The first part about mass etc relates more to sensitivity in my mind than anything else. I understand inertia case but drivers are as close to minimum phase as possible, at least it is what they say
Well the fact that the smaller driver needs to be displaced further to move the same volume of air in the same amount time was the only reasonable difference I could find between large and small diapraghms that could affect the hearing perception. That would cause the acceleration of the particles is also larger.
But I looked on impulse response of various IEMs and could not find very direct correlation
Ed: https://www.hypethesonics.com/iemdbc/ this is a very cool database where you could find (impulse response of various drivers - for example ER2SE vs. IE900, Andromeda, Dunu Luna). Can’t find any trend in them
Ed2:
And well, I have to disagree. It can move the same amount of air by "just* going further in Z axis
What is also interesting that on DIY speakers forums I found mostly that people evaluate the one large driver vs multiple smaller in terms of the cone area (that need to match), better efficiency in reaching lower of large subs, heat transfer and cost efficiency. Did not found a lot if anything on large subs sounding more full if SPL is. But that may be my information bubble, who the hell knows
Smaller dynamics need a longer linear excursion to achieve volume (as in mass) of atmospheric pressure…if you were to listen to a set of iems at sea level…they would sound differently than if you listened to them on Everest
Assuming that IEM <> eardrum system is almost sealed. Let’s imagine the piston being the driver in half cycle
How else I would achieve the same pressure change in the system if not by changing the internal volume by the same amount? So basically pushing in the same volume of air in.
This how I see it from static or close to static pressure perspective.
I dont give a damn about sensitivity in hear, but in my mind if 2 drivers achieve same REAL SPL at given frequency they need to move the same volume of air.
Another question probably is how flawed are measurements of IEC 711
Edit: sorry @hawaiibadboy for spamming your channel. Let’s talk some music. I learned about this polish girl from no other than @nymz - if not for my wife I would be in deep love
The difference between subs and IEMs (1DD) is that the sub is only in charge of lower frequencies.
So yes, a larger sub will give more air displaced and more sense of physical bass.
But a 1DD IEM is a full range driver. A large diameter DD may introduce some pros and cons to the sound, whether it’s bass speed/slam or midrange or treble.
Your on the right path my friend…the distance between the cochlea and your tip…the volumetric chamber…if you will…varies greatly between humans…our perception of sound is inherently tied to this since birth…what my wife perceives as staccato…I sometimes perceive as staccatissimo…sometimes legato doesn’t sound like legato at all to the both of us
If the acceleration of the mass (in this context) diaphragm is equal …and if the amplitude is also equal…with each pulse the larger cone will move more air
you have to remember that the cone is moving back and forth so to achieve the same amount of volume per stroke…you have to increase surface area…you can achieve this by using multiple smaller drivers and increase the pistonic speed but there will be phase issues that you have to contend with…and that’s why single DDs almost always sound appealing
Once a mass starts in motion…it stays in motion…unless acted upon by one of the four fundamental forces of nature
The distance traveled is not equal…as in internal combustion engines…bore vs stroke…smaller bore…you have to increase length to achieve same amount of volume…but since the piston (or diaphragm) is moving back and forth and at the same frequency …you have to increase frequency
relationship between the wave’s amplitude and frequency is such that it is inversely proportional to the frequency
It’s cyclical…the farther it moves in one direction…the further it has to move back…time phase now comes into play…larger diameter doesn’t have to move as far for a given amount of volumetric space and can do so more quickly…because it doesn’t have to change direction as often
the numbers are right there…all you have to do is the math
There are xmax (or following the previous nomenclature zmax) specified in speaker drivers specs, they do differ between different drivers.
If you have one with xmax=3mm and second with xmax=1mm without changing the f one can move with mean 1mm per unit of time and second 3mm in unit of time and they would be in phase in any given moment in the cycle. The excursion is direct proportion to voltage so there is nothing stopping that from happening
Keep in mind it can move couple of thousand times per second from 0 position to xmax to - xmax so for the speed of the max speed and acceleration of the driver should not be a problem especially in LF
Yes you are right in general…but…ahh… I’m not in the mood to retort…I’m tired and always seem to be in a room full of engineers with which invariably…turns into a pissing contest …I’m out
no…not yet brother…I have too many single DDs as it is so I’m waiting for a used set to pop up…I’m willing to go 600ish…but the way peeps rave about it…maybe a little more
You guys have far more expertise in this area than myself but isn’t this all just pointing to distortion being the only measurable possibility - when conducted at defined frequencies corresponding to the driver crossover ranges - to show the potential difference - not seen many IEM FFT measurements… Please feel free to correct me here as this is more a blurted thought than any refined rhetorical.
My understanding was that as diameter is decreased excursion decreases so volume displacement and consequently potential peak SPL decreases at an exponential rate opposed to diameter. A larger diameter therefore moves more air for less expenditure - with distortion being proportional to excursion and non linear distortion present through excessive excusion - subsequently this creates for signifcantly better distortion ratings. At lower frequency registers more volume is required to maintain SPL (as @BASS_0Range detailed earlier with one reason being in the form of leakage) but a smaller driver has a lower power range, presenting a higher risk of breakup and so requires a higher crossover point. For most use cases it is a balance of the directionality & dispersion gains of the smaller driver against the lower distortion of the larger driver / with a ‘bigger is better’ capitalist ethos and back of the fag packet calc shouting that bigger drivers being cheaper as an overall package as you need less to achieve the same driver area - that they would be the way to go BUT doing the math and assuming proper implementation - multi smaller drivers at defined crossovers would be the more efficient configuration for both power and air volume as well as offering better fit, higher register sensitivity & directionality placement
IMHO, not sure if the differences are substantial enough in IEM driver sizing unless the driver is significantly overdampened or we are beyond Kintsaki levels of SPL listening. Moreover there are so many additional factors such as magnet strength, suspension, diaphragm material, etc… To also weigh into this driver comparison discussion - driver diameter as an absolute defining choice we are highly unlikely to encounter SO yeah implementation IMHO is a better primary concern (as @veebee noted)
P.S. since I have essentially agreed with everyone I don’t know what the point of my post was so feel free to ignore
Moreover there are so many additional factors such as magnet strength, suspension, diaphragm material, etc… To also weigh into this driver comparison discussion - driver diameter as an absolute defining choice we are highly unlikely to encounter SO yeah implementation IMHO is a better primary concern (as 