Originally Posted by Spyro
I do not want to get too technical (because I am not an engineer) but the the entire hertz frequency range is pretty expansive. IMHO a single driver BA doesn't THOROUGHLY represent the whole range of the spectrum top to bottom with equal caliber. This was the whole reasoning behind having more drivers tuned to only certain ranges but as a WHOLE it becomes a glorious full-sounding concert hall. Everything is even and really tight!
While I haven't heard every IEM out there I have heard and owned many. As a single driver I always thought GR10 was like an upgraded Ety but after hearing UE900, I think it is sensational. Bright, detailed and expansive 3D type sound but still neutral like an Ety.
As gnalsagan was saying though, the ue900 is no where near the flat neutrality of the er4s. So you can't compare them in that regard. Saying that they cover the whole spectrum better than the er4s isn't a compatible statement, because they boost parts of the spectrum.
My opinion, based on hearing a butt load of IEMs is that what you say is in part true.
Most people do not prefer a truly flat response. I do. I think gnarlsagan probably does as well. For us a one driver is capable, because not more is needed, at least not in terms of the law of diminishing returns for price, performance, etc. For those 90% (a random guess) of people who want to hear and feel more bass, have details "stand out" more in the treble, etc., the single driver THEN becomes a challenge. Because I agree that a single driver cannot easily ADD a lot of bass to an earphone without sacrificing some qualities on the whole. So by adding another driver, it can more easily handle the much greater amount of bass. I'm sure there might also be instances where things like tightness and smoothness are improved with more drivers, but the pfe232 is a perfect example of my reasoning.
Most people that own it have found it superior in every way to other earphones with three or four drivers that cost almost as much. However, the pfe 232 only has TWO drivers. Which perfectly illustrates my reasoning. The pfe112 was capable of a neutral flat response with one driver with almost no fluctuations in the spectrum. To get the pfe 232 to have more bass and more treble they needed one more driver. Not three or four. To be honest, for the price of the westone 4r and the quality it gives out, I'm really shocked it requires 4 drivers. The only thing I could say about it that might lend it towards this necessity is that it handles eq very well. But I don't want to eq my earphones, because I don't want more bass or treble. :)
So my reasoning is that there is a point in manipulating frequencies at which another driver becomes necessary to get more of one part of the spectrum without sacrificing other parts. However, in a flat response, there is much less work the driver has to do if it isn't being demanded to perform super bass feats or other boosts. The only way to really know this for sure would be to show me a four driver IEM that has a perfectly flat response. I'll buy it immediately and compare it to the er4s. Unfortunately, in my oodles of searching, nothing like that exists. I assume this is because every time a manufacturer makes a flat IEM, they don't NEED more drivers. I can see people feeling the er4s lacks bass (this is a big debate), so adding a bass driver might be an excellent move for them to appeal to more people. Keep the drivers tuned to sound the same but increase the sub bass response. However, it might already be possible without another driver. The pfe112 has incredible sub bass. Flat, but incredible. So I assume they could probably tune the er4s that way if they wanted to. But they probably don't want to and haven't wanted to for 20 years, because engineers and enthusiasts find it accurate and high quality as it is.
Also, for what's it worth... If I add 6db of bass with my c5 amp, I don't hear any struggling with the er4s handling it while retaining the other frequencies either.
Anyway, I'll stop now, as I'm starting a novel here. I will end by saying that I don't believe an IEM NEEDS more drivers to sound better. Can they sound better? Maybe. Probably even. But I've yet to hear one. :)
Edited by luisdent - 4/6/13 at 6:22pm