Quote:
2) I am intrigued by your above remarks - this is pure speculation on my part, but is it possible that one of the mid or bass drivers is wired out-of-phase..? I don't know where the bass/mids are crossed-over - is it, perhaps, at the 125hz point you refer to in your EQ graph? Could it be possible that your experience of a 'cleaning-up' of the sound when dipping 125hz may relate not to an excess of 125hz muddying the sound but to a bunch of phase-incoherence muddying the sound, which negative EQ-ing may be minimising the obviousness of? If the bass driver is representing the music in one phase, and the mid is overlapping in the opposite phase, then dipping this phase inconsistency might be one plausible reason for the sound (subjectively) improving, mightn't it?
...I'm
also wondering if this might explain
Spekkio's strange auditory experience when listening to cymbals (though he may, perhaps, be right about the 5khz peak being to blame) - in any case, an out-of-phase treble BA-driver would absolutely be expected to make a 'mish-mash' of the sound, since there is such a huge abundance of subtle, but complex, phase information in a cymbal sound. One wouldn't
necessarily expect phase anomalies to be overtly visible on a straight pink noise plot, so that could potentially account for the apparent dissonance between the 'normal' frequency chart and the subjectively-perceived anomalies.
In Speekio's review, he says:
http://www.head-fi.org/t/582754/review-by-spekkio-unique-melody-miracle
"For the bass
around 120Hz or so – the midbass or drum beats portion, this was where it became more problematic. The bass, although retaining that ‘BA’ sound to it, which is the ‘clippy’ etymotic low decay bass sound,
is more round in texture and not as well defined. The notes hit but one cannot point to the exact instant where the note hit. It is more of an approximate guess."
(
Bold emphasis added by me)
Again, this sounds to me very much like a potential phase issue, either at crossover point between bass and mid drivers or between identical pairs of bass drivers or identical pairs of mid drivers, or a combination of these woes (i.e. just one mid driver out of the six drivers in one ear being accidentally wired out of phase etc.)
Obviously, I don't know where UM are crossing-over their drivers, so I may be wrong about the 120hz but I consider it no coincidence that Br777 is also talking about 125hz being an issue. With 6 drivers per IEM, I consider it quite possible that a rushed team of engineers, with excessive workload and insufficient sleep, might possibly have made a 1-in-6 wiring error, on the occasional IEM. Similarly, they may have taken on new/temporary staff for soldering duties, perhaps?
I'm nervously awaiting mine, in about a months time.
