[TobaccoRoad]

I'm asking this since my onboard sound card distorts really bad around 20-50hz. If I get a new sound card or a USB DAC would it solve the problem?

 

[ROBSCIX]

Yes. Onboards are not very good compared to good internals or good external gear. A new soundcard or external DAC would provide much better sound quality for you.

However, 20-50 Hz is very low bass are you sure it is the device distorting and the problem is not your headphones or speakers being unable to produce these low tone accurately?

 

[jcx]

often output caps will have audio frequency roll off with low Z cans - as high as 80Hz isn't unusual - and that's for a dedicated headphone out - expect really poor performance from lo Z cans on soundcard line outputs

and polar electrolytics may generate some low frequency harmonic distortion of the low frequencies near the roll-off