I was waiting to cross Rio Bravo at the I-25 interchange (on the shared-use trail). I pressed the button, a synthesized voice said, ‘Wait! Wait!’, then it beeped secondly until I got a green light. The beep’s volume varied with background noise. A lot of big trucks use this ramp, traffic can be heavy, noise varies greatly.
We have the a similar system here, at the intersection, volume can be variable but at least when it goes green it’s the synthesized voice telling you the walk sign is on to cross (street name) usually doesn’t vary that much but some seem to be louder than others.
All the new crossings on Central talk. I haven’t noticed the difference in volume.