At what bitrate does mp3 "beat" FM radio?

[petsematary]

Imagine you've produced a song or a piece of audio. It's uncompressed, 16/44 cd audio.

You then play the track on a good sounding FM radio station and listen over a high end hifi set. You also compress it to mp3 format (no special settings, just normal mp3) and play it back over the same system.

How high do you think the bitrate would have to be for the mp3 to sound better than the FM version? If you want to go VBR, state the overall bitrate.

[wado1942]

Different people will tell you different things because it's ultimately about perception. It depends SO MUCH on the quality of the encoder, the source signal etc. Also the power of the radio station, weather conditions, distance from the tower, receiver quality, radio processor etc. I think marketing people generally consider 192kbps for AAC and 256kbps for MP3 the breaking points. But again, that's making A LOT of assumptions and we're talking about marketing guys, not audio engineers.

[Ethan Winer]

Originally Posted by wado1942

Also the power of the radio station, weather conditions, distance from the tower, receiver quality, radio processor etc.

Indeed. Where I live, few FM stations come in well enough to beat even 64 kbps MP3.

--Ethan

[Hic&Nunc]

I think the fact every FM broadcaster uses signal processing make this question a bit obsolete.

jo.

[807Recordings]

I had a magnum dynalab tuner and I can say if it was a decent station the quality was pretty good. One night I was listening to a radio broadcast off a local university station and when the record started skipping I went to look at my turntable. But then again you could almost hear the compressors and gear used at the station with that tuner.

Sadly now that I live in Europe and radio is ok I no longer have this machine.

With most stations they broadcast now in mp3 so how can FM be better than the source?

[petsematary]

Yeah, yeah, I know there's tons of ifs to consider and I realize that "good sounding" is a very subjective concept indeed. And that weather etc. plays a part.

As far as processing, let's just assume you add some multiband, parametric eq etc. ITB to simulate the processing that goes on in FM. My main question I guess is just how high a bitrate it takes to "beat" the FM transmission that, we all agree, affects the sound in a bad way.

[Adam Dempsey]

Originally Posted by petsematary

As far as processing, let's just assume you add some multiband, parametric eq etc. ITB to simulate the processing that goes on in FM.

You can try that but you'd be maybe only 20% of the way there. And every station (and sometimes timeslot) differs.

Originally Posted by petsematary

My main question I guess is just how high a bitrate it takes to "beat" the FM transmission that, we all agree, affects the sound in a bad way.

Not sure I really understand your point, but if you wanted to pretend that all things were equal I'd have to suggest 320kbps AAC, or FLAC, or uncompressed PCM to "beat" digital radio broadcast bitrate. Remember any lossy and/or clipping artefacts of the source will only be exaggerated after the transmitter.

Off to do my radio show later today... and hope to discourage others at the local station from playing mp3s...

[wado1942]

Looking at it from a purely technical stand point. FM radio has a bandwidth of about 50Hz-15KHz and a signal to noise ratio of maybe 60dB.

A typical 192kbps MP3 has almost the same bandwidth (though you can manually adjust this) and S/N ratio of CD but there's no doubt that it sounds like crap compared to the CD source. Even at 112kbps, the frequency response is similar to a good FM radio station, though the S/N ratio is still 90dB. I'd take a good local radio broadcast over that gurgly, distorted mess any day. Though as I think one person mentioned, most radio stations are using MP3s, WMVs and AACs as their replay sources any way so who cares?

I'll tell you, there's one "HD" (yeah, that's a laughable term alright) station in my city that simulcasts in FM. It has a 17,500 Watt transmitter on a plateau on the north end of my city. 14 miles from that location, the MPEG transmission is notably clearer than the FM broadcast. They have VERY primitive equipment on the FM side of things, which sounds far worse than any other local FM station in the city. I don't know their specs for MPEG broadcasts unfortunately. I know in Europe, where "HD" radio is a lot more common, there's constant complaints over the quality of the AAC broadcasts, which are 64kbps. Although they're allowed up to something like 300kbps for their total bandwidth, the costs of broadcasting MPEG is so high, that they have to multiplex several channels into a single signal. Some stations have compromised and gone with 96kbps but only the most commercially successful stations can afford to do so. Even at that, people within a certain radius of a given station will say the FM signal sounds better while people outside of said radius, tend to prefer the MPEG side of it since the digital signal tends to either work or not, with little in between. On a side note, many "HD" stations have chosen to broadcast in mono to allow for better sound quality. Please note that AAC is significantly superior to MP3.

Overall, I'm not sure what your goal is with this question. Are you trying to simulate the sound of FM broadcasts through MP3 encoding? If so, that won't work because they're two different animals. Are you trying to start a pirate radio station and figuring out the breaking point between quality and compactness is? If so, the fees are pretty hefty for such a feat. If you're just trying to go for pure subjective comparison for the purposes of curiosity, again, they're two completely different animals. Which one looks better, Video-CD or VHS on EP mode? Well, they both suck for completely different reasons so it's ultimately up to you.

[glassmaster]

FM radio has the potential to sound fantastic. If you have ever had the pleasure of hearing the live Boston Symphony Orchestra broadcasts from Symphony Hall on WGBH, you'll know what I'm talking about. (I'm also dating myself.) MP3s don't come close (at any bit rate).

[LeeYoo]

Must agree with glassmaster. Fm radio can, and used to sound great with the proper tuner and aerial. Things have gone downhill with signal processors/compressors/limiters and lossy audio. I don't listen to radio anymore these days. One more thing I don't pick up in these posts is that FM stereo has only a bandwith of about 16khz, because the channels are "chopped" at a frequency of 19khz, to make stereo possible.

[petsematary]

Interesting, thanks. Yeah, I suppose it's an impossible question to answer, but this whole thing about the range and S/N ratio is what got me started. Technically, mp3 is way "better" in that sense.

[work2do]

Originally Posted by petsematary

Interesting, thanks. Yeah, I suppose it's an impossible question to answer, but this whole thing about the range and S/N ratio is what got me started. Technically, mp3 is way "better" in that sense.

FM radio and satellite radio here in USA play mostly mp3's all day long. Every song sent in via email is mp3 to PD's and mixshow. Mixshow dj's are using serato w/ mp3's. Been like this for a while. The songs are tested and bubblin long before the CD Pro's are even done.

[petsematary]

Originally Posted by work2do

FM radio and satellite radio here in USA play mostly mp3's all day long. Every song sent in via email is mp3 to PD's and mixshow. Mixshow dj's are using serato w/ mp3's. Been like this for a while. The songs are tested and bubblin long before the CD Pro's are even done.

Wow, that's sad. But I'm sure it happens all the time. Lotsa DJ's and journalists don't know much about audio. I remember a colleague of mine awhile back, who accidentially saved a _really_ important news story in mp3... 64kbps. But he was happy anyway because he'd listened to it over headphones fed thru the phone jack of a micro hifi set and it sounded "fine", so the whole mp3 scare was just bogus, he said. On the other hand, I've seen their educational videos where they explain the genius of walkman md's as field recorders. The day I'm using an old md walkman with 3,5" input with, like, 20dB S/N ratio, is the day I retire.

I heard some Satellite radio when I was over in the States last time and the quality was very... uh, all over the place. Fluctuating. Sometimes fairly good, sometimes like a cell phone call when the guy on the other end goes into a tunnel. Heard the BBC's DAB broadcasts a few months ago and they sounded great, probably the best I've heard. So that's the other end of the spectrum. But they're public service so I guess they probably have other standards than a lot of commercial stations.

It's always hard to explain the importance of sound quality to people. I guess the main thing I try to put across is that just because they themselves, at that particular point in time, using that particular equipment, can't hear the difference, doesn't mean it's not there.

[Greg Reierson]

Originally Posted by glassmaster

If you have ever had the pleasure of hearing the live Boston Symphony Orchestra broadcasts from Symphony Hall on WGBH, you'll know what I'm talking about.

I'd add KNXR in Rochester, MN to that list.

KNXR - Wikipedia, the free encyclopedia

Tom Jones


GR

[Petrus]

Originally Posted by petsematary

On the other hand, I've seen their educational videos where they explain the genius of walkman md's as field recorders. The day I'm using an old md walkman with 3,5" input with, like, 20dB S/N ratio, is the day I retire.

Something wrong with your setup, you can get easily S/N of 80 dB with a good MD recorder. Much better than average mp3, hard to tell apart form CD in real life. I have used a Sony MD recorder and Shure VP88 for radio documentary and the mic was the quality bottleneck.

FM quality can be very good, just ask BBC classical department... Pop/rock stations do not care about quality, because most listeners do not care either. FM listening used to be a big part of hi-fi scene especially in GB in the fifties to eighties.

[petsematary]

Originally Posted by Petrus

Something wrong with your setup, you can get easily S/N of 80 dB with a good MD recorder. Much better than average mp3, hard to tell apart form CD in real life. I have used a Sony MD recorder and Shure VP88 for radio documentary and the mic was the quality bottleneck.

FM quality can be very good, just ask BBC classical department... Pop/rock stations do not care about quality, because most listeners do not care either. FM listening used to be a big part of hi-fi scene especially in GB in the fifties to eighties.

Well obviously, I'm joking when i say that. And ATRAC compression is not that big a deal. But small MD's have inferior mic preamps, THAT is the big issue. The HHB Portadisc for example, is a great unit. But that's a DAT-sized pro unit, XLR's etc, that cost somewhere in the region of 1.000 pounds when it was still being made. Walkman's are nowhere near that level of performance. Not to mention the poor build quality of the unit. That might be ok if you're out somewhere where you might lose your unit or get robbed, but I would never use it for serious day-to-day radio work. Not durable enough, amateur connectors that pop out when you least expect it - and lousy mic preamp.

[Inharmonicity]

Originally Posted by wado1942

Looking at it from a purely technical stand point. FM radio has a bandwidth of about 50Hz-15KHz and a signal to noise ratio of maybe 60dB.

A typical 192kbps MP3 has almost the same bandwidth (though you can manually adjust this) and S/N ratio of CD but there's no doubt that it sounds like crap compared to the CD source. Even at 112kbps, the frequency response is similar to a good FM radio station, though the S/N ratio is still 90dB.

That's a really interesting starting point for trying to answer the question. I would have just said that it's totally unanswerable. It would be a great listening test to conduct to see what the relative bandwidths are for each format at the point where an *average* listener says the *quality* (such an abstract term) is roughly equal. Expert listeners would probably never be able to find such a point. For them it would be a case of "which distortion and how much of it do you prefer?"

Of course, the biggest thing that a few people have hit on here is that it depends a whole heck of a lot on the signal source. A clip of pop music will compress a whole lot differently than a clip of castanets or a cello will. I know you said you don't care about the ifs, but you really have to if you want a real answer.

[wado1942]

Heard the BBC's DAB broadcasts a few months ago and they sounded great, probably the best I've heard. So that's the other end of the spectrum. But they're public service so I guess they probably have other standards than a lot of commercial stations.

Well if the BBC is anything like PBS in America, it's a night & day difference. You go to the PBS station in my city and everything is state of the art, there's a person to do every job in the building etc. Go to any commercial station in my town and nothing works right, everything's falling apart. They're always understaffed for the kind of work they're doing. One station just upgraded for the first time since the early 80s and that was only to automate live broadcasts to where they only needed a third of the staff previously used. They're still using pretty old infrastructure though. I forgot to mention they're a network affiliate covering the entire state and are residing in the back of an auto parts store.

[petsematary]

Originally Posted by wado1942

Well if the BBC is anything like PBS in America, it's a night & day difference. You go to the PBS station in my city and everything is state of the art, there's a person to do every job in the building etc. Go to any commercial station in my town and nothing works right, everything's falling apart. They're always understaffed for the kind of work they're doing. One station just upgraded for the first time since the early 80s and that was only to automate live broadcasts to where they only needed a third of the staff previously used. They're still using pretty old infrastructure though. I forgot to mention they're a network affiliate covering the entire state and are residing in the back of an auto parts store.

Probably true although I don't know anything about PBS nor have I heard them. But the BBC definitely has a very high standard just like most public service networks - NRK, SR etc. But it's obviously quite a different thing to get hundreds of millions of dollars a year in tax funded licenses, than to operate on a completely commercial playing field. That's not to say I'm against public service, I love it, especially when it comes to news. Btw, gearwise lot of stuff that has been used in public service has been developed especially for them, they've had their own custom made preamps, mics etc. I think several of the Coles ribbons were made to BBC specs etc. And software, too. But of course a lot is off the shelf too.

[petsematary]

Originally Posted by Inharmonicity

That's a really interesting starting point for trying to answer the question. I would have just said that it's totally unanswerable. It would be a great listening test to conduct to see what the relative bandwidths are for each format at the point where an *average* listener says the *quality* (such an abstract term) is roughly equal. Expert listeners would probably never be able to find such a point. For them it would be a case of "which distortion and how much of it do you prefer?"

Of course, the biggest thing that a few people have hit on here is that it depends a whole heck of a lot on the signal source. A clip of pop music will compress a whole lot differently than a clip of castanets or a cello will. I know you said you don't care about the ifs, but you really have to if you want a real answer.

Maybe the comparison between FM and mp3 is like comparing two dead cats – one that's been run over by a car and one that's been mauled by an eagle. Which cat is the cutest?

That being said, I'm sure I could distinguish between a wav file and a 192 mp3 but only if I could A/B them. If someone played a high-res mp3 on his stereo it's not like I'd stop and go "man, this sounds bad!"

[wado1942]

I don't know anything about PBS nor have I heard them.

"Public Broadcast Corporation", similar to BBC but not nearly as big in scope.

Speaking of public services, the Library Commission for the Blind asked me to help them with restoring thousands of books on tape. They were 1/4" stereo 7.5I/S and had BAD hydrolysis. At first, they wanted me to do the work for them but I just don't have that kind of time to donate. So I told them I'd teach them how to do it and build them the necessary equipment if they'd reimburse me. I saw their facility and was amazed. None of their stuff was particularly great, but INCREDIBLY expensive. See, by law, they have to produce stuff that's commercially "nonviable" so EVERYTHING is proprietary. That's done so it'd be impossible to sell their product for a profit. Consequently, it takes three to four times as much money to accomplish the same thing and there's no money for any employees. In a 3-story building, there were two paid employees and the rest were volunteers.

[Cheebs Goat]

* The question itself doesn't make sense. It's like asking "at what point does too much space chorus on the drums 'beat' too much flanger on the drums?"

* One way or another, are we talking FM in theory or FM radio as it actually is? Because FM as it actually is takes a low bitrate mp3 as a starting point, mangles it through a tree shredder, and THEN puts it thought the FM encoder and broadcasts it.

My guess is that pure FM "beats" most MP3 bitrates. Somebody grab one of those car FM transmitters for portable players and run some tests.

[petsematary]

Originally Posted by Cheebs Goat

* The question itself doesn't make sense. It's like asking "at what point does too much space chorus on the drums 'beat' too much flanger on the drums?"

* One way or another, are we talking FM in theory or FM radio as it actually is? Because FM as it actually is takes a low bitrate mp3 as a starting point, mangles it through a tree shredder, and THEN puts it thought the FM encoder and broadcasts it.

My guess is that pure FM "beats" most MP3 bitrates. Somebody grab one of those car FM transmitters for portable players and run some tests.

My question has to do more with theory than reality.

I don't think it's that weird a question though. Regardless of technical differences, it's very possible that a majority of people would favor one version of the same song over another and that version would be the one that sounds "best".

FM stations broadcasting mp3 are not relevant here btw because I stated in my original post that the hypothetical track was uncompressed.

[Cheebs Goat]

In that case I propose the following:

Gather a wav file, a portable FM transmitter with an 1/8 in plug as commonly used for playing music in a car, and a receiver/amp/speaker combo that both plays mp3s and FM radio.

Encode the wav as an mp3 and play it on the receiver.

Broadcast the wav over the transmitter and tune it in on your receiver.

Flip back and forth on your receiver to compare.

If the FM sounds better, repeat with a higher bitrate mp3.



When that's done, do it over and over with different mp3 encoding engines.

[Petrus]

Originally Posted by Cheebs Goat

In that case I propose the following:

Gather a wav file, a portable FM transmitter with an 1/8 in plug as commonly used for playing music in a car, and a receiver/amp/speaker combo that both plays mp3s and FM radio.

Do you seriously believe that a cheap portable transmitter with 10' range represents a state-of-art FM transmitter technology?

I would say that FM is capable of at least equal quality than any mp3 format exept in frequency range extremes (bass mostly). In reality stations do not utilize this, and listeners do not have hi-fi recievers.

[Cheebs Goat]

Originally Posted by Petrus

Do you seriously believe that a cheap portable transmitter with 10' range represents a state-of-art FM transmitter technology?

Do you seriously want to invest hundreds of thousands of dollars in state-of-the-art FM transmitter technology to perform a listening test for a Gearslutz question? Lie to yourself and say that the short transmission distance makes up for the hardware quality gap.

It'll be a ballpark answer at least. And I can think of no other way to perform the test... and I can think of no way to answer the question without performing a test.

[LeeYoo]

I would compare FM radio to a good consumer reel to reel tape recording.

Who would compare Mp3 to reel to reel.....

[Cheebs Goat]

Originally Posted by LeeYoo

I would compare FM radio to a good consumer reel to reel tape recording.

Who would compare Mp3 to reel to reel.....

It's kinda' funny how HD radio is marketed as a sound quality upgrade to regular FM.

...or at least it would be funny if FM stations didn't chew their sound up bad enough to make that marketing claim seem plausible.

[Synæsthesiac]

I personally think modern FM radio is an abomination of sound. The big loud commercial stations are the worst. I physically cannot listen to the constant sandblasting hiss that seems to screech throught everything on FM radio. Don't even get me started on the auctioneer-like editing of blips, fx, lasers, bombs, and all the crap they must squeeze in every second of space. Give me lo-fi AM at reasonable RMS anyday.

[LeeYoo]

Don't just point the finger at the FM radio stations. The consumer is as bad.

We all went away from the expensive tuner-amps from the eighties, and replaced them with modern chinese crap.
What is the point of having a high standard there if 99% of the listeners don't give a hoot.

Forget radio and TV. I have learned to live without it.