Attn: Sound Nerds

[DJ_Perry]

I have resisted posting this for about a month now, but today I decided I would bring it up. Perhaps it's too minor to catch, but was hoping there is somebody out there who could explain, or notices what I do.

Recently while scanning the dial in my car, I hear certain songs on the radio that resemble a played out tape....like the fidelity comes and goes? I don't know how else to describe it, but I can't imagine it's the source files being broadcasted. I mean, KSLX and KOOL have a great reputation and I trust them on being strict with sound quality. Not only that, but I have noticed the same thing on Mega 104.3, and I can guarentee my sources are good and legit, when adding to their library.

So that leads me to wonder if maybe its my car stereo, or is it the processing? Or the transmitters? I am rarely in a location where the signal is distant, so perhaps the heat? Or maybe I am just getting old and losing my hearing....I am a sound nerd myself, but am unaware of an answer. Please comment any thoughts, thanks.

 

[ironbear]

Car radios have weird ways of compensating if the received signal is poor. Typically this is done by blending the (noisy)stereo to mono gradually as the signal becomes weaker, and some radios start to roll off the high frequencies as well. Personally, I prefer a bit of noise to that.

That's the closest guess I have about what you're hearing on these really well engineered, well processed stations (Mega for instance, is closely connected to the owners of CRL/Orban!)

 

[Wildstyle K]

My Zune player has FM dial on it. I notice when I hook up a Tunecast II FM Transmitter to my Zune and let it broadcast through my stereo dial while it's on radio, the sound will fluctuate up and down a lot, in many ways, similar to a bad cassette. Other than that, I haven't heard any bad "played out tape" style quality on any station for a long time. I used to hear it often with some songs on KVIB in both regular playlists and mixshows. There were also numerous low quality download sounding song plays as well played on KVIB in 2005 & 2006 or so, and I do remember one specifically that they used to let slide a lot - they had a very bad download audio quality recording of "I don't care" by Ricky Martin ft Fat Joe. I used to wonder why they just didn't buy the track or at least find a copy that was at least 192 kbps.

 

[DJ_Perry]

I kind of anticipated a response close to what Ironbear stated. However, i don't think those possibilities apply to me. I drive in the heart of the valley most of the time. I actually do pay attention to my deck and the "stereo" light is always solid. I am not impressed by fancy brands or gadgets, so my Alpine deck has does the job just fine by itself since 2007 (with the stock speakers). In the last 3 years, I don't recall noticing this, but recently I catch fluctuations in the high end. It's totally random, it comes and goes, its only certain stations, and only certain songs. It does not happen when i play CDs. So I have a theory:

In these days of MP3s, remastering, and maximizing volumes to be the loudest station on the dial, I believe certain songs are being overmodulated over the air. What this creates is a gate effect, which causes certain frequencies to get scrambled depending on the peaks of the song.

I believe radio stations are updating their libraries with remastered recordings which are intended to be brighter for the consumer. Yet the processing of the signal is overcompensating the "already adjusted EQ", and squishing the hell out of the volume. Once again, this is my theory. I am curious if anybody else has input or can relate.

 

[johndavis]

I kind of anticipated a response close to what Ironbear stated. However, i don't think those possibilities apply to me. I drive in the heart of the valley most of the time. I actually do pay attention to my deck and the "stereo" light is always solid. I am not impressed by fancy brands or gadgets, so my Alpine deck has does the job just fine by itself since 2007 (with the stock speakers). In the last 3 years, I don't recall noticing this, but recently I catch fluctuations in the high end. It's totally random, it comes and goes, its only certain stations, and only certain songs. It does not happen when i play CDs. So I have a theory:

In these days of MP3s, remastering, and maximizing volumes to be the loudest station on the dial, I believe certain songs are being overmodulated over the air. What this creates is a gate effect, which causes certain frequencies to get scrambled depending on the peaks of the song.

I believe radio stations are updating their libraries with remastered recordings which are intended to be brighter for the consumer. Yet the processing of the signal is overcompensating the "already adjusted EQ", and squishing the hell out of the volume. Once again, this is my theory. I am curious if anybody else has input or can relate.

Well, most car radios will show you a stereo light when they go into blend, mine included... and Alpine has been doing blend forever.

That being said, if you were to play a MP3 file on the air, anywhere, you might not recognize it coming out the other end. It's not so much the processing squashing the hell out of it (although that doesn't help), it's taking something that's been bit reduced and then running it through more analog to digital conversions.

Plus, equipment does fail. I had a client once whose digital STL (Studio Transmitter Link) ran only at 32kbps and my console feeding it was set to 48kbps. I had to keep the plant at 48k for compatibility with their co-located TV station, so we had a sample rate converter between the console and STL. Everything was great until the sample rate converter quit. They stayed on the air, but it sure didn't sound like music for the time it took to get a new rate converter installed.

 

[DJ_Perry]

That being said, if you were to play a MP3 file on the air, anywhere, you might not recognize it coming out the other end.

I can guarentee all stations now rely on MP3 formats. The bar has been lowered. Living in a Digital World, the Wav format is a lost breed now. I rarely receive CDs as promos any more. The labels now send links to download MP3s. Commercials are now produced as MP3, in addition to syndications, mixshow, etc. The industry as a whole is more concerned with speed and instant satisfaction, as opposed to quality. Even if you receive "Promo Only" CD Compilations, I know of many examples where those sources are also MP3s just turned into waves (just to shut the snobs up).

 

[oldiesfan6479]

I can guarentee all stations now rely on MP3 formats.

mp3 files copied to the KOOL-FM Audio Vault? Say it ain't so, Stevemeister!

I thought it was all CD product as the source for the good ol' good ones.

Although I vaguely recall some years ago then-morning guy Bill Gardner
playing a really (sonically) bad-sounding Royal Guardsmen song. Not sure
if it was Snoopy Vs. The Red Baron or Snoopy's Christmas.

 

[DJ_Perry]

I'm sure they do have a good amount of wave files in their vault. Just like we do as well on "Mega" and "The Beat." But there are plenty of exceptions, where certain songs become "out of print" and you can only get them on Amazon, I-Tunes, or random other sharing sites i won't expose!

It just seems that now in the music industry, it is overall accepted to omit being strict with file sources. MP3's are generally acceptable, since most of music sales are now sold digitally. Our standards have settled, as new technology works with MP3 (I-Pods, Internet Streaming, Satellite Radio, etc). Even the music we hear in public is MP3 now. Clubs, Restuarants, Stores, they all either stream something or use a laptop DJ program.

 

[bnzbz]

KOOL, along with the other AudioVault based stations in town and around the country actually are based off of MP2 audio. Same idea, slightly less lossy. Thats just how AudioVault works.

And to calm the fears of some... KOOL's library was for the most part ripped locally into MP2s off of CDs. There are boatloads of those CDs (and KMLE's as well) in storage at 840 N. Central.

I'd imagine most of KZON's music comes from the online record pools like Break The Crates.

 

[wattsup]

All music at the old house of KOY is linear, uncompressed .wav @ 44.1. Commercials are 4:1 MP2.
Storage is cheap, why cut corners? KMLE just re-dubbed most all of its library. Time to put this one to bed...move on, nothing to see.

 

[johndavis]

All music at the old house of KOY is linear, uncompressed .wav @ 44.1. Commercials are 4:1 MP2.
Storage is cheap, why cut corners? KMLE just re-dubbed most all of its library. Time to put this one to bed...move on, nothing to see.

When you can get a 2TB drive at Fry's for peanuts, it's never been cheaper to go linear.

It's a long way from my first automation system with a whopping 20 MB, and the drives alone were about $1200 a piece.

While spots are e-mailed as MP3's, that doesn't mean they sound good. At least they're short.

The station I jock for has started doing remotes with an iPhone. You record a .wav and the app FTP's it to the station. Station downloads, imports to VoxPro & edits, and puts it to air. Slick & uncompressed!

 

[Tom Wells]

I have noted something similar on FMs only...on three different car radios which are AM/FM (NOT Stereo).
Can't say for sure when the effect started because I don't listen to a lot of FM.
Here's what I notice; a 2 db drop in volume for maybe 30 seconds, then back up to "full" volume.
Not any real change in fidelity.. My radios are all old, non-AFC FM. So I tune up and down a little to see if the volume comes up, but no, it remains lower even as I tweak the tuning. Then it pops back up 2 db again.
No increase or noise or multipath intrusion, so it's not like the signal strength is dropping.
I've heard this on more than one station, and I only started noticing it this year, since I've been checking out FM more.
It's almost like something triggers an audio limiter, which holds the level down for a while, then "let's go", allowing
full loudness again.

I hear it on the music, spots or voice. Audio source doesn't seem to matter.
Wonder if we are hearing the same effect but your modern radios just also seem to make it sound like a reduction in fidelity...?
I suspect it may be an effect of HD being added but don't have anything to back this up as even being logical as a result of the sidebands. That doesn't yet mean that iboc is NOT the cause of this effect, but I HAVEN'T yet heard it on a station that doesn't have iboc.

 

[johndavis]

I hear it on the music, spots or voice. Audio source doesn't seem to matter.
Wonder if we are hearing the same effect but your modern radios just also seem to make it sound like a reduction in fidelity...?
I suspect it may be an effect of HD being added but don't have anything to back this up as even being logical as a result of the sidebands. That doesn't yet mean that iboc is NOT the cause of this effect, but I HAVEN'T yet heard it on a station that doesn't have iboc.

Sounds like an early implementation of blend or the annoying auto level control that tries to compensate for road noise yet all it does is turn down the volume when you hit the brakes.

HD isn't a factor. It just sounds like a crappy car radio. Foreign or domestic, there's no shortage of those.

 

[Tom Wells]

I hear it on the music, spots or voice. Audio source doesn't seem to matter.
Wonder if we are hearing the same effect but your modern radios just also seem to make it sound like a reduction in fidelity...?
I suspect it may be an effect of HD being added but don't have anything to back this up as even being logical as a result of the sidebands. That doesn't yet mean that iboc is NOT the cause of this effect, but I HAVEN'T yet heard it on a station that doesn't have iboc.

Sounds like an early implementation of blend or the annoying auto level control that tries to compensate for road noise yet all it does is turn down the volume when you hit the brakes.

HD isn't a factor. It just sounds like a crappy car radio. Foreign or domestic, there's no shortage of those.

No, these radios are 1966, 1972, and 1971. One Bendix, two Motorolas... No stereo, no blend, no AFC. Simple ratio detector.
In the summer I drive the '66, which I've had for 33 years. Just did a full alignment 2 weeks ago. Found no problems.
Sensitivity is still good, and I can still pick out the very weak out-of-market stations as before, as in WCCQ 98.3.
This issue is something new. I look at the ammeter when I hear this, I'm still charging just fine, so no voltage changes.
Not when hitting the brakes, this happens cruising along at constant speed or while sitting at a light.
Now, 2db is not very much at all, and the average listener might not notice at all. But it is happening, so I'm wondering about it.
I did not want mention it until I had lstened more, and had some time to think. But since someone else mentioned something so similar.....

Heard the effect this morning on WLS FM, WBBM FM, and WLUP.