[Spyro]

More from a scientific standpoint and not what your ears tell you......and let's leave this to SILICONE type tips only and we are also NOT talking about fit!  We are ONLY considering the sound differentiation with regards to the size of the exit hole.
 
On the surface I always figured a larger opening tip will always sound better or more open...but is this true?  I have 3 thoughts on this.
 
1)  On first thinking I would say, yes, a wider diameter exit hole (like a Westone "star" tip) will surely improve the sound over a grey flex sleeves or white tri-flange that has a smaller pinhole type exit hole.
 
2)  But then I wonder.....no matter how large the tip exit hole is...aren't you still limited by the diameter of the exit hole on the NOZZLE ITSELF?  
 
2)  Etymotic Research may be the most credible IEM company out there in trying to achieve 100% total sound reproduction accuracy and they supply silicone tri-flanges with all their products.  They apparently see no need to design a wider open diameter tip so maybe it doesn't matter???
 
Any thoughts?   Just for reference...I have been using star tips with my W4 but I don't like the fit.  My ears are different size and I almost feel like I need a size in between small and medium.   A white tri-flange modded down to a bi-flange with stalk cut off to be flush with bottom largest flange fits very snug and perfect. Sounds good...bass hits hard.    Logic would seem to think the the bi-tri-flange tips are better due to guarantee fit.
 
I am surprised there is not more discussion about this since, with universals, fit is absolutely critical!

 

[xnor]

Diameter and length of the tip's exit hole is going to have a much smaller impact than the volume between the tip of the tip and your eardrum.
 
Insert the IEM a bit deeper and the resonance will increase in frequency.

 

[Spyro]

Again.....we are talking all things being equal.
 
I am deducing that the larger opening new Westone "star" tips do absolutely nothing differently with the sound versus the old grey flex tips or the tir-flanges.

 

[xnor]

Don't know the difference of those tips.
 
But if really all things are equal except for the hole diameter, then larger diameter will lower the resonance frequency.
For example a tiny hole could result in a peak at 10 kHz, a large one could move that peak down to 8 kHz.
 
Depending on the frequency response of the headphone this might make a peak worse or flatten a dip.

 

[castleofargh]

I don't see how we could come out with one conclusion on this.
there is the diameter from the driver to the eardrum that would be one thing, but there are all the changes in diameter along the way and the shape of those variations to take into factor.
your W4 are multi BA driver, just that makes it hard to compare with er4. the risk of one driver interfering on the other is high, usually trebles get killed in multi BA config.
then the diameter will always tend to affect certain frequencies instead of others due to them reflecting on the inside surface of the noozle.
an then I guess there is a moment where the small size of the nozzle can be a problem for the bass driver to move enough air.
 
 
on the fitear f111 and Parterre you have a small tube that ends wider in a cone shape, and the purpose is to increase trebles.

 

[Spyro]

Nozzle size is unaffected otherwise they wouldn't make them the size they do.  Same must go for tips logically thinking.  

 

[ClieOS]

This might interest you: http://rinchoi.blogspot.com/2013/07/the-effect-of-ear-sleeves-tdk-ba200.html

 

[Currawong]

The new DITA IEMs are offered with three different types of tips, each which have a different hole size and each which affects the final sound differently. 

 

[Spyro]

I suppose it must have some slight affect.  But as hinted at above there are SO MANY other variables already going on with insertion depth, ear canal anatomy, directionality of the nozzle, etc, etc that it probably doesn't matter much from a scientific standpoint but is really more about what sounds good or better to the individual listener.

 

[proton007]

  I suppose it must have some slight affect.  But as hinted at above there are SO MANY other variables already going on with insertion depth, ear canal anatomy, directionality of the nozzle, etc, etc that it probably doesn't matter much from a scientific standpoint but is really more about what sounds good or better to the individual listener.

 
Eartips can change two aspects of listening:
-- The volume they occupy inside the ear canal. Some tips like the Shure yellow foam don't go in too deep, but rely on a tight seal. Others like the Etymotic triple flanges go deeper. The change in the shape and volume of the ear canal will affect the sound.
-- How close is the sound source (tube) with respect to the eardrum?
 
Hence, its like using monitors inside a studio. Your proximity to the speakers definitely influences what you hear, but the design of the studio and its acoustics also have an equally significant effect.

 

[Spyro]

So will a 1mm exit hole on the tip (not nozzle) impede some of the frequencies more so than a 2mm exit hole?

 

[proton007]

So will a 1mm exit hole on the tip (not nozzle) impede some of the frequencies more so than a 2mm exit hole?

 
I'd say that the transition from the nozzle's opening into the tip's canal will have some effect. How significant? I'm not sure.
 
The total length of the canal will affect the resonance.