I never used IEM until (50-yrs-old) a month ago. I bought a Sony Walkman, and thought the supplied IEM's were good enough. I then bought a Samsung Galaxy 4.0, and a pair of Klipsch S4A IEM's to go with it
(the supplied phones were so-so). At first, I thought they were great, but my opinion changed to so-so as soon as any noise entered the equation: central A/C, my wife watching TV, etc. While I was reading reviews online, I shoved the S4's in a bit further, and KABOOM! I had been listening with the volume set at 15-20 out of 30, and now had to turn the volume down to 5-8. I guess I was a bit leery about sticking things in my ear, and it was a small amount of extra push and twist that made all the difference. When I speak with the S4's in all the way now, my voice sound like I have my fingers stuck in my ears. Before, I could clearly hear my voice passing through the phones. I took a pair of Song buds, and slipped them onto the S4's. The Sony material is softer than the Klipsch stuff, and slid into my ear much more easily for the same tight seal. After one of the Sony buds came off the Klipsch and had to be pulled out of my ear canal this morning, I switched back to the Klipsch buds....LOL! The Klipsch seal just as well as the Sony, so that's that.
Sound Quality Now: Much more bass, even at 5-8 out of 30 on the volume setting. The bass can border on being a bit much with certain songs, but it's not a problem. Mids and highs are superb compared to when the phones weren't sealed properly, so I'm still in the initial stage of "WOW!" as far as that is concerned. I listen to mostly jazz and classical, and getting all the sound one would expect from those genres.
I bought mine from Amazon for $60 (amazon fullfilled order), and bought a pair for my wife as well. She gave the same "WOW!" at first, but was listening at 15-20 on her SGP 4.0. We switched the large buds for mediums yesterday, and she was able to get enough of a seal to reduce the volume setting by half. I know she's getting more sound now, because her voice level has doubled when she speaks and listens.