Does anyone with a high level sound science background want to give me the words to

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It's a matter of acoustic impedance Z
where the Ohm law R=VI becomes Power=acoustic impedance * membrane velocity p= Zv and is valid for dynamic headphones. The resistive part remains unchanged while velocity is related to frequency ( cycles ). With the earphones you'd get the same power till -thoretically- zero Hertz because there's pressurization between the membrane and the tymphanum.:eek:
 
communicate the hypothesis I'm playing with in the link below?
You conclude:
"The only conclusion from this is that a lot of the IEM's sound/volume/power is dying off in that one inch space between your ear opening and the part of your ear that actually has the nerves that hear sound. On the other hand, the headphone's sound is not dying as it travels that space, probably because the headphone's sound waves are more robust as they travel through your ear canal. To define that term, robust, they are more robust in the same way that the sound from a speaker is more robust. A speaker that puts out, say, 70db within one inch puts out 60 db five or ten feet away (without changing the volume of the source). A headphone that puts out 70db within one inch puts out like nothing five feet away, and very very little just say a foot away. An IEM that puts out 70db within a few mm puts out almost nothing just a few inches away."

Simply put, the inverse distance law (AKA inverse square law) states that for every doubling of distance in free space (outdoors, away from boundaries) SPL (sound pressure level) drops 6.02 dB. The inverse also occurs, each halving of distance increases level by 6 dB.

Sound propagation in rooms or small chambers (like an ear canal) is affected by resonant modes, so the behavior is more complex than in free space, levels may fall off at less than the inverse distance law would predict due to reverberation, or more due to room (or chamber) modes canceling certain frequencies.

SPL measurements of a speaker in the extreme near field, like a 12" speaker measured at 1 inch will not hold up to the inverse distance law, it would need to be measured at about the diameter of the speaker distance for the first measurement to be predictable at distance.

If a 2" diameter speaker at 2" distance measures 70 dB SPL, you should find results like this:
64 dB at 4"
58 dB at 8"
52 dB at 16"
46 dB at 32"
At increased distance, the speaker's SPL may fall below the ambient noise level and be unmeasurable with a typical SPL meter.

Art
 
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Live instruments sound better (more dynamic) than speakers. Sometimes headphones sound better than speakers (more dynamic) so I question your original thesis here.. :p If your IEMs sound less dynamic than your headphones, question your amp first.

If your speakers don't sounds like live instruments question your speakers first then the recording quality.

IEM's may sound more dynamic then headphones due to a lower noise floor. I have a couple pair that really block out the ambient noise - like earplugs
 
communicate the hypothesis I'm playing with

You are completely wrong - not in your measured result that different sized drivers with the same nearfield pressure will have varying farfield pressure, but in your conclusion that sound propagates differently.

For the same nearfield pressure, the power output goes up with the square of the diameter. Your 8mm in ear monitor will thus output 25 times less power than a 40mm headphone, and 25x25 or 625 times less power than an 8" driver.
 
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It probably has to do with psychoacoustics. Sound, when modulated by the asymmetry of the outer ear lobes provides additional phase cues (how you can tell sounds come from front or back or up or down with only 2 ears). IEM's have no interaction at all with outer ear, they will have good flat response, excellent dynamics, but completely lack spatial imaging beyond left and right.
 
If your speakers don't sounds like live instruments question your speakers first then the recording quality.

They do sound like live instruments, just not quite as dynamic. However two years ago they sounded considerably less dynamic than they do now and they've not changed in the meantime, the electronics has though.

Tentative conclusion - my speakers probably aren't the limitation of dynamics, the electronics is.
 
yep, as long as your speakers are cable of 125 db or so with no compression it's probably the amplifier or the recording

The above posters that informed you of the inverse square law already answered your question you posted at the headphone forum
 
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I don't know how an IEM is designed, but possibly the IEM is more directive (acoustic output) than the driver of a closed-type headphone. If so, that might explain the higher SPL reading for the IEM than for the closed-type headphone in your experiment.

If you could get a headphone and IEM of the same rated sensitivity for your experiment, and power them with a stereo amp with a balance control, then the position of the balance control would tell you which must be louder to obtain the same subjective loudness.

The vast majority of recordings are engineered for listening to speakers (in free space). Thus those recordings assume some ambiance contributed by the listening room. Also, with headphones or IEMs, when you move your head, there is no corresponding change of the sound that you hear which is the case when listening to live music or a stereo speaker system.

-Certainly not someone with a formal scientific training, but I hope you don't mind that I put in my two cents. cT
 
not all in ears are created equal i'd have to re-read the link and the thread but i don't recall the mention of a make.
in working with in ear monitors (mostly Shure stuff) i've resorted to using a stereo condenser or a coincident pair of SM 57's fed low level to the mixes to restore ambient sense and allow the musicians to hear audience reactions.
as a monitor tech/musician wannabe i struggled with In Ear Monitors at first because of that disconnect/loss of spatial cues; re-introducing a small amount of "house/stage" sound preferably in stereo really makes a "big" difference.
additional outboard EQ for creating "loudness contouring" is fast becoming a must for me.
 
not all in ears are created equal i'd have to re-read the link and the thread but i don't recall the mention of a make.
in working with in ear monitors (mostly Shure stuff) i've resorted to using a stereo condenser or a coincident pair of SM 57's fed low level to the mixes to restore ambient sense and allow the musicians to hear audience reactions.
as a monitor tech/musician wannabe i struggled with In Ear Monitors at first because of that disconnect/loss of spatial cues; re-introducing a small amount of "house/stage" sound preferably in stereo really makes a "big" difference.
additional outboard EQ for creating "loudness contouring" is fast becoming a must for me.


It was an SE846.

Thanks for the interesting technical info everyone.
 
You are completely wrong - not in your measured result that different sized drivers with the same nearfield pressure will have varying farfield pressure, but in your conclusion that sound propagates differently.

For the same nearfield pressure, the power output goes up with the square of the diameter. Your 8mm in ear monitor will thus output 25 times less power than a 40mm headphone, and 25x25 or 625 times less power than an 8" driver.

How does that disprove the idea that music that transfers greater distances before dissipating sounds better than music that travels a tiny distance before dissipating -- assume both of them have the same amount of sound energy when hitting your ear nerves?
 
on the matter of headphones sounding crappy as compared to live speakers i've heard some really good systems commercial and high end consumer rendered unlistenable by a bad acoustic environment.
i do prefer "open" listening and not being tethered by a curly cord but "Tubular Bells" on my Sennheiser Hd440's is still a sonic delight to me!
 
How does that disprove the idea that music that transfers greater distances before dissipating sounds better than music that travels a tiny distance before dissipating -- assume both of them have the same amount of sound energy when hitting your ear nerves?
Your hypothesis is nonsense because the mechanism for sound dissipating in air has been well known for a century or two. For sound waves in the audible frequency range over the distances you mention the dissipation is negligible.
 
How does that disprove...

!? :headbash:
The idea you speak of is nonsense. There are numerous other variables you have not considered as to why you would prefer the sound of speakers vs. in ear monitors. Some of the obvious ones: Frequency response, distortion, room acoustics, directivity's effect on radiated power in room (pretty much out of the picture in headphones of any kind). Even the perceived location of sound differs between speakers and headphones. In ear monitors are generally a bit uncomfortable and they block noises and increase your perception of biological noises. Headphones do this to a lesser degree. I'll leave the rest to others...
 
with respect to "increased perception of biological noises" hearing your voice via bone conduction because your ears are in effect "plugged" changes the perceived pitch that effect was uncovered years ago in recording studios when singers where required to monitor themselves on tight fitting closed back headphones for the purpose of preventing bleed into the vocal recording mic.
the same occurs to a greater degree with in ears which is why you will occasionally see an aware veteran performer intentionally remove an ear bud to insure he's on pitch.(i wish more inexperienced performers where aware of this effect would have saved me many a night listening to someone sing just a semitone off!!!eeeschh!)

i think ag is trying to justify his preference with a heretical understanding of sound and it's associated physics rather than simply saying it's what he prefers.
 
Your hypothesis is nonsense because the mechanism for sound dissipating in air has been well known for a century or two. For sound waves in the audible frequency range over the distances you mention the dissipation is negligible.

That's sort of like saying that, because we know how electrons or tiny cells behave, we know everything there is to know about how animals and other organisms behave. I'm not referring to the tiny particles of sound, and how each of them move through the air, I'm referring to sound as it's relevant to the human experience, and what affects how pleasing it is to our ears.

Again, the hypothesis is that as a general rule, music which dissipates in short distances sounds worse than music which takes long distances to dissipate, even if both deliver the same amount of energy to your ear nerves.
 
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Again, the hypothesis is that as a general rule, music which dissipates in short distances sounds worse than music which takes long distances to dissipate, even if both deliver the same amount of energy to your ear nerves.
Can I suggest you look up what dissipation of sound means and then rewrite whatever you are trying to say so that it can be understood. There is no significant dissipation of sound over the distances you mention.
 
Can I suggest you look up what dissipation of sound means and then rewrite whatever you are trying to say so that it can be understood. There is no significant dissipation of sound over the distances you mention.

I don't know why are you are having such a hard time understanding such a simple idea, but please let me break it down for you with a paint by numbers method of communication. Imagine two music sources. One of the sources dissipates in a very short distance. If you put your ear right next to the source it delivers, say, 80 db of energy to your ear nerves, and if you put your ear 1" away from that source, it delivers, say, 60db of energy to your ear nerves. The second source of music dissipates over longer distance. If you put your ear right next to the source, it will deliver 80 db of energy to your ear nerves, and if you put your ear 5 feet from that source, it too will deliver 60db of energy. I'm saying that the latter, as a general matter, will sound better than the former.

Your comments are as helpful as responding to a question about how to fix a broken leg by telling the person that bones are made of calcium, and then further responding by telling the person to look up the word calcium. Do you see why?
 
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