Can FM HD handle quadraphonic sound?

[Black_Shire]

Yes, I know I'm dating myself by even mentioning quadraphonic sound, but does digital-only FM HD (or perhaps even hybrid digital/analog FM HD) have the bandwidth to handle it, especially if the HD2 and HD3 streams aren't used? (I'm pretty sure that AM HD doesn't have sufficient bandwidth for it.)

If so, this might be a "cool new thing" (to the younger generations) that could make HD radio exciting. It would be something unique that wouldn't be available on any other audio transmission medium.

There are a fair number of existing works available in quadraphonic sound (I'm referring to studio master tapes), and with today's CD and MP3 technologies it shouldn't be too difficult to produce new quadraphonic recordings.

Since HD Radio reception in cars is reportedly less than satisfactory and because portable Walkman-type HD radios aren't practical (and may never be) due to power consumption requirements, HD Radio might as well concentrate on "high-end" home Hi-Fi receivers. Listeners don't balk at multi-hundred dollar prices for high-end receivers or tuners as they do for "mere" table radios, and the need to put up an FM dipole or TV rabbit ears isn't as aggravating to buyers of high-end equipment--after all, when you've just spent a few hundred dollars for a high-quality system, why skimp on the antenna?

I am no fan of IBOC. I'm dead-set against AM HD because of its many shortcomings, and I'm ambivalent about FM HD. But if FM HD can handle quadraphonic sound, this may be a niche application that would make FM HD worth having in some cases.

Your thoughts?



-- Black Shire

 

[700WLW]

"Since HD Radio reception in cars is reportedly less than satisfactory and because portable Walkman-type HD radios aren't practical (and may never be) due to power consumption requirements, HD Radio might as well concentrate on "high-end" home Hi-Fi receivers. Listeners don't balk at multi-hundred dollar prices for high-end receivers or tuners as they do for "mere" table radios, and the need to put up an FM dipole or TV rabbit ears isn't as aggravating to buyers of high-end equipment--after all, when you've just spent a few hundred dollars for a high-quality system, why skimp on the antenna?"

This is exactly, why HD Radio will never reach "critical mass", and will be a failure.

 

[Black_Shire]

"Since HD Radio reception in cars is reportedly less than satisfactory and because portable Walkman-type HD radios aren't practical (and may never be) due to power consumption requirements, HD Radio might as well concentrate on "high-end" home Hi-Fi receivers. Listeners don't balk at multi-hundred dollar prices for high-end receivers or tuners as they do for "mere" table radios, and the need to put up an FM dipole or TV rabbit ears isn't as aggravating to buyers of high-end equipment--after all, when you've just spent a few hundred dollars for a high-quality system, why skimp on the antenna?"

This is exactly, why HD Radio will never reach "critical mass", and will be a failure.

That's likely what will happen, and this old Shire won't shed a tear if HD radio fails. But having said that, it would be nice if *some* positive use could be found for the HD technology.

Quadraphonic sound FM HD would really jazz up (no pun intended) live jazz or classical music concerts, and it would give spatial depth to broadcasts of sports events, radio dramas, and talk programming.



-- Black Shire

 

[clichemoth]

Why bother with digital in that case, especially if there would be no multicasting? Analog quad FM already exists and a couple of stations (in Portland, OR and Cleveland, IIRC) attempted it in the 70s.

 

[Chuck]

Yes, I know I'm dating myself by even mentioning quadraphonic sound, but does digital-only FM HD (or perhaps even hybrid digital/analog FM HD) have the bandwidth to handle it, especially if the HD2 and HD3 streams aren't used? (I'm pretty sure that AM HD doesn't have sufficient bandwidth for it.)

In a word., "yes." When IBOC was first introduced, one of the "killer apps" the public radio folks were interested in was its ability to do 5.1-surround sound. Some stations were specifically interested in the technology for broadcasts of symphonic performances.

As I recall, about five years ago, there was a lot if interest in this idea among the Ibiquity folks. At one NAB show, there was a car on display in the exhibit hall with prototype HD radio installation. I'm fairly sure it was set up for 5.1 audio. There are a few obstacles to overcome to do this. First, HD reception has to be reliable in a car. So far, that's questionable, at least when you get some distance from the station. Second, there needs to be a supply of 5.1 surround program material. It's pretty common for movies, but like the old days of "Quad," there isn't a huge library of music available in this format. Lots of albums would have to be remixed. That idea was very popular at a recent Audio Engineering Society (AES) convention. The studio engineers in attendance were quit enthusiastic about the idea of years of work remixing popular music. Call it a "gravy train" if you wish.

Another potential problem is 5.1 would be done at the expense of HD-2 content. There is only so much bandwidth. It seems the powers that be have decided that secondary channels are more saleable. Only time will tell.

 

[clouseau]

FM HD is ALL about multicasting.


Now if the FCC counted HD-2 and HD-3 in the ownership limits, you'd see the end of FMHD 'casting in about 2.0 seconds.

Clouseau

 

[SUPERCASTER]

Yes, I know I'm dating myself by even mentioning quadraphonic sound, but does digital-only FM HD (or perhaps even hybrid digital/analog FM HD) have the bandwidth to handle it, especially if the HD2 and HD3 streams aren't used? (I'm pretty sure that AM HD doesn't have sufficient bandwidth for it.)

In a word., "yes." When IBOC was first introduced, one of the "killer apps" the public radio folks were interested in was its ability to do 5.1-surround sound. Some stations were specifically interested in the technology for broadcasts of symphonic performances.

As I recall, about five years ago, there was a lot if interest in this idea among the Ibiquity folks. At one NAB show, there was a car on display in the exhibit hall with prototype HD radio installation. I'm fairly sure it was set up for 5.1 audio. There are a few obstacles to overcome to do this. First, HD reception has to be reliable in a car. So far, that's questionable, at least when you get some distance from the station. Second, there needs to be a supply of 5.1 surround program material. It's pretty common for movies, but like the old days of "Quad," there isn't a huge library of music available in this format. Lots of albums would have to be remixed. That idea was very popular at a recent Audio Engineering Society (AES) convention. The studio engineers in attendance were quit enthusiastic about the idea of years of work remixing popular music. Call it a "gravy train" if you wish.

Another potential problem is 5.1 would be done at the expense of HD-2 content. There is only so much bandwidth. It seems the powers that be have decided that secondary channels are more saleable. Only time will tell.

Chuck is right, the AACplus core codec, used and licensed by both iBiquity/HD digital Radio and FMeXtra www.dreinc.com High Definition digital FM, has 5.1 surround sound modes implemented.
Here are links to the codec developer's website:
http://www.codingtechnologies.com/products/mpgsrnd.htm
Scroll down to see iBiquity among the Coding Technologies partners, (FMeXtra buys it's AACplus encoders from Orban who is the licensee).
http://www.codingtechnologies.com/partners/index.htm
Hear AACplus 5.1 surround sound here (if you have a modern soundcard such as Creative Soundblaster with front and rear outputs), some of the webstreams marked AACplus 5.1 are active:
http://www.tuner2.com/
5.1 surround sound contest/project:
http://www.tuner2.com/ismp.html

 

[Black_Shire]

I thank you for this information. Perhaps a few classical music stations and/or sports stations will try 5.1 Surround Sound with their FM HD equipment. Basketball would be particularly interesting to listen to in this format--with properly-placed microphones near each basket, you could literally hear which way the ball was being dribbled.


-- Black Shire

Yes, I know I'm dating myself by even mentioning quadraphonic sound, but does digital-only FM HD (or perhaps even hybrid digital/analog FM HD) have the bandwidth to handle it, especially if the HD2 and HD3 streams aren't used? (I'm pretty sure that AM HD doesn't have sufficient bandwidth for it.)

In a word., "yes." When IBOC was first introduced, one of the "killer apps" the public radio folks were interested in was its ability to do 5.1-surround sound. Some stations were specifically interested in the technology for broadcasts of symphonic performances.

As I recall, about five years ago, there was a lot if interest in this idea among the Ibiquity folks. At one NAB show, there was a car on display in the exhibit hall with prototype HD radio installation. I'm fairly sure it was set up for 5.1 audio. There are a few obstacles to overcome to do this. First, HD reception has to be reliable in a car. So far, that's questionable, at least when you get some distance from the station. Second, there needs to be a supply of 5.1 surround program material. It's pretty common for movies, but like the old days of "Quad," there isn't a huge library of music available in this format. Lots of albums would have to be remixed. That idea was very popular at a recent Audio Engineering Society (AES) convention. The studio engineers in attendance were quit enthusiastic about the idea of years of work remixing popular music. Call it a "gravy train" if you wish.

Another potential problem is 5.1 would be done at the expense of HD-2 content. There is only so much bandwidth. It seems the powers that be have decided that secondary channels are more saleable. Only time will tell.

 

[MotoMuzak]

Black Shire~
My thoughts you ask?

I am no fan of IBOC. I'm dead-set against AM HD because of its many shortcomings, and I'm ambivalent about FM HD. But if FM HD can handle quadraphonic sound, this may be a niche application that would make FM HD worth having in some cases.

(You read my mind, in other words.)

Before I mention any more and potentially date myself, I need to mention I am aged 22.
Last weekend I acquired a 1970's-era Marantz Superscope QR-450 quad receiver from my neighbour's mother who recently entered a retirement home and doesn't have much use for it any more. While I am largely opposed to IBAC radio (I prefer to use the term IBAC, as I feel "HD Radio" , other than a trademark, is hugely misleading) I still am quite skeptical about FM IBAC even having possibility of catching on in the long run.

(But my god--Electronica on 94.7 [KNRK] Saturday nights sure does sound awesome on that box! This also from the mouth/typing hands of a kid raised on Prologic via an early-1990's Technics receiver!)

I have posted numerous comments of this on the Portland Radio Boards (Hello, Semoochie--I saw you on another thread in this forum today!) and I am a newbie around here (this is my first Radio Info post) but a real-world scenario compounding my IBAC-nocatchie belief:

My best friend got, for her birthday this February, a Kenwood IBAC add-on slave end for her Kenwood car stereo. She also drives a 1979 Caprice. Driving around downtown Portland, her IBAC drops out so much (between that and the analogue) that it is completely unlistenable. (About this time she/I usually insert a CD or a tape.)

However, on the other hand a couplea weeks ago I was visiting the Vancouver Mall (Washington, not B.C.) Radio Shack store and got to listen to KKCW (103.3)'s IBAC feed, and aside from the tinny, metallic effect generated by the receiver codecs (which generally is my major beef with Ibiquity IBAC--it is *not* CD quality no matter how big a sermon Ibiquity's advertising department preaches) the signal was otherwise perfectly listenable and (so far as I could tell around the NRSC5 muck) crystal clear. This was tested on a Boston Receptor with a pair of Sennheiser earphones I usually listen to my CD player through.

Now, owing to the low bandwidth and large amounts of artifacting IBAC (especially Ibiquity's system) can't legitamitely claim to being an audiophile's "choice" format. (It could be tolerated, at best.) But due to the codecs design, it supposedly is capable of running Dolby 5:1. Ergo, since 5:1 is supposedly a "discrete" surround system I don't see why Ibiquity *couldn't* support quad as well.

(Compact Disc Digital Audio, the "Red Book" on the other hand, has supposedly always supported quadraphonic. But, I have yet to see any CDs or even hardware to be deployed that are equipped for it.......)

Clichemoth, 10 December 2006 04:56:55p~
"Analog quad FM already exists and a couple of stations (in Portland, OR and Cleveland, IIRC) attempted it in the 70s."

Portland's station was called KQIV (a.k.a. "KQ4") and was on 106.7 FM (which currently broadcasts oldies, ironically.) It reportedly was a quadraphonic broadcast ("Rockin' In Quad!", "All Quad's Children Listen...") but was later revealed it was merely a marketing gimmick. Hey it was a different world in the 70s, like I'd know 'coz I didn't finally come on the world-scene until 1984!

But there is a web page created by Larry Scott (KQIV DJ) and others: http://rockininquad.com/ . Check it out..........

And apparently later on, before it went bust Q4 applied for an SCA, possibly employing Zenith's short-lived Quad FM system..............


NEWBIE. Always a NEWBIE. I can't escape being a NEWBIE. NEWBIE NEWBIE NEWBIE. And how's BARBIE, Dr. Cox?

 

[Black_Shire]

MotoMuzak, I am heartened to read the words of someone your age (I'm 40) who is not only articulate but who has knowledge of and appreciation for things that came "before his time." Thank you for posting the link to Larry Scott's Rockin' In Quad web site--I'll check it out!

You sound like an audiophile yourself. If your Marantz quad receiver has phonograph audio inputs and external speaker outputs (I'm not familiar with the unit) and you can get ahold of a quad-ready turntable or tape deck, you may find CDs wanting after listening to it even "just" in stereo.

A late friend of mine once conducted an A/B/C comparison between a high-end Sony CD player, a Revox reel-to-reel 1/2" tape deck, and an Empire belt-driven turntable for me. He fed the audio from all three units into a Lafayette tube amplifier, and from there into a pair of Leslie tone cabinets from his Hammond X66 electric (not electronic) organ (those tone cabinets were literally pieces of furniture!). He played identical pop, jazz, and rock selections on each of the three units.

Compared to the Empire turntable and the Revox tape deck, the Sony CD player sounded dry, flat, and lacking in range. Between the other two units, the Empire turntable sounded very slightly better than the Revox tape deck, but both of them sounded amazingly sweet and rich.

That's why iBiquity's claim of "CD-quality" audio on FM IBOC doesn't impress me at all, because they've chosen an inferior standard (the CD) with which to compare their system. If FM IBOC sounded as good as an Empire turntable playing properly-cleaned and "de-static-ed" LP records, *that* would impress me.

For AM, the broadcast industry would do much better to ditch AM IBOC (it's really, *really* IBAC on AM!) and adopt C-QUAM AM Stereo instead. In fact, it is undergoing a small comeback right now, even for broadcasting music on AM. WNMB AM 900 www.wnmb.net recently went stereo and is encouraging other AM stations to do so as well. Most new vehicles still come with C-QUAM AM Stereo/FM Stereo receivers as standard equipment, and Sony Walkman and "boom-box" AM Stereo/FM Stereo receivers are readily available (I bought my Sony SRF-AX15 from Audio Cubes www.audiocubes.com ).

I have a 100 milliwatt C-QUAM AM Stereo transmitter made by AM Stereo guru Chris Cuff http://ourworld.compuserve.com/homepages/kevtronics/ccuff.htm , and I use it to listen to my CD player around the house in AM Stereo on the Sony SRF-AX15 Walkman. It sounds better than FM Stereo--it has the warmth and richness of monaural AM audio combined with the spatial depth of stereo sound.


-- Black Shire

Black Shire~
My thoughts you ask?

I am no fan of IBOC. I'm dead-set against AM HD because of its many shortcomings, and I'm ambivalent about FM HD. But if FM HD can handle quadraphonic sound, this may be a niche application that would make FM HD worth having in some cases.

(You read my mind, in other words.)

Before I mention any more and potentially date myself, I need to mention I am aged 22.
Last weekend I acquired a 1970's-era Marantz Superscope QR-450 quad receiver from my neighbour's mother who recently entered a retirement home and doesn't have much use for it any more. While I am largely opposed to IBAC radio (I prefer to use the term IBAC, as I feel "HD Radio" , other than a trademark, is hugely misleading) I still am quite skeptical about FM IBAC even having possibility of catching on in the long run.

(But my god--Electronica on 94.7 [KNRK] Saturday nights sure does sound awesome on that box! This also from the mouth/typing hands of a kid raised on Prologic via an early-1990's Technics receiver!)

I have posted numerous comments of this on the Portland Radio Boards (Hello, Semoochie--I saw you on another thread in this forum today!) and I am a newbie around here (this is my first Radio Info post) but a real-world scenario compounding my IBAC-nocatchie belief:

My best friend got, for her birthday this February, a Kenwood IBAC add-on slave end for her Kenwood car stereo. She also drives a 1979 Caprice. Driving around downtown Portland, her IBAC drops out so much (between that and the analogue) that it is completely unlistenable. (About this time she/I usually insert a CD or a tape.)

However, on the other hand a couplea weeks ago I was visiting the Vancouver Mall (Washington, not B.C.) Radio Shack store and got to listen to KKCW (103.3)'s IBAC feed, and aside from the tinny, metallic effect generated by the receiver codecs (which generally is my major beef with Ibiquity IBAC--it is *not* CD quality no matter how big a sermon Ibiquity's advertising department preaches) the signal was otherwise perfectly listenable and (so far as I could tell around the NRSC5 muck) crystal clear. This was tested on a Boston Receptor with a pair of Sennheiser earphones I usually listen to my CD player through.

Now, owing to the low bandwidth and large amounts of artifacting IBAC (especially Ibiquity's system) can't legitamitely claim to being an audiophile's "choice" format. (It could be tolerated, at best.) But due to the codecs design, it supposedly is capable of running Dolby 5:1. Ergo, since 5:1 is supposedly a "discrete" surround system I don't see why Ibiquity *couldn't* support quad as well.

(Compact Disc Digital Audio, the "Red Book" on the other hand, has supposedly always supported quadraphonic. But, I have yet to see any CDs or even hardware to be deployed that are equipped for it.......)

Clichemoth, 10 December 2006 04:56:55p~
"Analog quad FM already exists and a couple of stations (in Portland, OR and Cleveland, IIRC) attempted it in the 70s."

Portland's station was called KQIV (a.k.a. "KQ4") and was on 106.7 FM (which currently broadcasts oldies, ironically.) It reportedly was a quadraphonic broadcast ("Rockin' In Quad!", "All Quad's Children Listen...") but was later revealed it was merely a marketing gimmick. Hey it was a different world in the 70s, like I'd know 'coz I didn't finally come on the world-scene until 1984!

But there is a web page created by Larry Scott (KQIV DJ) and others: http://rockininquad.com/ . Check it out..........

And apparently later on, before it went bust Q4 applied for an SCA, possibly employing Zenith's short-lived Quad FM system..............


NEWBIE. Always a NEWBIE. I can't escape being a NEWBIE. NEWBIE NEWBIE NEWBIE. And how's BARBIE, Dr. Cox?

 

[grantchester]

While chatting with an audio dealer a few years back, I mentioned my friend's collection of old 'Quad' vinyl and tape recordings. He said the Sony 5.1 system uses the same encoding as the old SQ system. I've got some old tapes in the attic that are encoded, including ELP on King Biscuit with Karn Evil Live. That would be nice to hear again. There were a lot of quad recordings on the market in 73-74-75.
And I'm the only person I know listening to AM Stereo. It sounds good on 820AM-Fort Worth/Dallas, even though it's only on sounders and commercials. I wish they could make AM recievers with a full 15khz response. instead, they seem to be going the other way! I rented a Honda, and the radio had a 4k cutoff. Argh!
AM-Digital is going to ruin the band, and from what I've heard, FM digital doesn't seem worth it, for anything other than in home listening with an external antenna pointed at the transmitter. Back to the future!

 

[MotoMuzak]

*big grin*

Unfortunately I don't have an Empire turntable...I actually have my dad's 1981 Sanyo TP1012 (I do have a second-hand Revox cart I found at Goodwill tho) and I will say, even though I seem to be firmly entrenched in programming MPEG3 CD-ROMs (*far* more practical than the cassettes I was recording before, at least from a capacity & run-time standpoint) I still do far prefer the sound of vinyl over CDs (audio and/or MPEG3) any day.

And if that's not enough I even have (rather, "have access to") my Grampa's Akai 1720W. Not a Quad deck (those didn't come until the 1730s!) but she, too, has beautiful sound.

But the main trouble with Ibiquity's system is not only did they compare it to an inferior product (the CD) but, being based on the MPEG audio standard somewhat, from a sound-quality standpoint it *is* an inferior product.

But again I say I only listen to MPEG audio (MPEG1 Layer 3) on CD ROM because I can carry it easily with me when I go somewhere. And I might also say that while mounted on a bike, or doing free-style BMX, listening to music on a turntable is just a little impractical! That, and I would need a pretty long extension cord 'cos the track I always use is clear across town! ;o)

I don't have a Quad turntable (yet) but I hope to get one sometime soon.

And re: AM stereo: Yes, I have also noticed Cquam coming back somewhat (a couple AMs in Portland have started using it again.......and Radio Disney on 1640 KDZR doesn't count because that's by FCC mandate!!) but what I would like to see is the Kahn-Hazeltine system make a comeback. Don't know why the FCC outlawed it but by and far even it is a superior system to C-Quam, due to its use of independent sidebands. (It's not multiplexed like CQ is.)

From what I have read the KH system, due to its sidebands, is quite a bit higher fidelity than the multiplexed CQ and as such, is also more tolerant ("immune") to the platforming effect that CQ tends to be plagued by when the signal fades out.

Now, I might very well have heard a KH ststion without being aware of it, but in reality I would likely be too young to remember. However, I have heard the CQ system before (I have it in my truck on a factory-stock GM radio/tape/CD player) and as far as i can base my opinion, never having really noticed the KH system, it does sound like a major improvement over regular, mono AM. (So Grantchester, you can add me to your list of people you "know" listening to AM stereo!)

"I wish they could make AM recievers with a full 15khz response. instead, they seem to be going the other way! I rented a Honda, and the radio had a 4k cutoff. Argh!"

Unfortunately, with a 15kHz bandwidth, especially if you live in an area with lots of AM activity (especially at night) you would start running into huge multipath and crosstalk problems from adjacent frequencies. I have heard a 1940s-era Crosley AM/Shortwave rig at a friend's place (it was his Grandma's) and during the daytime it has probably the most beautiful sound I have ever heard from any AM radios that I have used. (Listening to Bing Crosby on 1550 KKAD seemed to be the most appropriate, after all....) But it just became a helllish, nightmarish mishmash of crosstalk at night, because not only do we live in a major radio market but we tend to get lots of skywaves from California as well. Truly affects the selectivity of the tuner.........

But I will admit the 4kHz does seem a bit low! I have encountered radios with such low BW the sound almost seems "garbled", like a bad telephone connection. It's like, when making new radios the industry is taking one step forward (i.e. introducing digital-controlled tuners....that is one of my favourites!) but then taking five steps back (i.e. unusually low bandwidths, and now the IBACs!)

But I would imagine the Ibiquity or any IBAC radios for that matter, by necessity, would have to have pretty wide-band AM sections if they are accurately going to play digital AM signals. So I wouldn't be surprised if these rigs are, in fact, some of the more sensitive, albeit not as selective, made in recent times.

(Maybe I will wait a couplea years to get one when I start seeing them in the bin at Goodwill for $20!!)