I just got my D10's and honestly, I can't say I'm too impressed. VS the TFZ No.3's, the only improvement is comfort. Sub bass is about equal in songs that call for it although not as detailed, mid bass is lower in the D10's (and not as clean), and while vocals might be slightly more forward in the D10's, they aren't as crisp. Comfort wise I'd give the D10's a 9.5 though while the No.3's get a 4, note that I apparently have fairly small ears.
These are my first impressions and I will update this post eventually. I was going to try out the Spinfit cp100's to see how they are, but Penon sent me medium instead of small, rip. I do have Ikko i-planet's that I'm going to be trying out though.
Update: You know what it sounds like? It sounds like there's those little clear plastic peel off protectors covering the filters, almost like the D10's are being needlessly suffocated, it shows more in certain songs, and EQ can't get rid of it. Still using the default tips which fit very well, I'll update again when I swap them.
Oh yeah, the right ear cuts out if I try to adjust it too, but I already contacted Penon about that. Edit: The cables are marked incorrectly as well, R is L and L is R. Decided to swap the L&R ear pieces as well just to see if the cutting out would still be and it still is, Penon is working on sending out a replacement, I'm just waiting on the tracking info.
Penon got back to me and they are aware of the issue so they are sending me out one of the newer cables, awesome customer support.
5/20/2020 Edit below:
Overall thoughts: Not very "clean" sounding, most genre's are bloated with an overall muddy sound, timbre is bad, and the mid bass is terribly textured. Sub bass isn't bad, but it isn't great, it's there when it's called upon as previously mentioned, but I'd actually say that the sub bass in the No.3's was cleaner and overall better. Some songs actually have me asking where the bass is. Soundstage is fairly large, and these have been very good in both competitive CS:GO and Valorant, so I'm happy about that. Comfort is still good, and I've settled on the Ikko i-planet tips as they seem to give the best seal (5/21/2020 Edit: they don't stay on the nozzle, so they aren't a good match). Vocal trance seems to be the best fit, rap is just alright, and rock is unpleasant (listening to rock is actually more unpleasant on the D10's than my $10 logitech speakers)
I'm actually really curious how I'd rate the H40's, but I was concerned about the bigger size, which is why I chose the D10's over them.
No.3's get a 7.8 out of 10 from me while the D10's get a 5.5 out of 10.
Conclusion:
I might have been satisfied if the D10's were $30.
5/30/2020 Edit below after 100+ hours of burn in:
Final thoughts: Clean sounding, while rock is probably not their strongest point, the "overall muddy sound" that I mentioned is gone and replaced with clarity and pleasant sparkle, timbre went from being bad to decent, and the texture of the mid bass has increased dramatically, it's much tighter and controlled as well. Sub bass is good, it's now cleaner and more defined, similar to the No.3's. Mid bass is stronger in the No.3's (as I recall) but it's equally as clean. D10's are also more intimate sounding than the No.3's. Soundstage is just right and anything more might give off an artificial sound. Comfort is still really good 10 days later as well. Vocal trance is now fantastic, rap is great, and rock while just "okay" isn't bad, but could be better.
No.3's get a 7.8 out of 10, while the D10's now get a 7.5 out of 10 (previously 5.5 out of 10 before 100+ hours of burn in) .5 points deducted for the subpar rock performance.
Note: I've never believed in burn-in being an actual thing, and I didn't expect the D10's to improve over time, during the past two or so weeks I've also been switching back and forth between my TR-X00 Ebony setup and the D10's, so it's not like my ears have adjusted.
Conclusion:
Satisfied with spending the retail price on the D10's at $175 USD. Yes, they were that bad out of the box.
