[medium jim]

I'm starting this thread in response to another were there is science saying the human ear cannot really hear bass under 40hz that well in relation to 3.5khz.

With that said, let's have a good debate!

Jim

[Devil Doc]

We have a member who's an audiologist. Perhaps he'll come along and end the debate, at least for me.

Doc

[a1p1]

I'm starting this thread in response to another were there is science saying the human ear cannot really hear bass under 40hz that well in relation to 3.5khz.

With that said, let's have a good debate!

Jim

The human ear is not as sensitive to 40Hz as it it is to 3.5kHz.  See below the lowermost curve.  This represents the thresholds (lowest intensity that can be perceived) across frequencies for individuals with normal hearing.   Threshold at 40Hz is about 50dBSPL while at 3.5kHz its -5dBSPL.  You can see that sensitivity continues to drop at even lower frequencies. 

AP

[medium jim]

The human ear is not as sensitive to 40Hz as it it is to 3.5kHz.  See below the lowermost curve.  This represents the thresholds (lowest intensity that can be perceived) across frequencies for individuals with normal hearing.   Threshold at 40Hz is about 50dBSPL while at 3.5kHz its -5dBSPL.  You can see that sensitivity continues to drop at even lower frequencies. 

AP

The following is a verbatim quote from JohnR in reference to this matter:

..."he's looking at the Fletcher Munson Curves for 0 dB. The threshold of hearing. At any normal level, the curves are much flatter.

And anyway, it's a complete red herring, as if you hear a certain thing in real life, then if reproduced accurately and at the same level, you will need the same (acoustic) level to hear the same thing."

I pretty comfortable in saying I can hear a 3db difference at 44hz

Jim

[werd]

Jim

You do not hear bass. You feel bass through a process called bone induction.

The natural resonant frequency for the human body is 6hz. This is why a reoccurring 6hz signal could kill you and not just make your deaf.

[Chromisdesigns]

You feel, as much as hear, a lot of bass frequencies.

[DaveC113]

I can't believe there is debate that the human ear has the same sensitivity across the frequency spectrum. Fletcher Munson was not just a fabrication... If you really want to know, play a 40 Hz tone at 80 dB and one at 3.5 kHz and see which one you perceive as being louder and more noticeable. Experience will then correlate with science...

[*Scotty*]

I would like to see the comments of a neurologist engaged in researching how our auditory systems work and the part our brains play in the perception of auditory stimuli. There has been research done on the areas of the brain stimulated by different genres of music but I am unaware of any research on the perceptual threshold of musical instruments or works of music based on the frequencies the instrument can produce or the harmonics contained in a piece of music.
 To clear up earlier misconceptions about how loud bass frequencies need to be before we can hear them, here is a graph and explanation cut and pasted from the Hyperphysics website


The measured threshold of hearing curve shows that the sound intensity required to be heard is quite different for different frequencies. The standard threshold of hearing at 1000 Hz is nominally taken to be 0 dB, but the actual curves show the measured threshold at 1000 Hz to be about 4 dB. There is marked discrimination against low frequencies so that about 60 dB is required to be heard at 30 Hz. The maximum sensitivity at about 3500 to 4000 Hz is related to the resonance of the auditory canal.

As you can see from the above explanation all we need to hear 32Hz is a SPL of 60dB and 20hz can be perceived at about a SPL of 73dB. This is why we can successfully reproduce and hear bass frequencies in our listening rooms. Obviously it doesn't need to be as loud as blast of thunder to be audible.
 I think one of the things that has been overlooked is the sensitivity our entire body to the spectrum of low frequency sound. As the frequency decreases our entire body becomes increasingly more sensitive to sonic stimulation. By the time a frequency of about 32Hz is reached it is generally agreed that sound is as much felt by the body as heard by the ear. Below 32hz you have increasingly transitioned to feeling the sound rather than just hearing it with your ears.
I think this sensation is one reason that accurately reproduced bass can be so addictive for many of us, myself included.
Scotty
http://hyperphysics.phy-astr.gsu.edu/hbase/Sound/earcrv.html#c1

[poseidonsvoice]

Completely agree. Great post Scotty. There is a reason why a tuba is the size that it is and a piccolo is a size that it is. Both instruments can produce bass although one is a little more audible than the other

Sorry for the off topic rant...

Anand.

[Davey]

Well, size is one factor.    Required SPL....if it's small....can reduce the size requirement quite a bit.

If I have my high quality earbuds installed and playing a 32Hz tone I can clearly "hear" it and also enjoy excellent bass response when playing music.  I'm not sure I agree that bass is "felt rather than heard"...in all cases.  I certainly don't perceive it that way when listening to headphones.

Cheers,

Dave.

[werd]

I would like to see the comments of a neurologist engaged in researching how our auditory systems work and the part our brains play in the perception of auditory stimuli. There has been research done on the areas of the brain stimulated by different genres of music but I am unaware of any research on the perceptual threshold of musical instruments or works of music based on the frequencies the instrument can produce or the harmonics contained in a piece of music.
 To clear up earlier misconceptions about how loud bass frequencies need to be before we can hear them, here is a graph and explanation cut and pasted from the Hyperphysics website


The measured threshold of hearing curve shows that the sound intensity required to be heard is quite different for different frequencies. The standard threshold of hearing at 1000 Hz is nominally taken to be 0 dB, but the actual curves show the measured threshold at 1000 Hz to be about 4 dB. There is marked discrimination against low frequencies so that about 60 dB is required to be heard at 30 Hz. The maximum sensitivity at about 3500 to 4000 Hz is related to the resonance of the auditory canal.

As you can see from the above explanation all we need to hear 32Hz is a SPL of 60dB and 20hz can be perceived at about a SPL of 73dB. This is why we can successfully reproduce and hear bass frequencies in our listening rooms. Obviously it doesn't need to be as loud as blast of thunder to be audible.
 I think one of the things that has been overlooked is the sensitivity our entire body to the spectrum of low frequency sound. As the frequency decreases our entire body becomes increasingly more sensitive to sonic stimulation. By the time a frequency of about 32Hz is reached it is generally agreed that sound is as much felt by the body as heard by the ear. Below 32hz you have increasingly transitioned to feeling the sound rather than just hearing it with your ears.
I think this sensation is one reason that accurately reproduced bass can be so addictive for many of us, myself included.
Scotty
http://hyperphysics.phy-astr.gsu.edu/hbase/Sound/earcrv.html#c1

Dude

You don't need a neurologist. All you need to do is hear what appears as part of soundstage in stereo as opposed to what can be felt. You can do this by turning off your sub and playing at low volume. A low concert E from any instrument can Appear in stereo in the sweets pot as a full note played by an instrument this is what we hear.  It will also resonate through a larger speaker with no apparent position of instuments, like what you get from a sub. You can hear and feel most instruments to resolve the note. The lowers notes that are felt just create an ambience and do not require a stereo signal to feel.

[medium jim]

Werd:

You are in the minority on this one....If the Munson Curves were correct, the amount of amplification required to produce bass that could be heard/discerned would be physically impossible.  That by itself blows a huge hole in his theory, wouldn't ya think

BTW, the Fletcher-Munson Curves originated in 1933 well before the advent of subwoofer technology and the device they used were headphones.  I wonder if the same testing was done on current technology if the result wouldn't be a bit different.

I hear what I hear, thank you very much...I also feel bass on certain occasions as well. 

Jim

p.s. As a courtesy, please refer to people you are responding to by their given moniker(s) and not "Dude"

[medium jim]

Werd:

Well integrated subs will also have proper instrument placement.  Bass while primarily energy, does have its own subtitles, nuances, placement, soundstage and frankly, is not transferred by most full range speakers. A good sub(s) will bring these qualities out moreso than full ranger IMHO.   

While you may hear bass in the lower registers from floorstanders, it isn't reproduced as recorded for the most part....I'm sure there are some mega a buck floorstanders that do, but I bet these really have subs incorporated in their design. 

Bottom line for me, I do hear the difference of 3db at 44hz and there is no science that will tell me otherwise.

Jim

[JohnR]

You are in the minority on this one....If the Munson Curves were correct, the amount of amplification required to produce bass that could be heard/discerned would be physically impossible.  That by itself blows a huge hole in his theory, wouldn't ya think

I'm not even sure I understand what you are saying here. But the curve is NOT related to how much amplification you need. It's simply the (standardized) curve on what the threshold of hearing is.

[*Scotty*]

Me either Jim, clarification please.
Scotty

[jimdgoulding]

I've heard that enveloping bass that doesn't seem to be coming from the speakers.  The room even.  It's pretty elating.  Was it actually a part of the recording (i.e. in the music) or the speaker's output engagement with the room?  I suspect the latter.  Don't recall ever having heard it live.  What say ye?

[ricardojoa]

Bass frequecies is like, the lower it gets, the deeper in your body sense. As the frequencies increases the sensation becomes more superficial.

[kevin360]

Hmm, let's think about this for a second. We're a highly social and marvelously vocal species with voices that cover the range (for the most part) from 200-8,000Hz. Our hearing is especially sensitive through that range. Does this really surprise anyone? If so, why?

The other argument concerning the extrapolation of power requirement for audible bass implied by the Fletcher Munson curve is just plain silly (although the amps in my subs are rated at 1800W ). However, the implication of that curve is why my system response is tilted up ~10dB in the lower bass.

[richidoo]

Sound is audible below 40Hz. But 20Hz for some people is not so much audible as it is felt. Extension to 20Hz gives a feeling of scale, authority, power. It gives the punch. There are some fundamental tones in music that extend that low and they are exhilarating when played loudly and cleanly. The lowest frequencies stimulate adrenal response to sonic stimulation. When tastefully added to good music they can also trigger dopamine response, the holy grail - joyous tears, and permanent memories.

People love LF sound because it triggers instinctive subconcious response. Most LF sound used for recreation is used to stimulate adrenal response, that is excitement based on fear. Loud bass drums, loud rock, airshows with jets, harley motorcycles, church organs, sci-fi movies, thunderstorms, etc. People love LF.  It has the energy to penetrate anything, so ears are not needed to perceive very low frequency sound, it shakes the flesh and is felt by touch.

[medium jim]

JohnR and *Scotty*

I know that the Munson curve has nothing to do with amplification, all I was pointing out was, if the Munson curve was correct, it would take a staggering amount of amplication of the 44hz signal to be at the same spl as at 3.5khz.  Yet we do hear the bass at 44hz and at the same or near same spl's at 44hz and 3.5khz.   This in itself debunks the curve, at least to me it does.

I hope this clarify's this.   

Jim