The IE800 is such a frustrating IEM for me. It does so much right to my ears, and then it goes WUB WUB WUB in the bass. It's like taking tea brewed from leaves harvested by the light of the moon and peeing in it.

WTF Sennheiser?

If they took the drivers and improved on the ergonomics of the housing and made the FR more linear at the bottom-end it would be one of my favorite IEMs for sure.

The main phase issues when designing multi-driver BAs (in my experience) are due to:

A) the inherent phase cancellation that can occur in the acoustic pathway between the individual BA output nozzles and the eardrum. So depending upon how many BA output nozzles you have, how they converge acoustically, the ear piece nozzle geometry, ear tip type and geometry, and an individual's unique ear canal geometry, you will get different peaks and troughs in the freq response above..say...5k-ish.

B) crossover topology and center frequencies. Size constraints make building a high-quality xover REALLY hard if not impossible. We have to use less-than-ideal SMT devices. 

This stuff gets very complex and difficult to simulate, so you have to just use intelligent estimates and a lot of trial and error. Ultimately, to control and smooth the peaks and troughs in high frequency response, you have to resort to an acoustic filter in the main output nozzle with a resistive equivalent of 200ohms to 3300ohms give or take.

And lets not forget that accurately measuring FR above 10k is not possible in IEMs with the tools we have today. Measure an IEM with an ear-simulating coupler, then take it out and put it back in (or even just tap it), and you can get wildly different results above 10k. I tend to be a little skeptical of IEM FR data above 10k for this reason. But maybe Senn has some proprietary measuring tools/techniques that can do it? Don't know.


So, I think there is some truth to the idea that an *ideal* single driver could potentially have better "control" at high frequencies or a smoother response because you're not having to contend with the complex acoustic interactions and phasing of multi-driver BAs and crossovers. Whether or not Senn has achieved this I cannot say.

Quote (selected)

With the IE 800, Sennheiser has succeeded for the first time in solving what is known as the ‘masking effect’. This effect, which has a negative influence on overall sound quality, is due to the way in which our ears work. “The human ear is unable to perceive low-volume frequency components of a sound if there are much louder sounds occurring in a lower frequency range at the same time," explained Axel Grell. "This means, for example, that very loud low-frequency sounds will ‘mask’ very quiet sounds in the medium frequency range. This is particularly apparent in in-ear headphones. The sealing of the ear canal by the earphones normally causes resonances that result in a peak in the 7kHz to 8kHz range. This has the effect of masking the actual higher-frequency components. Precisely this problem has been overcome in the IE 800 by the use of an absorber. Sennheiser’s patented dual-chamber system absorbs the energy of the resonance, thus preventing any unwanted peaks. As a result, all frequency components – even the finest nuances – in the music material become audible.

That's just marketing semi-bullshit. While many IEMs have the 7-8kHz peak, there are also many other IEMs which do not. Maybe Senn should have worried about the loud sub-bass to bass in relation to the rest of the spectrum, which obscures the mids and the treble. Seriously, I wonder if the folks at Senn are going deaf.

I do like the NO CROSSOVER approach. It's one reason I hold the ER-4S in such high regard even though its FR is not nearly as good the UERM's.

Couldn't agree more!

This isn't total bullshit...more like horseshit.

The main reason is probably the no-crossover option. The NAIL 2 which I like very, very much might not have the flattest FR but it sounds very, very good to me and I attribute it's wonderful sound to it having no crossover.

I'm kind of a fan of single driver BAs like the FitEar F111 and Final FI-BA-SS. They certainly have a "pulled together" and cohesive quality to their sound.

The F111 is kind of reminiscent of the Etys but more refined.