HD Radio: Why should you care?
(Credit:
HD DIGITAL RADIO)
HD Radio enables AM and FM radio stations to broadcast both digital and analog audio from the same channel, as well as add new sub-channels and text information. HD Radio has been on the market since 2002, and yet--over six years later--we're only just beginning to see the technology proliferate. Currently, there are only a handful of car stereo receivers that have HD Radio tuning built in, with the bulk of the units on the market requiring external, and at times expensive, add-on tuners.
So, why doesn't anyone seem to care about HD Radio? Most likely, it's because many people don't understand the benefits of the technology.
Increased sound quality
By moving to a digital format, HD Radio offers a huge jump in audio quality. Comparing HD Radio to analog radio is similar to comparing CDs to old school tapes, or DVD movies to VHS--the boost in quality is that noticeable, even on our Chevrolet Aveo's crap stock speakers. Digital AM stations begin to sound like analog FM stations, and digital FM audio quality begins to approach that of a CD. All of this is accomplished using 1-10 percent of the bandwidth and power of an analog station.
Currently most HD Radio stations are broadcast on the same redundant stations as the analog programming. When the receiver detects a digital station, it switches over to the digital feed. If the signal deteriorates, the receiver can drop back to a lower bandwidth digital signal or back to the analog signal.
Text information
HD Radio's digitally transmitted audio also features text information that could be used for station information/telephone numbers, announcements, or artist and title information. In the case of artist/title information, this opens doors for increased functionality. For example, the Alpine TUA-T550HD HD Radio receiver allows you to tag songs for downloading in iTunes when connected to a compatible iPod.
Subchannels
The bandwidth freed up by using a more compact digital signal allows multiple subchannels to be broadcast on the same frequency. That means a station could offer alternative programming on a subchannel. For instance, if a song you didn't like came on, you could just jump to the substation. Or your favorite Top 40 station could start offering classic rock and indie music subchannels to vary content. If a station goes all digital (forgoing the analog redundancy), up to seven subchannels will fit into a single frequency. More content is almost always good.
Subscription-free
Unlike subscription-based satellite-radio stations, HD Radio content is free. The only cost paid is the one-time purchase of the HD Radio receiver. HD Radio stations broadcast their digital content over the same radio frequencies as their analog content. Here in the San Francisco area there are about 26 digitally broadcasting stations, 17 of which have at least one substation with alternated content.
While the FCC hasn't mandated a digital switch for audio broadcasts, as they have with television, there will most likely come a day when it will. FFC mandate or no, we'll be seeing more and more digital broadcasts in the immediate future, with premium automakers starting to include HD Radio receivers as standard equipment in many cases.
False claims of audio quality, quality programming, and coverage - it won't be free for long when RadioGuard gets approved by the FCC:
[Editor's note: Deleted link]
I don't like scams and the jamming and hijacking of our free airways - you are not going to discourage me.
I don't know how people have put up with the hiss of FM stereo for so long and with the telephone quality of AM on most AM receivers for so long. But I guess it did take 15 years before the sale of CDs overtook the sales of cassettes. Once the auto manufacturers start including HD radio in most cars that are sold, people will never go back. I like the fact that you get the instant tuning of the analog signal and then the blend to digital, unlike digital TV where there is a 3 or 4 second lag between changning stations. The American digital radio is superior in sound quality and in other ways to the UK digital radio system; the UK system has a 4 second lag and will not fall back to analog when the signal is weak. (UK is the current leader in digital radio adoption)
When or if HD FM radio stations get the 10 fold increase in digital power (from 1% to 10% of the analog power pending FCC approval) it will be truly amazing, that is HD radio will have full crystal clear, full stereo separation in the same areas where the FM analog reception is challenging (in mono and noise cutting in and out). The concerns about adjacent channel interference will be substantially eliminated when pure digital FM takes hold.
According to the Ibiquity standard, if the AM signal goes all digital it will be a 32 fold increase in digital power (15 dB increase) and the range (for 50 kW AM stations) will be hundreds of miles with a sound quality equivalent to current FM stereo analog but without the noise. And a big plus, the concerns (by anti-HD radio groups) with AM adjacent channel interference would almost completely disappear, so I hope the FCC starts approving pure digital AM stations soon, in fact a few applications were turned down but this may change.
I have owned an HD radio in my car for about 1 year and this has been my most satisfying purchase in years and I'm a pure techie.
Come on people smell the coffee. It's the gadget that you didn't know you wanted. I feel like it's 1985 and I'm trying to convince people of the advantages of a CD over a cassette, or in 2001 trying to convince people about the qualily of high definition TV over analog. You would be surprised how many people told me the existing picture quality was fine. (Joe six pack would in 2001 say I can already see the picture so why do I need any better picture)
I've had a huge interest in listening to radio for over 30 years and primarily, because of this interest, got my BSEE to understand as much as I could about radio and electronics. I think it is really innovative the engineering that went into this technology to fulfill the demanding requirement of making it compatible with the existing analog band as far as technically possible.
HD Radio Rocks.
Let's say that a radio station has a 100% available bandwidth. To broadcast digital and analog signals redundantly, you have to limit the digital broadcast to about 1%. Within that 1% you can get pretty good audio quality. Now let's suppose you want to multicast an HD2 digital substation. Now you have to split that 1% between the two digital broadcasts. At this point you've got 99% analog and 2x .5% digital and it's still sounding pretty good--at least much better than what you had before.
Now, if a station decreased its analog output, it could boost its digital output proportionally. If a station boosted it's digital broadcast to just 10%, the range would exceed that of the 90% analog signal. If a station went all-digital, there would be enough bandwidth within the one FM frequency to multicast three full-power broadcasts and four additional reduced-quality sub-channels.
Digital is the way to go. It's happening with television broadcasts now and it will eventually happen with audio. Analog broadcasting is 100 year old tech, both poor sounding and energy inefficient.
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by NickTeck
January 3, 2009 10:18 PM PST
- Unfortunately, you can forget about HD radio. This thing is dead on arrival. You techies are so enamored with the technology you can't see what is really going on here. It has nothing to do with the technology -- it has everything to do with the CONTENT.
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(5 Comments)As a former radio broadcaster I follow the industry closely. After Clear Channel and other radio companies all but decimated the business with their consolidation, cost-cutting, voice-tracking, homogenized cookie-cutter formats, crappy over-researched playlists and firings of talented programmers and on-air staff, there is nothing left but an empty shell, a wasteland. Certainly there is virtually no one left from the creative/programming side capable of producing the kind of high-quality content that will be needed to fuel the supposed wave of new subchannels everyone is waiting for.
Morale in radio is at an all-time low; there are rumors of further mass layoffs; the people who are left are overworked and under-paid; there are rumblings that radio companies are putting in a half-assed effort in creating anything worth listening to on these HD channels. Typically they're just the repositories for long-abandoned old formats and the programming staff that are remaining have little motivation to take a creative risk.
It's a waste of time to spend your money buying an HD receiver that will ultimately be broadcasting garbage for content. You're better off surfing the internet FOR FREE and finding whatever your heart desires online.
Or you can go ahead and purchase an HD radio tuner and hear nothing special....in high quality.