My Sonic blaster is currently lvl34, i have soloed her from Outbreak 
I went for Energy melee as secondary, and like you, are a very affective blapper.
I suggest getting Sirens Song, this power is a life saver, and a great way to send whole groups of mobs to sleep, letting you take them out 1 at a time, before they wake up.
And if they do wake up, just use it again!
It has an amazingly long sleep-hold over the mobs, and with 2Acc's and 2 sleep duration enhances in it, missions will be a cake walk.
Next is Screech, now you may want to get this, but after trying this once, i respected it out. It dissorients, i found that dissed mobs tend to wake up at just the wrong moment, i would miss this power and choose a secondary / pool instead.
And as for Dreadful Wail 
Get it.....slot it.....love it
It takes out orange/red minions, and what it doesnt kill it disorients for enough time to finish them off (only if you have some CaB inspirations of course )
That's the kind of answer i was looking for. I was going to go for both Sirens Song and Screech. Surely used together they are gonna be great!
Sonic nova sounds good too. Like the disorient rather than energy nova knockback. At least then you have time to get away /pop a cab and finish em off.
Has anyone got very far with a sonic/* blaster?
At lvl 16 now and just wondering about the next few levels.
I tried the first couple of sonic primary AoEs at the lower levels before respeccing out as i'm a far more effective blapper atm.
But the next two available in the sonics primary look really good. Anyone got any advice or words of wisdom to what these are like?