HD Radio

[AMRadioGuy]

I agree.

HD doesn't really work too well around here anyway (too many hills), so I don't bother with it much. The few times that I have, I've found the HD feed to be somewhat harsh and overly bright compared to the normal analog feed.

Frankly, if the AM radio in my car didn't sound so muddy and dull (hard 4.5 kHz lowpass filter, probably), I'd be perfectly happy with that (all I listen to is KCBS anyway, and their AM 740 signal is much more reliable and solid around here than the FM 106.9 one is).

c

Yup... This thread from the Steve Hoffman Forums (lots of audio folks there) seem to concur that HD is not actually a better sounding alternative to analog FM, aside from noise floor.

Comparison Between FM, HD and Internet Radio

I am not an audiophile but I generally do not like the sound of internet radio streams or even HD radio. I prefer the over the air FM broadcast. A...

forums.stevehoffman.tv

 

[AMRadioGuy]

stereo separation is noticeably better when the HD kicks in.....

Some of that might be down to the processing the station uses, too, especially if they use different processing on the two because that can really alter a lot with the sound of a station.

 

[AMRadioGuy]

I find that HD AM station completely unlistenable - the compression is just dreadful. Thank goodness it never caught on or I would be no longer listening to AM. What the FCC ought to do with AM is allow stations to go back to broadcasting with more bandwidth during the day like they used to be able to do, especially with the band gradually clearing out now.

I don't think any of the AMs near me are even bothering to broadcast in HD anymore - I know the big 50kw giant was at one point but I think that's ceased.

They also ought to actually tackle the interference issue. I often chuckle because they'll come bust a pirate station and slap some hobbyist with a huge fine but do absolutely nothing when a problem transformer takes out AM reception for several blocks - waaaaaay over the 200 feet allowed for FM (AM's part 15 is a bit more complex).

You can really hear the compression on the FM side, too. I have to wonder if the standard could be updated to something that uses a bitrate that's actually competitive. Even listening to music on YouTube sounds light years ahead of HD FM and that's just sad. Analog FM really can sound superb - when it's set up properly and when good source material is used in the first place.

 

[Kelly A]

Also, they were pushing you to buy a standalone radio. Now they (seem to) have given up on individual radios, in place of getting the HD feature in cars....which has been pretty successful.

That's because just about the time they were encouraging consumers to buy aftermarket or portable HD radios, those same consumers had stopped buying new radios.

 

[Kelly A]

Yup... This thread from the Steve Hoffman Forums (lots of audio folks there) seem to concur that HD is not actually a better sounding alternative to analog FM, aside from noise floor.

That's simply not true. The stereo separation, frequency response, and noise floor of the digital "HD" side are all superior to analog FM. Now, if station engineers or programming folks hash up their audio like the 70's and 80's through over-processing, that's not the fault of HD.

 

[Wimmmex]

Yup... This thread from the Steve Hoffman Forums (lots of audio folks there) seem to concur that HD is not actually a better sounding alternative to analog FM, aside from noise floor.

"lots of audio folk concur" does not carry a lot of weight.

 

[Kelly A]

"lots of audio folk concur" does not carry a lot of weight.

The same 'folks' that still prefer to use the term 'Hifi'.

 

[cc333]

The same 'folks' that still prefer to use the term 'Hifi'.

Aside from myself and an unknown, but probably relatively small number of other younger people, I think most of those so-called "folks" being referred to here are squarely in the 65+ demographic.

c

 

[MVB13]

I use HD in my car sparingly. I used to use it for Alt 92.3 HD-2 but where I work I don't get the signal. I can get WDHA FM instead.

 

[Don CT]

The same 'folks' that still prefer to use the term 'Hifi'.

And will tell you vinyl is superior.

I flipped between HD and normal FM and there is no difference.

 

[Kelly A]

And will tell you vinyl is superior.

I flipped between HD and normal FM and there is no difference.

As I mentioned, if stations are processing both through the same processor, the audio is not only synced, but the level of processing is the same. The frequency response of analog FM tops out at around 13kHz. HD is 20kHz. Stereo separation for conventional FM stereo is around 40dB. With HD, stereo separation is whatever the program is recorded at. Same goes with signal to noise. HD is technically superior.

 

[PRyanR]

I LOVE HD radio. Won't buy a car that either doesn't have it or can't replace the factory radio (talking to you Honda) with one. Seattle used to be one of the most brutal reception markets anywhere, but with HD, I drove all the way from Everett to Olympia without a flicker of static. It sounded very close to CD quality. But, I agree.......HD station audio quality can vary.
Perhaps AM could revive itself if it switched to HD (tall order, I know). And many of the talk & sports stations now are either on the fm dial or an HD-2 channel where I live, so I have no reason to switch to AM.

 

[bossbill]

We have HD on our FM, all three are in use. Very few HD users know how to use them. The best use of these HD channels is for feeding FM translators, which listeners understand. For our 3 HD channels, we have 6 FM translators. If not for the translators, we wouldn't bother with HD.

 

[Dr. Bob]

As I mentioned, if stations are processing both through the same processor, the audio is not only synced, but the level of processing is the same. The frequency response of analog FM tops out at around 13kHz. HD is 20kHz. Stereo separation for conventional FM stereo is around 40dB. With HD, stereo separation is whatever the program is recorded at. Same goes with signal to noise. HD is technically superior.

The stereo separation for a conventional analog FM on a vehicle receiver could be 20 dB or less due to blending. Multi-path distortion is not present in HD reception. Another thing is that the HD channel is not pre-emphasized so the high frequencies can sound cleaner and less compressed.

 

[brian marchand]

I LOVE HD radio. Won't buy a car that either doesn't have it or can't replace the factory radio (talking to you Honda) with one. Seattle used to be one of the most brutal reception markets anywhere, but with HD, I drove all the way from Everett to Olympia without a flicker of static. It sounded very close to CD quality. But, I agree.......HD station audio quality can vary.
Perhaps AM could revive itself if it switched to HD (tall order, I know). And many of the talk & sports stations now are either on the fm dial or an HD-2 channel where I live, so I have no reason to switch to AM.

I completely agree in that I love HD radio and would not buy a car without out either or I would have to immediately be able to replace the radio with one that has HD. It is nice to hear from someone like me. I like the better sound quality and the extra classical music channels. It is my personality that I would not like not being able to pick up all the stations I could on a radio. I would never buy an analog only radio.

My wife has a 2003 Honda Accord so I know what you mean. I had to install a Visteon HD Radio Component Car Tuner in the Honda and play it through an unused frequency. That was probably 14 years ago. It is an excellent tuner.

For my 2016 Toyota Camry I had to buy a used Toyota HD factory radio and install it. It is unfortunate that in the past and maybe some now too HD radio was only put in the most expensive car packages that I could not afford. My previous car was a 2003 Oldsmobile Alero and I installed a Pioneer double Din HD radio in it that I now use in my house with an internet radio connected to it.

I do not understand why anyone would not understand how to listen to HD radio sub-channels. Using an HD radio is very easy.

 

[Kelly A]

I do not understand why anyone would not understand how to listen to HD radio sub-channels. Using an HD radio is very easy.

Based on what I read around these parts seem to be; those critical of HD either don't even own an HD-capable radio and are just sour grapes, or have heard from a friend of a friend that it's not that easy to use so it justifies their narrative.

 

[Kelly A]

And will tell you vinyl is superior.

I flipped between HD and normal FM and there is no difference.

Maybe the loss of hearing acuity? Hey, it happens as one gets older. I used to see regular posts from folks who claimed music on AM sounded every bit as good as FM. To me, it's the same argument with analog FM and HD.

 

[BruceB]

Maybe the loss of hearing acuity? Hey, it happens as one gets older. I used to see regular posts from folks who claimed music on AM sounded every bit as good as FM. To me, it's the same argument with analog FM and HD.

As others have pointed out, it could be the station he's listening to.in my area the classical music station,the difference is night and day. sounds great in HD, but the Classic Rock station? You really don't notice that much difference

 

[jonsmth62]

I live in the Berkshire Mountains of Western MA. This area is part of the Albany NY Radio/Television market. Most of the time I'm on the fringe or beyond the fringe of most of the Radio Stations in the market. With mountainous terrain and driving around in valleys, it's a challenge to clearly pick up any FM radio signals. Not often but once in awhile HD is periodically activated in my Truck. As Kelly A commented in an earlier post, when the HD does kick in the immediate thing I notice is Stereo separation. Most auto audio systems are designed to gradually decrease the stereo separation in the FM signal to the point that it's strictly mono in order to eliminate noise when the signal become weak. So, most of the time, I'm listening to mono transmissions from the FMs in my market. I live in a higher elevation of the Berkshires, so as I'm driving home, I get high enough in elevation to receive the HD Signals which are far superior to the analog signal I was listening to. The only issue I've noted with HD is one particular station in the market's audio level dramatically increases when the signal changes from analog to HD. So much, in fact, that I have to reach out and turn the volume down. I won't get into that in this post, but I do feel that some TLC on the Engineer's part could quickly correct this issue.

 

[AMRadioGuy]

That's simply not true. The stereo separation, frequency response, and noise floor of the digital "HD" side are all superior to analog FM. Now, if station engineers or programming folks hash up their audio like the 70's and 80's through over-processing, that's not the fault of HD.

That might be so... but it's not all about frequency response and noise floor and stereo separation.

I'm sorry, but analog FM sounds superior to me hands down. The reality is that the codec HD radio uses is... not great at all. It's outdated and very, very lossy.

Low bitrate mp3 files might have more stereo separation, frequency response, etc. than a decent cassette deck, but I'm taking the cassette every. single. time. At least it won't suffer from swishy drum syndrome.

Lets take a look at some specs and compare:

Bitrate: YouTube recommends a bitrate of at least 128kbit/s for audio. Lets remember that that's audio to accompany a video. HD FM radio tops out at... 128kbit/s and that's only if there are no extra channels added. 128kbit/s is absolutely pitiful by 2024 standards. I don't think any of the major streaming services are anywhere near that low at this point...

Stereo Separation: As for 40dB of stereo separation for regular FM being a limitation... you do realize a high-end cartridge played on a well-cut LP only yields around 30dB of separation, max? Many highly knowledgable audio folks are more than happy with LPs, despite their limitations. I don't hear a ton of complaints about stereo imaging and vinyl (aside from things like inner groove distortion which are obviously not applicable to FM radio).

Frequency Response: Frequency response of analog FM is limited to around 15khz. That's fine - a quick google search would suggest that it's common for people who are older than 25 to not be able to hear above that, anyway... Last time I checked, the average FM listener wasn't getting any younger, either. HD radio can get up to 20khz. But the reality is that almost any listener of a given station isn't going to hear that, anyway.

Lossy Compression: And this is where the wheels really come off for HD radio. I mentioned bitrate upstream. 128kbit/s is low. Really low. The compression standard is (as I understand it) similar to AAC. 128kbit/s is going to leave behind a lot of artifacts. Things like snare drums start sounding absolutely awful - swirly-like, reverb trails end up distorted, and all the stereo separation in the world doesn't matter a lot if it ends up distorted. From what I understand, a distorted stereo soundstage is indeed common at 128kbit/s.

If HD radio sounds better than conventional FM, there's no reason at all to use .wav files in station libraries. They ought to just compress 'em down to 128kbit/s AAC files and call it a day. After all, that's what HD listeners are hearing and if regular FM sounds worse...

Sure, analog FM has some issues too - things like pre/deemphasis can cause problems. But the reality is those problems are just not as awful sounding as the artifacts left behind by digital compression. Sometimes it's not just about specs - they don't always paint an accurate picture. Multipath distortion is also an issue with FM. But I don't think there's a lot of debate that analog distortion is more pleasing to the ear than digital distortion...

Based on what I read around these parts seem to be; those critical of HD either don't even own an HD-capable radio and are just sour grapes, or have heard from a friend of a friend that it's not that easy to use so it justifies their narrative.

You've called my bluff - I don't own an HD radio... But my mother's car has one, and I'm 22. I've spent quite a bit of time in her car (and driven it a lot, too). That's given me plenty of opportunities to flip back and forth between analog and HD FM stations and listen to the differences. I have been in friends cars who have HD radios and have done the same.

I have no "narrative" here aside from what my ears tell me from a lot of time spent listening.

Oh, and of course, none of this debate even matters if the STL is a lossy piece of crap... or the station uses lossy files on-air like one of the stations in my area does.

And, of course, the other reality is that most people today are just so used to listening to audio that is digitally compressed that they think that Sirius XM sounds good. I mostly exist in an analog world, so that digital compression stands out like a sore thumb to me. It is not pleasing at all.