Large amount of echo on Dahua doorbells using DMSS

[nkvoll]

I'm experiencing a echo on the doorbell side when in a call with DMSS on iPhone. I can hear everything I say echoed back at me with some delay. I believe this is caused on the DMSS side, because when I either mute the mic or turn off the volume in the app on the iPhone, it all goes away. This obviously does not happen with normal phone calls on speaker or FaceTime. On the iPhone side I hear no echo at all, it's just on the doorbell side this problem exists.

I've tested both VTO2311R-WP and VTO2202F-P-S2 and with three different iPhone models (Xs, Xr, 14 Pro). I've been unable to locate a setting to specifically enable any form of adaptive noise/echo cancellation on the app.

Is this something that is affecting more people than me, or am I missing some obvious setting somewhere? It's making the doorbells borderline unusable because it's very distracting to hear everything you say echoed back with a delay when trying to communicate..

 

[nkvoll]

I think I've exhausted the options on the iPhone user-side and have experimented with different speaker volume levels, but even at the very lowest volume the person speaking into the VTO gets their voice echoed back to them. No difference with holding the phone up to my ear, covering the speaker holes in the iPhone with fingers etc. Covering the microphone helps a little bit / muffles it but it's still a point of annoyance and is not a great solution. Muting the microphone or speaker on the phone works but with the obvious problems it brings to two-way communication it's not a great work-around either.

To me it just seems like there's missing AEC (adaptive echo cancellation) processing that needs to be enabled in the iPhone app, so I've attempted to contact the app developer and Dahua to see if there's anything they are able to pursue. (Or the doorbell could also perform AEC between the sound it transmits and the sound it receives -- but none of this seems possible to do without firmware/app updates.). I have not heard back from them yet.