For $13.50 USD (if you supply your email addr. for a 10% off code), it's well worth getting the full set
RHA Nozzles
There is a height difference; for some, this could be a world of improvement. Fortunately for me, both the stock and the RHA nozzles are a good fit. The knurling on the screen end of the FiiO is
*wider; which makes my repeated removal of a soft foam tip worrisome, as the retention is very high. On the RHA while the tips slip on/off easily, I've yet to experience a separation of tip in ear syndrome (AKA where are the screw'n tweezers).
I don't have a caliper to measure with, but
*the FiiO nozzle appears to have a wider diameter.
There is a notable difference to how the higher frequencies are effected by each respective nozzle/filter. But the low end is retained across all RHA nozzles.
As a test song, I chose "Spirit in the Sky", Norman Greenbaum.
Treble/Gold: in the intro, there's no escaping the level of white noise in the background
Reference/Silver: White noise is a step or two down, from the Gold. Overall soundstage (width) takes a small hit as well.
Bass/Black: much less white noise. Soundstage (width) feels the most pinched, of the three nozzles, still acceptable.
Please don't take my observation on the soundstage to be a detractor. All three nozzle/filters still have adequate soundstage, but it is noticeable as how each filter effects the overall presentation.
For $13.50 USD (if you supply your email addr. for a 10% off code), it's well worth getting the full set: link to RHA
I can see myself flipping between my 2 ply hack (for the stock nozzle) and the RHA Reference/[edit]]Gold Silver,[edit] depending on my mood & the time of the day
Qudelix-5K PEQ settings, with a -2.0 Pre Gain