Rooting a phone is not for the light hearted as some phones are easy to brick, some easy to recover softbricks and some can't be brought back at all. I haven't rooted an Android phone since my HTC Incredible or tablet since my Motorola Xoom, since the newer devices and versions of Android perform admirably. The previous versions of Android needed help and some overclocking. The best place to look for rooting and installing custom ROMs is xda-developers.com. You will have to learn a bunch before embarking on that journey and find a ROM that suites your needs. I have a Note 3 which supports native USB audio and in general performs rather well so I haven't considered rooting/ROMing it. My Note 3 is able to run all of my DACs, without a powered USB Hub. My iPod Touch 5G, using a Lightning CCK cable can run with a FiiO E18 without a powered Hub but can't run my other DACs without the powered Hub. I've had success using an OTG Y cable and a small USB Battery pack, sometimes referred to as a JuicePack.