Quote:
Quote:
I don't see how this thing that orban does, helps audio much. In fact it might create problems on some receivers due to the noise around pilot. HVZ should be able to give us an answer.
Ps i've seen this behavior locally with 2 radio stations using orbans. If you check the spectrum of the demod audio you will see that it doesn't get loud audio over 16khz. You can do much better with ST by setting your lowpass filter to more than 16khz which you should know that it might affect your RDS.
If you ask me i would prefer omnia's (telos) approach, they slightly widen the spectrum as it gets closer to the filter's limits and it looks much nicer. Stereo tool is kinda cutting the spectrum heavily but this might be also better for the vast majority of receivers.
Again i would love HVZ to give us a good "food for thought" on this one.
From what I’ve already found, Orban’s LPF gets way too close to the pilot. What I personally would do is at 16.4k is start slowly sloping the audio down until 17.2k where I would leave a little bit of audio (similar to the Orban) at about or below -60 (dB? whatever MPXTool is using for measurement on the MPX spectrum analyzer) until 17.8k have it start to slope down again and then by 18k have the audio completely cut off.
What you see is in that LPF is just minimal CPU usage in use for LPF - minimum dB per octave, just enough to fully protect pilot. There is other reasons, but that's main one.
Also you can see that 'slope' starts from around 15kHz. Important is first few dB's, so if you compare it with LPF from ST @16kHz, wich have much steeper/narrow slope (more dB/oct), it's actually superior to that one in Orban.
Both are just fine tho, receivers will anyways filter that on their own.