Q: Our station just got an exciter that takes “MPX192”, is that the same as OmniaDirect?, or AES192? What’s the benefit of using MPX192? We have an Omnia.9, how is AES192 different than feeding analog MPX?
Glad to hear you got a new exciter upgrade. MPX192, AES192 and OmniaDirect are all the same, referring to running composite MPX over AES/EBU, keeping everything in the digital domain, to answer your first question.
To answer your second question: I tell a lot of my customers that converting an airchain to AES192 is one of the last giant sonic improvements that can be made in an FM broadcast plant.
As a programmer, I remember the first station I programmed that went with a digital console - a difference I could clearly hear. Upgrading your processor to transmitter connection and running AES192 is one of those large “last mile” types of improvements.
The main benefit? Less noise. On most modern modulation analyzers, the amount of FM Noise your transmitter produces drops dramatically when the composite analog input is bypassed and you run a direct digital connection between the two. With most modern exciters, you’ll bypass an AtoD conversion and a DtoA conversion as well.
Should your STL from studio to transmitter be able to run 48khz/24 bit depth, your audio will arrive with about 132db of signal-to-noise. If you also run AES192 from processor to transmitter, you won’t be able to measure noise on most gear you have available.
As a program director friend recently said “once your station converts to AES192, you can’t unhear it. Another engineer when describing what it sounds like when a radio station goes dead-air and is running AES192 said “complete lack of noise...nothingness...like a black hole on the FM dial.”
Our support department as a few suggestions about running AES192, to summarize them here:
1) Like with analog composite cables, keep your digital AES192 cable run as short as possible (3-6 feet, ideally)
2) Use 100 ohm CAT 6 Shielded cable.
3) Do not attempt to use standard AES cables.
Both of our leading flagship FM audio processors give you AES192 outputs. In the Omnia.9 menu, you configure one of the AES outputs on the box as “AES192.” On newer Omnia.11’s there is a totally separate AES192 output from the regular AES/EBU IO.