Axiom Home Page Forums General Discussion Technical Questions below 20hz

Can someone explain exactly what happends when you play something below 20hz? My understanding is that a person can not hear anything below 20hz, you can experience, feel, the feq below 20hz.

I want to know what this feels like, Is there a test disk that loops playing frequency below 20hz?


tia

Stand outside during an earthquake.
The rumble and breeze you feel are sound waves below 20Hz.

I thought about that but we just dont have earthquakes around here, im stuck looking for a CD.

The Digital Video Essentials contains a Buzz & Rattle Test, 15 Hz to 300 Hz. The only problem is that the test starts at 15Hz then sweeps up to 20Hz and higher to quickly. I would perfer the signal to stay at around 16 for at least a minute, not one second. Regardless, it seems I can 'hear' the signal at 17Hz or 18Hz and I think im hearing it at 16Hz also, its kinda hard to tell.

Audacity will generate tones. Then export them as waves at cd quality. then burn them to an audio disk.

18 hz sounded like a line of dominos falling down, slightly sped up. this in on my 10 yr old altec lansing computer speakers.

audacity is good open source software.

Randy

Here's a minute of 20Hz as a WAV file... burn to a CD...

It's ZIPped to make it nice and small.

Bren R.

thanks Randy and Bren! didnt expect that.

Ill download the the open source and look for the tone generater I gues comes with the package. If not yall gave me an idea of how to google the sounds.

Bren, the link for the WAV file no longer exist.

Hopefully in a few days my ears will be trained and I will be able to stand up with authority and say "WOW!! did you fell that, that was a 18.33 Hz!!"

thanks again

You could give this cd a try.

Forgive my newbness but I'm doubtfull here.

OK, I'm sure a small % of people can hear noises below 20 Hz but what I'm trying to figure out is how the little computer speakers could actually produce anything that low.

Is it physically possible for a minature tweeter and a 3-4" (if your lucky) mid range to even produce noises less than 20Hz? (My uneducated guess is that they quit much higher than that?)
or
is it just interpreting and creating a signal the best it can that is much higher up in the audible spectrum?

Enlightenment please?

They can't. You shouldn't try to listen to this on computer speakers...

The cd I referenced to is a subwoofer test tone CD and not made to play on computer speakers, or anything other than a sub for that matter.

a heads-up from the avs board, something i didnt realize

"Be careful as sustained tones can cause damage to a driver; overheats the voice coil." ... "Risk of thermal damage"

not the ep500 or 600 digitals.

Oops... mistyped the url...

Here.

Bren R.

This question came up quite obliquely a while back, when someone suggested a surf of this site: rotary woofers . This link How low can we hear? shows some research of hearing tests going down below 20 Hz.
Have fun reading!
--Martin

Good answers and references.

I hope you will forgive me if I don't try the experiment myself with my own PC speakers. If the last link's chart data is correct in saying that you need at least 75 to 80 DB to hear below 20Hz, I'm afraid that the noise I will hear is the sound of my PC speakers blowing up as I try to get the volume anywhere near that high.

Great conversation though. My Avia test CD just arrived in the mail last night so I'm currently addicted to chatting about this stuff.

Next month it might be back to how to raise my center diff. skid plate without needing to get into a CV driveshaft or will I really need a new video card when Vanguard is released for the PC.

I vote yes on the new video card and as a mechanic are you talking about the double cardan(U-Joint) style or the actual CV with boot style driveshaft. The boot style is terrible for off road apps.