A range of smartphone models are used., page-23

Okay, I'll make one more attempt. You seem to have misinterpreted my post. I did not intend to argue with you, only to elicit more information. You have the confidence to claim more experience and knowledge than us. You tell us that we're wrong. Yet you give us none of the correct information that you possess.

Just so you know that you're not pointlessly wasting your time speaking with an ignorant layman with regard to your concerns about sound-recording hardware, allow me to offer a short biographical note about myself: 36 years in the software industry starting as a developer, progressing through software engineering, solution architect, and now an IT business analyst. In 2012 I enrolled part time at RMIT for my master's degree specialising in software engineering, algorithms and intelligent systems. The degree was conferred with distinction in 2015. I worked extensively with hardware systems during the 1980's. While I was never involved in designing the hardware we built, I wrote the control software. This is involved a lot of time with an oscilloscope and the circuit diagrams to test and isolate faults to hardware or software. I have experience with both digital and audio signal processing. I have the singular pleasure of never having had to deal with the DFA, the TVU or the TGA.

@maria1240 posts authoritatively about algorithms and software engineering in a way that allows her expertise to be recognised.

So I ask you again... why is it necessary to exclude all but a single type of phone? You've alluded to both hardware-related and FDA-related issues. What are they?

I assure you that there are intelligent, educated people listening, earnestly desiring to form a balanced and realistic view of this thing we've put our money into.