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View Full Version : FM radio vs. Streaming for sound quality



Guut_Boy
2014-04-22, 01:34
I am not sure it really makes sense to compare, but still, does someone have some thoughts on how the sound quality of the two compares? Obviously it depends entirely on the bit rate of the stream but what I was thinking of is: at what bit rate do you think streaming is equivalent or better than FM? (with a good signal of course)

I was thinking of this because I like to listen to many of the shows on BBC's Radio 6. However the bit rate of that stream is very low (maybe only for people outside the UK?), so I was thinking I would probably be better of using my FM receiver (I have BBC on cable radio).

As a bonus question: Did anyone ever make a plugin to make FM radio available on squeezebox? I mean I suppose you could connect an FM tuner to the server.

bpa
2014-04-22, 02:45
This is a very old topic and has been discussed here and other places many time before. Google you'll find what people think an internet stream radio would need to be to comparable with FM. Audio codec and stream speed make a big difference.

In the real world - BBC has a v. good quality stream 320kbsp AAC (44.1 IIRC) stream for Radio 3. All other National station are 128kbps. This is for UK only listeners. Non UK gets 56kbps / 32kHz. The R3 high quality stream It occassionally is opened to the world. BBVC also run WMA and Flash/AAC stream. ( IIRC WMA is 128kbps/UK and 48kbps Non UK)

BBC on cable system often come from the Freeview, DAB (does UK use DAB+?) service or Satellite as the signal is already digital and easy to process. None are FM quality (e.g. DAB is MP2 and BBC used to use DAB signal for internet streams see http://en.wikipedia.org/wiki/Digital_Audio_Broadcasting#Sound_quality , http://www.theguardian.com/technology/askjack/2009/aug/06/iplayer-best-sound-radio ) - you need to check your cable supplier to find where they are getting the radfio and then determine the actual quality but FM will probably be better.

I created a plugin for Squeezebox for the Griffin Radio Shark USB FM/AM tuner and still use it. I set it up when my local broadcaster (RTE) streamed at 16kbps mono but now most broadcast have acceptable quality streams. The difficulty these days is getting a USB radio Tuner as the need for one has gone away and there are no news ones made/sold. SDR (software defined Radio) USB devices are available and can do FM but require a reasonable processor ( radio signal processing is done in software and not hardware so these pdevices can be made to receive and process virutally any type of radio signal) but as I see it it is not worth the effort to create a plugin.

Apesbrain
2014-04-22, 02:47
Given that broadcast FM stereo is capable of audio performance roughly on par with the LP there is no "correct" answer to your question. (I don't know whether "cable radio" offers the same performance.) It's probably safe to say that for a station geographically close enough the FM signal will always be at least as good as the stream. If I had to offer an opinion, I'd say that 160kpbs is what's needed and as you've probably discovered that is rare. (It's volume-dependent as well so you'd be less sensitive to the diminished performance at low background levels.) Always best to listen to both options and decide yourself.

You can use the WaveInput plugin to patch any line level signal into LMS via the line-in on your server PC.

Guut_Boy
2014-04-23, 03:53
Thanks for your input. It sounds like (from you and what I could google) switching to old fashion FM radio is not going to make a big difference unless the stream is very low bitrate (like the BBC streams).

Julf
2014-04-24, 05:37
And remember that BBC FM broadcasts are distributed to the transmitter stations using a 14-compressed-into-10-bit/32 kHz NICAM digital distribution backbone.