[normie610]

It is, think of it as Trio with a deeper sub-bass and more organic richer tonality mids and smoother top end. Still the same airy extension of treble (as Trio), but Trio is just too V-shaped and piercing at the top while Duo is a noticeably smoother. And it does have a big semi-open back like soundstage. Sound leakage is not that bad, these are not open-back full size headphones you can't listen to in public. Yes, isolation is only -12dB, but you can easily use them in public transportation, maybe even at the library (or not)

Oh, and lower sensitivity means you have to push volume about 9-10 notches higher than other IEMs.

OK, here is Duo vs Trio in FR:

Looks like this will shine with R8 turbo mode

 

[twister6]

Hm, with only 2 drivers couldn't they make shells smaller? That was my main complaint with Nio/u12t, and that's one of the reasons i prefer Fir Audio iems, they fit me better.

Still a lot of stuff inside:

 

[Tiax]

Still a lot of stuff inside

Same for Fir, and yet they still managed to fit it all in more ergonomic shells

 

[twister6]

Same for Fir, and yet they still managed to fit it all in more ergonomic shells

This is fully tubeless design, even for DD driver. Chamber acoustics has to be taken into consideration, also part of the semi-open faceplate design, since both DD and tia are firing into the same nozzle opening.

 

[xenithon]

My personal view...the 64 Audio IEMs must be amongst the most ergonomic and comfortable IEMs.

If it is purely a matter of size, the likes of an IE900 may be more up your alley - though I personally could not come to grips with it precisely because it was so small and could not get a decent fit and seal.

 

[rantng]

So no 64 Audio logos...

 

[xenithon]

So no 64 Audio logos...

Looks like it has been moved to the inner side, looking at @twister6 's photo, in lieu of L/R:

 

[marvin3003]

I know the size is almost the same as the rest of the 64 audio line up but how does it compare to something like a A8000 in terms of size.
That male model on the 64 site was not able to fit them properly.

 

[xenithon]

That male model on the 64 site was not able to fit them properly

I suspect that the model had them in but not fully inserted, so you see more of the IEM in the imagery.

 

[twister6]

I know the size is almost the same as the rest of the 64 audio line up but how does it compare to something like a A8000 in terms of size.
That male model on the 64 site was not able to fit them properly.

Sorry, just a quick blurry phone shot, but here is A8000 (single DD) next to Duo (DD+tia):

 

[TheMiddleSky]

It is, think of it as Trio with a deeper sub-bass and more organic richer tonality mids and smoother top end. Still the same airy extension of treble (as Trio), but Trio is just too V-shaped and piercing at the top while Duo is a noticeably smoother. And it does have a big semi-open back like soundstage. Sound leakage is not that bad, these are not open-back full size headphones you can't listen to in public. Yes, isolation is only -12dB, but you can easily use them in public transportation, maybe even at the library (or not)

Oh, and lower sensitivity means you have to push volume about 9-10 notches higher than other IEMs.

OK, here is Duo vs Trio in FR:

Thanks for the FR Chart!

I guess Duo is nice to pair with silicone tips, while for me Trio is "a must" to pair with foam tips.

 

[twister6]

Thanks for the FR Chart!

I guess Duo is nice to pair with silicone tips, while for me Trio is "a must" to pair with foam tips.

Yes, and just like the latest U18s, Duo comes with a "spider" eartips holder and a full set of premium SpinFit (I believe CP145) silicone eartips. Those work quite good with Duo.

 

[HarveyLowis]

deleted.

 

[MatW]

https://www.64audio.com/products/ddd-uuu-0-6-4

 

[rantng]

Looks like it has been moved to the inner side, looking at @twister6 's photo, in lieu of L/R:

Admittedly, it does look a little plain with nothing on the faceplate.