I just had a brain fart, and realized I've never tried my westone 4r star tips on the er-4s. First, they fit perfectly. Second, they don't sound any better, but it is much easier to get a good seal quickly and with less (pretty much zero) fiddling. They still provide very good isolation. maybe not as much, but very close. I find the isolation seems to have something to do with not only the etymotic tips, but the fact the the whole nozzle is in your ear.
Anyhow, they work, they might sound a little more v-shaped with recessed mids, but I'm too lazy to do a hardcore side-by-side comparison. Needless to say, they give you a reasonable amount (not the most) of bass without hassle. So if you have other tips lying around, you might want to try them out just to see if the fit might be the reason you're not getting decent bass.
UPDATE: The long grey foam westone tips (grey ring for my size) are a bit more v-shaped I think. Definitely more open sounding in the high treble and a bit more bass body. I'm not sure if this is good or not, but they are a tad different. Pianos seem to stand out as more clear and separated from other instruments and drums are more open and crisp... Noticeably. Very noticeably, but smoothly. Putting in the black foam ety tips are a bit more mid centric in comparison. The westone are easier to use however.
So far I'd say they're the best overall. Bass is great, fit is uber comfortable. They don't need to go in as far as the black foam ety tips to get the same sound, so they're a little less pressure on your ear canal. Although, I find the black tips pretty much very comfortable as well.
