I tried the Talk back with headphones and it does sound way better than the TX audio. The different modes sound almost the same to each other, while the PA mode sounds the best. I wish the PA audio was what the AM TX audio sounded like.
Ok .. I got two radios side by side using head phones.
I was using headphones to test and audio and one the audio was good the other awful until my ear started to get REALLY hot from one of the headphones heating up so stopped. The volume control on these radios is very high as well that if you turn dial on full even with the inbuilt internal speaker you will blow an ear drum. LOTS of power running to the output audio
What I did do is get two radios somewhat apart from each other with volume control turned down so much that no feedback would occur but enough to hear myself.
AM was so OVERDRIVEN at level 15 mic gain no wonder it's distorted. Also the back ground noise being detected.
Am I turned down to a 10
SSB I turned down to a 12
FM I also turned down to 12
If you try talk back mode you can hardly hear yourself from the inbuilt speaker but once you go to transmit mode .. the second receiving radios speaker BOOM loud as hell even when it's volume level very low
These radios are really over driven.. FM they can get away with it and sounds good. SSB they can get away with it .. but AM it is over driven but reducing mic gain improved that. AM audio can't tolerate the bass levels compared to FM can so this is what we are experiencing
BUT perhaps we have different opinions on audio quality as many people do but I actually think the audio is loud and clear with a lot of oomph behind it. High mic gain and talking too close to the stock mic definitely causes problems, causing bass and muffled audio but that is to be expected. I found talking sideways into the mic or on an angle helps and not talking directly into it.
One more thing is your powered desk mic has more control over the audio sound. The one your using is top of the line so processing the audio alot better than the stock mic. I am not surprised it's helping AM audio greatly, if it didn't improve audio at all then no one would buy them.
I am going to do some more testing anyhow... but so far I think these radios are actually decent.