As far as I know yes.
It depends on the hardiness of the target. The harder the target the better sonic as more -resistance gets stacked.
On Bosses (maybe), Elite Bosses and Above Sonic is better, on Lts and below Ice is better. Ice also has better AoE, while Sonic has better Damage per Endurance.
If you're wanting to take out EBs, AVs, Monsters, and Giant Monsters then I'd tell you to go Sonic for the longer very focused Boss fights. The better Damage per Endurance will be as important in long fights as the -resistance.
In one set of example builds:
High End Ice Blast can hit 100dps @ 4.6 eps*
High end Sonic Blast can hit 65dps * (1--resistance) @ 3.0 eps
Anytime you perma-stack 3 or more -resistance blasts then Sonic is matching or exceeding Ice and doing it for a cost of 1.6 less eps.
* This does not include primaries, temps, pools, procs, special IOs, etc. Ice can excessively well procced making an entirely different ball game. However, even well procced Sonic typically maintains the eps advantage even if the dps advantage lessens. It should also be noted that the majority of content in the game is NOT EB, AV, GM level and for that content the AoE of Ice as well as the front loaded damage that doesn't rely on the stacking of multiple -resistance powers will be an advantage for Ice over sonic. Sonic will however Always be an advantage when teaming, the larger the team the larger the advantage. It's a very complex issue.
Ice is in second place after Sonic right?