DVB-S audio bandwidth
differences in audio of satellite radio
... and why the theoretically possible is not happening
Digital satellite radio could make great sound for audiophiles up to 24 KHz audio. But it doesn't. The reason: Many stations use DVB-S to feed their transmitters. FM is limited to 15 KHz. And that is why the feed is already prepared for that. Then you don't need filters in each transmitter again. Another reason for a poor spectrum is a lower sample rate or bit rate. Anyway I checked some German stations which ususually use 48 KHz sample rates and high bit rates of 256 or 320 KHz. In addition to that it's neccessarry to check stations at various times. Audio sources seem to be very different. Right now I'm listening to a classical concert on Deutschlandfunk that is cutting around 16 KHz. Only in loud passages the Hicut seems to move higher but there is still a cut. Many stations like Bremen 1 have two cutting points: Above 15200 Hz the spectrum is significantly reduced by 20 dB, above 15700 KHz nothing is left. Other stations have a Hi-Cut that is constantly adjusted in 500 KHz steps (see image from DLF). The dynamic Hi-Cut-Frequency with these noise blocks in the spectrum is either an effect of the audio codec (MPEG 1 Layer 2) or a result of sound processing. The marks in the spectrum are 2/4/6/10... KHzAstra 19°E
| station | audio hi-cut |
|---|---|
| Radio Horeb | 12000 |
| Bayern 1-5 Bremen (1/4) | 15200/15700 |
| DasDing | 15800 |
| DKultur | 17500 |
| DLF | 20500 |
| DWissen | 20500 |
| FFH | 16000 |
| MDR (all) | 15700/16200 |
| NDR (all) | 15800 |
| Nordwestradio | 17500 |
| SR 2 | 15700 |
| SWR 2 | 20000 |
| WDR 3 | 18000 |