Servo movements reading from sensor. Advice? (K9 Robot)

I'm building an fully autonomous and animatronic K9 replica from Doctor Who and would just like some advice on how I would go about controlling its ears.
I want the ears to move towards the source of sound to imply its listening.
I haven't used sound sensors before so I'm not sure whether this is the best way to go about it as I'm concerned about noise interference as it'll most likely be displayed in noisy areas.

I was thinking something along the lines of:

If sound1.value = >50 then
servo.value = 120
elseif 90
if sound2.value =>50 then
servo.value = 20

with soundx.value being the sensor (one of two in this case)

Is this the best way of going about this?

Any advice would be greatly appreciated.

I have attached a link so you can check out my campaign on Indiegogo for more info towards the project.

Cheers

Adam

When you attach a small tube on a electret mic, it becomes sensitive for a direction.
You can use a tube of the size of the mic, about 6mm diameter. But you can also attach it on the mic over the hole in the middle with a tube of diameter 1mm. The 'tube' doesn't have to be metal, it can be plastic and it can even be rubber or silicone material.