Digital noise from speakers in flight simulator (X-Plane)

On 3/24/2018 12:09 PM, John Doe wrote:
>> No, I don't think [an HDMI pass-through with audio
>> extractor] is gonna save your day,
> It did not. The same noise is present with the HDMI audio
> extractor.

I didn't think so, because you still have a direct ground connection
between your computer and your speakers. Try the ground isolator that
recommended.

But . . . are you sure that the noise you're not hearing isn't a
constant background sound that's created by the flight simulator
program? Does it go away when you close the program? I don't remember if
you've mentioned this.




--

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

Mike Rivers > wrote:

> John Doe wrote:

>>> No, I don't think [an HDMI pass-through with audio
>>> extractor] is gonna save your day,

>> It did not. The same noise is present with the HDMI audio
>> extractor.
>
> I didn't think so, because you still have a direct ground
> connection between your computer and your speakers. Try the
> ground isolator that recommended.
>
> But . . . are you sure that the noise you're not hearing
> isn't a constant background sound that's created by the
> flight simulator program? Does it go away when you close
> the program? I don't remember if you've mentioned this.

Difficult to remember something you haven't read. Seems you
ignored everything in my original post, in your first reply.

I could understand if you were replying to the subject line,
sometimes I do that. But even the subject line answers your
current question.

On 3/24/2018 1:16 PM, John Doe wrote:

> Difficult to remember something you haven't read. Seems you
> ignored everything in my original post, in your first reply.
>
> I could understand if you were replying to the subject line,
> sometimes I do that. But even the subject line answers your
> current question

OK, ignore my advice if you choose. I was only trying to help based on
"digital noise," which isn't very specific. Breaking a ground connection
cures a lot of ills.

> The noise corresponds to what is displayed on the screen. It
> changes when a menu choice is selected. Sounds like an oscillator.

Is it a whistle? Does it have a pitch? What kind of oscillator? Sine
wave? Sawtooth? When you wrote "noise" I assumed noise. Sorry for trying
to first-guess you.

Could you make a video with audio and post it somewhere so I/we can hear
what you're hearing?



--

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

John Doe > wrote:
>
>The HDMI audio extractor (Tripp Lite P130-000-AUD4K6) should tell
>that one. If there is still noise, through the 3.5 mm stereo output
>jack, I will assume the SPDIF on the extractor link would not work
>either, that the noise is introduced before that point.

This is likely a D/A converter in a box and as such may affect your
sound. However, it might be better than whatever D/A you're using
currently.

>I will lose the SoundBlaster equalizer software, using HDMI audio,
>but I suppose there is a replacement.

God, I hope so. Get all that awful crap out of your signal path, and
keep it as far away as possible.

If I were you, I'd just look into fixing the ground loop. Are you running
an XLR cable out of your soundcard into the powered speaker, or are you
trying to pull out of an unbalanced output? If it is the unbalanced output,
try lifting pin 1 on the XLR side and adding 0.1uF ceramic caps between
pin 1 and 3 and pin 2 and 3 on the XLR connector. This lifts the ground at
the speaker side and filters some RF off... it's not as nice as a real
transformer but it's often a workable solution if you can't get a proper
balanced output.
--scott

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

(Scott Dorsey) wrote:

> John Doe > wrote:
>>
>> The HDMI audio extractor (Tripp Lite P130-000-AUD4K6) should tell
>> that one. If there is still noise, through the 3.5 mm stereo
>> output jack, I will assume the SPDIF on the extractor link would
>> not work either, that the noise is introduced before that point.
>
> This is likely a D/A converter in a box and as such may affect
> your sound. However, it might be better than whatever D/A you're
> using currently.

> If I were you, I'd just look into fixing the ground loop. Are you
> running an XLR cable out of your soundcard into the powered
> speaker,

There is an electrical difference between TRS cables and XLR cables,
going to the speakers from the same soundcard stereo output jack?









--

> or are you trying to pull out of an unbalanced output?
> If it is the unbalanced output, try lifting pin 1 on the XLR side
> and adding 0.1uF ceramic caps between pin 1 and 3 and pin 2 and 3
> on the XLR connector. This lifts the ground at the speaker side
> and filters some RF off... it's not as nice as a real transformer
> but it's often a workable solution if you can't get a proper
> balanced output.

I meant "TS cables", just distinguishing between the connector types.

On 3/25/2018 3:47 PM, John Doe wrote:
> There is an electrical difference between TRS [you mean TS] cables and XLR cables,
> going to the speakers from the same soundcard stereo output jack?

Yes. TS cables have one conductor and a shield, TRS and XLR (and
TRS-to-XLR) cables have two conductors and a shield. There's a detailed
article on my web page about the differences and why they matter:

https://mikeriversaudio.files.wordpr..._revised. pdf

The short version is that TRS and XLR cables are used when making
"balanced" connections. TS (or RCA, for that matter) cables are used
when making "unbalanced" connections. The difference is that for a
balanced connection, the cable shield, which is conventionally connected
to the chassis ground, doesn't carry the signal voltage, and in an
unbalanced connection, it does. If there's noise present on the ground
of one or both of the devices that you're connecting, the noise gets
added to the signal when you have an unbalanced connection. With a
balanced connection, _unless there's a wiring problem in the equipment_,
noise that's on the cable shield doesn't go anywhere important.

And before you ask, in order to make a balanced connection, the devices
on both ends of the cable must have connectors that carry two signal
wires and the shield. You can't make an unbalanced output balanced just
by sticking a TRS plug in a TS jack.

--

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

Mike Rivers > wrote:

> John Doe wrote:

>> There is an electrical difference between TRS [you mean TS]
>> cables and XLR cables, going to the speakers from the same
>> soundcard stereo output jack?
>
> Yes. TS cables have one conductor and a shield, TRS and XLR (and
> TRS-to-XLR) cables have two conductors and a shield. There's a
> detailed article on my web page about the differences and why they
> matter:
>
> https://mikeriversaudio.files.wordpr...he_ins_and_out
> s_of_gozintas_and_gozoutas_revised.pdf
>
> The short version is that TRS and XLR cables are used when making
> "balanced" connections. TS (or RCA, for that matter) cables are
> used when making "unbalanced" connections. The difference is that
> for a balanced connection, the cable shield, which is
> conventionally connected to the chassis ground, doesn't carry the
> signal voltage, and in an unbalanced connection, it does. If
> there's noise present on the ground of one or both of the devices
> that you're connecting, the noise gets added to the signal when
> you have an unbalanced connection. With a balanced connection,
> _unless there's a wiring problem in the equipment_, noise that's
> on the cable shield doesn't go anywhere important.
>
> And before you ask, in order to make a balanced connection, the
> devices on both ends of the cable must have connectors that carry
> two signal wires and the shield. You can't make an unbalanced
> output balanced just by sticking a TRS plug in a TS jack.

Are you saying that the difference between a "balanced" and an
"unbalanced" connection can be made simply by the cable used?

In other words... An ordinary stereo output from a PC soundcard can
be balanced by simply using XLR cables?

I like balanced.

A new power supply arrives today or tomorrow. Will see whether it
helps. The idea that increased power draw might cause the problem is
logical.

John Doe > wrote:
>
>Are you saying that the difference between a "balanced" and an
>"unbalanced" connection can be made simply by the cable used?

No. However, if you have a _differential input_ that is intended for a
balanced source, you can use the differential input to break the signal
ground connection effectively and eliminate the ground loop.

>In other words... An ordinary stereo output from a PC soundcard can
>be balanced by simply using XLR cables?

No, because the output is still not balanced. However, you CAN still
use the differential input to break the ground connection.

There is a discussion of this stuff on the Rane website, also a very
good one in the Yamaha Sound Reinforcement Handbook.

>I like balanced.

It's nice, in part because you can break grounds with impunity then.

>A new power supply arrives today or tomorrow. Will see whether it
>helps. The idea that increased power draw might cause the problem is
>logical.

It's likely to reduce some of the noise, but just fix the damn ground loop.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

On 3/25/2018 6:04 PM, John Doe wrote:
> Are you saying that the difference between a "balanced" and an
> "unbalanced" connection can be made simply by the cable used?

No. I tried to tell you that in a shortened form. Read the article.

> In other words... An ordinary stereo output from a PC soundcard can
> be balanced by simply using XLR cables?

No.

> I like balanced.

So do I. But you can't make an unbalanced output balanced just by using
a different cable. You can make a balanced output unbalanced by using a
different cable, but not the other way around.



--

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