Why does my KZ PR2 or Salnotes Zero and Samson SR850 sound thin and piercing on a TaoTronics TT-BA07 bluetooth adapter (but with LOTS of volume - max volume is TOO loud)? None of them have high impedance values, and none of them are super insensitive. EQ successfully tames treble, but EQ for Sub-bass(even significant EQ of 4 or 5dB) fails to really bring back the depth and intensity of the bass when driven from better sources. It reminds me of the behavior of an under-powered livingroom stereo system with good speakers running from a weak amplifier.
On a ‘Good’ source like Sound Blaster X G6 (Raw output mode, no sound effects or EQ applied) or my UTWS5 from FiiO none of them are piercing, they sound warm and reach deep and low and have plenty of slam and rumble.
That said, lots of people claim that sources don’t matter and you don’t NEED an amplifier for IEM’s usually due to the generally high sensitivity and low impedance values. I noticed this same thing a year or two ago with the FiiO FH3 when transitioning from a Galaxy S10+ to an LG G8 ThinQ. The FH3 sounded significantly warmer and bassier with a ton more sub-bass presence on the G8 and sounded virtually identical when driven from the FiiO UTWS5 and the Sound Blaster X G6, so I’d say they sounded “correct” on the G8. The S10+ has a mediocre output and every earphone or headphone consistently had enough volume but way too little bass (especially sub bass) and far too much treble emphasis. I’m a computers and electronics guy, so I can say with full confidence there was no “sound improvement” software active on the S10 at the time and no EQ enabled. The same kind of tone is achieved when driving any of my headphones and IEM’s from workplace laptops (the kind that focus on being workhorses, not multimedia kings), and other portable devices that put little importance on the quality of the headphone output quality (Quest 2, Nintendo Switch, various DS consoles, shitty chinese MP3 players, and the aforementioned TaoTronics TT-BA07).
If it’s not a matter of the amp inside or a volume issue, what is it, exactly?? I’ve got the tools to fix the issue if I have an answer. Is it the output impedance? Is it a DSP thing? Is it a matter of low output power but high gain causing perceived loud output but without any ‘oomph’?