All headphones I have sound not so good on my PC, but incredibly good on my iPhone. Why's that? Would a PCI sound card help? What about an Audio Interface? My audio drivers are all up to date.
Motherboard: Atermiter X79G

 

Have you checked your sample rate/bit depth settings in the control panel?

 

Yes. 24 Bits, 48kHz. What do you suggest?

 

I know this probably not your problem, but a few days ago my DT-990pros started sounding really bad, with static, etc. The 1/4" to 1/8" headphones cable adapter had failed! I have never seen this happen, ever.

 

headphone impedance?? or specific model??

 

Pc Case grounded properly ?
Maybe the DAC of the Mobo is broken ?

is a bit unspecific

 

Assuming you're not talking about distortion or noise or anything like that, it could be that the converters are just not that good on your pc.

 

Yeah, that's not the problem I having... I don't use any adapters but my headphones still sound cheap on my PC... Thanks for your answer .

 

No distortion, just cheap audio quality. Thanks for the answer!!

 

So both would solve this problem, right? I'll go for a USB Audio Interface then. Thanks dude!

 

Yes, as long it's not the cheapest USB interface
around 40-$50 can suffice
(something like that, for an example
https://www.thomann.de/de/behringer_u_phoria_umc22.htm)
It's not perfect ( on the Mic´s when you hit the Preamps above 80% they become distorted ), but the output sound is not cheap.

 

i was always wondering about these external interfaces, won't they have disadvantages because they need the USB ports to communicate with the main system, and wouldn't internal cards always produce better and faster results? i've tried to use external DACs once and found them quite a hassle to use, that was about five years ago though and i suppose things have gone forward since then.
i'd also guess using ASIO with them must be a bit more cumbersome than with internal cards.

 

On one hand it's correct that an USB interface communicates with the system, so the theoretical max possible amount of 680 mono tracks (at 44,1/16) isn't achieved. On the other hand a whole industry would disagree that this results in a significant disadvantage. The main bottle neck is still the driver of the interface (apart from CPU, RAM, MB and drive).