For PvE: Sonic works nicely with Kinetics because the -resistance raises damage higher than the damage cap, which can be reached with Fulcrum Shift. Also Siphon Speed will help you stack Stuns and Sleeps much more easily. The only power in /sonic that doesn't always work for teaming is Shockwave, which is knockBACK not knockDOWN, as it says in its description. The nuke is also good, providing a nice stun and with transferance it's less of an issue to get back to Defending.
For PvP: Shout is your winner, as the longer activation time means the damage can reach into 600 after a few self-buffs. Screech is also pretty good as the debuff lasts a little longer. Shockwave might be useful for PvP (I use Repel instead) to keep melee types on their back, but requires practice so you can still heal from them. Besides that, Transferance is handy for the big endurance sap, and Don't be too shy to use Fulcrum Shift on just the one target, it's still a +50% damage buff even if you're nowhere near them.
Defiant EU
Quaver: Kinetics/Sonic Defender
Semiquaver: Sonic/Kinetics Corruptor
Wow so seems a good choice then 
thanks alot Q very helpful
Shh don't tell anyone :P (definitely one of the most fun Defender combos I've tried; in pvp watch out for high defence, obviously kinetics is nothing if it all misses. And always use Siphon Speed as soon as it's ready) Have fun
Defiant EUQuaver: Kinetics/Sonic DefenderSemiquaver: Sonic/Kinetics Corruptor Make sure you pick up assault and tactics.
He will honor his words; he will definitely carry out his actions. What he promises he will fulfill. He does not care about his bodily self, putting his life and death aside to come forward for another's troubled besiegement. He does not boast about his ability, or shamelessly extol his own virtues. - Sima Qian.
Assault on a Kin? Won't Fulc Shift tend to cap you on teams anyway?
It's initially the better pre prerequisite before tactics.
He will honor his words; he will definitely carry out his actions. What he promises he will fulfill. He does not care about his bodily self, putting his life and death aside to come forward for another's troubled besiegement. He does not boast about his ability, or shamelessly extol his own virtues. - Sima Qian.
Well i rolled a kin/sonic for pve, but would they be good in pvp because of the debuffs + the high dammage from sonic, can you guys help me with this and let me know what you think,
cheers