SGS2 received mixed reviews about sound quality. IMO its due to some earlier or country versions have Yamaha sound chip. So after checking this page I am pretty sure that my SGS2 has a Wolfson audio chip:
From that page:
Notable new Wolfson Audio Hub, DSP and subsystem product adoptions in Q3 2011 include selection by:
- An existing high volume Tier 1 customer for its new 2012 smartphone platform
- An existing Tier 1 customer for its next generation high volume 2012 smartphone platform (announced at Interim results in July)
- Samsung for Droid and Epii handsets, a new Galaxy S2 model, the Galaxy R smartphone and various Samsung Galaxy tablets
- LG for its Optimus range of mobile phones including the Sol, Q2, EX, Net and LTE handsets, and the LG V909 tablet
- Sony Tablet S and Lenovo LePad tablet PCs
- Fujitsu and Toshiba for new Japanese smartphones
Why am I sure? Becasue I have a Sansa Fuze (Rockboxed) and my SGS2 sound quality trashed it out even with its stock music player.
I simply quit using Fuze.
On your SGS2 just be sure to select Normal from EQ settings (disables EQ) and Music Clarity from the players setting. I cannot pass the 1/4 volume and adding an amp is useless for me (tried with Kramer modded, recabled, 75ohm resistor modded KSC-35's).
Recently I have upgraded to IceCreamSanwich and loaded CyanogenMod9. Sound quality didn't change after these mods. But I have seen a menu to activate the USB dock audio on the CyanogenMod9 menu.
Edited by Baycode - 7/18/12 at 2:44pm