(UFO) Low frequency sinus wave of 5.0 Hz or 7.46 hertz shuts down Denon Receiver 1909 ?!? (VIDEOS)

[Skybuck Flying]

Yesterday I was trying to re-create the sound of a UFO, according to the website of Bob Lazar:

Website of EX-UFO Reverse Engineer guy:
https://boblazar.com/

The website mentions a frequency of 7.46 Hz (Hertz).

So I thought it would be easy to re-create that sound with Delphi and ASIO4ALL v2.14 sound driver and my Laptop L670 and Denon Receiver 1909 and Creative Gigaworks S750 speaker set !

But boy was I in for a surprise !

At 7.46 Hertz the Denon Receiver 1909 would shut down ! and it's power light would start blinking RED.

VERY STRANGE. So yesterday I checked all connections, removed some spider web from back right speaker, removed a little fly. Found my glasses super tiny little screw near central speaker which was funny with my flashlight, never thought I would see it again. Another backup screw was lost, funny story but oh well. Moved/bend back some copper wire at the back of receiver, it might have been touching a screw (still some air in between) but it was never a problem.

So I basically ruled-out any connection problem, as was mentioned by the denon receiver manual which I also checked, which explained to check connections. It also mentions something about speakers having a wrong inpedeance or something but I don't understand that part.

Anyway the denon receiver has basically never malfunctioned like this. I can remember hearing some plops on some rare occasions, most on old PC, these might have been some atmospherical/astronomical or loopback issues, but besides from that music always plays excellent, gaming is excellent, youtube is excellent, rarely any problems.

Only weird thing is if I turn on kitchen power that it stops playing for 1 second as well as laptop I guess.

Anyway today I decided to investigate the problem further and to record it on video because otherwise people are not going to believe. Another reason is because of "Skinwalker Ranch" tv show/youtube/history channel series and they report a strange 2.6 GigaHertz signal every time UFO sightings occur or something strange/whatever.. probably satelitte related. But anyway this was my main reason to investigate "audio signals" and "frequency ranges".

So finding this 7.46 Hertz CRASH was quite spectacular and very strange and alarming.

However the laptop has a defective GPU which has some of it's contacts lost most likely or some kind of defective transistor inside of it so it's unusable for 3D, but the rest seems to work ok. So I kinda doubt it's the GPU at fault. The HDMI also seems to work ok.

Anyway I did some experiments, I also used a web tone generator, that worked fine. I managed to record my own tone generator a little bit with the recording equipment on this laptop by enabling it. It was strangely very soft volume output which I don't quite understand, but I enhanced it with goldwave and changed/maximized the volume a couple of time and played it again to see if the wave form would crash the denon receiver it did not !

At first I thought that maybe the negativity of the samples has something to do with it, maybe, but I am not so sure... I don't think it's that... but it's strange.
I tried all negative samples at higher frequencies and then denon does not crash.

Only with below 10 Hertz frequencies does the Denon Receiver "crash"/go into standby mode and only if HDMI is used.

I also tested the analog inputs to the denon receiver by using my older/main PC which I try not to use anymore because of leaky capacitators, it has a Creative Labs X-Fi Elite Pro soundblaster... and there whatever I did, the denon receiver would not crash.

I also played/changed to different formats for the Denon Receiver on the laptop. Switched from 24 bit, 96000 Hertz to 16 bit, 441000 Hertz, but the crashing remained.

So by ruling out other cases I think I have isolated the problem to the:

ASIO4ALL driver version 2.14 and the usage of HDMI.

So two possibilities now remain:

1. Either it's the ASIO4ALL driver version 2.14 and it has some kind of bug which causes it to crash the Denon Receiver 1909. Perhaps it's outputting some kind of malformed HDMI packets or something.

This could lead to the discovery of some kind of HDMI packet attack against receivers ?

Maybe the Denon Receiver 1909 is detecting the malformed packets and puts itself in standby mode or something to protect itself ?!?

2. Or the Laptop's slightly defective GPU is causing some kind of malformed HDMI packets ?

Basically same conclusion as above Denon Receiver detects it and protects itself from a possible attack ??

Strange clicking/popping can also be heard when the sound starts.

Other possibilities include:

3. Perhaps some bug in Delphi ASIO software package, however it did not show up on the old PC/analog connections, so maybe that is not it.

4. Perhaps bug in my simple software routine, but again I don't think so... because it works fine on old PC.

Some questions:

5. It should be valid to generate double floating point values ranging from 1.0 to -1.0 ?

Or at least 0.99 to -0.99 but even smaller values still crash the denon receiver via asio4all driver at low frequencies.

So I am pretty sure it's not 3 or 4, 5 was also tested and is most likely not it, 1.0 and -1.0 might overflow to 1.00001 and -1.00001 and such but even lower values still crashed it, so this cannot be it.

So as far as I am concerned it leaves some possibilities:

1. Either the ASIO4ALL v2.14 has a serious low frequency bug.

2. The laptop's damaged GPU/HDMI has something to do with it.

3. It could also be some hardware bug in AMD HDMI output device.

(Perhaps some malformed HDMI packet).

1. Anyway, what you can do to rule out or comform the bug in ASIO4ALL version 2.14 is install it on your system.

2. Download my tone generator, which I will make available. Run it and then see if it also crashes your Receiver if you have one.

If it does crash then we could be on to something and then that could mean that Receivers are crasheable somewhat via HDMI packet attacks.

If it doesn't crash with this ASIO4ALL v2.14 driver then it must be this shitty laptop... and then hopefully this issue will disappear when I buy new computer.

Anyway I test a lot of stuff and I have seen plenty of weird/whacky problems, this is one of them.

Oh, I almost forgot, videos to prove this issue is real lol, they are uploading now, fortunately I bought a new fast but hot 256 GB SD card, it's so tiny it's crazy ! Could fit between my teeth ! HAHA. (It goes into a bigger SD card so it fits into my camera hehe... some day petabeta SD devices will exist I am sure :) as long as they can cool it hehe)

VIDEOS TO PROVE AND INVESTIGATE THE ISSUE:

PART 1: Weird Audio Bug In ASIO4ALL v2.14 with HDMI (?) Part 1 of 4
https://youtu.be/gjnnf_MZmhQ

PART 2: Weird Audio Bug In ASIO4ALL v2.14 (with HDMI) Part 2 of 4
https://youtu.be/aAC8mnlrGvs

PART 3: Weird Audio Bug In ASIO4ALL v2.14 (with HDMI) Part 3 of 4
https://youtu.be/rqVfsobfEr8

PART 4: Weird Audio Bug In ASIO4ALL v2.14 Part 4 of 4
https://youtu.be/pGksplVR8PQ

It's still uploading as I write this. I am going to catch a drink.

If everything goes well these videos will be available in a few minutes to sink your teeth into it ! Quite fascinating to see a Receiver crash/shut down like that... never happened before ! HAHA.

It reminds me of stories of UFO witnesses that say their CARS malfunctioned or all their electronic equipment starting to ACT WEIRD ! ;) =D

Bye for now,
Skybuck.

[Scott Dorsey]

Skybuck Flying <skybuc...@gmail.com> wrote:
>
>At 7.46 Hertz the Denon Receiver 1909 would shut down ! and it's power ligh=
>t would start blinking RED.

You bet. It's going into protection to prevent it from blowing itself up.
Those speakers can hardly drive 75 Hz, let alone 7.5 Hz. Be glad you have
protection logic in your amp instead of a bunch of ruined hardware.

You're trying to drive those speakers more than ten times out of their
operating range. You wouldn't expect your car to behave very well if you
tried to drive it at 800 miles an hour instead of 80 either.
--scott

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

[Tobiah]

When I first got an FM synth (80's) I experimented with low
frequency sine waves. I was able to play frequencies lower
then 7.5hz without a problem. I could see the woofer of my
rather ordinary speakers dutifully pushing in and out in
accordance with the signal. I never had any problems doing
that.

It seems that your car comparison would play better if
we were talking about the amplitude of the signal.
What is it in an amplifier circuit that is under stress
at 7.5Hz? I could imagine that capacitors would fill up
which I could see causing problems.


Tobiah

[John Williamson]

Loud signals at low frequencies need a lot of power to be fed into the
speaker, and speaker impedances tend to reduce at low frequencies, as
they are mainly inductive devices as far as the amplifier is concerned.

Add the two together, and it is easy to trip the protection or blow the
fuses. Most commercial amplifiers are designed to reduce the output
levels below about 20 Hz, which avoids the problem.


--
Tciao for Now!

John.

[Scott Dorsey]

In article <tbrjhj$1hni$1...@gioia.aioe.org>, Tobiah <to...@tobiah.org> wrote:
>When I first got an FM synth (80's) I experimented with low
>frequency sine waves. I was able to play frequencies lower
>then 7.5hz without a problem. I could see the woofer of my
>rather ordinary speakers dutifully pushing in and out in
>accordance with the signal. I never had any problems doing
>that.

First of all, measure the DC resistance of your speakers. An eight ohm
speaker is likely around 2 to 3 ohms resistance, and at 7.5 Hz you are
pretty close to DC. Your amp won't like driving much power into that load.
And what is worse, most of the energy is going into resistive losses in
the voice coil, which will get pretty hot.

You can see the cones moving in and out, but you won't actually move very
much air either.

>It seems that your car comparison would play better if
>we were talking about the amplitude of the signal.
>What is it in an amplifier circuit that is under stress
>at 7.5Hz? I could imagine that capacitors would fill up
>which I could see causing problems.

The amplifier is under stress because it's got a very low impedance load
on the output. It might be fine putting out a couple watts, but it will
go into protection if you try and put much power out. Unless it's an amp
designed for very low-Z loads in which case the speaker will vaporize long
before the amp.

[palli...@gmail.com]

Scott Dorsey wrote:
================
> Skybuck Flying

> >
> >At 7.46 Hertz the Denon Receiver 1909 would shut down ! and it's power ligh=
> >t would start blinking RED.
>
> You bet. It's going into protection to prevent it from blowing itself up.

** Nearly all stereo amps and receivers from Asia have switch on delay, plus DC offset & low frequency protection.
This usually consists of one or more a speaker relays driven by a special IC that monitors the output from each channel and will hold the relay/s open if a fault condition is sensed.
The switch on delay is for "anti thump" and there is also a fast fast off when AC power is removed for the same reason.

IME, low frequency detection operates from about 5 to 10 Hz downwards at level of about 10V peak at the output.
This is mainly to save woofers from damage due to over excursion, plus it sounds horrible.
How do these high level sub sonics ever arise in normal use?
From rough handing of a turntable with the volume advanced.

FYI 1
the standard test of such protection schemes is to feed in a sine wave of about 5Hz from a bench generator with NO load connected.
The relays typically react by cycling on and off ( ie clicking audibly ) or locking out until the test signal is removed.

FYI 2

" Skybuck Flying" does not inhabit the same planet as you and I.


..... Phil

[Ralph Barone]

Not to mention he probably couldn’t hear anything, so turned up the volume.

[Skybuck Flying]

OK,

Mystery solved. The 100% volume low frequency sinus wave/signal causes the protection circuit of the denon 1909 receiver to be activated !

This can happen with HDMI and ANALOG connections/signals as well.

The culprit is more or less the ASIO4ALL driver I think... it has no volume control, it will simply output the signal at 100% volume ?!?
(But the wave is so slow, it cannot be heard without a subwoofer)

Though I am not entirely sure about ASIO4ALL volume level... but that is my hypothesis for now...

Dave Platt wrote a nice explanation on the sci.electronics.design newsgroup ! Check it out there !

I will copy & paste it here just in case you don't have that newsgroup:

"
This is unsurprising. The receiver is not "crashing" - it is behaving
as it was designed to behave, It has nothing directly to do with your
ASIO or other software. It's all about the (low) frequency you are
trying to play.

Your receiver is designed to reproduce music and normal theater-
type sound effects (typically 20 - 20,000 Hz). What you're
playing isn't "in its scope".

What you are seeing, is the "ASO / DC protection" feature operating
normally. You should find this described in the owner's manual
(the only one I could find on-line is the Japanese version) and the
feature and the error blinking patterns are described in the
receiver's service manual.

This receiver is designed to protect your loudspeakers from being
accidentally overdriven with DC or sub-sonic power which could damage
them. Many modern audio speakers are of a "ported" or "vented"
design, and it's possible to damage these by driving them with
high-level signals which fall below the resonant frequency of their
woofer. You can actually drive the woofer so far forwards or
backwards that the voice coil pops out of the gap (in the front) or
hits the magnet (in the back). THWAP... permanent damage.

Speakers can also be damaged by a fault in the amplifier itself...
e.g. a shorted output transistor. Such short circuits can cause the
output voltage to "slam against the rails" (maximum positive or
negative), and this will both pop the woofer out to its maximum
excursion limit (as above) and turn the small voice coil into a
hundreds-of-watts heater. In his book on audio amplifiers, Doug Self
reports that deliberately DC-faulting an audio amplifier in this
general power range can destroy a loudspeaker system within a second
or so - the voice coil and cone literally caught fire!

So, many audio amplifiers and receivers (and yours is one such) have a
DC fault protection circuit. They monitor the average voltage level
at the output, and if it moves far enough away from 0 volts for long
enough, the protection circuit kicks into action and turns off the
outputs (and sometimes even the power supply) to protect the
loudspeakers. Think of it as a sophisticated electronic "fuse" of
sorts.

Apparently, a 7 Hz signal (at the level you're trying for) is
low enough in frequency to be interpreted as either "DC fault"
or "sub-sonic power capable of damaging loudspeakers" and the
protection circuit is operating. That's probably a more
conservative limit than you'd find in a high-end amplifier, but
it seems reasonable for a home-theatre amplifier and it allows
the circuit to react rapidly in case of a fault.

The analog input to the receiver (or the analog output of your sound
card) probably has a high-pass filter which blocks signals as low as 7
Hz. HDMI, being digital, doesn't have a simple passive filter like
this, and so it's capable of passing very-low-frequency signals.

If you want to generate subsonics like this, and want to risk your
loudspeakers by playing them, you'll need a different amplifier - one
which was designed for that purpose (or, at least, one which doesn't
have a "protect the owner's expensive loudspeaker from expensive
accidents" safeguard).
"

He was probably slightly mislead by my previous analog experiment where the protection did not trigger (tests was not at 100% volume), but my recent experiment (with 100% volume) showed that the protection is also there on analog signals ! ;)

See below for more details, I know this text below is fuzzy but wth, see below for links to videos proving it:

I just tested it on analog connections and the same thing happens eventually, the receiver goes into "protection" mode.

Old stinky DreamPC from 2006 situation:

The reason why it did not happen the other day was because the volume was not at 100%.

(The Creative X-Fi Elite Pro soundblaster has control over volume as well as the web browser/tone generator)

Both must be at 100% to mimic the situation which occurs on the other system:

The toshiba L670 laptop which uses HDMI and ASIO4ALL driver.

With the laptop situation the volume is always at 100% because the ASIO4ALL driver does not seem to have any control over volume.

So I think I now understand what happens:

The sinus wave is very slow at 1 to 5 Hertz or so... so it's not or barely hearable... at least on speakers, on a subwoofer it might be different, but I have no subwoofer currently.

Because the membrane of the speakers move so slowly it cannot be heard.... but because the volume is set to 100% to membranes of the speakers are pushed to their outer limitations... and this could cause maybe damage on some speakers, like described by the other two persons, they might fall out, or touch something.

Perhaps with my speakers this is not an issue because as far as I know/can tell there is no damage, or at least I think so lol.

Since the sinus wave is moving rather slowly... 5 times per second or 7 times per second, the risk of damage is maybe low.... or maybe not... depends on how hard the membrane vibrations, 5x or 7x per second can still be quite fast....

So setting the volume to 100% has no effect on hearability of the wave, because it's moving so slow... it's not hearably... even at 100%.

Perhaps not enough air is being moved around at this frequency... at least from these little speakers.

I could do further testing and remove the foam on the front of the speakers to verify that they are indeed vibrating, but I am not going to do that, because I have seen enough.

I find Dave Platt's explanation believable, except he was wrong with one thing. The protection is available for HDMI but also ANALOG signal.

I will upload the finally video now...

Denon Receiver Shutdown Mystery Solved Part 1 of 2:
https://youtu.be/cnruFMnrrrw

Denon Receiver Shutdown Mystery Solved Part 2 of 2:
https://youtu.be/A9xSgRI8cvA

So there was some thruth to my conspiracy theory... haha... there is some circuitry in there that can shutdown the receiver if it receives a "strange signal" / "strange audio wave" :)

Bye,
Skybuck.