"HD Radio awaits listeners"

[Chuck]

Thanks for the suggestions...

In your editorial you mention the impact limiting AM to 5 kHz can have on audio quality. Seems to me there was a study done either by or with the support of Jeff Littlejohn on whether or not listeners could hear the difference between a 5 kHz, 7.5 kHz and 10 kHz cut off. According to the study, listeners could hear a dramatic difference between 5 kHz and 7.5 but less between 7.5 and 10 kHz. After much rationalizing, the conclusion was that a 5 kHz cut off was an acceptable trade-off to accommodate HD-Radio. But the study failed to prove that point and an argument can be equally made that it is not acceptable.

I believe it was published in Radio World.

db

As someone who has been a member of the Audio Engineering Society (AES) for about 35 years, I had a hard time swallowing that report. Limiting audio at 5KHz might be OK for voice only applications. It's quite unacceptable for music. It completely eliminates the entire top two octaves. There is a lot going on up there that helps increase intelligibility, spacial perception, and most importantly "warmth" that makes listening to music a fulfilling experience. Cutting of at 5 kHz is analogous to driving your car at 70 MPH with a fogged over windshield. Perhaps you can do it, but it takes most of the fun out of it.

I find it hard to believe that most of the people who participated in those tests couldn't tell the difference between various frequency response curves. If it is true, it is quite a damning statement about the quality of all the radios used for the test. Can you say "garbage?" I wouldn't be at all surprised to find out that they were all hand selected for the test to sound especially revolting. Either that or the test was held at the Helen Keller Institute.

Obviously full frequency response is not going to happen on analog AM any time soon, but the technology does not preclude that. One of the promises of HD is improved frequency response for AM. Maybe so. What I've heard did have greater frequency response, but it also had very noticeable artifacts that in many ways were more disconcerting than modestly limited frequency response ever could be. Your brain has the ability to "fill in the blanks" when there is a constant that it can deal with. Most people can compensate for a missing half octave or even a full octave. Much more than that is quite a stretch for most folks. Because of their random nature, there is no way for you to compensate for intermittent dropouts and artifacting. Maybe we will be forced to learn how to cope with it, and it will become a new listening "norm." You can train yourself how to listen, so it is a possibility.

For most people, these problems simply causes listener fatigue. They may not be aware of what is happening, but the effect is real. In radio terms it might result in a lower TSL (Time Spent Listening.) That's cash out of someone's pocket

I'm sure some of the reason HD does this is because we are trying to use a band-aide approach. If the HD signal were higher power, then many of the drop-out problems would go away, but the resulting interference would be unbelievable. If the bandwidth were greater, then a lot of the artifacting problems might go away. I'm sure as we progress, new and improved codecs will be developed that can make excellent audio in limited bandwidth. That's well and good, but it does little for people who buy the current generation of HD radio that can''t be upgraded to an improved codec. In other words, buy now, hoping that they can figure out how to fix this thing. Then because your new radio can't be upgraded, you can put it in the same landfill as your analog radios.

Surely, we're not the only ones who think this is foolish. If we're going to do it, let's do it right.

 

[PocketRadio]

Thanks for the suggestions...

In your editorial you mention the impact limiting AM to 5 kHz can have on audio quality. Seems to me there was a study done either by or with the support of Jeff Littlejohn on whether or not listeners could hear the difference between a 5 kHz, 7.5 kHz and 10 kHz cut off. According to the study, listeners could hear a dramatic difference between 5 kHz and 7.5 but less between 7.5 and 10 kHz. After much rationalizing, the conclusion was that a 5 kHz cut off was an acceptable trade-off to accommodate HD-Radio. But the study failed to prove that point and an argument can be equally made that it is not acceptable.

I believe it was published in Radio World.

db

Thanks... I'm adding more info on the number of HD radios sold and lack of interest from the Big 3 etc...

 

[SUPERCASTER]

Thanks for the suggestions...

In your editorial you mention the impact limiting AM to 5 kHz can have on audio quality. Seems to me there was a study done either by or with the support of Jeff Littlejohn on whether or not listeners could hear the difference between a 5 kHz, 7.5 kHz and 10 kHz cut off. According to the study, listeners could hear a dramatic difference between 5 kHz and 7.5 but less between 7.5 and 10 kHz. After much rationalizing, the conclusion was that a 5 kHz cut off was an acceptable trade-off to accommodate HD-Radio. But the study failed to prove that point and an argument can be equally made that it is not acceptable.

I believe it was published in Radio World.

db

As someone who has been a member of the Audio Engineering Society (AES) for about 35 years, I had a hard time swallowing that report. Limiting audio at 5KHz might be OK for voice only applications. It's quite unacceptable for music. It completely eliminates the entire top two octaves. There is a lot going on up there that helps increase intelligibility, spacial perception, and most importantly "warmth" that makes listening to music a fulfilling experience. Cutting of at 5 kHz is analogous to driving your car at 70 MPH with a fogged over windshield. Perhaps you can do it, but it takes most of the fun out of it.

I find it hard to believe that most of the people who participated in those tests couldn't tell the difference between various frequency response curves. If it is true, it is quite a damning statement about the quality of all the radios used for the test. Can you say "garbage?" I wouldn't be at all surprised to find out that they were all hand selected for the test to sound especially revolting. Either that or the test was held at the Helen Keller Institute.

Obviously full frequency response is not going to happen on analog AM any time soon, but the technology does not preclude that. One of the promises of HD is improved frequency response for AM. Maybe so. What I've heard did have greater frequency response, but it also had very noticeable artifacts that in many ways were more disconcerting than modestly limited frequency response ever could be. Your brain has the ability to "fill in the blanks" when there is a constant that it can deal with. Most people can compensate for a missing half octave or even a full octave. Much more than that is quite a stretch for most folks. Because of their random nature, there is no way for you to compensate for intermittent dropouts and artifacting. Maybe we will be forced to learn how to cope with it, and it will become a new listening "norm." You can train yourself how to listen, so it is a possibility.

For most people, these problems simply causes listener fatigue. They may not be aware of what is happening, but the effect is real. In radio terms it might result in a lower TSL (Time Spent Listening.) That's cash out of someone's pocket

I'm sure some of the reason HD does this is because we are trying to use a band-aide approach. If the HD signal were higher power, then many of the drop-out problems would go away, but the resulting interference would be unbelievable. If the bandwidth were greater, then a lot of the artifacting problems might go away. I'm sure as we progress, new and improved codecs will be developed that can make excellent audio in limited bandwidth. That's well and good, but it does little for people who buy the current generation of HD radio that can''t be upgraded to an improved codec. In other words, buy now, hoping that they can figure out how to fix this thing. Then because your new radio can't be upgraded, you can put it in the same landfill as your analog radios.

Surely, we're not the only ones who think this is foolish. If we're going to do it, let's do it right.

Thanks for your posts. I agree.

 

[MasterTheseus]

A perspective from a manufacturer of radios we are actually finding a huge learning curve with the advent of digital software driven radios.

What we are seeing that user-upgradeable product demand is dramatically increasing. The real problem with that becomes that as radios become more software based and like computers interface problems begin presenting themselves. We could make a USB interface for our radios, but then we need to make sure it will shake hands with most computers regardless of the OS. We now have to become computer programers. This is edging the prices upwards and begins to get impractical with every small change. If we could get the market to agree to a slightly higher purchase price so that we can better prevent the need to buy a new product for new features the better off we will all be, but lets face it what are the chances we can get people to understand with and accomodate that?

 

[Chuck]

A perspective from a manufacturer of radios we are actually finding a huge learning curve with the advent of digital software driven radios.

What we are seeing that user-upgradeable product demand is dramatically increasing. The real problem with that becomes that as radios become more software based and like computers interface problems begin presenting themselves. We could make a USB interface for our radios, but then we need to make sure it will shake hands with most computers regardless of the OS. We now have to become computer programers. This is edging the prices upwards and begins to get impractical with every small change. If we could get the market to agree to a slightly higher purchase price so that we can better prevent the need to buy a new product for new features the better off we will all be, but lets face it what are the chances we can get people to understand with and accomodate that?

It's an interesting quandary. If you will check back a few hundred posts or so, you will note that I predicted that all radios will eventually be software defined. It simply makes sense. As I look inside the HDT-1, the most prominent feature is a Texas Instruments DSP chip. Putting two and two together, I understand why R. Bruce Carter is reluctant to tell us everything he knows.

Looking at the DSP chip, my guess is it can do just about anything (within reason) that you tell it to do. In other words, we have a "software defined radio." For better or worse, software is, or soon will be more important than the hardware. That is a quantum leap for most radio manufacturers. For those of us who get nostalgic over the warm glow of a #80 or a 5U4 rectifier tube, we'd better get over it.

The up-side of this is you can make a radio that does whatever you want. That might be HD, AM, FM, FMExtra, DRM,or all of the above. It might even be something we don't know about as yet. In fact, I'd bank on the "something we don't know about" as the right answer. You are welcome to have a different opinion.

Bottom line, any radio that is not software upgradeable is likely to be left behind, no matter how good it is today. Even if it is upgradeable, there is still a good chance it will still be left behind, just like the Betamax. There is no guarantee that it will be able to cope with new standards. I have a pre-WW II Brunswick radio that proudly boasts that it is upgradeable to "Television." There is an 11 pin octal socket on the rear of the chassis for the "Television Converter." The whole idea was wishful thinking on their part, but the historic reference is worth remembering. We do tend to repeat ourselves. If you want to know where we are going, it pays to study where we've been.

The only upgradeable consumer radio I know of at this point, other than Ham Communications receivers, seems to be the Aruba. It comes set up for FMExtra, but is capable of other standards as well. It does have a USB port for future upgrades, and will even play music off of a USB Thumb Drive when inserted in the port. "Upgradeable" is the key to the future. We simply don't know where we are going, but it is likely to be an interesting journey.

 

[MasterTheseus]

I agree. Now, don't get me wrong, the HDT-1/X, and HDR-1 are all upgradeable for firmware updates, but there is no provision for consumer upgrades. The unit has to be sent to us for this to be done.

 

[Chuck]

I agree. Now, don't get me wrong, the HDT-1/X, and HDR-1 are all upgradeable for firmware updates, but there is no provision for consumer upgrades. The unit has to be sent to us for this to be done.

The addition of a USB port may look like a good idea before this is over. We seem to have a work in progress....

 

[SUPERCASTER]

If Jeff Littlejohn VP Eng. Serv. for Clear Channel claims that according to his research most listeners can't tell the difference between low-fi and hi-fi broadcasts, doesn't that totally negate the sales pitch for HD radio on AM or FM?

Since FMeXtra digital for FM can provide additional programming channels and is simpler, cheaper, longer range, saves power, is totally compatible with analog FM and does not use adjacent channels or cause interference, then why not use it for FM, and abandon HD radio for AM or FM entirely?

http://www.dreinc.com/

The argument has been made by supporters that the broadcast industry has invested too much in expensive, deficient HD radio technology to abandon it now is a spurious argument at best. FMeXtra does not require the expensive purchase, extensive continuing maintenance, finicky adjustments, or additional power required to transmit HD radio. Since HD radio has never performed as promised or advertised, continues to be problematic, will never be as efficient, and creates unnecessary interference, broadcasters should simply return the HD radio equipment and demand a full refund from iBiquity. Then go with FMeXtra.

 

[MasterTheseus]

I agree. Now, don't get me wrong, the HDT-1/X, and HDR-1 are all upgradeable for firmware updates, but there is no provision for consumer upgrades. The unit has to be sent to us for this to be done.

The addition of a USB port may look like a good idea before this is over. We seem to have a work in progress....

USB would seem like a better option, but also presents a whole other host of problems I am not going to get into right now. We will see where it goes, but we will likely see a dramatic improvement in the availability of user-upgradeable radios, not just in HD Radio, but in most others.

 

[Chuck]

We will see where it goes, but we will likely see a dramatic improvement in the availability of user-upgradeable radios, not just in HD Radio, but in most others.

I agree that user-upgradable radios will be a near-necessity for some time to come.