Fearless S6Pro UPDATED - Only issue I have with this set, which I need some more time to mentally adjust to, is the small peak at 4.5khz. I EQ it out pretty easily by dropping the 4khz 1.5db. This does highlight verge of sibilants, or what would be if the set didn't tame that frequency so well, but on some tracks it is a bit much for me to "relax in the click" when testing this out as a stage IEM. As time goes on this really isn't a big issue and may still be resolved with tip rolling. I need more time to adjust to the sound signature, but I wouldn't call it shouty but sizzle. The bass is present and very accurate. I got new tips for these and it really cured the minor bit of bass issue I had. It could easily be older worn out foamies giving me a not so tight seal.
Will keep this here and can reference the difference in the chart as it does add a bit more stability to the bass:
With a minor EQ tweak gives a bit of firmness. A 1.5db bump at 125hz, 1.5db bump at 64HZ and 1.5db at 32Hz helps bring out the bass lines in a stable and well presented manor. More testing will need to be done.
Both these adjustments are really salt and pepper and really could come down to how my ears perceive the sound. Someone else may think these adjustments are not needed. Really the only thing that I see consistently with this series, and knew it would more than likely bother me going in, is that small elevation in the 4Khz area. If it was just brought down a bit this would be a true golden set. With ever so slight EQ this is as close to studio monitor sound as I could ever want to get.
Here are my measurements which sync up pretty well to HBB but I do not have as nice a setup as him. Dayton Audio imm-6 with calibration file in AudioTools. Small tube connecting IEM with foam tips(just like HBB old setup). Using Crinale's PPN file out of my Focusrite Forte.
Don't put to much weight on anything past 7khz and up, it is not accurate with this setup.
As far as how I determined what I believe to be "reference" is by ABing my fully calibrated studio 2.1 setup. A pair of JBL LSR 305 and one LSR310s subwoofer. Playing these at 85/90DB and then ABing the setup. After getting new tips and spending some more time with a larger amount of music, the stock S6pro, is near identical 1:1 in sound.
This is really what I am after for my studio situation. Something I can trust and not really have to think about when I track at night or when I am playing to a click. Wondering what the S8Pro would be like I took some time to EQ a close enough curve to get a taste. I am positive this is not going to sound the same but just to get an idea it works well. It also really shows how well the S6Pro takes EQ. What ever you give it, it takes. If I give it 3DB boost it gives me a 3DB boost. And it does it all cleanly without breaking a sweat. Pretty fun to play around with really. Even though I am more a vanilla EQ with ever so slight adjustments like you saw me note above. BUT this thing can do the heavy EQ thing.
I ran the "Ultimate Headphones Test" various tests on their site and confirm that these things have audible bass to 10hz(at which it stops the test) and believe it goes even lower. Check the site out if you haven't. Just be careful with your volume!
Updated Graphs with a bit better full spectrum picture.
S6Pro Right
S6Pro Left
S6Pro compensated EQ(see above)
*just for fun* This is just to show how well these really can be EQed. No distortion at all at this level. Made a pho S8Pro FR graph. Can say if the S8Pro sounds like this it would be a very good stage monitor.
Hand Held quick measurement of JBL305/310s in room - pretty down and dirty measurement but gets the idea across. This is how I evaluate things as studio reference. If they match up with this. May not be the best way to do it but the above pretty well mimics what I hear in my room as "flat".