This looks like it's getting old, but I just thought I'd chime in here to say a few things on bass and quality.
Let me start by saying this. I love the sony ex85lp. Really. To this day, I think it is a phenomenal IEM that is way too underrated. Look at this graph:
Compared to the er4s it is a jet engine of bass. In reality though, if I listen to a few songs with the ex85lp I find that I completely forget it is bass heavy and the bass just starts to sound good. The overall presentation is warm and details with surprisingly good separation and realism. However, the thing that started me on my search for the ultimate IEM is the lack of real extension and flat treble up high past 8-10khz. Point being, you can definitely get used to something and change your perception of a thing. I listened to them for a few years straight and thought they were the cream of the crop and couldn't be beat. I still respect what they are, but now I can't even listen to them and not think "oh my god, the bass... stop the bass.....noooo"
Well, not really. In fact I wish the ety has the bass impact of the ex85lp without the quantity. Maybe that's a dynamic driver thing? I dunno.
Anyhow, I went through about 30-40 IEMs before arriving at the ER4S, which I think is the best so far and most accurate overall. I've tried everything from $10 sonys to the $600 pfe232. And to answer your question gnarlsagan, I had the W4R for a while and although it is an excellent IEM, it was very mid bass heavy, which masked the treble it was very capable of producing. On the whole though, I find the ER4S just as capable with complex music. If not more so in some regards.
Anyway, back to my bass canon ex85lp point. With the ER4S, I'm always immediately thinking "I wish these had more bass". And while I really do feel they would benefit from a bit more sub bass, even graph wise, once I listen to a few songs and don't "think about it", sometimes I actually think I hit a small bass boost on my amp or something, because the bass sounds so good. What is really happening is that I'm forgetting about analyzing the sound and just taking it all in. When I do this, I find the bass is very flat in relation to the other frequencies, therefore I'm hearing everything, bass included, very clearly. Granted, it isn't massively punchy or much felt as heard. However, it sounds great. I'm sort of torn between the 6db addition myself.
I find the er4s is perfect down to about 50hz. I don't think 6db of low bass does too much to the upper spectrum, but if it encroaches on the mid bass forget it. Then I start to lose treble details. It's actually quite amazing how easy this happens. When I had the W4R I would EQ down the mid bass area, say from 100-500hz roughly and it was amazing how much that made them sound more open and detailed while still having excellent bass, because everything under 100hz was giving the power and punch. This led me to using more eq and accudio. After a while I realized they were an awfully expensive IEM if I'm EQing them anyway. I started EQing other cheaper earphones and I was amazed at how similar they sounded to each other when they were all EQd. There are sometimes differences in soundstage, etc., but if those things are roughly equal, EQing them would make them practically identical. I did this with three different "high-end" multi driver IEMs (w4r, se535, pfe232) and in ever case the single driver IEMs I compared sounded just as good. I don't believe multiple drivers adds anything except possibly the ability to control the frequency curve of the earphone more easily. However, they never seem to use that to help make the IEM flat. Also, they end up with crossover issues they have to deal with.
Long story long... The bass on the er4s is pretty close to what is considered reference flat. In fact, the only thing closer in my mind is the pfe112, but that doesn't have as good treble or overall smoothness. Everything else I've seen is pretty much too boosted. Some will want the tactile sensation, but unfortunately, adding more bass is doing just that... adding more bass, not feeling. I know what you spyro about the speaker analogy, and I wish the er4s could mimic the bass of my infinity tower system. But now that I'm more familiar with my er4s, it doesn't bother me as much. I think you need to listen to the bass details and try to ignore the bass quantity. For me, that has helped. Granted, I do EQ my sub bass up to what is considered reference by most graphing standards. I find that only improves things more. You still won't get the same impression as a speaker, but it sounds better.
For some people, I think they are willing to sacrifice treble to get bass "compensation" and they think the boosted bass sounds better. To others, like me, and I'm assuming gnarlsagan, we don't want to ruin that amazing smooth treble that we strive for. So, the er4s is my main IEM for the time being. If I ever found one with a flatter sub bass than the er4s while retaining the highs I'd snatch it instantly even at a much higher cost. Especially if it were more comfortable ;)
I'm probably rambling now, and way of point, and I don't even remember what I came here for... Good night. :-P