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Mike Rivers

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May 7 17 8:44 PM

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Bluegrass Country is a local low power FM, digital FM, and streaming broadcast where a few friends of mine have programs. Since they don't have much access to the real studio, many of them are assembling their programs at home and uploading them where they get loaded into an automation system and get fired off at the appropriate time. I've been noticing lately that the low power FM broadcast (I can receive it in my car, but not in my house) has a "fizzy ringing" on peaks. It's most noticeable during announce breaks, but it's present on music, too. It's not coming from a single outside producer - I've noticed it on several shows. Sometimes it doesn't do that, and I think that's when there's a live announcer in the studio or when the program comes in from a network (usually American Public Media) source. The Internet stream doesn't seem to have this artifact. I have a crummy HD radio, but it sounds OK on that, too.

I don't know what format people are uploading to the automation system. It could be a really low bit rate MP3, or maybe it gets MP3ed too many times on the way to the LPFM transmitter. But it definitely sounds like a digital artifact and not something resulting from FM multipath or a crummy radio.

Take a listen to the 6 second or so sample of an announcement and see if you can make a guess as to where this artifact is coming from. I looked at a spectrogram and there appears to be a lot of crap above the normal voice range, as well as a lot of crap around 560 Hz (which could be legimate voice). Maybe somebody with iZotope RX can pick out what I'm hearing.

Hopefully this link will work:

https://www.dropbox.com/s/h8atdwqu64e6htv/Short_Break_BluegrassCountry_HomeTownSpecial.wav?dl=0

 



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spiritwalker

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May 7 17 10:57 PM

Yes it's called a WTF
What The Fact!

Sounds like a crappy mic encoded as you say as an .mp3 at a low bit rate.
I know someone who did their whole CD collection as low bit rate mp3's and the sounded similar at points.

OK it's cold here

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tim halligan

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May 8 17 12:58 AM

It sounds to me like a less-than-stellar mic...recorded too low (Soundblaster? ) in a shitty, noisy room...then boosted to get "better" levels...then smacked into mp3 at potato quality.

Then re-encoded into something else...

Then broadcast with the inherent limitations of that...emphasis coupled with hard LPF.

Cheers,
Tim

An analogue brain in a digital world

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silvertone

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May 8 17 5:46 AM

I've been hearing that on radio for years now Mike. Once digital transmission took over. Seems to be some kind of fuzzy distortion being cause my some too hot level driving some particular processor too hard.

There was a reason Orban invented the Optimod for broadcast in the analog world, maybe digital brocast needs something similar.

It could also be noise shaped MP3 being converted into even lower kb MP3's.

It's now called Extra-terrestrial Radio, cause you get so much more than just music.

Silvertone Mastering, celebrating 28 years in business.

www.silvertonemastering.com

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Mike Rivers

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May 8 17 6:11 AM

I wouldn't worry about the sound of the mic. Home-producers can't afford RE20s or U87s, and besides, this sample recording was made with an external dynamic mic plugged into my phone, though with an app that disables the phone's automatic volume control and lets me record a real WAV file.

I guess I'll go complain to the station. It might help, or might not. Maybe they can at least provide some guidelines for their producers. My first thought was that it was some overcompression and over-data reduction in the link to the transmitter (which is somewhere across town), but the fact that some programs don't have that fuzzy sound suggests that this isn't the case.



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waltzingbear

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May 8 17 9:48 AM

My guess would be multiple encoding with low bit rate. Does the "live" APR stream go thru the automation? probably not, its joined in progress, and that would be a clue.

Alan Garren
Waltzing Bear Audio

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timc

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May 8 17 10:40 AM

image

I put the sample in RX-6 and pulled out the bkgd noise to produce this spectrogram. Looks like most of the program is below 15 k with the front edge of some words producing spikes that are above 20 k. (It doesn't sound like the stuff above 2 k is "real" program.) There is sort of a quieter gap between 1 and 1.5 k. The loudest stuff seems to be between 400 Hz and 800 Hz. That bkgd noise was impressively loud. I have no guess what would cause this... 

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soapfoot

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May 8 17 10:43 AM

what does it sound like when a broadcast phase rotator moves clipped peaks to the middle of the waveform, around the zero crossing?

brad allen williams

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Mike Rivers

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May 8 17 3:08 PM

timc wrote:
I put the sample in RX-6 and pulled out the bkgd noise to produce this spectrogram. Looks like most of the program is below 15 k with the front edge of some words producing spikes that are above 20 k. (It doesn't sound like the stuff above 2 k is "real" program.) There is sort of a quieter gap between 1 and 1.5 k. The loudest stuff seems to be between 400 Hz and 800 Hz. That bkgd noise was impressively loud. I have no guess what would cause this... 
 


That spectrogram looks about like my Sound Forge spectrogram, but in Sound Forge, you can't see the "playback head" cursor move as you play the file, so it's hard to correlate the fizziness with the speech peaks - though I'm no expert in interpreting spectrograms, which is why I never bought into the RX programs.

I tried a steep high cut filter at around 2 kHz and it didn't take out much of the fizz. If you were to chop out that 400-800 Hz band with RX-6, does that get rid of it? And is what I'm complaining about the same thing that you call "background noise?" Or are you talking about something else? I think of background noise as something that's continuous, at least over some significant time span. The noise that bothers me sounds like it's keyed by the speech (and music, too) peaks. Is it there between words, too? I couldn't really tell.

Maybe I should ask Bob Orban. Nobody knows more about what screws up broadcast audio than he does.



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Mike Rivers

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#9 [url]

May 8 17 3:11 PM

soapfoot wrote:
what does it sound like when a broadcast phase rotator moves clipped peaks to the middle of the waveform, around the zero crossing?


Is that what a phase rotator does? I'd think that would sound a lot like crossover distortion, which, for the same numerical percentage of THD, is much more noticeable than harmonics.



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maarvold

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May 16 17 9:26 PM

Mike Rivers wrote:
...Home-producers can't afford RE20s or U87s...

Although I get what you're saying, this statement made me angry.  I mean, why don't we abandon ALL costly aspects of production and just broadcast with two soup cans and a string?  The reason this is happening is because it's easier to train the public to expect next-to-nothing and then fulfill the 'need' by spending next-to-nothing and paying next-to-nothing.  Also, fwiw, I absolutely think it's completely inappropriate and unprofessional for talking heads on CNN to 'broadcast' from their home office which has no acoustic treatment and compromised video quality: the quality of their broadcast should be similar to the quality of their knowledge... otherwise we have a situation that is out-of-balance and unworthy of being made available to a national audience.  Let's try to bring some honor to the thing we're presenting.  Rant over.  

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jesse decarlo

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May 16 17 11:34 PM

I feel that rant too. There's a lot going on in the world of modern audio and video broadcast and playback that (literally, I think) increases my blood pressure when I hear and/or see it.

Anything that sounds like 128k MP3 or worse will cause me to change the station or turn off the radio - I can't deal. It's like eating an otherwise fine meal that has been lightly sprayed with some noxious chemical.

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Mike Rivers

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May 17 17 6:34 AM

maarvold wrote:

Mike Rivers wrote:
...Home-producers can't afford RE20s or U87s...

Although I get what you're saying, this statement made me angry.  I mean, why don't we abandon ALL costly aspects of production and just broadcast with two soup cans and a string?  The reason this is happening is because it's easier to train the public to expect next-to-nothing and then fulfill the 'need' by spending next-to-nothing and paying next-to-nothing.  Also, fwiw, I absolutely think it's completely inappropriate and unprofessional for talking heads on CNN to 'broadcast' from their home office which has no acoustic treatment and compromised video quality: the quality of their broadcast should be similar to the quality of their knowledge... otherwise we have a situation that is out-of-balance and unworthy of being made available to a national audience.  Let's try to bring some honor to the thing we're presenting.  Rant over.  
 


If only we could change the world. And if this what a thread about what I thought that FCC Commissioner Adjit Pai said at the NAB show (that nobody else seemed to mention, so maybe I completely misinterpreted it) I would completely agree with you. What I thought I heard there was that the FCC was happy to see commercial broadcasters go off the air and distribute their programming over the Internet. But like with musicians and recordists, there are millions of amateur broadcasters. And like musicians, a small handful of them make money, the rest do it for fun, for their ego, and because they think they have something to say to a small part of the world. Those are the people who can't afford U87s or RE20s. And furthermore, their listeners may not all have the wherewithal to listen to high bit rate streaming audio and only have "a big enough antenna" to stream 64 kbps audio.

But there's no reason why the producer can't send an uncompressed or minimally compressed audio file to the streaming server, even if it takes all night for the upload to complete.

This is the problem at the station that I started this discussion about. There are about three paid staff, one available "pro" studio and a couple of dozen volunteer programmers, only three or four of whom actually come into the studio to do their shows live. There isn't enough studio time available for people close enough to do so to come in to pre-record there shows there. The rest send in their programs from all over the world.

Those are the people who could do better. I don't care if they don't have an acousltically great room for their announcements. I don't care if they don't have a high end turntable to play their records on. But if the artifacts that bother me are embedded in what goes into the stream, that's what could be improved by changing a setting and allowing more time for uploading shows.

 



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maarvold

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#14 [url]

May 17 17 9:03 AM

Mike Rivers wrote:
...Those are the people who could do better. I don't care if they don't have an acousltically great room for their announcements. I don't care if they don't have a high end turntable to play their records on. But if the artifacts that bother me are embedded in what goes into the stream, that's what could be improved by changing a setting and allowing more time for uploading shows.

At the risk of pouring gasoline on the fire, isn't that like a form of discrimination?  For example, kind of like saying, "I can live with everything I hear being up 4 dB in the sibalance region, it's that digital fuzz in the sound that bugs me.  I suppose you might be able to make a case for the fact that it's a steady-state problem vs an 'intermittant' one (since a cheap microphone is not constantly going to air).  I have so many people who have called me up over the years and ask--essentially--"How can I get a $2,000 [insert piece of gear or microphone here] for $200?".  There is generally no correct positive answer for this question.  

In so many ways, the music business has become an exercise in, "How many people can we eliminate before the whole thing falls apart?".  Casualties so far include: acousticians, full-time techs, cartage guys, assistant engineers, engineers, producers, copyists, arrangers, songwriters, composers, publicists, agents, orchestral musicians, drummers, anyone who's instrument of choice can be sampled and on and on.  

P.S., Mike--I'm not trying to beat up on you specifically because I know you didn't create this situation with the music business.  I hope you don't feel caught in the crossfire.  

Last Edited By: maarvold May 17 17 9:11 AM. Edited 2 times.

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Mike Rivers

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#17 [url]

May 17 17 6:17 PM

maarvold wrote:
At the risk of pouring gasoline on the fire, isn't that like a form of discrimination?  For example, kind of like saying, "I can live with everything I hear being up 4 dB in the sibalance region, it's that digital fuzz in the sound that bugs me.  I suppose you might be able to make a case for the fact that it's a steady-state problem vs an 'intermittant' one (since a cheap microphone is not constantly going to air). 

 


Well, OK, that's two things that bug me, and I could probably think of some more. One, for sure, is that I don't like the music that the DJ is playing, but my solution to that is just to listen to something else. Actually, though, the digital fizz isn't an intermittent problem, it's in the music, too. It's just that, depending on the musical content, it runs from barely noticeable (and ignorable, at least by me) to just as noticeable as on the DJ's mic. In an acapella vocal, that fizz is noticeable during every pause for breath. It's not a mic problem, it's a system problem.
 

In so many ways, the music business has become an exercise in, "How many people can we eliminate before the whole thing falls apart?".  Casualties so far include: acousticians, full-time techs, cartage guys, assistant engineers, engineers, producers, copyists, arrangers, songwriters, composers, publicists, agents, orchestral musicians, drummers, anyone who's instrument of choice can be sampled and on and on.  


That's true, but in today's economy and with today's listening habits, when one paid employee goes away, there's a volunteer willing to fill at least part of his job. Thing is that some jobs get unfilled. Where's the music director who listens to all of the programs on different radios, in different locations, and on computers if that's one of the company's broadcast formats and says "Hey, these four announcers always sound funny when they talk. Somebody from engineering go figure out why and fix it." Problem is that the engineering guy, if there is one at all, is an IT tech, not a broadcast engineering tech.

This, fortunately, isn't an epidemic. There are lots of college, community, and other non-commercial broadcasts that I listen to over the Internet or FM radio that sound just fine. I just notice it enough to bug me on Bluegrass Country because that's where I usually have my car radio tuned (to their FM broadcast). And the FM, FM digital, and stream all have the same problem with the same program(s) - and not with other programs.
 



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