line noise / interference from power lines etc?

[[email protected]]

I'm trying to record cassettes and LPs to my PC and am experiencing
line noise, possibly from some other device in the house. I have not
determined the source of this noise, but it occurs at random times
during the day, and causes clicks and pops that ruin any recordings. I
have tried moving the computer & audio equipment from the basemeent to
different rooms in the house and still am hearing noise.

The equipment being used is

* System: Pentium 4 PC running Windows XP Pro
* Software: Sound Forge
* Audio Interface: Tascam US-428
* Cassette deck
* Turntable (with preamp)

I have used most of this equipment for a long time and not had
problems with noise like this in other houses/apartments, and I've
only noticed noise like this in this house in the past couple of
months (then again I haven't tried transferring LPs or cassettes in
this house, however I have recorded guitar/drums/etc here for a couple
of years and not experienced this kind of noise).

A recording of the noise and images of the waveforms can be heard &
seen here:
http://www.geocities.com/usenet_daughter/line_noise.htm

Can someone tell what device in the house might be causing this (the
house has all the normal amenities - lights, A/C, W/D, etc.) or how to
filter this noise out of the signal loop before it reaches the
recordings?

Much appreciated!

 

[Richard Crowley]

I'm trying to record cassettes and LPs to my PC and am experiencing
line noise, possibly from some other device in the house. I have not
determined the source of this noise, but it occurs at random times
during the day, and causes clicks and pops that ruin any recordings. I
have tried moving the computer & audio equipment from the basemeent to
different rooms in the house and still am hearing noise.

The equipment being used is

* System: Pentium 4 PC running Windows XP Pro
* Software: Sound Forge
* Audio Interface: Tascam US-428
* Cassette deck
* Turntable (with preamp)

I have used most of this equipment for a long time and not had
problems with noise like this in other houses/apartments, and I've
only noticed noise like this in this house in the past couple of
months (then again I haven't tried transferring LPs or cassettes in
this house, however I have recorded guitar/drums/etc here for a couple
of years and not experienced this kind of noise).

A recording of the noise and images of the waveforms can be heard &
seen here:
http://www.geocities.com/usenet_daughter/line_noise.htm

Can someone tell what device in the house might be causing this (the
house has all the normal amenities - lights, A/C, W/D, etc.) or how to
filter this noise out of the signal loop before it reaches the
recordings?

Much appreciated!

The time scale of your images is so long that the interference only
appears to be 1-pixel-wide blips on the timeline. Analysis of the
waveform would require significant zooming in on an individual
spike.

OTOH, at first glance, they look something like the interference
we see from GSM cell-phones. It typically sounds something
like: brrrrrup--brrrrrup--brrrrrrup. It is particularly noxious in
wireless microphone systems, but I've seen it get into other
low-level audio circuits (such as from a phono cartridge, etc.).

There has been much discussion of GSM and other cell
phone interference over on the film sound newsgroup:

Note also: http://en.wikipedia.org/wiki/Gsm
"It is a common occurence for a nearby GSM handset to induce a "dit, dit
di-dit, dit di-dit, dit di-dit" output on PA's, wireless microphones, home
stereo systems, televisions, computers, and personal music devices. When
these audio devices are in the near field of the GSM handset, the radio
signal is strong enough that the solid state amplifiers in the audio chain
function act as a detector. The clicking noise itself represents the power
bursts that carry the TDMA signal. These signals have been known to
interfere with other electronic devices, such as car stereos and portable
audio players."

 

[Benj]

Can someone tell what device in the house might be causing this (the
house has all the normal amenities - lights, A/C, W/D, etc.) or how to
filter this noise out of the signal loop before it reaches the
recordings?

Much appreciated!

No we can't tell you what in the house is causing this. It might not
even be in the house. I had severe noise and crap on my house power
that seemed to be welding machines somewhere in the neighborhood. Even
though I went out trying to track the noise with a radio I never found
the source. In your own house you can start shutting down circuits
and suspected sources and observe it the noise leaves.

Usually the pole transformer tends to block heavy noise from the rest
of the neighborhood, (but not always!). So the way you filter out
line noise is to install a power line noise filter! (duh!) However
note that many things sold as "line filters" and surge suppressors are
really non-linear devices soldered across the line to clip spikes.
They are not very effective though can off a bit of improvement.
You'll need a "REAL" line filter with Ls and Cs to get rid of the
noise. You can buy these units. Note however, that the noise MIGHT
not be getting into your recorder up the power line!!! If the noise
is on your house wiring, the noise might be TRANSMITTED through the
air from the wires in the walls to your gear! In that case a power
line filter won't help. Look into resonate transformer voltage
regulators as they will also act as great filters. Best would be to
borrow one and try it before laying out the (big) bread.

Benj

 

[Michael Black]

([email protected]) writes:

Come on, bozo, you're as bad as the troll "radium".

Why in the world did this have to be cross-posted to
rec.audio.pro
rec.music.makers
comp.sys.ibm.pc.soundcard.tech
sci.electronics.basics
sci.physics.electromag

Figure out your ability, and post there. Or figure out the
most appropriate newsgroup, and post there.
Don't use carpetbomber to "increase" the chance that you'll
get an answer you like.

I've yet to see a post of yours that isn't massively cross-posted,
to highly disparate newsgroups.

Michael

 

[Dave]

you missed a couple possible noise sources associated with the computer...
does it have bluetooth? wifi? wireless internet card?? or did you lay
your cell phone near the equipment?? sure sounds like some kind of digital
communications stuff, though it could still be some kind of line noise. i
have also heard crosstalk within a pc from wired mice that kind of sounded
like that, you can usually tell these since the noise changes as you move
the mouse.

to get rid of it, assuming it is rf and not an internal noise, add a
ups/line filter. change all audio cables to shielded types. Make sure all
equipment is powered from the same ups/filter. keep all cords short.
disconnect speakers if you have separate wired in ones while you do the
dubbing since their cables are generally long and can pick up noise. try
unplugging or turning off breakers to other stuff in the house and see if
the noise goes away. try unplugging other stuff on the computer and see if
it goes away, even the monitor.

 

[[email protected]]

The time scale of your images is so long that the interference only
appears to be 1-pixel-wide blips on the timeline. Analysis of the
waveform would require significant zooming in on an individual
spike.

OTOH, at first glance, they look something like the interference
we see from GSM cell-phones. It typically sounds something
like: brrrrrup--brrrrrup--brrrrrrup. It is particularly noxious in
wireless microphone systems, but I've seen it get into other
low-level audio circuits (such as from a phono cartridge, etc.).

There has been much discussion of GSM and other cell
phone interference over on the film sound newsgroup:

Note also:http://en.wikipedia.org/wiki/Gsm
"It is a common occurence for a nearby GSM handset to induce a "dit, dit
di-dit, dit di-dit, dit di-dit" output on PA's, wireless microphones, home
stereo systems, televisions, computers, and personal music devices. When
these audio devices are in the near field of the GSM handset, the radio
signal is strong enough that the solid state amplifiers in the audio chain
function act as a detector. The clicking noise itself represents the power
bursts that carry the TDMA signal. These signals have been known to
interfere with other electronic devices, such as car stereos and portable
audio players."- Hide quoted text -

- Show quoted text -

So *that's* where that "dit di-dit" sound comes from! Thanks! I
thought my wife's JVC car stereo had a hardware defect. When playing
CDs (not the radio, even), we'd get that every now and then on an hour-
long road trip. Not sure if it happened while she was receiving a
text message, but normally her GSM phone would ring if a text message
were received.

Michael

 

[Richard Crowley]

So *that's* where that "dit di-dit" sound comes from! Thanks! I
thought my wife's JVC car stereo had a hardware defect. When playing
CDs (not the radio, even), we'd get that every now and then on an hour-
long road trip. Not sure if it happened while she was receiving a
text message, but normally her GSM phone would ring if a text message
were received.

In a moving vehicle, most likely as you were handed-off while
moving from cell to cell.

 

[[email protected]]

I'm trying to record cassettes and LPs to my PC and am experiencing
line noise, possibly from some other device in the house. I have not
determined the source of this noise, but it occurs at random times
during the day, and causes clicks and pops that ruin any recordings. I
have tried moving the computer & audio equipment from the basemeent to
different rooms in the house and still am hearing noise.

The equipment being used is

* System: Pentium 4 PC running Windows XP Pro
* Software: Sound Forge
* Audio Interface: Tascam US-428
* Cassette deck
* Turntable (with preamp)

I have used most of this equipment for a long time and not had
problems with noise like this in other houses/apartments, and I've
only noticed noise like this in this house in the past couple of
months (then again I haven't tried transferring LPs or cassettes in
this house, however I have recorded guitar/drums/etc here for a couple
of years and not experienced this kind of noise).

A recording of the noise and images of the waveforms can be heard &
seen here:
http://www.geocities.com/usenet_daughter/line_noise.htm

Can someone tell what device in the house might be causing this (the
house has all the normal amenities - lights, A/C, W/D, etc.) or how to
filter this noise out of the signal loop before it reaches the
recordings?

My first experiment is see if you can hear it in between stations on
an AM Radio. Then use the radio as a direction finder.

Here are a list of things to try:

http://www.oldtemecula.com/theremin/noise/index.htm

Good Luck,

* * *
Christopher

Temecula CA.USA
http://www.oldtemecula.com

 

[Havatcha]

I'm trying to record cassettes and LPs to my PC and am experiencing
line noise, possibly from some other device in the house. I have not
determined the source of this noise, but it occurs at random times
during the day, and causes clicks and pops that ruin any recordings. I
have tried moving the computer & audio equipment from the basemeent to
different rooms in the house and still am hearing noise.

The equipment being used is

* System: Pentium 4 PC running Windows XP Pro
* Software: Sound Forge
* Audio Interface: Tascam US-428
* Cassette deck
* Turntable (with preamp)

I have used most of this equipment for a long time and not had
problems with noise like this in other houses/apartments, and I've
only noticed noise like this in this house in the past couple of
months (then again I haven't tried transferring LPs or cassettes in
this house, however I have recorded guitar/drums/etc here for a couple
of years and not experienced this kind of noise).

A recording of the noise and images of the waveforms can be heard &
seen here:
http://www.geocities.com/usenet_daughter/line_noise.htm

Can someone tell what device in the house might be causing this (the
house has all the normal amenities - lights, A/C, W/D, etc.) or how to
filter this noise out of the signal loop before it reaches the
recordings?

Much appreciated!

From your recordings, this sounds like impulsive noise. Typical sources
of impulsive noise are electrical motors or other devices that create
sparks.
The following gives an overview...

http://www.bbc.co.uk/rd/pubs/whp/whp-pdf-files/WHP080.pdf


the other possibility is that your neighbour has recently bought a
Power-Line home network kit and is currently spurting RF noise in every
direction.

http://www.bbc.co.uk/rd/pubs/whp/whp-pdf-files/WHP116.pdf

 

[Mikey]

From your recordings, this sounds like impulsive noise. Typical sources of
impulsive noise are electrical motors or other devices that create sparks.
The following gives an overview...

http://www.bbc.co.uk/rd/pubs/whp/whp-pdf-files/WHP080.pdf


the other possibility is that your neighbour has recently bought a
Power-Line home network kit and is currently spurting RF noise in every
direction.

http://www.bbc.co.uk/rd/pubs/whp/whp-pdf-files/WHP116.pdf

Refrigerator? Freezer? A/C?

Mikey Wozniak
Nova Music Productions
This sig is haiku

 

[Havatcha]

Refrigerator? Freezer? A/C?

Possible, but the pulses sounded a bit too frequent to be switches from
those devices.

 

[Mark]

Possible, but the pulses sounded a bit too frequent to be switches from
those devices.- Hide quoted text -

- Show quoted text -

do the noise pulses occur at the SAME TIME in both the left and the
right?

in one case it sounded like no.

It is hard to imagine any EMI creating noise at different times in
the L and R.

Mark