[kevms89]

I notice that the xba3 has a frequency response of 4-28,000hz while the xba30 has 4-25,000.

What does this mean? Which is better?

 

[SilverEars]

I notice that the xba3 has a frequency response of 4-28,000hz while the xba30 has 4-25,000.

What does this mean? Which is better?

It means what range of tones the iem can output.  Science says we can hear up to 20k.  And its gets less than that as you age.  
 
So, this should answer your question.  Those values doesn't tell you anything.  You want to look at a graph.  Problems with graphs is there are differences based on who and what measured it.  I say the useful specs are impedance and sensitivity. 

 

[tinyman392]

  It means what range of tones the iem can output.  Science says we can hear up to 20k.  And its gets less than that as you age.  
 
So, this should answer your question.  Those values doesn't tell you anything.  You want to look at a graph.  Problems with graphs is there are differences based on who and what measured it.  I say the useful specs are impedance and sensitivity. 

 
You say the important specs include sensitivity...  The sensitivity is measured in the same way the frequency graph is.  In reality, the frequency chart (which does have standards, and are actually rarely different if you adhere to those standards, especially if you just compare raw measurements) is measured in the same way the sensitivity is... 
 
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@OP, SilverEars is right about what it means...  It's the range of tones (measured in Hz) that the drivers can generate to a measurable level.  Keep in mind that just because it's at a measurable level doesn't mean it'll be loud (it may be +100 dB at 1 kHz and +1 dB at 25k, they can still say it has response at 25k).  Human hearing is limited to hearing tones from 20 Hz to 20 kHz...  Sub-bass can be felt under 20 Hz, but it's rare in an pair of IEMs or headphones. 

 

[SilverEars]

   
You say the important specs include sensitivity...  The sensitivity is measured in the same way the frequency graph is.  In reality, the frequency chart (which does have standards, and are actually rarely different if you adhere to those standards, especially if you just compare raw measurements) is measured in the same way the sensitivity is... 
 
______
 
@OP, SilverEars is right about what it means...  It's the range of tones (measured in Hz) that the drivers can generate to a measurable level.  Keep in mind that just because it's at a measurable level doesn't mean it'll be loud (it may be +100 dB at 1 kHz and +1 dB at 25k, they can still say it has response at 25k).  Human hearing is limited to hearing tones from 20 Hz to 20 kHz...  Sub-bass can be felt under 20 Hz, but it's rare in an pair of IEMs or headphones. 

This can be said of all measurements.  Just to add, impedance and SPL is at 1kHz.

 

[tinyman392]

  This can be said of all measurements.  Just to add, impedance and SPL is at 1kHz.

 
It's measured at 1 kHz, but it's measured the same way as the frequency response is...  Impedance is measured the same way the impedance is as a whole...  So saying the frequency graph is unreliable, but saying that the sensitivity measurement is...  When it is a subset of the frequency response plot, is a little contradictory.  Impedance will only say something if the source you are using has high output impedance or you're using resistance (possibly custom cables). 

 

[ClieOS]

I notice that the xba3 has a frequency response of 4-28,000hz while the xba30 has 4-25,000.

What does this mean? Which is better?

 
To the case of XBA-3 vs. XBA-30, it does NOT mean squat.
 
It is just some marketing term headphone companies like to throw around to 'impress' uninformed buyer. An actual frequency response needs to tell people its tolerance, not just its range. But tolerance is what 99% of all companies conveniently forgot to mention. Without it, frequency response is about as useless as it can be.
 
If you want a bit more info, read this: http://www.ecoustics.com/articles/understanding-speaker-frequency-response/

 

[Inks]

Exactly^ FR on the box means nothing for the most part, maybe between the iems of the manufacturer since the same standard is used but definitely not for comparisons outside of manufactures. Also some companies set the tolerance so low, claims like 3000k limit get put out when the iem in reality only reaches around 20k.