KinGensai
500+ Head-Fier
Something interesting has come to my attention, and I've been thinking about what is going on here and why the pieces aren't matching. For context, the data in question is below.
My main area of concern is the sound bore size effects in this data set, as they seem to contradict my understanding of the physics at play (acoustic impedance) and my direct experience of the tips in question (Tanchjim T300 tips here). I find them to present sound as advertised, whereas here the data set Edric collected and his reported experience is contrary to mine for reasons I'm trying to comprehend.
I'm not a subject matter expert in either acoustics or materials science, so I would like to explore this topic in depth. I believe that there might be an inconsistency between the T300B and T300T in flange design that could cause this sort of unintuitive contradictory effect in a measurement rig, but I might be wrong and I want to get to the truth of this matter.
Happy holidays tip-rollers! I did some experiments on my ghetto measurement rig, trying to understand how different factors impact the sound of eartips in the most controlled environment possible, and to understand my own listening impressions. All using my Final E500; they are open-back, which is a plus for this experiment. The factors I'm interested in are:
Here are the results. Surprisingly, they all agree with my listening impression.
- Sound bore width.
- For this experiment, I decided to go with Tanchjim T300T (wide) vs T300B (narrow), two tips that, to my bare eyes, are identical up to the bore diameter.
- Sound bore glossy-ness / matte-ness.
- For this experiment, I decided to go with Tennmak Whirlwind vs KZ Whirlwind. I might make post about how to differentiate them at some point, but for the purpose of this post, Tennmak Whirlwind visibly has a more glossy soundbore than KZ Whirlwind. Another candidate for this would be JVC SpiralDot FX9 vs FX10, but those two are more different in their materials than in their textures.
- Sound bore length.
- A natural candidate for this is Sedna (Original) vs Sedna Short, but for this purpose of being comparable to other results, I decided to go with the approach of adding a 1mm o-ring to the end of the E500 nozzle to shallow-fit the Tennmak Whirlwind and to simulate a longer sound bore length. Note that this effectively increases the eardrum-to-driver distance by adding extra length via eartip's sound bore.
- Fit depth.
- For this experiment, I vary the depth in which the E500/Tennmak Whirlwind is inserted onto my measurement rig. This would be equivalent to going a size up to shallow-fit or going a size down to deep-fit your IEM into your ear canal. Note that this effectively changes the eardrum-to-driver distance by adding/subtracting length via ear canal.
- The effect of sound bore width (unnormalized & normalized at 1kHz)
- No surprise that the overall absolute volume are roughly the same between narrow bore and wide bore, although narrow bore can be perceived to be louder due to it being louder in the midrange. Narrowing the sound bore has two effect: boosting the upper-midrange and creating a dip in the treble. Depending on the depth in which you fit your IEM, this dip can happen at the mid-treble or upper-treble. In my case, it is the upper-treble and translates to a narrower soundstage and faster instrument decay. The boost in the upper-midrange is very noticeable too, but less so than the most extreme Final E tips. This translates to a more intimate presentation of images in the midrange.
- The effect of sound bore glossy-ness / matte-ness (unnormalized & normalized at 1kHz)
- A matte sound bore sounds like a treated room and a glossy sound bore sounds like an untreated one. That's basically it. Like in a two channel system, treatment or the lack thereof isn't always better. It depends on the speaker, the room and the bass response you are trying to achieve.
- I have a theory that oddities inside the sound bore (e.g. the ridges in SpinFits and Spring Tip, the dots in SprialDots) sound like furniture in a room, but there isn't a pair of earips in my collection that enables me to do a controlled experiment on this. SpinFit fans, any suggestions?
- The effect of sound bore length (unnormalized & normalized at 1kHz)
- The "front o-ring" means deep fitting the eartip onto the nozzle (short sound bore) and the one without means shallow fiftting the eartip onto the nozzle (long sound bore). Sorry for the confusion. The shorter the sound bore, the darker the treble.
- The effect of depth of fit (unnormalized & normalized at 1kHz)
- The deeper the fit, the more absolute volume/energy you are getting in the midrange, especially upper-midrange, extending into lower treble. On the contrary, the shallower the fit, the more bass and treble extension you are getting. The increase in treble overwhelms the increase in bass. Depending on the smoothness of your IEM's treble response, this can translate to extra sibilance and/or a bigger soundstage, when combined with the more distant midrange.
- Bonus: Tennmak Whirlwind vs T300T, two of my favs
My main area of concern is the sound bore size effects in this data set, as they seem to contradict my understanding of the physics at play (acoustic impedance) and my direct experience of the tips in question (Tanchjim T300 tips here). I find them to present sound as advertised, whereas here the data set Edric collected and his reported experience is contrary to mine for reasons I'm trying to comprehend.
I'm not a subject matter expert in either acoustics or materials science, so I would like to explore this topic in depth. I believe that there might be an inconsistency between the T300B and T300T in flange design that could cause this sort of unintuitive contradictory effect in a measurement rig, but I might be wrong and I want to get to the truth of this matter.