15 replies to this topic

[jmander]

Just wondering if anyone here knows what equipment/software would be needed to test for infrasound levels during paranormal investigations. Is there relatively inexpensive audio equipment out there that can detect infrasound, or would it cost a fortune?

[Mark London]

Hi Jmander

Im certainly no expert on tech but a decent DVR is good...surely !?!

[jmander]

Hi Jmander

Im certainly no expert on tech but a decent DVR is good...surely !?!

I'm not sure...infrasound is sound that is of a frequency below that which can be heard by human ears. I don't know whether or not a digital voice recorder can detect infrasound, but I'm under the impression that it cannot. Anyone else know what can be used to test infrasound levels?

[HRPRG_Belinda]

I'm not sure if this is what your talking about but I use an instrument called a sound level meter. If we are sitting quietly during an investigtion trying to record evp we can turn it on and I have seen it register noise when there was none. Later when we check the recording there will be evp where the sound level meter registered the unheard (by us) noise.
Belinda

[stoner]

I'm not sure if this is what your talking about but I use an instrument called a sound level meter. If we are sitting quietly during an investigtion trying to record evp we can turn it on and I have seen it register noise when there was none. Later when we check the recording there will be evp where the sound level meter registered the unheard (by us) noise.
Belinda

Hi all, we came accorss a design to build an infrasound detector from a large 15--18" speaker and an amp, it worked to some degree but was not great, too big and the speaker was a very bad mic.

So with huge help from people on line we have build an electronic one , will measure 12 Hz and up, if anyone is interested in it pop me a PM

[Infrasound]

I'm not sure if this is what your talking about but I use an instrument called a sound level meter. If we are sitting quietly during an investigtion trying to record evp we can turn it on and I have seen it register noise when there was none. Later when we check the recording there will be evp where the sound level meter registered the unheard (by us) noise.
Belinda

Hi all, we came accorss a design to build an infrasound detector from a large 15--18" speaker and an amp, it worked to some degree but was not great, too big and the speaker was a very bad mic.

So with huge help from people on line we have build an electronic one , will measure 12 Hz and up, if anyone is interested in it pop me a PM

I need such a meter asap. Could you let me know whether your meter is certified as a device officially and can be purchased.

Also, I just registered at Ghostvillage (for the very reason to contact you. Please, reply to my e-mail, if you can. If not, advice how to let you know my e-mail, so it would not become public.

Thanks and regards.

[CaveRat2]

Forget software and using conventional audio for infrasound. Instead consider vibration detection equipment. These will go down well into the subaudio frequencies. I use an inductive sensor for this which floats in a magnetic field and utilizes the surface area itself as a sensor. It will respond to .5 Hz up to about 15 Hz. The output is displayed on an oscilloscope since it is below the range of human hearing and must be seen rather than heard.

As for commercial sources consider seismic equipment used in earthquake detection as this is more along the lines of what you need.

[afterlife]

That sounds interesting maybe I'll get one to!

[OMPRDave]

Going to the other end of the spectrum, has anyone tried ultrasound detectors (like the kind used for recording bat echolocation)?

[CaveRat2]

I have used ultrasound detection, and there is quite an array of sounds in those frequencies. However to date I have not detected anything that couldn't be attributed to nature in some way. Nothing paranormal. I have done frequency hetrodyning as well as direct visual display to detect these frequency ranges, same results both ways.

[OMPRDave]

Thanks, Jim. I've always been interested in seeing how those two ends of the spectrum have been explored in paranormal research and to hear of the results.

[Gheist]

hello gang, i just registered today, and i'm quite interested in the topic. i rather new to the topic and i possess no degree sound recording , so if i sound a little "blonde", do forgive. i've read a few articles about infrasound and i's become a big fascination of mine... that, and ghosts

here'z tha catch:

i'm a musician, and i want to record various infrasounds and put them in my music. i want to amplify the infrasound so you can hear it, but i also want the unhearable version so it could be played from a special set of speakers that can emit its frequency.


soooooo my question is: where can i get a quality mic and speaker that can capture and produce these sounds? um, same goes with computer software... can MIDI pick up on the unlistenable infrasounds? can recording on a vinyl record capture these sounds? if not what can?

[Zack Lemons]

hello gang, i just registered today, and i'm quite interested in the topic. i rather new to the topic and i possess no degree sound recording , so if i sound a little "blonde", do forgive. i've read a few articles about infrasound and i's become a big fascination of mine... that, and ghosts

Welcome to the forum.

TCPSI uses the members equipment they have available. So far we use a few Kodak "Easy Share" 9.2 Megapixel cameras purchased at Walmart. But the sound recording on these cameras "gargle" the human voice so badly the EVPs we picked on these sound awful.

For our best sound we have used mp3 recorders. One member has a DXG 3 Megapixel camera that he uses just for sound. It has a sound only setting and gets good quality sound for being such a low quality camera.

i'm a musician, and i want to record various infrasounds and put them in my music. i want to amplify the infrasound so you can hear it, but i also want the unhearable version so it could be played from a special set of speakers that can emit its frequency.

Don't expect it to go platinum...

Oddly enough Shane and I were at the Calvary Cemetery in Kawkawlin and a female entity was following us the graveyard unknown to us at that time. When we dumped the mp3 on the PC we found her voice was slightly audible to us without increasing the volume. So not all EVPs are whispers. Theories vary that the EVP is the ghost's ability to manipulated digital equipment or make an actual sound wave. During the session Shane's camera batteries died and and I knew they were fresh so at that point you have an entity draining the batteries to generate the sound. We use a program (free) Audacity to filter the sound we run a high pass and a low pass filter at 85 Hz and 255 Hz which singles out the human voice range.

soooooo my question is: where can i get a quality mic and speaker that can capture and produce these sounds? um, same goes with computer software... can MIDI pick up on the unlistenable infrasounds? can recording on a vinyl record capture these sounds? if not what can?

Some will say that since the ghost doesn't use the mic to make the sounds, you don't need a quality mic. I play these sounds though my stereo hooked to the PC. MIDI to my understanding cannot reproduce the human voice? If so, then even if you got an EVP it would just sound like a bunch of random notes.

Vinyl? Who uses that any more? I suppose that it could but you will be needing to amp it up through an amp head instead of using the digital media. I understand if a ghost can manipulate tiny micro electronics of a recorder I am sure they could wiggle a needle.

The very first EVPs (That I am aware of) were recorded using hand held magnetic tape recorders. Much like the one seen in the movie "The 6th Sense" where the doctor is in his basement listening to the old session.

Zack

[CaveRat2]

hello gang, i just registered today, and i'm quite interested in the topic. i rather new to the topic and i possess no degree sound recording , so if i sound a little "blonde", do forgive. i've read a few articles about infrasound and i's become a big fascination of mine... that, and ghosts

here'z tha catch:

i'm a musician, and i want to record various infrasounds and put them in my music. i want to amplify the infrasound so you can hear it, but i also want the unhearable version so it could be played from a special set of speakers that can emit its frequency.


soooooo my question is: where can i get a quality mic and speaker that can capture and produce these sounds? um, same goes with computer software... can MIDI pick up on the unlistenable infrasounds? can recording on a vinyl record capture these sounds? if not what can?

You are not going to be able to do this in a conventional manner. Audio amplifiers, even high end amps genrally don't reproduce below 20 Hz. This is the low end of hearing. There are special DC amplifiers which will process these frequencies, but almost no one who would be listening to your music would have equipment capable of reproducing them.

But assuming you want to do this, a condenser mic should be able to capture these low frequencies. (Not the little electret mics you find in consumer equipment, I am refering to professional grade ribbon mics. ) Next you will need a DC operational amplifier to boost the levels. Standard amplifiers like you find in audio gear generally use coupling capacitors which will block extremely low frequencies. Direct coupled amps will pass them. Recording can be done using digital since analog tape also suffers from rolloff at sub audio frequencies. Digital has the advantage of being able to record down to DC levels (Vinyl can capture these low frequencies, but no pickup cartridge has sufficient low end response to capture them from the record. Plus there are tone arm damping factors which would prevent this from being practical.) Speakers are not a real problem as long as you are using a direct coupled amplifier in playback as well to drive them.. Any large loudspeaker will reproduce infrasound, but the larger the speaker cone the better. It should also be mounted in an airtight enclosure for best results.

Now, may I ask, why do you want to do this?

[Ghost_hunter_1954]

A key word here is "cheap". The answer is depending on your deffinition of "Cheap" no. Infrasound falls into the range of 19.9Hz to .01 Hz. As such, it requires some specialized equipment to allow recording, and then you can only see the waveform with software, not hear it.

Here is what we use to record Infrasound:

Earthworks M-50 Measurement Omnidirectional Microphone
http://www.google.co...ed=0CD8Q8wIwAg#
Cost= $1299.00

USB-Pre Microphone Interface - Flat down to 10Hz, but can measure lower:
http://www.google.co...ed=0CFgQ8wIwAw#

Cost=about $550.00 plus shipping and tax online

A laptop computer

Software - There really isn't any entry level software in which an untrained person could use available. If you have some knowledge of Fast Fornier Transforms and audio engineering principles, a relatively low cost solution is Sigview Spectrum Analysis software,

http://www.sigview.com/index.htm

The cost is a measly $139.00 which is a bargain. There is a PDF manual available for free on the site, as well as a free 21 day trial version of the software. However, you will need some extensivce knowledge of audio analysis protocols to prperly use it, because we are using the software in an area where there are no instructions for use. None the less it works.

There is a tone of free RTAs out there, none of which work below 20 Hz. There is a low cost pro software called ARTA, but it will only go down to 10 hz, but it is good software. I use Smaart v.7 License: $895

Not for entry level use. It is professional forensic grade software that is an industry standard for audio measurement and analysis.

http://www.rationalacoustics.com/

Not easy or cheap, but a very important part of the puzzle, and you are right in thinking about incorporating it in any paranormal research

Just wondering if anyone here knows what equipment/software would be needed to test for infrasound levels during paranormal investigations. Is there relatively inexpensive audio equipment out there that can detect infrasound, or would it cost a fortune?