Human Hearing.....

[mtrycrafts]

How would I do this test without speakers? I'm not gonna jab the probes into my ears, ya know.

Repeat after me- "This site is called AUDIOHOLICS, not Videoholics".

I only used that number because that's what I was told years ago. To be honest, I don't really care what the frequency is- I just find it annoying.

When I said be careful, I didn't say not to. Just watch the volume levels as the tweeters don't forgive much power into them.
I think I kept increasing the volume to see if that helps. It didn't
Yes, this is AH not VH, but we do talk about TVs and video here nonetheless.

 

[mtrycrafts]

...

Surlykke and Kalko found that bats emit a sound that is stronger than any other animal in air. The exceptionally loud sounds exceed 140 decibels (dB) SPL (Sound Pressure Level measured at 10 cm from the bat's mouth). This is louder than the 115 - 120 dB that is emitted at a loud rock concert and the 120 dB human threshold of pain."

It would be interesting to know if that ultrasonic frequency decreases at a different rate than our audio band at 6 dB per distance doubling in free space.
10 cm is pretty close to that animal, 4"

 

[mtrycrafts]

That's insanely loud! I'm glad we can't hear that otherwise my ears (and tweeters) would explode every time I watched the Planet Earth Caves episode. According to the book below, dolphins echolcation signals can reach 230 dB!...

Yep, they like to talk to each other over long distances a lot

 

[yepimonfire]

That's insanely loud! I'm glad we can't hear that otherwise my ears (and tweeters) would explode every time I watched the Planet Earth Caves episode. According to the book below, dolphins echolcation signals can reach 230 dB!

http://books.google.com/books?id=qjemeaVFBTUC&pg=PA392&lpg=PA392&dq=dolphin+echolocation+spl&source=bl&ots=bq3T0cGMBI&sig=lZkgY_Upt9ySYp6cnPSALvBHYw4&hl=en&ei=i-yFS_fLFYi6NvXK5bUM&sa=X&oi=book_result&ct=result&resnum=1&ved=0CAYQ6AEwAA#v=onepage&q=dolphin echolocation spl&f=false

230 DB is enough to kill you

 

[highfigh]

Yep, they like to talk to each other over long distances a lot

And the thing about them communicating in water that makes the extremely high SPL necessary is that the sound is as close to a point source as we're likely to find, so it's really important that it goes in all directions well. Given that the speed of sound in water is in the area of 3000 ft/sec, it's amazing that they can determine locations and contours & react so quickly.

 

[GO-NAD!]

In high school, they had ultrasonic motion detectors and my brother & I could hear them. I later found out that they worked in the range of 23K, although it's possible that I was hearing some sub-harmonic. It definitely wasn't a octave lower, though and it was more like a feeling of pressure than a specific tone but it was immediately felt when they were turned on or off.

I think I know what you're talking about. Many years ago, when I was 18, I had just joined the Navy and during basic training, there was lots of rifle drill. Well, the rifles were kept in a secure storage room and at the start of each drill period, we'd have to walk through one door, pick up a rifle and walk out another door. I always hated walking through the room as I could hear and feel an oppressive noise that almost seemed like an electrical shock. I can't describe it any better than that. I asked other guys about it, but they had no idea what I was talking about. I can only assume it was part of the security system.

Then, 13-14 years later, I was assigned to an honour guard, that included - you guessed it - rifle drill. For the first guard practice, and with great dread, I headed into that very same room to pick up a rifle. Surprise, surprise, I couldn't hear that same noise anymore. I wasn't sure if I should be happy or sad about it...

 

[highfigh]

I think I know what you're talking about. Many years ago, when I was 18, I had just joined the Navy and during basic training, there was lots of rifle drill. Well, the rifles were kept in a secure storage room and at the start of each drill period, we'd have to walk through one door, pick up a rifle and walk out another door. I always hated walking through the room as I could hear and feel an oppressive noise that almost seemed like an electrical shock. I can't describe it any better than that. I asked other guys about it, but they had no idea what I was talking about. I can only assume it was part of the security system.

Then, 13-14 years later, I was assigned to an honour guard, that included - you guessed it - rifle drill. For the first guard practice, and with great dread, I headed into that very same room to pick up a rifle. Surprise, surprise, I couldn't hear that same noise anymore. I wasn't sure if I should be happy or sad about it...

Are you sure the inability to hear the oppressive noise wasn't due to being exposed to all of the gunfire? That's incredibly bad for hearing/ears.

 

[GO-NAD!]

Are you sure the inability to hear the oppressive noise wasn't due to being exposed to all of the gunfire? That's incredibly bad for hearing/ears.

Well, in the situation I was referring to, it was just parade drilll - no shooting on the range. As for being exposed to the noise of gunfire, I only went to the range, just for a day, every year or two to remain "qualified". And, we always wore hearing protection, although I don't know how effective it was.

In my job, I was more exposed to machinery noise in ships/submarines. Whatever hearing loss I've experienced over the years, I blame on that.

 

[3db]

Well, in the situation I was referring to, it was just parade drilll - no shooting on the range. As for being exposed to the noise of gunfire, I only went to the range, just for a day, every year or two to remain "qualified". And, we always wore hearing protection, although I don't know how effective it was.

In my job, I was more exposed to machinery noise in ships/submarines. Whatever hearing loss I've experienced over the years, I blame on that.

I can relate to the machinery noise having grown up on a farm and being around it without hearing protection