Super.fi 5 Pro - Ultimate Tweaking

Hi you all. It has been a few weeks since I have bought the Superfi 5 Pro, and I've found many way to improve their sound.
I want to share my findings to you all for an impressive (and underrated) IEM that's coming closer and closer to the Triple.fi 10 Pro.

Presentation of the Super.fi
The stock Super fi 5 Pro are said to have strong bass, sometimes overpowering (but not as bloated and intrusive in the midrange as Atrio M5), slightly recessed mids (due to the difficult fit and prominent bass), somewhat sibilant highs.
These are the issues we want to address.
Soundstage is considered smaller than Triple fi's, and the Triples don't have any sibilance even with bad recordings. The Triple fi have also deeper, more detailed bass than the Superfi 5 Pro.

Tweak 1 & 2: Shure black foamies mod, Westone ES2 cable
I already talked about these two tweaks (look at a link in my signature for further details).
Basically, the Westone ES cable reduces the bass, bringing forward the midrange and improving the details drastically, as well as soundstage. The sound is more balanced, bigger, detailed. The bass is still less deep and detailed than the Triple fi, but already very pleasing: it has presence, but doesn't overpowers the midrange anymore.

When I started to use the ES-recabled Super.fi 5 Pro, I was coming from Apuresound Etymotic ER4S. It's an extremely sharp IEM, so at first I didn't notice any sibilance on the Supes. I defined the highs as creamy, soft, needing some crispness.
After a week, I grew accustomed to the Supers sound and started to notice a strong sibilance with some old recordings, like Cat Stevens', Pink Floyd early works, Beatles "Sgt. Pepper", Robert Wyatt's "Rock Bottom", and two great album by Pere Ubu.
Sibilance = overrepresented, "sibilant" sound of "S", "CH", "SH" with some singers, sharp/metallic sound with a few instruments.

Tweak 3
I was told by FeedMeTrance that adding an Etymotic P to S adapter brought some improvement to the sound of the Superfi.
Adding a resistor before an IEM usually screws up the frequency response, making the sound different, being it for the good or the bad.
So I was very skeptical at first, thinking the resistor would have degraded the sound of my Super.fi and benefits would have been marginal.
The P to S adapter (75 Ohm) actually made sibilance disappear. Other changes involved less impactful bass, darker midrange (less air to the vocals), more strength in upper treble. I wasn't sure I liked the sound.
I thought that 30-40 Ohm (instead of 75) could do wonders, tho.

A few days later, a good Headfier (redrich2000) sent to me is Shure inline attenuator as gift. I tried the ES-recabled Superfi with its variable impedance, and after a few days these are my findings (impedance set at the equivalent of 20-40 Ohm):

Bass: tighter, possibly deeper, very detailed.
Midrange: only slightly darker
Treble: it has great presence without a hint of sibilance. Can be very emotional, as opposed to "sharp and dry"

All albums I listed before don't have a hint of sibilance

Soundstage is HUGE! It's extremely big, almost incredible for a IEM. Both unamped from my JVC Alneo XA-HD500, and amped with the iBasso P2.
The overall improvements are great, but can be summarized in "removed sibilance, bigger sound, tighter bass". Not bad at all for a 14$ volume attenuator.

And this is where my tweaks end, waiting for the recable Apuresound is making for Ultimate Ears IEMs.

The chain:
JVC Alneo XA-HD500 -> iBasso P2 -> Shure volume attenuator (~40 Ohm) -> Westone ES recabled Super.fi 5 Pro -> Shure black foam tips -> Me

Cya to the next tweak.

The UE attenuator is basically a male jack with input socket. It's extremely strong in attenuating sound. I used to have it with my Triple fi (but used it only when listening to loud/hissy sources), but now I don't have it anymore. It's an extremely high impedance and I'm not sure it would do the trick like the Shure attenuator.

Just to clarify, detail-wise we are at ER4P level (both with and without the attenuator, thanks to the ES cable and foam tips).

It's different here, but it can be a matter of seal/fit. Good foam tips can make all the difference of the world (me = hated Triple fi with silicon tips/biflanges, loved them with Shure Olives. I also had the same feeling with Etymotic ER4P: hated the plastic sounding triple flanges, loved foamies).

Weird. We surely have different hearing (and thinking -> taste).

JDN, I've got it from Jaben.
Ask to Wilson to trim it to fit the Super.fi.

I didn't like them when I had them. Bass was present even when the song didn't need it, always intrusive. Midrange was recessed, distant, lacking detail. Treble was weak but at least not sibilant. Imaging was very diffused and not precise.

I know many love them, some after a long journey with IEMs, others having bought them as first serious headphone.
By the time I tried them, I was already spoiled with ER4P/S (properly equalized/amped), Shure E500 and alikes.

Yes, I know. There are also people who favoured the Atrios over everything else before discovering better IEMs for their taste (like Altec Lansing iM716). Subjectivity is a strange beast, and sometimes people end favoring cheaper solutions (Atrios) over something overpriced (the E500). I thought the M5 are better value than the Shures, but if the E500 cost 130$ I'd get them in a blink.

My M5 were fully burnt in and I wasn't the first owner. I used them for at least40 hours myself, anyway.
It's strange you talked about harshness, since I didn't find any.

Anyway, let's keep the thread about the Superfi.

Cheers!

Fai, I realized that you could have put the Westone cable the wrong way, which makes them sound out of phase. You have to put the right wire (red dot) pointing to the opposite direction than the right earpiece's UE logo. While the blue dot has to be put in the same direction as the left earpiece's UE logo.