The rule of thumb is wider bore = less bass amplitude, which then results in clearer perception of mids and treble.
Other way around is it not?, wide bore has more bass response according to Symphonium audio as they tested a bunch of tips on their range of iem’s and recommend the following (copy/pasted from their website, I use wide bore on my symphonium meteor and with my 7hz Zero 2
1. Insertion Depth and Fit
With a deep fit, a listener will hear treble more tamed; while with a shallow fit, a listener will hear treble as more aggressive and forward. Manufacturers will design the shell (and how deep it should optimally fit) based on the way they tune the IEM.
Some brands choose to design their earphones to fit shallower, while other brands may opt for a deeper fit. There is no wrong or right here! It depends on what the manufacturer sets out to do.
For example, shallow-fit IEMs tend to feel more comfortable at the expense of less security within the ear. Or, it could be that they just prefer tuning IEMs with a shallow fit!
At Symphonium, we design and account for our IEMs to be worn deep-fitted. This allows us to fit complex crossovers and proprietary acoustic designs within our shells. We also value the feeling of security as we move around, whether for walks or during commutes. Most importantly, we find that treble quality is enhanced with a deeper fit. Using our IEMs with a shallow fit will cause the treble to sound unintendedly forward and the IEM will also feel less secure within your ears.
In addition, some listeners may have a collection of different ear-tip designs to best enhance the sound qualities of their IEMs. Ear-tips with a wider bore size smooth out treble response while tips with a narrow bore size tend to cause treble response to sound peakier and sharper. Which ear-tip you use is entirely based on your own preference; find the best mix of comfort and sound quality.
We tune our IEMs with wider-bore ear-tips for a smooth, whilst extended treble response.
However, that does not mean our IEMs do not synergise well with narrow-bore ear-tips. We’ve received feedback from some of our customers indicating that they prefer the sound of our IEMs with narrow-bore ear-tips!
I have a question for all you fine people perusing this thread. Do any of you ventilate your tips?
I feel like I'm the only one who does. Unvented IEMs drive me crazy, so I solved it by making small perforations and cuts to tips to give air pathways to equalize. I don't see anyone else mention doing anything like this though, makes me feel like I'm a crazy hermit here lol.
Surely if you cut your tips you will not be able to get an airtight seal?, iem’s rely on an airtight seal so that the molecules of air in your ear canal can be pressurised thus transmitting the vibrations of the iem transducer to the ear drum, air pressure will always take the path of least resistance which in this case will be out of the perforated/cut section.
(full 6pairs)
