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-   -   O.T. Speakers static/humming (http://www.pcbanter.net/showthread.php?t=1104210)

Mark Twain May 21st 18 10:54 PM

O.T. Speakers static/humming
 
I have a Dell XPS 8500, with Windows 7 Professional, SP1,
with Spywareblaster, Malwarebytes, Avast , Windows Defender
and Windows firewall.

(1) TB HD
Intel (R) Core (TM) i7-33-3770 CPU @ 3.40 GHz
Ram 12.0 GB
System type : 64-bit operating system

I also have

I have a Dell Optiplex 780 Tower, with Windows 7 Professional,
SP1, with Spywareblaster, Malwarebytes, Avast , Windows Defender
and Windows firewall.

Intel (R) Core 2 Duo 2.93 GHz
4GB RAM, 750 GB HD
System type : 64-bit operating system

and (external hard drives)

(8500)
WD BLACK SERIES WD2003FZEX 2TB 7200
RPM 64MB Cache SATA 6.0Gb/s 3.5" Internal
Hard Drive

(780)
Seagate Desktop HDD ST2000DM001 2TB 64MB
Cache SATA 6.0Gb/s 3.5"
Internal Hard Drive


The problem concerns the 8500; I have an intermittent problem,
for some reason when I logged on today there's a humming/buzzing
sound coming from the speakers. This has happened several times
recently. I haven't done a thing other than logging on.

I tried restarting and disconnecting and reconnecting the speaker
connections but it doesn't seem to go away until I power off/on.

So what could this be?

Thoughts/suggestions
Robert

Paul[_32_] May 21st 18 11:39 PM

O.T. Speakers static/humming
 
Mark Twain wrote:
I have a Dell XPS 8500, with Windows 7 Professional, SP1,
with Spywareblaster, Malwarebytes, Avast , Windows Defender
and Windows firewall.

(1) TB HD
Intel (R) Core (TM) i7-33-3770 CPU @ 3.40 GHz
Ram 12.0 GB
System type : 64-bit operating system

I also have

I have a Dell Optiplex 780 Tower, with Windows 7 Professional,
SP1, with Spywareblaster, Malwarebytes, Avast , Windows Defender
and Windows firewall.

Intel (R) Core 2 Duo 2.93 GHz
4GB RAM, 750 GB HD
System type : 64-bit operating system

and (external hard drives)

(8500)
WD BLACK SERIES WD2003FZEX 2TB 7200
RPM 64MB Cache SATA 6.0Gb/s 3.5" Internal
Hard Drive

(780)
Seagate Desktop HDD ST2000DM001 2TB 64MB
Cache SATA 6.0Gb/s 3.5"
Internal Hard Drive


The problem concerns the 8500; I have an intermittent problem,
for some reason when I logged on today there's a humming/buzzing
sound coming from the speakers. This has happened several times
recently. I haven't done a thing other than logging on.

I tried restarting and disconnecting and reconnecting the speaker
connections but it doesn't seem to go away until I power off/on.

So what could this be?

Thoughts/suggestions
Robert


Debug by section.

1) Plug headphones into the LineOut Jack of the
8500, where the speakers are currently connected.
Is the headphone sound clean ?

2) Plug a portable source (Sony Walkman, iPod, or similar)
to the speakers. Is the humming and buzzing still there,
with a driven source (that floats with respect to AC) ?
I even have a transistor radio that will serve for this
purpose (an FM radio with a synthesizer tuner).

It's possible the amplified speakers have a leaking cap in
the power supply section. Since you had a "power event" at your
place, and all your gear operated for a time at the wrong
voltage, just about anything could be wrong with it.

But first you want to separate the 8500 from the speakers,
as in (2) and verify the speakers are the author of their
own misfortune.

When my computer speakers acted up, I ended up running
a finger over the solder points inside it, until I found
a solder point that "made a difference" and the sound
started working properly again. I re-soldered that point
(it was a cold solder joint).

Trouble is though, some computer speakers are *glued*
shut, so this is not as easy as it seems. They can be very
hard to open up. I actually used a saw on mine, and sawed a
slot where I could get prying tools jammed into the
seam and used brute strength to separate the
glue. And the speaker still works :-) It no longer
looks all that nice though. I won't be selling it
on Ebay ("slightly used, some scratches").

Paul

Mark Twain May 22nd 18 09:38 AM

O.T. Speakers static/humming
 
I don't have headphones, a walkman
or iPod etc. to test and the speakers
are brand new Harman Kardon (after the
electrician fried all my components)

https://www.google.com/search?q=Harm...lboe9gT-etK1M:

When I logged on later everything is back
to normal. As I say, it's intermittent.

Robert


Paul[_32_] May 22nd 18 10:04 AM

O.T. Speakers static/humming
 
Mark Twain wrote:
I don't have headphones, a walkman
or iPod etc. to test and the speakers
are brand new Harman Kardon (after the
electrician fried all my components)

https://www.google.com/search?q=Harm...lboe9gT-etK1M:

When I logged on later everything is back
to normal. As I say, it's intermittent.

Robert


Does the Harmon Kardon have a two or three prong plug ?

Computer speakers should have a two prong plug. This
prevents ground loops from forming. The 1/8" plug has
the only ground between the two units, so there's no
ground loop.

If the audio equipment has three prongs, it *might* need
a hum-breaker, which is a form of transformer coupling
between units. These require precisely constructed
transformers for best results (some of these have
a bandwidth of 10KHz or so, not that impressive).

You can also solve hum problems, by using stuff
like TOSLink between units (optical interconnect,
red LED light flowing over plastic large aperture
dental fiber). You would have to look at the input
options on the HK speakers, to see if there's another
way to get there (a way that avoids this stuff).

I've never really owned any "spectacular" audio gear,
and 1/8" audio input is about as fancy as anything
I've had on my gear here. I didn't even have S'PDIF
to play with.

*******

I've had your problem, between my Mac G4 and the stereo
I used for other sources. And the Mac G4 was the only
one with funny radio station noises, hum and other
garbage. I never managed to fix that. While it's
possible to couple radio station signals into audio
cables, and have them rectified by the front end of
the speaker or stereo, it's hard to say why
this happens. I could use the same cable between
two different audio sources, have the problem on
one source and not the other.

Lots of devices in the room with you, use capacitors
on input and output for DC blocking. This is supposed
to prevent one device from applying a DC input to
a transistor on the input of another device, and driving
it into a non-linear area of operation. If you look
at the sound chip on the computer motherboard, it
uses capacitors on all inputs and outputs for this
reason. A defective capacitor might cause a problem,
but when it happens identically on both left and
right channel, you have to wonder whether it's
a design issue.

You could also move audio with something like Bluetooth,
but the default profile for audio isn't all that good.
And that would also add latency, which might upset lip sync
while watching movies.

Paul

Mark Twain May 22nd 18 07:47 PM

O.T. Speakers static/humming
 
The Harmon Kardon speakers use a
two prong.

Here's the setup connections:

https://www.google.com/search?biw=17...u-MK58fLu9ONM:

It's odd that it's intermittent, you would
think if it were a capacitor it would happen
all the time.

Well, I guess I'll just live with it
and just power off/on when it happens.

Thanks,
Robert

Paul[_32_] May 22nd 18 10:21 PM

O.T. Speakers static/humming
 
Mark Twain wrote:
The Harmon Kardon speakers use a
two prong.

Here's the setup connections:

https://www.google.com/search?biw=17...u-MK58fLu9ONM:

It's odd that it's intermittent, you would
think if it were a capacitor it would happen
all the time.

Well, I guess I'll just live with it
and just power off/on when it happens.

Thanks,
Robert


So that looks to me, like a 2.1 amplified computer
speaker, with LineOut for the satellites and CenterSub
connector for the larger speaker in the base unit ?

Are both audio connectors plugged into the computer ?

Do you have a center-sub connector on the 8500 ? I
presume so.

According to the standard colors table here, black
is "Surround" and lime-green is "front left and front right".
You would think they'd want an orange connector for
a center-sub (so the computer can send a "sub" signal
to make the larger speaker in the base unit work).

https://en.wikipedia.org/wiki/PC_System_Design_Guide

If you leave the second connector "floating", it might
pick up hum. Especially as the Sub probably extends
to 60Hz for the hum (the Sub would normally be band-limited
as to which frequencies it could reproduce).

You also want the computer audio settings in the 8500,
set to a setting which "matches" the wiring you're
using. If your speakers are 2.1, and two plugs are
used, you want to select "2.1" in some output selection
panel to match.

You have a bunch of stuff to check.

I thought originally, this was a simple 2-channel setup,
with a single green plug to plug in. If you left a
plug unplugged, that could well explain the extraneous
noises.

Paul

Mark Twain May 23rd 18 12:03 AM

O.T. Speakers static/humming
 
Yes, both connectors (green and black) are
plugged into the computer and I followed
their diagram to the letter. The plug-in's
to the base module are beige and yellow and
one plug is square and other a triangle so
it's impossible to mess it up.

The speakers are actually the ones I picked
with the 8200 and when I bought the 8500 I
just used them. When the electrician fried
everything I wanted the same speakers because
I liked them allot and found a new set on eBay
still in it's original box.

I've never had to set-up any software previously
and they work just fine.

This what I've found;

http://i65.tinypic.com/29qi4h0.jpg

http://i66.tinypic.com/263k83l.jpg

https://lh5.googleusercontent.com/-A...s640/audio.jpg

http://i63.tinypic.com/rwrihv.jpg

http://i67.tinypic.com/4g6t6e.jpg

http://i68.tinypic.com/2ef8804.jpg

http://i68.tinypic.com/11t1rhg.jpg

http://i64.tinypic.com/103x6wx.jpg

Robert

Paul[_32_] May 23rd 18 02:05 AM

O.T. Speakers static/humming
 
Mark Twain wrote:
Yes, both connectors (green and black) are
plugged into the computer and I followed
their diagram to the letter. The plug-in's
to the base module are beige and yellow and
one plug is square and other a triangle so
it's impossible to mess it up.

The speakers are actually the ones I picked
with the 8200 and when I bought the 8500 I
just used them. When the electrician fried
everything I wanted the same speakers because
I liked them allot and found a new set on eBay
still in it's original box.

I've never had to set-up any software previously
and they work just fine.

This what I've found;

http://i65.tinypic.com/29qi4h0.jpg

http://i66.tinypic.com/263k83l.jpg

https://lh5.googleusercontent.com/-A...s640/audio.jpg

http://i63.tinypic.com/rwrihv.jpg

http://i67.tinypic.com/4g6t6e.jpg

http://i68.tinypic.com/2ef8804.jpg

http://i68.tinypic.com/11t1rhg.jpg

http://i64.tinypic.com/103x6wx.jpg

Robert


So the software seems to know it's driving four
speakers. But it doesn't have any common notation
for the mode showing, to confirm that. It seems to
have figured out the jacks on the back of the machine
are in usage, and perhaps it has the proper side
contacts for plug presence detect for HDAudio.
It's probably in quadraphonic mode right now.
(When the number of channels in the content, doesn't
match the number of speakers, they can fake it
by using various math transforms.)

2.0 Plain stereo
2.1 Left, right, plus a subwoofer
4.0 Quadraphonic (stereo front and stereo back speakers)
5.1 Stereo front, Stereo back, Center, and Subwoofer (three plugs)
Might match some common movie setups.
7.1 Four plugs, don't know all the speaker names right off
hand, but I could go look them up :-)

One question I have about this setup, is what was
the intention of the HK design ? Is it advertised
as a 2.1 system with a left, right, and a Sub ?
It seems a strange choice of packaging, if the thing
is actually a quadraphonic system (four speakers,
two front and two back).

Does the HK speaker have a *model number* on the
back, on a plate or similar, that I can go look up ?

Not that this has anything to do with "funny noises".
I doubt the wire is actually floating and undriven by
a signal. The computer audio is bound to have put
some signal on there.

And if the HK has a two-prong plug, it probably
isn't a ground loop. You could try putting the power
plug of the HK speakers, on the same power_strip as
the computer is using. There's no reason to suspect
this will do anything though... It should not make a
bit of difference. When a two prong powering is used,
the power should "float" with respect to the rest of
the room, and the ground on the computer audio plugs
should establish ground for everything. Preventing
ground loops and humming.

Paul

Mark Twain May 23rd 18 06:23 AM

O.T. Speakers static/humming
 
The Harman Kardon set-up is 2.1 with (2)
stereo speakers and a base(Sub).

The model number is HK695-01

The speaker plug is in the same APC surge arrest.

http://www.apc.com/shop/us/en/produc...r=SEC-756-GOO-[53166061159]-[269259981065]-S-[]

As I say, this is an intermittent problem
that comes and goes. Most of the time
everything is fine.

Robert

Paul[_32_] May 23rd 18 07:05 AM

O.T. Speakers static/humming
 
Mark Twain wrote:
The Harman Kardon set-up is 2.1 with (2)
stereo speakers and a base(Sub).

The model number is HK695-01

The speaker plug is in the same APC surge arrest.

http://www.apc.com/shop/us/en/produc...r=SEC-756-GOO-[53166061159]-[269259981065]-S-[]

As I say, this is an intermittent problem
that comes and goes. Most of the time
everything is fine.

Robert


What a weird design :-)

I've never seen anything like this before.

https://www.top4runners.com/computer...on%20HK695.pdf

It accepts what is effectively quadraphonic input (two front,
two surround signals) and does a transform of sorts to 2.1
or maybe even a sort of 3.0 .

*******

One neat feature, is the interface has a diagnostic output
jack, that sweeps low frequencies and gives you a test
stimulus for the speakers (PDF page 17). So you don't even need
a Sony Walkman or a tape recorder, to inject a test
sound to test the speakers.

The test tone sweeps from 40Hz to 400Hz. The crossover
on the sub is at 180Hz. Frequencies above 180Hz, you would
expect those to go to the satellite speakers.

This also means, the input signals hardly go directly
to the amplifiers inside the unit. The input signals
would go to the DSP chip. The DSP chip would process
the signals and drive the amplifiers from there.
As I don't know of a way to convert 4.0 to 2.1, using
only RLC circuits from an Electronics 100 course :-)

Google let me down, in terms of theory of operation
or any of that sort of stuff. No take-apart
pictures to see what is inside.

The design is a good deal more complicated than
your average computer speaker, at a guess.

Paul

Mark Twain May 23rd 18 09:06 PM

O.T. Speakers static/humming
 
I'm sort of a vintage stereo guy,,..
and Harman Kardon is a good name
brand.

It's a good set-up and I had to pay
extra for it at the time.

I was thinking,...even though it was
new in the box would the years since
it was made 'oxidize' circuits etc
and that's the cause of the intermittent
static?

I would be interested, if you wanted
to spend the time. Of your opinion
of my stereo system. I bought this
while in the Navy 1979-1980.

Yamaha A-1 Integrated Amp:

http://www.classic-audio.com/yamaha-a1-p-405.html

http://www.hifi4sale.net/t9572-yamah...amplifier-used

Yamaha- T-1 Tuner:

https://www.hifiengine.com/manual_li...maha/t-1.shtml

Pioneer Pl-L100 Linear Tracking Turntable:

https://www.vinylengine.com/library/...pl-l1000.shtml

Teac C-3 Tape Deck:

https://www.hifiengine.com/manual_li...teac/c-3.shtml

Speakers:

http://www.thevintageknob.org/pioneer-HPM-150.html

http://www.vintage-speaker-review.co...er-review.html

Thanks,
Robert

Paul[_32_] May 24th 18 01:17 AM

O.T. Speakers static/humming
 
Mark Twain wrote:
I'm sort of a vintage stereo guy,,..
and Harman Kardon is a good name
brand.

It's a good set-up and I had to pay
extra for it at the time.

I was thinking,...even though it was
new in the box would the years since
it was made 'oxidize' circuits etc
and that's the cause of the intermittent
static?

I would be interested, if you wanted
to spend the time. Of your opinion
of my stereo system. I bought this
while in the Navy 1979-1980.

Yamaha A-1 Integrated Amp:

http://www.classic-audio.com/yamaha-a1-p-405.html

http://www.hifi4sale.net/t9572-yamah...amplifier-used

Yamaha- T-1 Tuner:

https://www.hifiengine.com/manual_li...maha/t-1.shtml

Pioneer Pl-L100 Linear Tracking Turntable:

https://www.vinylengine.com/library/...pl-l1000.shtml

Teac C-3 Tape Deck:

https://www.hifiengine.com/manual_li...teac/c-3.shtml

Speakers:

http://www.thevintageknob.org/pioneer-HPM-150.html

http://www.vintage-speaker-review.co...er-review.html

Thanks,
Robert


It is possible for 1/8" connections to act up.
In some cases, there isn't sufficient control of
dimensions, or sufficient spring force, and it's not
making good contact.

I did think of a way for the LineOut to have
DC on it. HDAudio chips support jack re-tasking.
That means an output, can be used as a microphone input,
and the mode changes in software.

To support electret microphones, they take a voltage
source, and maybe a 2Kohm resistor, and bias tip and ring.
There's no particular pattern to what they select for
a voltage source, and it could vary anywhere from 3.3V to
5V or so.

/\
tip ---- 2K ------- 3.3V

|| ring ---- 2K ------- 3.3V

|| sleeve ------------- GND

The idea is, the electret pulls down the
level, when the electret receives some sound
pressure. Basically, the computer provides a
source of power to make the electret work. On
modern enough systems, the microphone is stereo in,
and a separate bias is placed on tip and ring
(for left and right).

The bias source should be switched off by the
software, when the jack is in output mode.

The next time the speakers do it again, try using the
diagnostic output and routing it to the green and black
inputs as a test. And see if that signal source behaves
differently.

What you want, is a way to prove it's the computer
that is doing it.

If the volume pot on the speakers was a bit
dirty, it could function as a noise source. But
you'd also notice this, if adjusting the volume
control created all sorts of extraneous noise.
It doesn't take too many twists of a volume knob
to figure out it's a noise source.

*******

And I think you've got me beat on stereo equipment :-)

Paul

Mark Twain May 24th 18 04:26 AM

O.T. Speakers static/humming
 
I'll do the diagnostics next time it happens,..

It says if I hear the test tone in all speakers
then everything is working OK, otherwise I'll have
to go into detailed troubleshooting techniques.

The volume on the satellite speakers are push
+/- push buttons and I don't adjust the base.

Thanks about the stereo,..

Robert

Mark Twain May 29th 18 06:07 AM

O.T. Speakers static/humming
 
I went and looked at the diagnostic
troubleshooting and one of the suggestions
was to move the speakers away from the
monitor as much possible.

So I did that; maybe that was the issue?

As I said I'll test it if it happens
again. Kinda of cool that the speaker
has it's own test diagnostics.

Robert


Mark Twain August 9th 18 03:15 PM

O.T. Speakers static/humming
 
The speaker hum/static sound came back today
and this time I tried the diagnostics. I unplugged
the speakers and tried each one in the diagnostics
port for low and high frequencies and both played
although they sounded the same to me. So according
to the test the speakers are working normally.

Afterwards the humming stopped.

Robert


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