Frequency Ranges of Speakers? (and what's safe?)

[ShaneC]

After looking at the SPL's and hearing Loss thread, I decided to test out a freq generator on these speakers.

(PC -> Pioneer RG-9 -> Sansui G-3500 -> Technics SB-G500)

I didn't want to run it long, for fear of damaging anything, but I successfully (and audibly) hit 22,101hz on the highend.

I'm apparently deaf at 20hz, but I could feel it.

At 3hz I could still tell the woofers were moving. Below 3hz, absolutely nothing.

So, what's the chances of damaging anything if I run this "test" again just for giggles. Everything seems fine so far, but its not something i plan on doing everyday either.

 

[basite]

of course the woofers are moving at very low frequencies, it's called rumble. However, we wouldn't hear a darn thing even when whe'd be able to hear so low.

 

[matt_mcg]

I was playing around doing something similar at the weekend. I had a suspicion that a new (cheap) receiver was cutting off the bottom end. So I used my PC as a signal generator.

I couldn't hear anything below 30hz from the speakers. From about 40hz up the sound was loud and clear.

 

[Tropical]

You may hear the harmonics, too, as speakers can't be treated like a pure freq generator.

 

[Zilch]

Most all woofers will play down to DC. If you crank them up below 30 - 40 Hz with a signal generator trying to hear them down there, you could damage them. Sine waves have more energy content than music. Same at the high end. Use common sense and low to moderate levels.... :yes:

 

[dnewma04]

Most adults, even with near perfect hearing don't hear much past 16khz. Kids with no exposure to loud noise can sometimes get into that 20khz range but even most kids fall well short. Thats not to say you can't perceive sound at higher freq. I've learned to ignore claims of hearing <20hz and >20000hz as they are almost always hearing things like harmonics, vibrations in the environment etc. What i'm getting at is don't feel bad about not being able to hear 20khz, you're in the 99th percentile. Typical human hearing doesn't approach 20-20khz, it's most often in the 26hz-16khz range.

 

[Charivari]

You may hear the harmonics, too, as speakers can't be treated like a pure freq generator.

Indeed, particularly with the upper end extension. Many tweeters, at least those used more often for lower cost, at the top end of their extension tend to produce audible sub-harmonics that can be mistaken for hearing ultrasonics.

Even when one's hearing is extended, it can be greatly diminished at the top end such that audibility requires unnaturally high levels as to be impractical. Interestingly, though many may no longer hear tonality up to 20kHz, there can be enough residual hearing ability as to have a strong signal up there cause discomfort without recognizing the cause -- something that can make for a slightly entertaining prank to pull on friends.

With high quality drivers not prone to sub-harmonics, the frequency generators themselves can cause them be it test bench gear or with a soundcard and software program. My HP 200CD audio oscillator tends to whine with the frequency it's producing and can be louder than the driver itself at the frequency extremes.

Typical human hearing doesn't approach 20-20khz, it's most often in the 26hz-16khz range.

For the low end, I'd have to disagree. While with headphones, the typical human may not be able to hear low bass, I do strongly believe that synæsthesia tends to kick in. Our brain interprets the low frequency vibrations the body feels to be sound and thus we can hear what we feel. It can also work in reverse: There have been many times that while listening to music on my headphones, I've had to check to make sure my subwoofer was off as I was feeling the bass notes in addition to hearing them. All things considered, this would be an important survival mechanism as those who "hear" the 8Hz-10Hz rumble of a predatory cat's growl well enough to know to run is more likely to produce more kids who hear what they feel. Research studies have shown that participants feel very anxious when exposed to such low frequencies.

- JP

 

[dnewma04]

Good catch, I only specified perception with high freq. Obviously, we can perceive lower freqs, as well. It's a much more noticeable phenomena. So, while humans can perceive sound that extends well above and below the quoted 20-20k range, we generally speaking (read generally speaking as not a single person ever tested by a doctor/professor who works extensively with human hearing for 30+ years) cannot hear 20-20k.