Hi,
Just in case you want an easy to built Sine wave signal generator you can use the Exar XR2206 monolithic function generator chip add some components and you have a simple sine wave generator with variable frequency. In case you can not use the MP3 option. I built one to test my amplifiers.
Just in case you want an easy to built Sine wave signal generator you can use the Exar XR2206 monolithic function generator chip add some components and you have a simple sine wave generator with variable frequency. In case you can not use the MP3 option. I built one to test my amplifiers.
Well, it didn't quite all go to plan but it ended up being an interesting exercise.
There are some test tracks attached to this post.
Test track 1 WAV and Test track 1 MP3 are 10 seconds at 440Hz and then 2m 50s at 7.81 Hz. Same track but different formats.
My MP3 players would not reproduce the low frequency at all. A laptop would but with visible noise. You could burn these files to a CDR/CDRW which should be pretty much perfect.
Test track 2 WAV and MP3 are 15 seconds of pure 440Hz sine tone and then 15 seconds of 'sine' from a synthezised function generator. If you listen carefully you should hear the distortion from the generator in the second half.
The pictures shows the 440 Hz generator derived signal. Its super clean but if you look carefully at the sine tips you will see there is a slight discontinuity and that is audible as distortion. It adds a slight harshness to an otherwise pure tone.
The next two pictures (this is where it didn't go to plan) show the problems of connecting a portable device and then using it as a high quality line source (rather than using headphones as intended). The only difference in these last two are the lead connecting to the scope. The first is a proper audio lead, the second a BNC test lead. The only difference is in the capacitive loading each presents and as you can see the audio lead upset the laptop output feed with the presence of HF oscillation and noise on the top part of the sine. Adding a load resistor of 1k or so cleaned things up.
So this really does seem to confirm that many players really do 'use' the headphone loading as part of the output filter/network and that running unterminated can cause an issue. Final picture are the leads.
So I would say 'everything' depends on the quality of the player used and that you must confirm with a scope that all is well. Don't assume it is.
Test Track 1 MP3
Test Track 1 WAV
Test Track 2 MP3
Test Track 2 WAV
Attachments
Hi Mooly, wwenze and Tauro0221!
wwenze, thank you!
From what i have read the 7.83hz frequency is mentioned as pure sine wave yet when people try to reproduce it, the circuit described generate square wave but this and this might be exceptions.
Tauro0221,
I will look at the Exar XR2206 monolithic function generator!
Mooly,
So much work! this is very very kind of you.
I heard slight distortion before the second half but this might be because of repeated listening.
Many thanks to you, this is great!
wwenze, thank you!
I do not have any technical informations on the acoustic revive except this picture (the device that i have seen was closed)
The accoustic revive has a pcb antenna but the earthsafe is different, this one too.
From what i have read the 7.83hz frequency is mentioned as pure sine wave yet when people try to reproduce it, the circuit described generate square wave but this and this might be exceptions.
Tauro0221,
I will look at the Exar XR2206 monolithic function generator!
Mooly,
So much work! this is very very kind of you.
I heard slight distortion before the second half but this might be because of repeated listening.
I will test the 555 square wave generator, mp3 player and a portable cd player (as test)
Many thanks to you, this is great!
No problem, pleased it was useful.
Its always good to do a bit of practical testing too because if you had asked me would an MP3 player reproduce even 10Hz or 20Hz I would have said 'of course it will'. The evidence says otherwise though... which is a characteristic of the player not the files or format. The PC soundcard will go that low but again, if its a portable device like a laptop then beware. As I found, the output is not really clean although it would clean up with a simple R/C filter to get a clean 7.81Hz signal.
(A portable CD player should be fine (those I have used and tested and they do go pretty low, even if not quite as low as the red book standard)
Well if we have a stick that we don't know what its resonant frequency is... though we can expect it to be very high compared to single digit hertz... and we try to put a square wave through it and crank the volts until we get any useful output of the fundamental frequency...
Maybe the cancer helps to repair the damaged hair cells in my cochlea.
Maybe the cancer helps to repair the damaged hair cells in my cochlea.
Hi!
That was an amazing day!
we tested a lot of things and heard many stories (all the club members, parents who were interested, my teacher and his dad!)
We had two oscilloscopes one analog and one digital.
I had a sony portable cd player, 555 square generator, mp3 player and cd with 7.83hz, 8hz and 10hz.
Club members had mp3 players (and one mp4 player) and a portable cd player (don't remember the brand)
Someone also had a dds function generator.
The sony portable cd player worked at 10hz and 7.83hz (but slight skipping sound also slight distortion)
No mp3 players could play the frequencies except three who could play as low as 8hz with slight distortions.
555 square wave generator worked ok (could really fine tune the frequencies)
The dds function generator also worked (resolution 0.01hz)
I showed my antenna but someone explained that a coil should also be wound to compare the two.
We learned about various coil (i never knew there was flat coils!)
My teacher father explained that he had seen a portable device (forty years ago i think) that a friend received.
The circuit generated a square wave and had a small ferrite rod and a coil.
Thank you very much Mooly, wwenze and Tauro0221 for your time and support in our club project!
That was an amazing day!
we tested a lot of things and heard many stories (all the club members, parents who were interested, my teacher and his dad!)
We had two oscilloscopes one analog and one digital.
I had a sony portable cd player, 555 square generator, mp3 player and cd with 7.83hz, 8hz and 10hz.
Club members had mp3 players (and one mp4 player) and a portable cd player (don't remember the brand)
Someone also had a dds function generator.
The sony portable cd player worked at 10hz and 7.83hz (but slight skipping sound also slight distortion)
No mp3 players could play the frequencies except three who could play as low as 8hz with slight distortions.
555 square wave generator worked ok (could really fine tune the frequencies)
The dds function generator also worked (resolution 0.01hz)
I showed my antenna but someone explained that a coil should also be wound to compare the two.
We learned about various coil (i never knew there was flat coils!)
My teacher father explained that he had seen a portable device (forty years ago i think) that a friend received.
The circuit generated a square wave and had a small ferrite rod and a coil.
Thank you very much Mooly, wwenze and Tauro0221 for your time and support in our club project!
A coil is not a VLF transmiting antennae. Again , google it.
Then again why should reality be a concern now. If this pseudo science is supposed to be education, there's something wrong going on. Why not build a mind reading machine in your science class? You can probably even fool your selves into believing it works.
Then again why should reality be a concern now. If this pseudo science is supposed to be education, there's something wrong going on. Why not build a mind reading machine in your science class? You can probably even fool your selves into believing it works.
Hi,
I found this site. Is this is what are you looking for to accomplished ?
Here it is the link:Schumann Resonance Devices for Electro-Magnetic Safety
I found this site. Is this is what are you looking for to accomplished ?
Here it is the link:Schumann Resonance Devices for Electro-Magnetic Safety
Hi tauro0221!
Thank you for the link!
the size is very good, i thought the earthsafe was only for the home and not portable (i will try to search if a circuit is available!)
The ideal is a device of this size (we will first try with a 555 circuit, it's easier for us)
I found a picture of the inside of the revive and one of a similar device.
Another picture (from the factory), a clone.
Circuit details of the accoustic revive.
cbdb,
I'm sorry but i don't understand what you mean, i explained that we are members of a junior audio club (not science class) are you asking something?
Thank you for the link!
the size is very good, i thought the earthsafe was only for the home and not portable (i will try to search if a circuit is available!)
The ideal is a device of this size (we will first try with a 555 circuit, it's easier for us)
I found a picture of the inside of the revive and one of a similar device.
Another picture (from the factory), a clone.
Circuit details of the accoustic revive.
cbdb,
I'm sorry but i don't understand what you mean, i explained that we are members of a junior audio club (not science class) are you asking something?
Hi,
Here is another link with an schematic on how to built it.
Link:The Soliton Pulses Generator experiment by Jean-Louis Naudin
Here is another link with an schematic on how to built it.
Link:The Soliton Pulses Generator experiment by Jean-Louis Naudin
cbdb,
I'm sorry but i don't understand what you mean, i explained that we are members of a junior audio club (not science class) are you asking something?[/QUOTE]
I though audio used science, my mistake. I'm not asking, I'm telling you that those are not VLF antenae. Are there any numbers for the output of those devices? Say the volts /meter field at a 2 meter distance.
I'm sorry but i don't understand what you mean, i explained that we are members of a junior audio club (not science class) are you asking something?[/QUOTE]
I though audio used science, my mistake. I'm not asking, I'm telling you that those are not VLF antenae. Are there any numbers for the output of those devices? Say the volts /meter field at a 2 meter distance.
Hi,
Quote: "What matter is a clean sine wave frequency tuned to 7.83hz (this is the only requirement)"
I think you can use an Arduino Uno using the PWM command to generate this frequency. The Arduino PWM can generate a square signal from 0 to 488 cycles.
Here it is link explaining it. :Secrets of Arduino PWM
Quote: "What matter is a clean sine wave frequency tuned to 7.83hz (this is the only requirement)"
I think you can use an Arduino Uno using the PWM command to generate this frequency. The Arduino PWM can generate a square signal from 0 to 488 cycles.
Here it is link explaining it. :Secrets of Arduino PWM
Hi!
We decided what we will test which is:
dds function generator
555 square wave circuit
PWM arduino circuit (Thank you tauro0221 this was a great idea!)
The original accoustic revive has a pcb antenna, we will try that and coils (this is mentioned in this thread)
Thanks a lot for your help, this forum is really great!
We decided what we will test which is:
dds function generator
555 square wave circuit
PWM arduino circuit (Thank you tauro0221 this was a great idea!)
The original accoustic revive has a pcb antenna, we will try that and coils (this is mentioned in this thread)
Thanks a lot for your help, this forum is really great!
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