I bought those IEM 2 years ago, paired with F.Audio Xs-03 and FA3. I used them shortly then replaced with other iem because of their bad sounding. Those DAPs have an output impedance of 20 or so ohms on the SE outputs and I think higher on the BAL outputs. I read that multi-BA iems are affected by an high Zout unlike DD-only iem (the TFZ Essence sound good with F.Audio daps) then the Nx7 is maybe too sensitive to high Zout (some KZ multi-BA iems are not bad paired with F.Audio, as well as the NiceHCK M6) So, my 3-star rating if an halfway between usage with the now dismissed F.Audio and my last new DAP.
BUILD AND CONFORT - Looks solid, the design of the faceplate is nothing special. Good fit, the metal nozzle allow good fit and insertion achieving nice isolation. Quite good confort.
SOUND (Part one, with F.Audio DAPs, balanced output) -
Bass is deep with good sub-bass rumble and good texture. The upper bass is quite messy with little definition.
Midrange is recessed, unnatural and weird, seems that the 4 BA are a bit outphased and not coherent. Overall unpleasant.
Highs are brilliant, too brilliant, emphasized by the recessed mid-range.
Very detailed but also harsh, the piezo seem strong but not very refined.
Soundstage is unnatural, affected by the uncoherency of the BAs and excessive brilliance of the piezo.
Overall, I would give 2 stars.
SOUND (Part 2, with HiBy R3 Pro Saber, 3,5 SE output) -
The HiBy DAP has a Zout of 2 ohm on both SE and BAL outputs.
Bass is similar even if a bit more powerful than F.Audio DAPs
that has bass roll-off unlike the HiBy R3.
Midbass is nicely textured and a bit recessed.
Midrange is quite cold but musical and tonally correct, far better than with F.Audio. I wondered how much it improved switching from F.Audio to HiBy, it really seem that the Zout played a big role on the way the BAs working.
The highs remain too brilliant and harsh, tamed by the far better presence of the midrange so they are lesser fatiguing but still unnatural.
Soundstage is average, anyway improved and enjoyable than before with F.Audio
Overall I would give 3,5 stars so the rate of 3 stars is due in my opinion to the too high sensitivity to the Zout. I made a quick try to my IEMs in SE to compare with the BAL out of the R3 that is definitely better, but not with Nx7. The Nx7 drove by the BAL out of the R3 Pro Saber keeps all the pros shown on the SE out except the highs that become hyper detailed and fatiguing. Even if the bass is tighter and more energetic, overall I would prefer to stay on the SE out.
All this if not wanting to work with EQ and MSEB that can partially fix some issues... (the HiBy's MSEB works very nice, however)
BUILD AND CONFORT - Looks solid, the design of the faceplate is nothing special. Good fit, the metal nozzle allow good fit and insertion achieving nice isolation. Quite good confort.
SOUND (Part one, with F.Audio DAPs, balanced output) -
Bass is deep with good sub-bass rumble and good texture. The upper bass is quite messy with little definition.
Midrange is recessed, unnatural and weird, seems that the 4 BA are a bit outphased and not coherent. Overall unpleasant.
Highs are brilliant, too brilliant, emphasized by the recessed mid-range.
Very detailed but also harsh, the piezo seem strong but not very refined.
Soundstage is unnatural, affected by the uncoherency of the BAs and excessive brilliance of the piezo.
Overall, I would give 2 stars.
SOUND (Part 2, with HiBy R3 Pro Saber, 3,5 SE output) -
The HiBy DAP has a Zout of 2 ohm on both SE and BAL outputs.
Bass is similar even if a bit more powerful than F.Audio DAPs
that has bass roll-off unlike the HiBy R3.
Midbass is nicely textured and a bit recessed.
Midrange is quite cold but musical and tonally correct, far better than with F.Audio. I wondered how much it improved switching from F.Audio to HiBy, it really seem that the Zout played a big role on the way the BAs working.
The highs remain too brilliant and harsh, tamed by the far better presence of the midrange so they are lesser fatiguing but still unnatural.
Soundstage is average, anyway improved and enjoyable than before with F.Audio
Overall I would give 3,5 stars so the rate of 3 stars is due in my opinion to the too high sensitivity to the Zout. I made a quick try to my IEMs in SE to compare with the BAL out of the R3 that is definitely better, but not with Nx7. The Nx7 drove by the BAL out of the R3 Pro Saber keeps all the pros shown on the SE out except the highs that become hyper detailed and fatiguing. Even if the bass is tighter and more energetic, overall I would prefer to stay on the SE out.
All this if not wanting to work with EQ and MSEB that can partially fix some issues... (the HiBy's MSEB works very nice, however)