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BAD Analog Audio on IBOC AM

R

rbrucecarter5

Guest
Just like I predicted over a year ago - nobody knows how to implement a 5 kHz low pass filter correctly. There are three IBOC AM's in my city that play music - every one of them has the same problem: skew on analog audio harmonics. What that means is that singers sound hoarse, like they have sore throats. What is really bad is that one station - Radio Disney - is playing a lot of songs by Miley Cyrus and Vanessa Anne Hudgens - both of whom have high voice ranges full of harmonics. Picture this scenario - Radio Disney pitches digital to its audience, hoping the parents will go out and buy IBOC receivers. But half the audience hears "we are now digital" - and nothing else. The audio sounds like crap, the parents remember how much better analog cellular sounded and how digital cellular is crap, makes the mental association: "digital sounds like crap" - not realizing you need a new radio.In order to implement a 5 kHz low pass correctly, you need a filter with flat group delay - a Bessel filter! It will take more stages to acheive the same roll-off, but it won't make singers sound like they have sore throats!
 
I have no idea what "skew on analog audio harmonics" is, but excessive clipping on the high end (or upper mids, in this case) can certainly sound like the problem you describe. Two points: CC owned stations have the analog cutoff at 6 kHz on their HD music stations, I believe, and group delay on those old 5 kHz. telco network lines was horrendous back in the day, yet Gene Rayburn never sounded hoarse announcing NBC 'Monitor'! ;)
 
A before/after (Out of Band Adjacent Channel) OBAC (IBOC is a fraudulent lie) analog comparison of AM stations switching to digital HD Radio proves the analog audio suffers, and listeners are lost. The added buzz, noise, brick wall filtering, interference, and related effects are not worth the minute number of people who are interested in buying expensive digital radios just to get daytime AM HD Radio.A spot check of the ratings of AM stations switching to OBAC shows a net decline.The jamming caused by this defective system is increasing each time another digital AM station comes on the air.Transmitting antenna pattern protection ratios are compromised on adjacent channels when deliberately adding continuous adjacent channel buzz to the airwaves. The pattern is valid for the carrier frequency, not necessarily adjacent channels, and often causes new adjacent channel interference in "protected" directions.HD AM makes the analog audio SEVERELY SUCK.In New Jersey WWJZ 640 AM (Disney) recently began digital broadcasting. Very noticeable noise was added, over a wide area, to 660 WFAN NYC.
 
I'll say upfront that I realize that I am making a mistake commenting on this but here goes anyway;"A before/after (Out of Band Adjacent Channel) OBAC (IBOC is a fraudulent lie)"Have you observed a properly operating station running IBOC on a spectrum anylizer? I have and while typical AM radios might have what appears to be interference from a station operating IBOC, the problems are with the receivers and not the transmitters. Looking at the signal of a properly operating IBOC signal their is not out of band operation. The problem lies iin the selectivity of many receivers. The transmissions are in band."HD AM makes the analog audio SEVERELY SUCK.In New Jersey WWJZ 640 AM (Disney) recently began digital broadcasting. Very noticeable noise was added, over a wide area, to 660 WFAN NYC. "Funny, I live in the NY market and WWJZ causes no interference to WFAN in it's protected contour. I work in Manhattan and WWJZ can not be heard here. South Jersey is not part of the WFAN protected contour. Anyway, before you know it WFAN will be running a digital exciter itself.
 
autopaint-1 said:
I'll say upfront that I realize that I am making a mistake commenting on this but here goes anyway;"A before/after (Out of Band Adjacent Channel) OBAC (IBOC is a fraudulent lie)"Have you observed a properly operating station running IBOC on a spectrum anylizer? I have and while typical AM radios might have what appears to be interference from a station operating IBOC, the problems are with the receivers and not the transmitters. Looking at the signal of a properly operating IBOC signal their is not out of band operation. The problem lies iin the selectivity of many receivers. The transmissions are in band.
The following link leads to a spectrum analyzer display from a paper by David Maxson.  It clearly shows that the digital sidebands of hybrid AM+HD occupy r-f spectrum in adjacent channels above and below the hybrid station.http://i62.photobucket.com/albums/h85/rfry-100/HDAMOBWHybridMode.gif(Later) Also here is a link to the spectrum content of the complete hybrid system...http://topazdesigns.com/iboc/AM-IBOC-Parameters.html***
 
Another TALK and / or SPORTS station that needs 15 kHz of bandwidth in stereo so their commercials and musical beds can be in stereo. If you think a talk / sports station needs IBOC to compete, why didn't every news / sports station convert to C-Quam 25 years ago because it, too, offered audio improvement and stereo?
 
Excuse me? 15kc audio? Where do you get that? Certainly not IBOC. Look over the specs. Receivers the problem? Perception = reality. Listeners are going to think that hey, before digital I could hear the station just fine. With digital it is noisy. Not their problem....
 
Your right......No one knows how to do it right cause its all garbage and no one really cares....... Almost every station in my area has had to drop thier IBOC for days causer they were having problems with it.. (No one really likes it,i dont know why they are wall giving in so easily)I have hated this IBOC stuff ever since first hearing about it....It compromises the analog frequencies and that makes me mad!!!!!!
 
The Dude said:
Your right......No one knows how to do it right cause its all garbage and no one really cares....... Almost every station in my area has had to drop thier IBOC for days causer they were having problems with it.. (No one really likes it,i dont know why they are wall giving in so easily)I have hated this IBOC stuff ever since first hearing about it....It compromises the analog frequencies and that makes me mad!!!!!!
A question: are radio stations in networks (Clear Channel, Infinity Broadcasting, etc.) free to choose whether or not to implement IBOC, or is it a "Top Down" decision from the networks?If the former is the case, listeners could contact their stations and encourage them to concentrate on their programming content and "Just say NO to IBOC."-- Jason
 
"A question: are radio stations in networks (Clear Channel, Infinity Broadcasting, etc.) free to choose whether or not to implement IBOC, or is it a "Top Down" decision from the networks?"I'm sure there's some discussion but remember, these properties are owned by corporations and so unless there's some unusual reason for not converting to IBOC they are going to become IBOC stations. Can people list their objections to IBOC? I know some in marginal situations complain of interference. Honestly, they are so few in number in comparison to the overall population that those complaints willl mean nothing. Another group, DXers can also stop complaining. Radio broadcasters don't care about DXing. It's a hobby of very few relative to their audience and broadcasting is a business, not a hobby. I love my HD Receptor. It does make AM stations sound like FM. WNYC has improved their IBOC operation and now I don't hear any artifacts on their transmissions. That goes for both talk and music. The local noise (computer generated) goes away when IBOC is decoded and the sound quality is fantastic and in stereo.
 
So how is that stereo talk? Do they put people on separate mikes? We experimented with that, people complained it was irritating. IBOC is a WASTE on talk stations. You could do more for quality with broadband mono. NOBODY cares if a talk station has stereo musical beds or stereo commercials.
 
autopaint-1 says:
JasonW says:"A question: are radio stations in networks (Clear Channel, Infinity Broadcasting, etc.) free to choose whether or not to implement IBOC, or is it a "Top Down" decision from the networks?"I'm sure there's some discussion but remember, these properties are owned by corporations and so unless there's some unusual reason for not converting to IBOC they are going to become IBOC stations.
Sadly, yes they are. Dave is quite correct about that!Generally, individual radio stations in large commonly owned groups are NOT free to choose whether or not to implement IBOC and it IS very much a "Top Down" decision from "top" station group management. Simply put, there are contracts these station groups have made with Ibiquity which must be honored. There is too much investor money in Ibiquity for this to go away quietly. The station groups have made these commitments to install IBOC and now they must make good on them. Ibiquity needs to have this happen if it is ever going to have its public offering which will be the only way that the venture capitalists who originally invested in this inferior technology will ever possibly be compensated. Time is running out. So now there is a furious push to get this inferior technology on the air. It has been under development for nearly ten full years now. It's time to pay the piper.Had Ibiquity not paid so much to stop competing and superior technologies from being developed in the U.S. and embraced them instead, they might be in a different financial position today and find a public that is friendlier and more accepting overall of this technology, but alas, this was not the case. It should be very interesting to see how this all plays out over the next year or so when the AM and FM broadcast bands start to get overpopulated by HD.What's in your wallet?Cal
 
NOBODY cares if a talk station has stereo musical beds or stereo commercials.
I disagree here. Slick stereo imaging can increase the shine on ANY station--including a talk station. Plus, a lot of talk stations produce long-form montages for big news events and sporting events. These productions are much more fun in stereo. Obviously, you don't get AS MUCH bang for your buck with stereo on a talk station, but there's absolutely NO reason to broadcast in mono. In fact, consider this analogy: Remember in Schindler's List when we see a little girl in a red dress? It's a black & white film, but the use of the color red in that instance had nice artistic flair. Believe me, Creative Directors at Talk stations like to have a little color on their pallette. And stereo gives them the ability show off now and then.
 
autopaint-1 said:
The problem lies iin the selectivity of many receivers. The transmissions are in band."
So how many millions (maybe billions) of existing radios have this problem? I suspect that most of them do. I'm not very likely to buy a new car to get a different radio with HD, even if one existed, which, at least right now, it doesn't. I'm also not likely to spend $300 plus installation for a new radio that looks funny in my car. Have you seen what modern aftermarket radios look like? Only a teenager would appreciate them. They certainly are not what I'd call "user friendly."It's easier to just change to a different station.
 
"So how many millions (maybe billions) of existing radios have this problem? I suspect that most of them do. I'm not very likely to buy a new car to get a different radio with HD, even if one existed, which, at least right now, it doesn't. I'm also not likely to spend $300 plus installation for a new radio that looks funny in my car. Have you seen what modern aftermarket radios look like? Only a teenager would appreciate them. They certainly are not what I'd call "user friendly."So I have a suggestion, Don't buy one. Growing up, my family didn't have a factory installed FM radio until 1975. I did use an FM converter in my first car, which only had an AM radio. I didn't have a factory installed FM radio until 1979 when I bought my first new car. FM was around for years before it caught on. Hopefully in time the same will happen with the digital conversion. I wonder what everyone in here will do when their analogue TV's become unusable, unless of course they purchase a converter. There are millions of analogue TV's and although I haven't gone HD yet I'm aware that the clock is running on my current TV's. That's progress. No one suggested that you purchase a new car so that you can listen to the IBOC radio stations. This is a long term plan and we're at the very dawn of this changeover. I bought my receptor which is a tabletop radio and paid 299 for it. To me it delivers everything promised and the programing on the FM HD 2 & 3 channels is much fresher than what's available on the current stale FM band.
 
XM, Sirius, or a few HD2 and HD3 formats that I can't even get because I'm in the suburbs 60 miles from the towers. Hummmm--- I think I'll go with XM or Sirius not HD when I get a new car radio. Instead of half a dozen HD2 in addition to the stuff that I already get, I can get over a hundred fresh, unique formats that won't fade out 10 miles from the tower. And I can listen to them all over the country without re-tuning the radio every few miles hoping to find an HD station within range.AM C-Quam was good for 300 miles daytime, hundreds more at night. No way AM IBOC will ever equal that! Not everybody lives in New York City. Some of us live in the wild west where you can drive 100 miles without seeing a house, FM is useless because it is line of site, and you can find areas without a single FM station on the dial, and precious few AM. But what few AM's there are, C-Quam worked. Now stereo is subtracted from rural listeners so somebody in New York City can put their Receptor radio next to a flourescent light bulb, TV, computer, and light dimmer and still hear talk radio without buzzing and interference. Can somebody plot the overall usuable square mileage of useful IBOC on a map of the US, and compare that to the square miles where it will only cause interference to rural listeners? I suspect less than a tenth of a percent of the total square miles in the US can actually benefit from IBOC. And I don't care how many people live in a few concentrated urban centers, because it won't make a difference to us out West!
 
"XM, Sirius, or a few HD2 and HD3 formats that I can't even get because I'm in the suburbs 60 miles from the towers. Hummmm--- I think I'll go with XM or Sirius not HD when I get a new car radio. Instead of half a dozen HD2 in addition to the stuff that I already get, I can get over a hundred fresh, unique formats that won't fade out 10 miles from the tower. And I can listen to them all over the country without re-tuning the radio every few miles hoping to find an HD station within range."If you live in a major market this is simply not true. First off, how many diffferent musical formats do you listen to? I might listen to 2 or 3 at most and with nearly every HD FM station running a different format on their HD 2's from what's on their HD 1's we've already doubled the available formats and we even have an HD 3 music format. As they close down the analogue transmissions more HD channels can be opened up and best off... There's no monthly bill. Also most people don't wander 100 miles from home. Most people might travel 30 miles a day. The HD's have no trouble with that kind of range. "AM C-Quam was good for 300 miles daytime, hundreds more at night. " There are still some C-Quam stations and no one under the age of 50 will listen to a current AM music station. With the competition on FM and the audience for AM dwindling, forget about Am's appeal. Why do you think they have the equivilent of 10 presets for FM and only 5 for AM stations? "No way AM IBOC will ever equal that! "It doesn't have to. 99% of the public wants to hear a local loud radio station. They don't want to hear fading, crackling, noisy AM as it stands now. If you had a business where you knew the audience would disappear and soon, wouldn't you do something to make that business appeal to a new audience? As IBOC comes on board a lot of thee talk stations will go away and more music will be reintroduced to the AM band."Not everybody lives in New York City."That's your loss. "Some of us live in the wild west where you can drive 100 miles without seeing a house, FM is useless because it is line of site, and you can find areas without a single FM station on the dial, and precious few AM."I'm sorry for your problems but lets face it. There are 15 million of us here and that's in NY metro alone. The vast majority of people live in urban or suburban areas. You can't hold back technology from the majority for the few who feel they might have a problem." But what few AM's there are, C-Quam worked."NOt really. It might have worked technologically but there are few 20 something AM listeners and even though IBOC was available on car radios for years, no one cared. Only a few techie types. "Now stereo is subtracted from rural listeners so somebody in New York City can put their Receptor radio next to a flourescent light bulb, TV, computer, and light dimmer and still hear talk radio without buzzing and interference. Can somebody plot the overall usuable square mileage of useful IBOC on a map of the US, and compare that to the square miles where it will only cause interference to rural listeners?"Maybe this will work out and many of those marginal stations will go off the air. Therr's way too many stations operating now. Let me ask you, at this time on AM IBOC runs daylight hours. What interference do you rceeive from NY stations? Oh and maybe we should power down those 50 KW stations we have so that you receive less interference. " I suspect less than a tenth of a percent of the total square miles in the US can actually benefit from IBOC. And I don't care how many people live in a few concentrated urban centers, because it won't make a difference to us out West!"Let's wait and see. I think if you are being interfered with by NY stations running an IBOC exciter during daylight hours you have the most remarkable receiver. If you are assuming that you will suffer if and when IBOC goes 24 hours I'd say never assume.If you are that far west NY stations will not interfere with your reception unless of course RF transmited in IBOC defy's the laws of physics and the D layer.
 
autopaint-1 said:
"Not everybody lives in New York City."That's your loss.
That is certainly a matter of opinion. I really enjoy visiting NYC. There is a lot that I really like about it, but I couldn't imagine living there. Obviously those of you who do live there are sold on the city, and that’s great. But despite claims to the contrary, it really is not representative of most of the USA.
autopaint-1 said:
I'm sorry for your problems but lets face it. There are 15 million of us here and that's in NY metro alone. The vast majority of people live in urban or suburban areas. You can't hold back technology from the majority for the few who feel they might have a problem.
Once again, that is a rather myopic point of view.
autopaint-1 said:
Maybe this will work out and many of those marginal stations will go off the air. Therr's way too many stations operating now.
The "thinning of the heard" theory sounds great, unless you happen to own or work for one. You might have a different opinion in that case.
 
"That is certainly a matter of opinion. I really enjoy visiting NYC. There is a lot that I really like about it, but I couldn't imagine living there. Obviously those of you who do live there are sold on the city, and that’s great. But despite claims to the contrary, it really is not representative of most of the USA."Maybe, but Sinatra once sang if you can make it there (NY) you can make it anywhere. I'll tell you what, I'll take NYC and you can have the rest."Once again, that is a rather myopic point of view. "And you opinion isn't?"The "thinning of the heard" theory sounds great, unless you happen to own or work for one. You might have a different opinion in that case."Possibly but I didn't always work at the network level. I worked in radio for a daytimer (before the whole post sunset thing took place) and to be honest many of these marginal stations don't hire staff. They take syndicated long form programing, like satelite delivered music or talk from providers. Many are now owned by group owners such as Clear Channel. Too all those complaining of IBOC interference, shutting down those facilities will go a long way to relieving all the intereference on the medium wave.
 
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