I have been working getting this to work properly all day. Constant reading suggestions and "fixes", uninstall and re-installs etc. At this point i have just gta4 with lcpdfr installed. No other mods. I do not get police radio audio unless I pause the game and alt tab in and out. I test this by calling medics and etc, so it is not just related to dispatches. There is complete radio silence until I alt tab. Then it only lasts for a few minutes  of getting audio dispatches and radio chatter. When it isnt working I can still see dispatches in text, and when i call for a medic all that happens is my character speaks, no radio sounds and no dispatch replies audibly. All of this is while on duty of course. Any ideas and how I can get this to work properly without having to pause and alt-tab every 60 seconds or so?

I have been working getting this to work properly all day. Constant reading suggestions and "fixes", uninstall and re-installs etc. At this point i have just gta4 with lcpdfr installed. No other mods. I do not get police radio audio unless I pause the game and alt tab in and out. I test this by calling medics and etc, so it is not just related to dispatches. There is complete radio silence until I alt tab. Then it only lasts for a few minutes  of getting audio dispatches and radio chatter. When it isnt working I can still see dispatches in text, and when i call for a medic all that happens is my character speaks, no radio sounds and no dispatch replies audibly. All of this is while on duty of course. Any ideas and how I can get this to work properly without having to pause and alt-tab every 60 seconds or so?

 

Yep. I had this same exact problem ages ago, the only known way to fix it is to alt tab out and back in the game. If you can just pause and do it when you first load in, It shouldn't take long. I believe Jay or Sam or somebody responded to my topic a while ago and they were wondering why it happened as well, it since stopped for me but that was the only way i could get it to work.

 

You should only have to alt tab once, If you have to continue doing it then I'm not sure, sorry 

I have discovered this only happens after activating LCPDFR (alt-p). I can spawn a police unit or get in one off duty, and the ambient and random police chatter continues as normal, but as soon as I press alt-p before going into the station to dress out, it stops. I have also discovered when on duty and i summon a tow truck or a medical investigator via the Police Helper PDA, those units are dispatched over the radio like normal, but only that is what i hear on the radio, regular dispatches and chatter then still is mute.  And I have also discovered alt-tab trick in windowed mode does not fix the issue at all. I had been playing in window mode because it is slightly more stable and crashes less, but can;t get my police chatter and dispatch sounds to work. I never had this issue before until I had to get a new hard drive and decided finally to reinstall gta4 so I could play LCPDFR again...it is getting extremely frustrating to say the least. :( 

Take your Gta out of compatibility mode, or move it to a more current operating system, I switched over to EFLC and had the same issue. I just run it as an administrator and BAM it works

I run it as admin on win 8.1 with Win 7 compatibility. I have since found a fix. I was running it in compatibility mode, because GTA 4 will not run on my 8.1. I read running it in Vista mode worked, and it did. But I happened to up it to Win 7 compat. mode and it has solved the sound issue with the police radio. No more alt-tab and crashing multiple times to get it to work.