@Encrypted I thought echos were a reverberation taking longer to return to your ear.
A reverberation is perceived when the reflected sound wave reaches your ear in less than 0.1 second after the original sound wave.

Yea Machines unit voices (i've been looking them up) just sound like they are either filtered through an autotune (like soundwave from transformers), or have that radio effect over them.
Give this SITE an experiment for autotuned filters ^ ,^ heaps of fun.

Very starcraft that game sound. Adun'twain-us