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Question About FM Radio


jcmusic

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Jeff,

 

Compression of FM broadcast signals could be offset partially if you have a multiband expander/compressor running on a computer in real time to feed the FM signal into.   I would try upward expansion of the treble (1-6 kHz) separately from the midrange (250-1000 Hz).  I would not expand the extreme highs above 10 kHz--just leave those alone for the moment.  My best guess is that you're listening to a lot of bass compression (below 100 Hz) and midrange compression (250-1000 Hz). Midbass boost (100-250 Hz) will muddy the sound so I'd avoid this area initially, at least until you can successfully expand the midrange and perhaps bass regions.

 

Is this what you were intending to see?

 

Chris

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 Wow, don’t let your non-audio friends or family know how obsessed you are, they’ll call for the white coats.  As someone who used to listen to WJZZ in Dolby FM, I admire your obsession but can’t begin to follow it regarding FM.

 

When it comes to all things compression I defer to @Chris A.  Perhaps he has suggestions.

 

I do have a question.  Is quality FM the only source to be played on the subject setup?  If not, how will you easily switch to other sources?

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1 hour ago, Chris A said:

Jeff,

 

Compression of FM broadcast signals could be offset partially if you have a multiband expander/compressor running on a computer in real time to feed the FM signal into.   I would try upward expansion of the treble (1-6 kHz) separately from the midrange (250-1000 Hz).  I would not expand the extreme highs above 10 kHz--just leave those alone for the moment.  My best guess is that you're listening to a lot of bass compression (below 100 Hz) and midrange compression (250-1000 Hz). Midbass boost (100-250 Hz) will muddy the sound so I'd avoid this area initially, at least until you can successfully expand the midrange and perhaps bass regions.

 

Is this what you were intending to see?

 

Chris

Chris,

Ok firstly my name is Jay, LOL!!!

Now while I agree with you I was thinking more along the lines of using the Xilica to adjust just the FM Tuner channel I have created in the Xilica. Like maybe boosting the tweeters  or mids a little but, you are correct there is more to it and I think I am hearing some bass and that's what may be creating the muddy sound...

 

Jay

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1 hour ago, DizRotus said:

 Wow, don’t let your non-audio friends or family know how obsessed you are, they’ll call for the white coats.  As someone who used to listen to WJZZ in Dolby FM, I admire your obsession but can’t begin to follow it regarding FM.

 

When it comes to all things compression I defer to @Chris A.  Perhaps he has suggestions.

 

I do have a question.  Is quality FM the only source to be played on the subject setup?  If not, how will you easily switch to other sources?

Neil,

We have a couple great FM stations here in New Orleans and I do like to listen on certain day/nights but, the compression just ruins the sound and makes it hard to enjoy...

 

Jay

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Here in Europe, DAB+ has become quite popular. On my Denon micro-system, I can do A/B comparisons, and though DAB is 'clean', in my experience, FM has more 'charm' and better stereophonic sound stage. Perhaps I'm imagining things, though...

 

Edit:

Well, I need to update here. I re-did the A/B, and my results are in fact the opposite now: DAB+ has a broader stereophonic sound stage, while FM has more bass.

 

 

Edited by ILI
changed contents in an important way
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FM stations are still in a state of flux on the technical side, and may still be for a long time. Most transmitters are located quite some distance from their studios, and have traditionally been connected by special phone lines to get the signal from point A > B. Many stations use Livewire, which handles audio over ip, at a 48Khz sample rate to get the signal to the transmitter. They do far less compression and/or eq with the signal. The cost has come down tremendously, and the broadcast quality has gone up. Livewire is more in the broadcast arena, but there are other heavy hitters in the studio/broadcast market using audio over ip. Those would include:

 

Dante by Australian company Audinate.

Ravenna, an almost open source product from Europe (notice the joke on Dante, as he was from Ravenna)

Livewire, used extensively in the US for broadcasting.

Telos Systems

ALC Networks

Lawo

and others.

 

The great thing is they all use/implemented the AES67 standard, so most of them can interoperate. Ravenna itself supports super high sampling/data rates, even though most broadcasters are at 48Khz, which has been used in the audio industry for a long time.

 

Our local public radio station here switched to a digital format and the signal quality really went up, so it's better when even listening on older analog radios.

 

 

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9 hours ago, Marvel said:

FM stations are still in a state of flux on the technical side, and may still be for a long time. Most transmitters are located quite some distance from their studios, and have traditionally been connected by special phone lines to get the signal from point A > B. Many stations use Livewire, which handles audio over ip, at a 48Khz sample rate to get the signal to the transmitter. They do far less compression and/or eq with the signal. The cost has come down tremendously, and the broadcast quality has gone up. Livewire is more in the broadcast arena, but there are other heavy hitters in the studio/broadcast market using audio over ip. Those would include:

 

Dante by Australian company Audinate.

Ravenna, an almost open source product from Europe (notice the joke on Dante, as he was from Ravenna)

Livewire, used extensively in the US for broadcasting.

Telos Systems

ALC Networks

Lawo

and others.

 

The great thing is they all use/implemented the AES67 standard, so most of them can interoperate. Ravenna itself supports super high sampling/data rates, even though most broadcasters are at 48Khz, which has been used in the audio industry for a long time.

 

Our local public radio station here switched to a digital format and the signal quality really went up, so it's better when even listening on older analog radios.

 

 

  Is that the HD or still an analog carrier? 

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I've got a vintage Pioneer TX-9500 Tuner that was refurbished and aligned a few years back.  These days, it sits idle in my equipment rack.  My digital setup allows me to access many of my preferred FM stations via their internet broadcast.  Given the convenience, and in some cases better audio quality, that's become my preferred method of listening to FM these days.  Sign of the times, I guess....

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