There are 2 separate issues being discussed in this thread.
Overall Volume Level AND Volume Offset for the 436HP scanner.
The 2 items may or may not be related, but this thread my need to be split and/or members need to be VERY clear on what issue they are concerned about.
I received my 436HP with Firmware Version 1.03.00 already installed, so I cannot comment on any perceived maximum Volume differences between different Firmware versions. Also it may be possible that Uniden may or may not have done something with the Volume steps between firmware versions or like many things maybe there are problems with speakers or amplifiers that are degrading after some short period of time. All I can say is my 436HP is reasonably loud enough. I will try to closely compare to my 396XT at some point, but for now, I am assuming there is not a maximum Volume problem/issue with my 436HP. I can say the Keybeep is VERY loud on my 436HP when the Volume is set to max and this is the Keybeep set to Auto. So this seems to confirm that I think my 436HP seems to be working as expected.
I did some experimenting only on my 436HP with the Firmware Version 1.03.00. I did not try these tests with my 536HP yet.
Also for the purposes of my tests, there was no AGC turned on or enabled. AGC is a WHOLE different discussion for the X96 and x36 radios that needs to be discussed IN DETAIL and we need to somehow figure out of the ACG actually WORKS on these radios and HOW. No clear discussion about how each setting functions or examples on how to set the AGC are anywhere that I have looked. Maybe I have missed the AGC pot of gold somewhere??
First anyone that is trying to "fix" or "correct" for a highest/loudest Volume deficiency using a positive (+) Volume Offset is going about things the wrong way. I have set up a NOAA Weather channel with a 0 and +3 Volume Offset and compared the scanner max Volume by toggling between these 2 NOAA channels and the best I could tell the maximum Volume from the scanner was no different. This is what I would expect as the "Offset" is most likely just a software step that increases to Volume by up to +/- 3 fixed Volume steps. I assume when you get withing 3 steps of maximum Volume a + Volume offset is only capable to making an step adjustment up to the maximum Volume step. A +3 Volume Offset is basically "ignored" for the last 3 maximum Volume steps.
One to the Volume Offset experiment.
I make a new "Favorites List" and named it Weather. I then configured my best NOAA Weather frequency in 6 different configurations. I set up NFM and configured a -3/0/+3 Volume Offset and named each configuration as Weather NFM V-3, Weather NFM V0, Weather NFM V+3, Weather FM V-3, Weather FM V0, Weather NFM V+3. Then I put the scanner on Channel Hold so I could manually switch between the different NOAA configuration and see if the Volume Offset work and how much of a difference the IF setting made in the overall Volume level.
What I found is on my scanner the Volume Offset did appear to work. I also found there is a Volume difference between using FM vs NFM. Overall the difference between FM and NFM was not that great, maybe about 2 Volume steps overall.
I did not use any soft of audio level meter, I could, but for this test did not think anything other than a subjective listening ear would be needed. I figured if the Volume Offset did not work, I would not need anything other than a good ear to confirm this.
So, at least with my 436HP scanner running Firmware Version 1.03.00 my Volume Offset appears to function and I believe function relatively correctly at least using a NOAA Weather channel as a "source". There was also about 2 Volume steps difference in the sound level between the FM and NFM setting.
Some may find differences in P25 systems, I have not tired or tested this yet. I was going to start maybe with a control channel if the scanner would open the squelch on the control channel or I may need to configure the channel as an Analog channel to listen to the control channel??
So for anyone that "thinks" their Volume Offset does not work, I suggest you test it similiar to my test and make sure the total scanner Volume is not set higher than 12 when you run the test, turn off all AGC and then report back your findings.
Consistency in testing and comparing will be required to determine if there is any soft of Volume Offset problem.
Also for the "total" Volume issues people are reporting, some way to compare and test will need to be identified, it may even involve bad loading the scanner Firmware, however, I do not know if this is a very easy thing to do.