AM HD Radios receive C-Quam AM Stereo!

[Mike Walker]

Apparently several of the new AM HD Radios receive C-Quam AM Stereo. Hell, it may be a part of the instructions on the rom for ALL HD Radios. After all, they're software defined, so implimenting it cost nothing (no decoder chips to pay for).

At least the Accurian from Radio Shack and the Sangean component tuner have been confirmed to receive C-Quam AM Stereo. Here's a recording a guy from another board recorded from a local AM Stereo station. Highs are lacking, particularly in comparison to radios like the Sony SRF-A100 from the 80s which was flat to 10khz, and the Carver TX11a which was flat to 15k! But let's admit it...opening up am THAT wide means lots more interference unless you're REALLY close to the tower! The stereo separation is quite nice. Here's a link to the file at my website http://www.theproductionroom.net/accurianstereo.mp3

 

[700WLW]

Apparently several of the new AM HD Radios receive C-Quam AM Stereo. Hell, it may be a part of the instructions on the rom for ALL HD Radios. After all, they're software defined, so implimenting it cost nothing (no decoder chips to pay for).

At least the Accurian from Radio Shack and the Sangean component tuner have been confirmed to receive C-Quam AM Stereo. Here's a recording a guy from another board recorded from a local AM Stereo station. Highs are lacking, particularly in comparison to radios like the Sony SRF-A100 from the 80s which was flat to 10khz, and the Carver TX11a which was flat to 15k! But let's admit it...opening up am THAT wide means lots more interference unless you're REALLY close to the tower! The stereo separation is quite nice. Here's a link to the file at my website http://www.theproductionroom.net/accurianstereo.mp3

So - DAB/DRM is struggling in the UK and DAB is failing in Canada; if they try and implement something other than IBOC in the US, it will fail too - there is NO consumer demand for digital terrestrial radio, or AM stereo of any form (remember, how it failed in the 1980s), anywhere ! Gosh, maybe we could hear talk and news shows in stereo !

 

[Mike Walker]

If someone here said that breathing was good, and life-sustaining, would you post something negative about that, 700WLW? Is that your purpose here, to be the "anti" whatever anybody else says, about ANYTHING?

Analog AM Stereo actually worked quite well. Still does, in fact. The clip I posted has quite wide separation...certainly an improvement over mono. And yes, talk sounds great in stereo (although many AMs in my area still play music!) You are so fond of pointing out (falsely, by the way) that DAB is failing in the UK. Are you aware that the BBC makes a point of using stereo very creatively for talk programming? "Sport" programming is in stereo in the UK as well. You can sample some of it at their website.

Pick up a UK Audio magazine (Hi Fi Choice, What Hi Fi, etc.) They're full of reviews of DAB portables, tabletop models, and component tuners, and information on how DAB is gaining slow but steady acceptance (as it will here). In metro areas like London, DAB is almost universal. In the countryside, implementation is still spotty, but growing. Brit audio mags seldom review analog only tuners, receivers, or radios anymore. Few analog only devices are even available! MOST new models receive digital AND analog. And one of the most often cited reasons listeners give for buying a digital tuner is "more channels".

Canada, God bles 'em, suffers from being just over the border from us. Our standards eventually become their standards. I kind of feel sorry for them. But though they're geographically huge, their population is, well kindly, sparse! There's a reason everyone near the border listens to American radio, and watches American TV. There's a reaon there was a huge black market for XM (and Sirius) radios in Canada before they became available legitimately (it was easy for someone in Windsor, for instance to get a US post office box in Detroit, and give that as their address so they could activate an XM account). American media is produced on a larger scale, for a larger audience, with greater production values, and is sought by viewers, and listeners, everywhere. Sad, but true (although I really enjoy CBC and RCI programming on shortwave and the 'net!)

What SHOULD have happened is that we should have adopted the L band for digital radio in this country. THEN there would have been a sufficient demand for radios to ensure a steady supply, and Canadians would have bought thtm eo hear what they really want...radio from the American side of the border!

 

[700WLW]

If someone here said that breathing was good, and life-sustaining, would you post something negative about that, 700WLW? Is that your purpose here, to be the "anti" whatever anybody else says, about ANYTHING?

Analog AM Stereo actually worked quite well. Still does, in fact. The clip I posted has quite wide separation...certainly an improvement over mono. And yes, talk sounds great in stereo (although many AMs in my area still play music!) You are so fond of pointing out (falsely, by the way) that DAB is failing in the UK. Are you aware that the BBC makes a point of using stereo very creatively for talk programming? "Sport" programming is in stereo in the UK as well. You can sample some of it at their website.

Pick up a UK Audio magazine (Hi Fi Choice, What Hi Fi, etc.) They're full of reviews of DAB portables, tabletop models, and component tuners, and information on how DAB is gaining slow but steady acceptance (as it will here). In metro areas like London, DAB is almost universal. In the countryside, implementation is still spotty, but growing. Brit audio mags seldom review analog only tuners, receivers, or radios anymore. Few analog only devices are even available! MOST new models receive digital AND analog. And one of the most often cited reasons listeners give for buying a digital tuner is "more channels".

Canada, God bles 'em, suffers from being just over the border from us. Our standards eventually become their standards. I kind of feel sorry for them. But though they're geographically huge, their population is, well kindly, sparse! There's a reason everyone near the border listens to American radio, and watches American TV. There's a reaon there was a huge black market for XM (and Sirius) radios in Canada before they became available legitimately (it was easy for someone in Windsor, for instance to get a US post office box in Detroit, and give that as their address so they could activate an XM account). American media is produced on a larger scale, for a larger audience, with greater production values, and is sought by viewers, and listeners, everywhere. Sad, but true (although I really enjoy CBC and RCI programming on shortwave and the 'net!)

What SHOULD have happened is that we should have adopted the L band for digital radio in this country. THEN there would have been a sufficient demand for radios to ensure a steady supply, and Canadians would have bought thtm eo hear what they really want...radio from the American side of the border!

Only a million, or so, digital receivers have been sold in the UK, over a number of years. Canada has given up, with the idea of installing in-dash digital terrestrial radio, and is going with Satellite Radio instead. The whole point is, so far, all forms of digital terrestrial radio have been met with apathy, and with all these other technologies (e.g., Wireless Internet Radio) DAB will fail to reach any sort of critical mass.

 

[Mike Walker]

"Wireless internet radio"...now there's solid, reliable technology. Never a pause for "buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering"

And a million receivers is a LOT in the UK. They are a much smaller country than the US. MOST new radio products there incorporate DAB. Pick up a UK audio publication and find an analog radio, receiver, or tuner. Pretty hard to do!

 

[clouseau]

"Wireless internet radio"...now there's solid, reliable technology. Never a pause for "buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering"

OK this gave me a chuckle. Not exactly fair, but not exactly wrong either.

And a million receivers is a LOT in the UK. They are a much smaller country than the US. MOST new radio products there incorporate DAB. Pick up a UK audio publication and find an analog radio, receiver, or tuner. Pretty hard to do!

I'm pretty sure I saw a couple of articles about analog radios being discontinnued in a couple of major retailers in the UK, but I don't recall exactly where, so I haven't mentioned it. I AM wondering about the validity of this continued claim of "UK Struggles" though.

Clouseau

 

[700WLW]

"Wireless internet radio"...now there's solid, reliable technology. Never a pause for "buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering, buffering"

And a million receivers is a LOT in the UK. They are a much smaller country than the US. MOST new radio products there incorporate DAB. Pick up a UK audio publication and find an analog radio, receiver, or tuner. Pretty hard to do!

They have 45 million citizens, so 1 million digital receivers sold is not many, and of course, it is never reported how many have been returned; this also applies to the HD Radio Cartel - they have never reported the number of HD radios sold:

"If you build it will they come?"

"That leaves a very, very rough estimate of 60,000 HD radios in the hands of consumers."

http://www.hear2.com/2006/10/if_you_build_it.html

Let's subtract the number of HD Radios returned, due to lousy reception and poor programming !

 

[Mike Walker]

Have you personal knowledge that a single radio has been returned due to either cause? If you have no figures, it's just as reasonable to assume that the number is zero as that it's large!

 

[700WLW]

Have you personal knowledge that a single radio has been returned due to either cause? If you have no figures, it's just as reasonable to assume that the number is zero as that it's large!

All it takes, is a bit of common sense, and many personal testimonials (see, "HD Radio Receiver Sensitivity" thread) to that affect.

 

[audiophile.]

Have you personal knowledge that a single radio has been returned due to either cause? If you have no figures, it's just as reasonable to assume that the number is zero as that it's large!

I returned one... ;D

 

[clouseau]

Have you personal knowledge that a single radio has been returned due to either cause? If you have no figures, it's just as reasonable to assume that the number is zero as that it's large!

I returned one... ;D

Thanks for a totally reasonable answer to a totally reasonable question. I was chasing one returned for programming, actually, but it was nice to see someone answer. Was your's one of the Famous "defective Receptors?" They have a reputation.

Clouseau

 

[audiophile.]

It wasn't worth the price, so I returned it.

 

[clouseau]

It wasn't worth the price, so I returned it.

Fair enough. We asked for specifics and you declined to provide them.. Count it as "Returned"

Clouseau.

 

[Chuck]

Have you personal knowledge that a single radio has been returned due to either cause? If you have no figures, it's just as reasonable to assume that the number is zero as that it's large!

I have two friends in Dallas, and one in Massachusetts who got BA Receptors and returned them. One of those got the Acurian on Black Friday and says it is OK. His main complaint is the HD-2 channels have disappointed him so far. I think he has it connected to a larger stereo system, so the small speakers are not an issue for him. He tells me that it is a pretty good analog radio, so he has no complaints.

There is at least some truth to the problems reported about the BA radios.

 

[clouseau]

There is at least some truth to the problems reported about the BA radios.

No doubt. The BA's are not very good . At least ALL OF THEM.

Seriously, MY Accurian sounds good. Not an AM dxer, though.

Clouseau

 

[wnmb]

As a broadcaster in AM STEREO I am elated that some of the HD receivers decode and play this awesome sound. As Paul stated earlier, AM Stereo actually works quite well. At WNMB in North Myrtle Beach, we are using a Delta Stereo generator and an Optimod 9100B processor. The on the air sound is absolutely fantastic. It is very smooth and the stereo separation is truly great. While I am not qualified to debate the merits of HD for my medium, I can tell you we have many AM Stereo listeners (mostly car radios like the Explorers, Expeditions and Thunderbirds, and many Chrysler products) and it has made a significant difference for us. It's is likely going to be some time before HD radios are really numerous out there, if ever, and in the meantime, I would think any AM broadcaster who wants his or her station to sound its best would get AM stereo up and running.
PS: My comments about sounding great are related to the technical side, since programming is a subjective thing. However, fyi, we play "oldies", or as I should say now, "classic hits".
Website with lots of AM stereo info is www.wnmb.net

 

[Mike Walker]

I love AM Stereo Bill, and have been a supporter for a long time. Question...do you know Dave Lingafelt at WNNC in Newton, NC? He mentioned a "friend" who was really into AM Stereo at his station, and I immediately thought of you.

While the C-Quam system works quite well (I've seen it in a proof measure 45-50db of separation! Those are FM-level specs!), my only beef with the system has been the steep rolloff of bass below 50hz (to get rid of audio before the 25hz pilot tone). Admittedly most people won't hear it on table radios, and typical car stereos. But the lowest note in most rock/pop music is the 42hz open e-string on the electric bass, so AM Stereo should go to at least 40hz! Were it introduced today, with better, sharper filter technology, it probably would. Heck, it still COULD. With headphones connected to the mod-monitor at a well engineered station (the last AM Stereo station I worked at was WKSK in West Jefferson NC back at the turn of the new millennium), you can just hear that the lowest lows are a little m.i.a.

Now that's being picky! AM Stereo is great technology, and doesn't ruin your neighbor's spectrum the way AM HD seems to. If you try an Accurian, and it works well, please let us know. Heck, why not post a sample from your station recorded from the Accurian so we can hear!

 

[Chuck]

If you try an Accurian, and it works well, please let us know. Heck, why not post a sample from your station recorded from the Accurian so we can hear!

If the Accurian decodes AM Stereo as well, that might make it worth buying, just to play with....

 

[radioskeptic]

To follow up on reply No. 16:

I’m glad to see someone who supports C-Quam finally acknowledging the problem with the extreme low end. But extending the response down to 40 cycles is not the be-all-and-end-all just because the open E string on either a bull fiddle or an electric bass is 41.2. The low C of a pipe organ’s 16-foot stop is 32.7; the low A on a standard 88-key piano is 27.5; the low A-flat of a contrabassoon is 25.96; and the low C of the organ's 32-foot stop is 16.35.

That’s the low note sustained throughout the beginning of “Also Sprach Zarathustra,” and it's represented only by its harmonics on most sound systems. It’s also the lowest note on the 97-key, 11-foot Bösendorfer Imperial Grand piano. But of course, it isn't in very much real world music.

But sounds in the 30's do occur frequently in real music. So it would be better to have an AM stereo system that didn’t need a low-bass pilot tone (which is a slightly sharp G-natural; that G should be 24.5).

The Kahn independent sideband (ISB) system had three advantages over C-Quam: (1) There was no pilot tone. (2) There was no platform wobble. (If Kahn ISB was no better than mono AM under adverse reception conditions, at least it was no worse.) And (3) ISB was no wider than a mono signal with the same audio bandwidth.

And a Kahn receiver has an advantage over C-Quam even on mono reception: Monkey chatter from an upper first adjacent appears only on the right channel, and that from a lower first-adjacent only on the left – the so-called “cocktail party effect.”

So if Kahn AM stereo was so much better, why did the FCC choose Motorola’s C-Quam?

Well they didn’t, at least not initially. They chose to let “the market” decide. Of course, there is no such benevolent conscious entity as “the market” (that’s just a right-wing myth!), so that meant that those with the most economic muscle would decide.

Motorola supplied almost all the semiconductors -- diodes and discrete transistors as well as chips -- to General Motors’ Delco division, and they gave Delco a real break on chips that worked only with C-Quam, but not with the other three systems. When GM began offering C-Quam-only radios, Ford and Chrysler followed suit, and most AM stations soon recognized the de facto “marketplace” victory of the distant second-best AM stereo system. And so did the FCC, after the fact.

So the marketplace triumph of C-Quam was NOT the “survival of the fittest” its boosters would have you believe. It was only the survival of the best-promoted.

 

[Mike Walker]

Actually Kahn may have been the best system in retrospect. But it ain't THAT clear that one system is technically superior to another. Some facts.

Kahn's separation never measured more than about 15-20db in the midband, and was into the single digits at a few khz. The reason is obvious...using independent sidebands is cool, but the higher the frequency, the more bandwidth is occupied by each sideband. If your if bandwidth is opened enough to allow decent high frequency response, then there will be very little high frequency separation. If it isn't, well, there will be very little high frequency response (treble). But this isn't lose/lose. Because there was no phase component to Kahn AM stereo, what stereo image there was was rock stable, even in critical hours and at night when fading and interference occurs. While C-Quam leaves the station at a much higher fidelity level (broader separation, better frequency response), a few miles out from the tower it gets beatan up pretty badly, until the stereo image of the received signal tends to wander back and forth. Sometimes the "platform motion" could get downright nauseating.

My conclusion was that C-Quam left the station much cleaner, but by the time the signal reached a real radio, Kahn's AM stereo signal was in much better condition for providing a reasonable listening experience.

The 25hz pilot tone is a good example separating the systems, except you may recall that in the late 80s when C-Quam receivers were pretty numerous, Kahn asked for and received permission to use a 25hz pilot. I'm not sure how many stations actually adopted it, though.

I don't see what the big deal is with the pilot, and never saw any reason to rolloff an octave (or more) of bass to accomodate it. The pilot tone is not an integral part of the C-Quam system. Stereo is prefectly receivable without it. The Sony SRF-A100, for instance, has no pilot tone detector, or stereo pilot light for AM Stereo. It decodes C-Quam (and the other three systems) just fine. The worst thing that could happen if stations defeated the low-end rolloff is that, in the presence of really low bass, an AM stereo radio would switch back and forth between stereo and mono. A hard wired mono switch would fix that.

You're right that there are musical notes lower than 40hz. But not in the vast majority of music (rock, pop, and country) that's on the radio. The typical rock or country band...rhythm and lead guitar, electric bass, and drums CANNOT produce any fundamental tones that are lower. Of course if you add a syntheseizer, then all bets are off. Bass below 40hz may be an issue in 15 percent of recordings (tops), and in perhaps 2 percent that are actually played often. But bass between 40 and 50 hz (although it's only a couple of notes), well...that cuts into LOTS of mainstream music!

Still local radio stations carry all types of programming...including church organs on Sunday mornings. Some deep bass would sure help with that. I've preached for years to engineers at AM stations..."the radios may not have great highs, but that's no reason to kill the bass too!"