Sound EQ
Forgive me if I butcher this as I'm not a Electrical Engineer by trade, so can only pass on what I have learned and am pretty sure if I miss represent anything someone will chime in.
Without having the adapters you have (as the WhyEars Shopify store is permanently closed now) the only other place to get adapter like you mentioned with the adjustable Bass Dial is EU4A in Japan who has listed on his site he is NOT taking on any new orders at this time.
The only other adapters I've seen on line do not have the Bass Adjustment, so we all cannot enjoy the advantage you have of being able to cable roll with standard 4 wire 2 pin connector cables.
BUT.....
One advantage of going with an 8 wire design is the fact you are now "spreading" the signal over multiple cables and lowering the electrical resistance vs a 4 wire, AND you are taking 2 of those 8 wires and dedicating it to the bass adjuster and the pin for low frequencies in the JH Audio 4 pin layout (See photo)
While your adapters as far as frequency range do the same by feeding only the low frequency pin a modified signal, you are not getting the advantage of reduced resistance which does have an effect on sound.
Utilizing electrical resistance properties is why cable makers are adding metals like Palladium to cables as it alters the signals "oh so much" that result in a difference in sound heard.
I know its a very HUGE debate here on Head-fi if cables and the theory of changed electrical resistance actually makes a sound difference for the cost so won't get into that part of the debate.
I'll just state, that it In My Opinion (IMO) it does make a difference of what I am hearing.
I purchased the CIEM’s Roxanne’s knowing that they are out of the box a little “dark” sounding (just as you noted), but walking around and demoing at Can Jam, chose them because they have a really amazing soundstage/depth and an impressive low end rumble that can be hard to get until spending considerably more, but the Roxanne’s highs were just OK.
But from past experience with other IEM's I knew I could “tune” that part of the sound later by changing out the cable from the stock OFC or OCC copper, to something different (Silver, Copper, Palladium Etc).
And I'm emphasizing “Tune” If the IEM’s don’t have a sound signature close to what you want NO cable is going miraculously fix that. If they are close, cables will help IMO
Knowing that and having tried other cables on other IEM's I own and testing other's JH Audio Cables, I formed opinions of who's sound approached what I wanted to change in my Roxanne's and from there approached the vendors, who confirmed which cables they offered did what to the sound, and then made my decision
For me, the PlusSound Tri-Sliver and the Effect Audio Leonidas 2 were the cables I settled on. Other reviewers on Head-Fi (Example - Twister6 in these forums and his own blog, and Marcus on Headfonics just to name 2 there are many more) have all stated that these 2 cables achieve the same goal with only slight subtleties and these small subtleties as well as other issues in this Covid-19 world (IE getting things out of the far east due to delays in shipping) led me to pull the trigger on the PlusSound cable.
I can honestly tell you I hear a difference even over my older Silver-Dragon cable from Moon-Audio (Another 8 wire with bass adjusters)
There was an improvement form the stock cable to the Silver-Dragons, and maybe for some that is all the improvement they would want. But I was looking for a little more extension in the highs without sacrificing any of the soundstage or mid and bass response. I definitely hear the difference as the IEM's I came out of to move to the Roxanne's had great high frequency extension but the Mid Bass and Lows were never what I wanted despite using cables that help tune that spectrum of the sound.
An professional audio engineer I know suggested the JH Audio IEM's (and several other IEM manufacturers) so I went to Can Jam, listened to all the IEM's I had targeted found the rough signature I was looking for in the Roxanne's and then set forth looking to fine tune via the cables, and found the combo I've been looking for.
Will what I've said work for everyone? Maybe not. but I'm willing to share all of the tuning I've gone through (which also includes DAC/AMP combos and Source Audio Material) to get where I am now for anyone who asks, so perhaps someone I can save someone a little trial and error (they will still need to do this as Audio is such a subjective art, and what I will state is IMO).
Sorry for the long winded reply, and YES I think the cables I bought are what I needed, especially since I can't get the adapters you have.
but I can say without a doubt, ask the cable manufacturer you are using now, what they think an 8 wire design might do for you. In some cases the might say nothing, but reviews through out Head-fi talk about how the 8 wire design changed the sound signature from the 4 wire version of the EXACT same cable. (Take a look for the reviews of the Leonidas 2 vs Leonidas 2 Octa, or there are reviews of the PlusSound EXO (4 wire) vs their X8 (8 Wire) where the reviewer talks about the difference between the 2, and for PW Audio their single wire 1960 (a 4 wire equivalent) to their 2 wire (A 8 wire equivalent) .
But I do leave anyone I talk to this advice when buying audio gear. "Audition/test until you can't hear a difference, look at the price and then go one model/spec back and see if you can justify the cost difference. If you can, buy it."
In many cases people can't hear a difference so they are happy with what they own (Price/Value proposition)
But each has to make that decision on their own.
But again YMMV and all of the above is IMO
