I am a big fan of Etymotic Research. I have their HF-5 and ER4P-T (which I always use as ‘S’ with adapter) earphones. I discovered them when searching head-fi.org and found this massive thread: http://www.head-fi.org/t/538615/if-you-still-love-etymotic-er4-this-is-the-thread-for-you this forum could be edited in to a high quality book on the pursuit of the perfect music listening experience.
I went through the various types of supplied Etymotic ear tips and felt like the foam tips were not for me, the silicone tips were better sounding to me but not exactly a good fit. I was so used to the Howard Leight Fusion earplugs I use when working with loud tools or running the tractor that I could not get the Etymotic tips to feel comfortable. The Fusion ear plugs have a hollow end to accept a lanyard, on close inspection it appeared the hole went almost to the tip of the earplug. I dissected a pair and found that was the case.
The tip can be cut off at the last flange:
The base is then cut at the line where the green turns to yellow:
The hole at the back is too small to insert on the Etymotic earphone, so I force it as far as it will go on a 3.5 mm jack for a few hours to loosen it up:
I then carefully twist it on the Etymotic earphone making sure not to put any strain on the earphone:
I get amazing sound isolation (the Fusion are rated for noise reduction prior to my mod and hold a lot of their sound isolation properties after mod). I am happy with the sound, the yellow internal silicone (molded propriety material?) is firmer than the outer green and I feel it transfers sound without noticeable dampening. The Fusion loaded on the Etymotic goes in my ear until the corner of the headphone grounds out on my earlobe putting the music as physically close to my brain as possible (where it belongs). The green Fusion are the small size which fit my ears, the blue Fusion is regular size if you have larger ear canals. They can be found at Amazon or via general web search, about $2.50 per pair in small amounts or just over $1.00 per pair in lots of 100. A pair last months with regular use, they clean up well with hand soap and water. They ‘form’ to my ear canal after a week or so and remember the shape.
I use a FiiO X3 with flac files (unamped) no EQ, Gain set on low.
*It took me a while to get used to the feel of the Fusion earplugs vs foam earplugs (for work use prior to turning in to headphone tips). It was like getting a new bike seat, uncomfortable to break in but fine after getting used to it. I found them in an attempt to find an industrial quality earplug that did not need to be thrown away daily like the foam ones do, adhering to our farm ethos to find a style of earplug that could be cleaned and reused many times. I am happy to find that with a few simple cuts and several hours getting stretched out on a 3.5 mm jack they also work as long lasting ear tips for my Etymotic headphones.
From reading a suggestion by Etydave on this page of the thread http://www.head-fi.org/t/538615/if-you-still-love-etymotic-er4-this-is-the-thread-for-you/9825#post_13019770 I decided to cut off another section of the front of the earplug:
This shortening of the tip greatly improved the sound. As I learn more from reading the Head-Fi forums I suspect that the original mod was restricting some of the sound because of the tapering down of the inner opening to the end of the tip. They feel slightly less stable in my ears now because they are shorter ear tips. I flip the ER4P-T and wear them over ear and they feel solid, it is all worth it for the sound.
As I have been focusing on my eartip mod I thought to go back and retry the original ear tips that came with the ER4P-T. I was surprised to hear a marked lack of bass with the stock tips. I put my Fusion tips back on and the bass returned. I think the composition of the inner yellow tube material in the Fusion somehow channels the bass more effectively? I would like to hear if anyone else experiences this with these eartips.