earbuds...

[whjr15]

I'm just curious as to how such a small speaker can produce the same low range as a much bigger speaker.

I thought the general rule of thumb said that as the speaker gets smaller, so does the bass response.

I clearly hear a normal range through them. However, the instant that you move the earbuds away from your ear, the bass is gone.

I dunno. I just thought about this the other day, and have been trying to make sense of it.

 

[LIMiT]

hi...

I don't know exactly how the 'earbuds' are designed...but if you're listening to MP3's...there's only lows and mids going on...with *usually* tinny or brittle high end.
There have been lawsuits filed against Apple over hearing loss from 'iPods and earbuds'.

I use the Shure E3's (custom molded), which are a dual driver earphone (tweeter, woofer)...and they REALLY bring out the harshness of MP3's...even at 192kbps...but you can listen to them at less than half the volume of the earbuds because of how much they isolate from exterior sound.

-LIMiT

 

[SouthSIDE Glen]

I'm just curious as to how such a small speaker can produce the same low range as a much bigger speaker.

I thought the general rule of thumb said that as the speaker gets smaller, so does the bass response.

I clearly hear a normal range through them. However, the instant that you move the earbuds away from your ear, the bass is gone.

Often times this can be accomplished by tricking the ear into thinking it's hearing lower fundamentals that are not really there. There is a property of human hearing that states that if one can reproduce the harmonics of a fundamental note, the brain will actually "synthesize" - or think that it's also hearing - the fundamental note itself. Using this psychoacoustic trick to create exact harmonic series that are within the workable range of the small loudspeaker can make us think we are hearing the lower notes that would otherwise be un-reproducable.

When you take the buds away from your head, the volume of many of those harmonics decreases to the point where they become inaudible and/or buried in the wash of the rest of the midranges and the brain no longer synthesizes the fundamental.

Additionally, there is some bone conduction (physical vibration of the bones in the head, you boneheads ) that enhances lower frequency response when the buds are in your ear. Take the buds out and that conduction stops, along with the direct physical transmission of lower frequency vibrations.

There are other factors involved, like the stiffer and lighter materials that loudspeaker drivers are made out of these days, the possibility that the player may have a bit of bass boost equalization built into it's circuitry to compensate for the buds, etc., but I think the synth'd fundamental and the conduction principles are probably the big ones (someone correct me if I'm missing another big one).

G.

 

[Tim Gillett]

As a general rule the bass is weaker with smaller speakers but that's not the whole story. More true to say the smaller speaker cannot produce the same VOLUME of bass as it can maintain the same volume of higher frequencies.
Bass is all about pumping large amounts of air, but slowly. That's the limitation. Small speakers can produce the same volume of bass as larger ones but only by having a correspondingly longer cone excursion. But of course there's a physical limitation to that excursion.

Why if it's only about size can relatively small microphones capture the full audio spectrum? Because they only have to respond to the soundwaves, not create them.
In my experience, headphones can give very good bass although I admit it's not the same human sensation as listening to speakers which make the walls, the floor and even one's body shake.

Cheers Tim.

 

[Tim Gillett]

Often times this can be accomplished by tricking the ear into thinking it's hearing lower fundamentals that are not really there. There is a property of human hearing that states that if one can reproduce the harmonics of a fundamental note, the brain will actually "synthesize" - or think that it's also hearing - the fundamental note itself. Using this psychoacoustic trick to create exact harmonic series that are within the workable range of the small loudspeaker can make us think we are hearing the lower notes that would otherwise be un-reproducable.

G.

Not sure if it's quite accurate to say the brain "thinks it is hearing the fundamental". Perhaps better to limit it to the brain working out from hearing a 100hz note that there is perhaps a 50hz fundamental underneath of which the 100hz is just a harmonic.
Because when you play the same track through a better speaker you are in no doubt you didnt hear that 50hz, at least not like you now are. There is no comparison.

Tim

 

[Farview]

The phenomenon is along the same lines as an optical illusion. Without any other frame of reference you clearly see what you see. With another frame of reference, the illusion collapses.

The other thing you have to keep in mind about ear buds is that they only have to pressurize the volume of air in your ear canal. The headphones can reproduce low frequencies, they just can't project them that far.

 

[rayc]

All of the above & esp with MP3's the suite of bass boost etc junk that seem to be a) optional or worse b) integral to the player to compensate for the lack on the track.
Bones have a lot to do with it & think about the diff of how you sound recorded & how you sound to your self. Bones transmit & modify a lot of sound information.
Do heed the warning about bud deafness too.

 

[Tim Gillett]

All of the above & esp with MP3's the suite of bass boost etc junk that seem to be a) optional or worse b) integral to the player to compensate for the lack on the track.
Bones have a lot to do with it & think about the diff of how you sound recorded & how you sound to your self. Bones transmit & modify a lot of sound information.
Do heed the warning about bud deafness too.

1.Nothing wrong with bass boost if done right.
Think of the great old Bose sound reinforcement speakers with the multiple small speakers and serious bass boost to get them flatter. Without the special Bose eq module they sound like....
Or the entire history of analog tape and disc recording. Serious eq manipulation to optimise noise and distortion.
With portable mp3 players, bass boost can be a big help so long as it's tailored to compensate for the particular headphones.

2. mp3 files arent inherently lacking bass.

3. Sure bone conduction affects the way we sound to ourselves but the main reason for the difference is probably that our ears are not where the mic is, or should be!

cheers Tim

 

[Farview]

1.Nothing wrong with bass boost if done right.
Think of the great old Bose sound reinforcement speakers with the multiple small speakers and serious bass boost to get them flatter. Without the special Bose eq module they sound like....

I'm not sure 'flat' and 'bose' should really be used in the same sentence.

Or the entire history of analog tape and disc recording. Serious eq manipulation to optimise noise and distortion.

That EQ is used in an 'encode/decode' fashion. Same with vinyl. It isn't meant to change the sound of the material, it's meant to preserve the sound of the material.

 

[legionserial]

Earbuds and mp3 compression have nothing to do with each other. I have a portable CD player and listen to it with earbuds. I'm sure some people listen to DVD's on their laptops using earbuds. You can listen to WAV's on mp3 players.

As for the bass thing however. I always assumed that it was relative. Yeah, the speakers are smaller, but then they have a smaller range to push the sound.

 

[SouthSIDE Glen]

Not sure if it's quite accurate to say the brain "thinks it is hearing the fundamental". Perhaps better to limit it to the brain working out from hearing a 100hz note that there is perhaps a 50hz fundamental underneath of which the 100hz is just a harmonic.

I'm not sure exactly how you're splitting the difference there. Either way, like Farview correctly said, it's basically an aural illusion. The 50Hz fundamental does not need to actually exist to be perceived as existing. Whether one wants to call that "thinking it's hearing" or "working out"...I'm not sure how you mean different?

Sure bone conduction affects the way we sound to ourselves but the main reason for the difference is probably that our ears are not where the mic is, or should be!

There are now microphones for communication that are located in the earpiece - and in fact are nothing *but* an earpiece - that are designed to get much of their energy specifically from bone conduction and not so much from air conduction.

Tim G., Rayc, and Jay all bring up good points about the bass inside the volume of the ear and the throw range of the driver. The old addage about larger speaker diaphragms being needed to reproduce bass is kind of misleading in it's implication. A big part of that has not do not with the actual frequency it can reproduce, but with the amount of energy it can impart to the air. In general, the lower the frequency, the more energy that's required to reproduce the same volume levels. Put another way, it takes more energy to make a 50Hz signal sound as loud as a 500Hz signal. This means having to increase the amplitude of the sound waves, which in open air means having to push more air. Larger speakers can push more air (and also, in general, can handle more amplifier power.)

In earbuds, there is a limited volume of air that has to be pushed, namely that inside the ear canal. Therefore as long as one has a driver that can reproduce the needed wavelengths (the lower the frequency, the longer the wavelength) fairly accurately - and modern strong and lightweight manufactue designs allow that much better than old-fashoned paper cones (for example) - and can move the air inside the ear canal fully, they can give bass. But remove the buds from the ear canal, and they are just not moving enough room air to hear bass at your ears.

G.

 

[Tim Gillett]

I'm not sure 'flat' and 'bose' should really be used in the same sentence.
That EQ is used in an 'encode/decode' fashion. Same with vinyl. It isn't meant to change the sound of the material, it's meant to preserve the sound of the material.

I said of the Bose EQ module, "flatter", not flat. I used the relative term. You used the absolute one.

Of course the EQ was not meant to change the final sound of the material and I never said it did either in the case of the earbuds, the Bose speakers or in analog recording. It was meant to preserve it. My very point.

In fact I specifically mentioned bass boost "tailored to the particular earphones". Clear implication: the bass is boosted by the same amount the earphones are deficient in so that the result is as flat as it can be to the hearer.

Yes, analog eq, whether NAB, IEC or RIAA "isnt meant to change the sound of the original material, it's meant to preserve the sound of the material."
And it does that by minimizing ( optimising was a poor choice of word perhaps) system noise at one end, and system distortion at the other.

What you say is implicit in what I said. I just gave the explanation as to HOW the sound of the material is preserved, by avoiding noise and distortion. Why else would one want to reduce unwanted noise and distortion unless it was to "preserve the sound of the material"? Is there any other reason in sound recording?


Cheers Tim.

 

[Tim Gillett]

I'm not sure exactly how you're splitting the difference there. Either way, like Farview correctly said, it's basically an aural illusion. The 50Hz fundamental does not need to actually exist to be perceived as existing. Whether one wants to call that "thinking it's hearing" or "working out"...I'm not sure how you mean different? There are now microphones for communication that are located in the earpiece - and in fact are nothing *but* an earpiece - that are designed to get much of their energy specifically from bone conduction and not so much from air conduction.


G.

Glen, If the 50hz fundamental's not there, its not there.


How is one supposed to infer there is "really" a 50hz tone there of which the 100hz note is just an overtone? Might it not be just as possible there is NO such 50hz fundamental there (in the original recording) and the 100hz tone IS the fundamental? How does one tell the difference? On what information can one glean that? That was behind what I was saying.
How can one tell at all at all unless there's some sort of aural cue?

The "difference" between what you and Farview were saying and my thought is, I think, a valid one:

If one hears a 100hz tone one can easily imagine a 50hz tone that MIGHT be there if one had better speakers to hear it on. That's because it's easy to think of a tone an octave down from the one one is hearing, just as a singer can sing an octave higher or lower than a given note without even thinking about it. It's not so easy to know if there's meant to be that deeper tone in the original recording unless one has some sort of other clue(s). That's all I was saying.

I guess I'm not sure there's even an illusion of deeper bass at all. Sure, mixing in more of the 100hz harmonic on a 50hz bass guitar note will make the track sound more "bassy" on less capable speakers but that's just obvious. You're getting bass even if it's not the fundamental. But it's the 100hz you're hearing, not the 50hz.
Cheers Tim.

 

[SouthSIDE Glen]

Glen, If the 50hz fundamental's not there, its not there.

Hence the use of the term "illusion" In reality it takes more than just a single "overtone" to create the illusion. I'm unsure of the number, but I believe it's generally the more overtones there are, the greater the illusion of the fundamental (though there's probably a diminishing return on that illusion at some point.)

There is indeed an illusion, a psychoacoutic "trick" played on the brain (or maybe that the brain plays on itself). It's like if you look at the avatar/logo at the top of my post, it may sometimes look like the black outer square is leaning a little left, though it isn't. It's a trick played on the brain*. It's a similar type of effect here, except it's aural and not visual; the brain thinks it hears a fundamental frequency that's not actually "there".

A while back someone posted a link to a website that actually demonstrated this illusion using WAV or MP3 tones generated by clicking different notes on a scale. I didn't keep that URL, but maybe a reader has it and can post it here?

*No I dodn't make that logo with that illusion in mind at all. That optical illusion is just something I happened to notice the other day.

G.

 

[Farview]

If one hears a 100hz tone one can easily imagine a 50hz tone that MIGHT be there if one had better speakers to hear it on.

Just like with any other illusion, as soon as you study it or think about it, the illusion disappears. If the fundamental actually existed, it wouldn't be an illusion.

Try the optical illusion in this link (the blue one)
http://www.coolopticalillusions.com/optical_illusion_collection.htm

You know that the blue things aren't moving when you move your head closer and farth from the picture, but you still percieve it. That is the point.

Maybe I'm missing your point, but it really sounds like you are trying to argue that the illusion isn't real. Of course it isn't, but the perception is.

 

[Jouni]

OK, ... I'm gonna grab that "less air to move in earcanal" approach...

Would the size of earcanal matter??

I had earplugs molded in ear, and the maker/molder said I've got the smallest earcanals in his 10-year career... More bass???

 

[SouthSIDE Glen]

OK, ... I'm gonna grab that "less air to move in earcanal" approach...

Would the size of earcanal matter??

I had earplugs molded in ear, and the maker/molder said I've got the smallest earcanals in his 10-year career... More bass???

Damnit Jim, I'm an engineer, not an audiologist!

I'm not and audiologist, for sure, but I'd bet that it is nowhere near that simple, Jouni. The fact that buds can generate triple-digit SPLs in any ear of any size would tell me that slight differences in ear canal volume are not going to make a huge difference, at least not based upon total volume alone.

If you really want to dig into it and get confused way beyond the scope of this forum, here's a couple of links for you :

http://jslhr.asha.org/cgi/content/abstract/36/1/178
http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1053213

I dare anyone here to get too much beyond the abstracts before getting lost .

G.

 

[Tim Gillett]

Hence the use of the term "illusion" In reality it takes more than just a single "overtone" to create the illusion. I'm unsure of the number, but I believe it's generally the more overtones there are, the greater the illusion of the fundamental (though there's probably a diminishing return on that illusion at some point.)

There is indeed an illusion, a psychoacoutic "trick" played on the brain (or maybe that the brain plays on itself). It's like if you look at the avatar/logo at the top of my post, it may sometimes look like the black outer square is leaning a little left, though it isn't. It's a trick played on the brain*. It's a similar type of effect here, except it's aural and not visual; the brain thinks it hears a fundamental frequency that's not actually "there".

A while back someone posted a link to a website that actually demonstrated this illusion using WAV or MP3 tones generated by clicking different notes on a scale. I didn't keep that URL, but maybe a reader has it and can post it here?

*No I dodn't make that logo with that illusion in mind at all. That optical illusion is just something I happened to notice the other day.

G.

No need to have it "explained" to me what an illusion is. It's that I'm just not aware of ever having heard this illusion, the perception if you like. The website with the tones would be ideal if someone remembers it.
Recalls my comments the other day about talking about audio rather than listening to it. As Eliza Doolittle said, "show me", aurally speaking at least.

Tim

 

[noisewreck]

How is one supposed to infer there is "really" a 50hz tone there of which the 100hz note is just an overtone? Might it not be just as possible there is NO such 50hz fundamental there (in the original recording) and the 100hz tone IS the fundamental? How does one tell the difference? On what information can one glean that? That was behind what I was saying.
How can one tell at all at all unless there's some sort of aural cue?

Simple acoustics and the relationships of the overtones to the fundamental.

The first overtone is defined to be an octave higher from the fundamental.
The second overtone is an octave+5th above the fundamental.
The 3rd overtone is 2 octaves above the fundamental.

Just with these 3 overtones you can already infer what the fundamental frequency is (or should be).

Given your example, if you have a 100hz tone and it is the first overtone, then the second overtone is going to be 150hz, with the fundamental (real or inferred) at 50hz. However, had your 100hz tone actually been the fundamental, you wouldn't have a 150hz overtone. The first overtone in this case would be 200hz. So, given your example, just the presence of a 150hz tone above the 100hz tone would suggest that there is a 50hz fundamental.

Hope that makes sense

BTW just an interesting tidbit, most modern brass instruments (aside from the tuba) have a very hard time reproducing the fundamental which should be theoretically possible given the length of their tubing due to the fact that they are rather narrow. Their "real" range normally starts from the first "overtone". Going further back, the old baroque and classical era valvless trumpets and horns couldn't even reproduce that, instead starting on the 3rd overtone, which kinda helped them in being able to play more melodic passages by pushing the playable "harmonic series" further up, where they're lined up closer to one another.

Did I just muddy the waters some more?

 

[Farview]

Not to mention that the beat frequency of 150Hz and 100Hz is.....









Come on.........





















You guessed it!!!!!











Yup! it's 50Hz!