What quality music do radio stations broadcast?

johnnm

johnnm

Audio Enthusiast
I have no idea how radio stations work. I understand how the basic underlying technology of radio works, but I've never been inside a station. I'm assuming all their music is stored digitally on a server somewhere, yes? If so, is there a standard quality stations use? (ie MP3 @ 320kbps VBR or something similar?)

Is FM broadcast analog?
 
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All FM stations broadcast an analog signal (many station also broadcast a digital HD Radio signal, which requires a HD Radio equipped tuner to hear); what happens before the transmitter varies widely. I think the common practice is tending more to all-digital music storage and signal processing, but many stations still have analog tape and even vinyl records(!) as a program source, some even broadcast live audio programs, either voice or music. The link from the studio to the transmitter may be digital or analog.

There's no "standard practice" nor simple answer other than "it varies" as far as the hardware is concerned. The FCC does require certain minimum standards for noise and distortion, deviation limits and so forth, and stations almost always employ limiting and compression to make their signal "louder", the amount depending on their intended audience and market.
 
For digital music storage there is no "standard", but I'd say typical today would be linear. Some years ago with storage much more limited at least cost wise, then for a while you'd run into more mpeg2 or Apt-X. But for some time now, with large storage volume possible and cost effective, music storage at anything other than WAV's are not seen very often.

BTW...the FCC does not any longer have audio standards for distortion or S/N, just modulation limits and RF standards for spurious and harmonic kind of stuff. It's assumed, perhaps not entirely correctly, that audio quality will be keep adequate by competition and that they only need to worry about keeping the broadcaster within their channel and not causing others problems with any trashy emissions.

Mark
 
evsentry3 said:
For digital music storage there is no "standard", but I'd say typical today would be linear. Some years ago with storage much more limited at least cost wise, then for a while you'd run into more mpeg2 or Apt-X. But for some time now, with large storage volume possible and cost effective, music storage at anything other than WAV's are not seen very often.

BTW...the FCC does not any longer have audio standards for distortion or S/N, just modulation limits and RF standards for spurious and harmonic kind of stuff. It's assumed, perhaps not entirely correctly, that audio quality will be keep adequate by competition and that they only need to worry about keeping the broadcaster within their channel and not causing others problems with any trashy emissions.

Mark
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FYI, Under Japanese laws, FM broadcasting is regulated by modulation limit (up to 100%) , and they are filtering 15khz and higher of the source signal before modulating. But commercial FM stations occasionally ignore this regulation (150%) in order to send dynamic sound of special live recording or live performance, while national FM station never does it. .:smoke:
 
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In music on hard drive live assist or automation, compressed music files are very frowned on (MP3 especially so). MP2 was used on older systems. MP3 doesn't work well over multiple generations at all without audible artifacts. AAC or APT-X are preferred when compression is needed. Sound cards like DigiGram and AudioScience are prevalent in broadcast automation. I use BSI (Broadcast Software International), Arrakis Systems, and BE (Broadcast Electronics) AudioVault systems in broadcasting. Post or PM if you have any broadcasting related question. I can answer most. :tresbon: 100% modulation is the legal limit in the USA. Audio Processing (usually Orban Optimod or Omnia) is common and needed to some extent.
 
Yep. Good old maximum compression. Who cares if the music sounds good as long as it's loud?

Such is progress, I guess.
 
Some compression is necessary, even on classical music. The dynamic range of the FM signal is much less than for CD (or digital), so the compressor just brings the lowest dynamics up to the noise floor. The real issue is how much compression a station applies--"just enough", or "as much as possible".
 
As a sound quality minded broadcast engineer (management is in my family). I run my Orban Optimod processing lightly. I use only enough to make quieter music audible in cars or noisy locations. I don't believe in excessive loudness. Too many of these boxes are wrongly adjusted by ill informed operators. :tresbon:
 
i work on radio station and have to admit i've quit listening to due to ovecompression, even classical music.

dynamic range is reduced to 10db, doesn't matter the genre (pop, rock, folk, jazz, electronic, classical...).
 
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