:58 PM UTC-4, John Williamson wrote:
On 06/09/2018 17:36, mcp6453 wrote:
Here's what I've found. The problem is definitely EMI. There's a cell
phone tower less than a block away. Moving the mic in the room can
exacerbate or eliminate the noise. Unfortunately there is not a
practical position that will eliminate it. So, I took an RE15, RE18,
MD421U, and Beta 87A. All of the mics eliminated the noise although
there was still a little with the 421. Since the 87As were the only ones
I had two of, I used those. They didn't sound so good for this
application and need to be replaced.

If the interference is from a cell tower a block away, then it is RFI,
and can probably be stopped dead by putting ferrite beads on the mic
cables near the mic and mixer (If used). Cell interference has a
characteristic sound, and is not a hum.

EMI is much shorter range, will be a constant or intermittent hum or
buzz, and will likely be from a transformer or light fitting choke
you've not found yet. Moving the mic will show where the field is
strongest, and lead you to what needs to be turned off. Changing the
angle of the mic may help with this, as the sensitivity depends on the
relative angles of the mic and the field, though changing the mic angle
will also foul up the recording...


--
Tciao for Now!

John.

I'm with John on this one. 3 million years ago when I got my first DAW (AKG DSE7000) I set it up only to find that the CRT was blowing a ring of noise right at my 421. I moved on to a Gefell M71.

Wow looks like a newsgroup post from what 20 years ago?

Regards,

Ty Ford

[John Williamson]

On 06/09/2018 19:23, Mike Rivers wrote:
On 9/6/2018 1:02 PM, John Williamson wrote:
If the interference is from a cell tower a block away, then it is RF

RFI is a special case of EMI. They're both electromagnetic radiation.
What you get from a power line or a wall wart is interference from
electromagnetic induction.

Picky, picky.

Not really. What I call EMI is usually low frequency, directly induced
in the coils, while RFI is a modulated higher frequency, which normally
only affects circuits with a semiconductor or other rectifying component
in them, such as a preamp.

I find it a useful distinction to draw, as the cures are different.

The OP describes a hum or a buzz, rather than the typical "chirping"
sound of a cellphone being picked up, so I was guessing at LF, possibly
from a choke, fluorescent light or (Unlikely) a SMPS near the
microphone, which doesn't have a humbucking coil. It's hard to get
interference from cellphone transmissions, even from base stations,
more than a few feet from the microphone due to the low power and
inverse square law of propagation, though an experienced movie sound guy
can often tell what make of cellphone is about to ring on set.....


--
Tciao for Now!

John.

[Mike Rivers[_2_]]

On 9/7/2018 2:30 PM, John Williamson wrote:
The OP describes a hum or a buzz, rather than the typical "chirping"
sound of a cellphone being picked up, so I was guessing at LF, possibly
from a choke, fluorescent light or (Unlikely) a SMPS near the
microphone, which doesn't have a humbucking coil. It's hard to get
interference from cellphone transmissions, even from base stations, more
than a few feet from the microphone due to the low power and inverse
square law of propagation, though an experienced movie sound guy can
often tell what make of cellphone is about to ring on set.....

Some people describe any noise that isn't hiss as "hum" or "buzz." My
friend with the noise from the cell tower sent me a recording and I'd
describe it as "hash." It was absolutely confirmed to be coming from the
cell transmitter because when a Verizon tech climbed the pole and turned
it off, the noise stopped, and resumed when he turned it on.

I have a recording of "mic near a ringing (with the ringer turned off,
of course) cell phone" noise that I used in a talk I've given, "Hums,
Buzzes, and Things That Go Bump In The Night." That's what you get when
there's a speaker at a podium who thinks he turned his phone off before
getting up to talk.

With today's cell phones, there's no such thing as "off" until you take
the battery out - and I don't think there's a new one available today
that has a removable battery. I've tried unsuccessfully to find one,
figuring that the phone will last longer than the battery, but then
realized that applications get updated for the latest version of the
operating system, and the phone makers rarely offer more than one OS
update, if that.


--

For a good time, call http://mikeriversaudio.wordpress.com

[geoff]

On 8/09/2018 6:30 AM, John Williamson wrote:
On 06/09/2018 19:23, Mike Rivers wrote:
On 9/6/2018 1:02 PM, John Williamson wrote:
If the interference is from a cell tower a block away, then it is RF

RFI is a special case of EMI. They're both electromagnetic radiation.
What you get from a power line or a wall wart is interference from
electromagnetic induction.

Picky, picky.

Not really. What I call EMI is usually low frequency, directly induced
in the coils, while RFI is a modulated higher frequency, which normally
only affects circuits with a semiconductor or other rectifying component
in them, such as a preamp.

I find it a useful distinction to draw, as the cures are different.

The OP describes a hum or a buzz, rather than the typical "chirping"
sound of a cellphone being picked up, so I was guessing at LF, possibly
from a choke, fluorescent light or (Unlikely) a SMPS near the
microphone, which doesn't have a humbucking coil. It's hard to get
interference from cellphone transmissions, even from base stations, more
than a few feet from the microphone due to the low power and inverse
square law of propagation, though an experienced movie sound guy can
often tell what make of cellphone is about to ring on set.....



Could be from a laptop SMPS , especially if the noise problem is that it
is showing on a recording (rather than live). If on a recording only,
try the laptop on battery-only, to confirm.

geoff

[geoff]

On 8/09/2018 7:07 AM, Mike Rivers wrote:
On 9/7/2018 2:30 PM, John Williamson wrote:
The OP describes a hum or a buzz, rather than the typical "chirping"
sound of a cellphone being picked up, so I was guessing at LF,
possibly from a choke, fluorescent light or (Unlikely) a SMPS near the
microphone, which doesn't have a humbucking coil. It's hard to get
interference from cellphone transmissions, even from base stations,
more than a few feet from the microphone due to the low power and
inverse square law of propagation, though an experienced movie sound
guy can often tell what make of cellphone is about to ring on set.....

Some people describe any noise that isn't hiss as "hum" or "buzz." My
friend with the noise from the cell tower sent me a recording and I'd
describe it as "hash." It was absolutely confirmed to be coming from the
cell transmitter because when a Verizon tech climbed the pole and turned
it off, the noise stopped, and resumed when he turned it on.

I have a recording of "mic near a ringing (with the ringer turned off,
of course) cell phone" noise that I used in a talk I've given, "Hums,
Buzzes, and Things That Go Bump In The Night." That's what you get when
there's a speaker at a podium who thinks he turned his phone off before
getting up to talk.

With today's cell phones, there's no such thing as "off" until you take
the battery out - and I don't think there's a new one available today
that has a removable battery. I've tried unsuccessfully to find one,
figuring that the phone will last longer than the battery, but then
realized that applications get updated for the latest version of the
operating system, and the phone makers rarely offer more than one OS
update, if that.




Even if not fully 'off' I think on most you can kill the wi-fi,
bluetooth, and mobile service though. Airplane Mode should do that.


geoff

[Trevor]

On 8/09/2018 5:07 AM, Mike Rivers wrote:
With today's cell phones, there's no such thing as "off" until you take
the battery out - and I don't think there's a new one available today
that has a removable battery.

Thankfully mine is a couple of years old and still has a removable
battery. Not that I really need to remove it, but so much cheaper to
replace it. Dumped in order to make the phones a few mm slimmer of
course. :-(


I've tried unsuccessfully to find one,
figuring that the phone will last longer than the battery, but then
realized that applications get updated for the latest version of the
operating system, and the phone makers rarely offer more than one OS
update, if that.

But the phone keeps on working until they turn off the towers for the
system it uses like they have here with 2G. 3G next to go. And old apps
like your browser generally keep on working, or when companies like
Google break them, there are often alternatives that still work fine.
However the inability to simply update a smartphone like you can a
computer is certainly one of the reasons I'd never pay $1k for one like
many do every year or two. But some people love the built in
obsolescence, gives them a reason to keep buying the "latest and
greatest". Losing them or breaking them often occurs first though.

[Mike Rivers[_2_]]

On 9/7/2018 10:16 PM, Trevor wrote:
But the phone keeps on working until they turn off the towers for the
system it uses like they have here with 2G. 3G next to go. And old apps
like your browser generally keep on working, or when companies like
Google break them, there are often alternatives that still work fine.

I practically never use my phone as a phone, but I use it as a platform
to run a lot of applications. The ones that don't need Internet access
continue to work, but the ones like travel apps like airlines and hotels
are always updating their hosts, and the old apps won't work with the
new hosts. A couple of rounds of app upgrades will run on the old OS,
but then they'll come up with one that requires a newer OS, and, at
least in the Android world where my phone lives, the manufacturers do
the OS updates - until they decide it's time for you to buy a new phone,
and then they no longer send you an OS update. It's not like Windows
where it doesn't matter if you have a Dell or an HP or a custom job with
a Gigabyte motherboard. You can continue to upgrade the OS from
Microsoft until your hardware will no longer support it - and then you
can sometimes upgrade the hardware, though a new Intel CPU and a few
more gigabytes of memory costs about as much as a new smart phone.

However the inability to simply update a smartphone like you can a
computer is certainly one of the reasons I'd never pay $1k for one like
many do every year or two.

Me, neither. That's why I buy $100-$150 Androids. If I have to buy a new
one every couple of years to continue to use it like I've been using it,
it's not that expensive, though it does take a fair amount of time and
trouble to housebreak a new phone. There are always apps on my phone
that Google doesn't know about, so they won't automatically install with
the latest versions when I register the new phone.

But some people love the built in
obsolescence, gives them a reason to keep buying the "latest and
greatest". Losing them or breaking them often occurs first though.

Oh, yeah, to both. My present phone is a warranty replacement for one
that they no longer had any stock of, so they sent me the next newest
model which I don't like as much as the one it replaced. Then, a couple
of months ago, it fell out of my pocket and landed on a corner, so I've
joined the Order of the Cracked Screen, and I'm shopping for a new phone
now. They keep getting worse as far as features I don't like.



--

For a good time, call http://mikeriversaudio.wordpress.com

[Phil Allison[_4_]]

mcp6453 wrote:


Here's what I've found. The problem is definitely EMI. There's a cell
phone tower less than a block away.


** Well out of range then.


Moving the mic in the room can
exacerbate or eliminate the noise. Unfortunately there is not a
practical position that will eliminate it.


** So it's not the cell tower.


So, I took an RE15, RE18,
MD421U, and Beta 87A. All of the mics eliminated the noise although
there was still a little with the 421.


** The RE15, RE18 and MD421 all have hum bucking coils, while the 87a is a condenser mic.



Upon further research, I discovered that the PR40 (my favorite
spoken-word mic) and the RE20/27 have humbucking coils. With God as my
witness (ala WKRP), after all this time, I never knew about the coils.
How I overlooked it escapes me.


** The others escaped you too.


What this experience has taught me is
that it is a REALLY good idea to use mics with humbucking coils whenever
possible - particularly in unfamiliar territory. Since I almost always
use a PR40, I've avoided the problem in most cases. However, the PR40 is
very large for on-camera use, so I'm thinking about a couple of RE16s,
unless someone can suggest less expensive alternatives that also include
effective humbucking coils.


** Condenser mics do not need such coils.

There is a big hum field in or near that office room you have yet to uncover.



..... Phil

[Scott Dorsey]

Ty Ford wrote:
I'm with John on this one. 3 million years ago when I got my first DAW (AKG DSE7000) I set it up only to find that the CRT was blowing a ring of noise right at my 421. I moved on to a Gefell M71.

This also is direct magnetic interference. CRTs are awful for this... big
coils operating at 30 Hz and 17 KHz, spewing magnetic fields all over the
place. They couple into microphones.

And, as noted, the 421 is specifically designed to deal with magnetic fields
using a bucking coil, so if the 421 is picking it up, you've got a big one!

The good thing about direct magnetic interference is that, as Mike noticed,
it's directional. Turn the microphone until it's parallel to the field and
the noise goes away. Secondly, as you should notice if you have ever played
with permanent magnets on the fridge, the field drops off very quickly with
distance.

I am thinking the cell tower is a red herring and that what you've got here
is a magnetic field.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Scott Dorsey]

John Williamson wrote:
Not really. What I call EMI is usually low frequency, directly induced
in the coils, while RFI is a modulated higher frequency, which normally
only affects circuits with a semiconductor or other rectifying component
in them, such as a preamp.

EMI is everything under the sun. E-field coupling, B-field coupling,
RF coupling. Anything that isn't directly acoustic is EMI.

RFI is RF coupling, one specific kind of EMI.

I find it a useful distinction to draw, as the cures are different.

The OP describes a hum or a buzz, rather than the typical "chirping"
sound of a cellphone being picked up, so I was guessing at LF, possibly
from a choke, fluorescent light or (Unlikely) a SMPS near the
microphone, which doesn't have a humbucking coil. It's hard to get
interference from cellphone transmissions, even from base stations,
more than a few feet from the microphone due to the low power and
inverse square law of propagation, though an experienced movie sound guy
can often tell what make of cellphone is about to ring on set.....

What he describes is consistent with magnetic pickup. Which is one very
specific case of EMI... but EMI is really a catch-all term.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Trevor]

On 8/09/2018 12:34 PM, Mike Rivers wrote:
On 9/7/2018 10:16 PM, Trevor wrote:
But the phone keeps on working until they turn off the towers for the
system it uses like they have here with 2G. 3G next to go. And old
apps like your browser generally keep on working, or when companies
like Google break them, there are often alternatives that still work
fine.

I practically never use my phone as a phone, but I use it as a platform
to run a lot of applications. The ones that don't need Internet access
continue to work, but the ones like travel apps like airlines and hotels
are always updating their hosts, and the old apps won't work with the
new hosts.


Since I never use those apps because of their desire to take control of
your data in most cases. it doesn't bother me. I just use a browser like
Opera. Anything serious is done on my computer or laptop anyway. Apart
from calls and SMS, the main phone data use for me is usually weather
reports and email. :-)


A couple of rounds of app upgrades will run on the old OS,
but then they'll come up with one that requires a newer OS, and, at
least in the Android world where my phone lives, the manufacturers do
the OS updates - until they decide it's time for you to buy a new phone,
and then they no longer send you an OS update.

Right. Far more incentive for them NOT to upgrade old phones
unfortunately. What I'd love to see is open Linux OS for mobile phones.
After all Android is partly based on it anyway.


It's not like Windows
where it doesn't matter if you have a Dell or an HP or a custom job with
a Gigabyte motherboard. You can continue to upgrade the OS from
Microsoft until your hardware will no longer support it - and then you
can sometimes upgrade the hardware, though a new Intel CPU and a few
more gigabytes of memory costs about as much as a new smart phone.

Certainly NOT the latest top line Apple or Samsung that many people
"must" have though.



However the inability to simply update a smartphone like you can a
computer is certainly one of the reasons I'd never pay $1k for one
like many do every year or two.

Me, neither. That's why I buy $100-$150 Androids. If I have to buy a new
one every couple of years to continue to use it like I've been using it,
it's not that expensive, though it does take a fair amount of time and
trouble to housebreak a new phone. There are always apps on my phone
that Google doesn't know about, so they won't automatically install with
the latest versions when I register the new phone.

But some people love the built in obsolescence, gives them a reason to
keep buying the "latest and greatest". Losing them or breaking them
often occurs first though.

Oh, yeah, to both. My present phone is a warranty replacement for one
that they no longer had any stock of, so they sent me the next newest
model which I don't like as much as the one it replaced. Then, a couple
of months ago, it fell out of my pocket and landed on a corner, so I've
joined the Order of the Cracked Screen, and I'm shopping for a new phone
now. They keep getting worse as far as features I don't like.

That is often the unfortunate part of buying cheaper models. Not that
the expensive ones are much better though. :-(

[Ty Ford[_2_]]

A number of years ago, I had a room added to the house. The long and short of it was that I had to have a house power upgrade. To do it they ran a 220 cable down the fascia of the roof, into the car port and down the car port wall to the basement.

Some time later I was in the dining room with a dynamic mic, mixer and cans. I was about 16 inches from the wall when I got this big AC hum. It took a few minutes, but I figured out it was the field around the AC service cable pushing into my dining room.

In retrospect, I'm glad I didn't run it through the ceiling of my studio. Single pickup guitars have made me aware that I have enough stray AC fields down there.

Regards,

Ty Ford

[geoff]

On 10/09/2018 12:11 AM, Scott Dorsey wrote:
John Williamson wrote:
Not really. What I call EMI is usually low frequency, directly induced
in the coils, while RFI is a modulated higher frequency, which normally
only affects circuits with a semiconductor or other rectifying component
in them, such as a preamp.

EMI is everything under the sun. E-field coupling, B-field coupling,
RF coupling. Anything that isn't directly acoustic is EMI.

RFI is RF coupling, one specific kind of EMI.

I find it a useful distinction to draw, as the cures are different.

The OP describes a hum or a buzz, rather than the typical "chirping"
sound of a cellphone being picked up, so I was guessing at LF, possibly
from a choke, fluorescent light or (Unlikely) a SMPS near the
microphone, which doesn't have a humbucking coil. It's hard to get
interference from cellphone transmissions, even from base stations,
more than a few feet from the microphone due to the low power and
inverse square law of propagation, though an experienced movie sound guy
can often tell what make of cellphone is about to ring on set.....

What he describes is consistent with magnetic pickup. Which is one very
specific case of EMI... but EMI is really a catch-all term.
--scott


And there was me thinking that EMI was at one point the fourth largest
recording industry corporation, and owner of Parlophone ! That's the hum
I heard ...

geoff

[Scott Dorsey]

geoff wrote:

And there was me thinking that EMI was at one point the fourth largest
recording industry corporation, and owner of Parlophone ! That's the hum
I heard ...

Indeed, and RFI was once Radio France International, which resulted in a
number of jokes over the years.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Phil Allison[_4_]]

mcp6453 wrote:




I'm trying to think what I might have that's transformerless. My TLM67
doesn't have a transformer, but I only have one. (We need two matching
mics for video aesthetics.) What about the Beta 87A?



** Condenser mics normally use Mu-Metal shielded transformers OR are transformerless. In both cases nearby magnetic hum fields have little or no effect.

Dynamic mics pick up nearby hum fields via their **voice coils** - examples like the SM57 & SM58 have an unshielded transformer buried in the handle as well that also picks up induced hum.

Few mics have hum bucking coils fitted, suggesting that most users regard it as a non problem and simply move the mic away from the hum source.


..... Phil


so without a hum bucking coil to defeat the effect are all excellent hum det

[mcp6453[_2_]]

On 9/7/2018 8:47 PM, geoff wrote:

Could be from a laptop SMPS , especially if the noise problem is that it
is showing on a recording (rather than live). If on a recording only,
try the laptop on battery-only, to confirm.

I'm still not clear on the source of the noise. However, it's safe to
say that the noise is electromagnetic. I found a couple of like-new EV
N/D 767a mics at my local Guitar Center for $69 each, so I bought them.
They have humbucking coils in them and are totally quiet. Their sound
was also quite decent. They'll do until the broadcaster can spring for a
couple of Heil PR40s.

[Phil Allison[_4_]]

mcp6453 wrote:



I'm still not clear on the source of the noise. However, it's safe to
say that the noise is electromagnetic. I found a couple of like-new EV
N/D 767a mics at my local Guitar Center for $69 each, so I bought them.
They have humbucking coils in them and are totally quiet.


** The correlation between having a humbucking coil fitted and being noise free in the office room appears 100%.

The odds are high that an adjoining room or one above or below is used for AC power distribution, is fitted with high current cabling and a switchboard.

Wherever Active and Neutral conductors travel separated rather than running in close parallel, the external magnetic field generated is much greater than usual - easily enough to cause the hum interference you have described.



..... Phil

[Scott Dorsey]

mcp6453 wrote:

I'm still not clear on the source of the noise. However, it's safe to
say that the noise is electromagnetic. I found a couple of like-new EV
N/D 767a mics at my local Guitar Center for $69 each, so I bought them.
They have humbucking coils in them and are totally quiet. Their sound
was also quite decent. They'll do until the broadcaster can spring for a
couple of Heil PR40s.

No, it's magnetic, not electromagnetic. There's no e-field involved, and
consequently you can use the microphone itself as a sensor to hunt down the
source of the problem.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."