> it doesn't degrade gradually as signal gets worse

That has a lot more to do with the dated implementation and less to do with digital radio. There are a number of digital broadcasting techniques which can minimize and compensate for noise, including a slight delay with a signal correction and fault tolerant codecs.

DAB was implemented using the old MPEG2 audio codec. DAB+ uses the now 15 year old codec HE-AAC which isn't really designed to handle corruption. Opus handles loss a lot better (see their examples https://opus-codec.org/examples/ )

> DAB was implemented using the old MPEG2 audio codec. No, it was MPEG 1 layer 2 often at 192 kbps. Later they switched to HE-AAC with DAB+.

DAB+ uses EEP (and RS) which was deliberately chosen to give better signal quality all the way to the point of losing reception. Old DAB used UEP which degrades faster, but instead of having no signal, it went to a muddier / warbling kind of sound that characterised early DAB receivers.

And technically while some people do call it MPEG2, it's actually MP2, also known as MPEG-1 Audio Layer 2, an audio codec in the same family as MP3 (MPEG-1 Audio Layer 3).

I imagine that today they'd probably use something like Opus and a fountain code or similar, yes... But you can't expect everyone to replace their radio every 10-15 years ;)

> I imagine that today they'd probably use something like Opus and a fountain code or similar, yes... But you can't expect everyone to replace their radio every 10-15 years ;)

Certainly not, which is why I believe DAB (no plus) is still floating around. And I'm not really suggesting that they made a bad choice.

I'm mostly pushing back on the notion that digital means all or nothing audio. If broadcast audio stays alive (which it may not) then I hope the next standard is opus, fountain codes, and QAM-64 or similar so we can stuff a bunch of bits into error correction while still having graceful degradation, better than analog, when the signal degrades.

I could be wrong, but I think DAB uses DQPSK (which can be thought of as a special version of QAM 4 if you squint a bit) and not anything like the higher QAM constellations because it's deliberately designed for mobile (road, train etc) where you don't have a steady signal, it can vary a lot with motion, so QAM 64 wouldn't really be possible.

Though I did a quick check and apparently DRM+ uses QAM-16, so perhaps my knowledge is far too out of date :S

LTE and 5g both use QAM 256 and higher. Wifi 7 can use QAM 4096 (though not a lot of motion there).

That's a good point about LTE/5G. Thanks!

Bit of hindsight bias there, DAB was first developed in the mid 1990s, ubiquitous fast wireless IP in everyone’s pockets is at least a decade, perhaps nearer to 20 years in the future. There are quite a few transitionary technologies that we needn’t have developed had we just waited for something better to come along (but without the R&D into some of them…).

(Also doesn’t analogue FM also kinda cut off fairly abruptly?)

FM stays listenable even with heavy distortions when you drive out of range and you can decide for yourself when you no longer tolerate the signal. Digital doesn’t give you warnings and just goes silent

DAB+ receivers can (and many do) display signal quality. Not playing distorted, noisy signals is a feature I greatly appreciate.

It’s a digital cliff. Analog fades away but is never a true replication digital remains stable for over but then vanishes.

At the same quality dab is still perfectly long after fm becomes gabled. It then vanishes.

The problem with dab in early days was the lower strength, the poor quality decoding, and the lower bitratr than should be been used for the codec.

Not entirely true. There's quite a bit of error correction applied: https://en.wikipedia.org/wiki/Digital_Audio_Broadcasting#Err...

Which either recovers or doesn’t. The gap between fully recovered and indecodavle is tiny.

> Not playing distorted, noisy signals is a feature I greatly appreciate

Haha. The DAB+ signals are compressed as much as possible.

Some more than others. E.g. Deutschlandfunk Kultur is broadcasted in decent quality, as is NDR3. Klassik Radio fares poorer, but that's due to the bandwidth allocated to them.

Comparison here is FM, not FLAC.

In my experience DAB goes painfully 'squawky' and squeaky before finally cutting out, it's unbearable in headphones.

This video gives a good example of the signal breaking down from 00:38

https://www.youtube.com/watch?v=B-ihmXOy1h4

Especially so with digital public TV. its absolutely unusable. and now they can't stand that people want to share sports broadcasts, so they are updating it again to add encryption. I can't believe anyone watches it.

I have a DAB radio and it gets constant interference. Meanwhile FM is stable. In the same set up.

Really soured me on this digital radio technology.

One-to-one communications and broadcast communications are different. Perhaps every 4G tower could broadcast the news on a special data channel, but it would be a separate system from the main 4G data channel.

At the very least, I wish Digital Radio Mondiale won out over DAB. It’s designed to use the existing long, medium and short-wave bands and can even co-exist with an AM broadcast. I imagine digital radio would work quite well with the propagation characteristics of the mediumwave (and longwave) broadcast band.

There’s also DRM+ for the VHF band, including the FM broadcast band.

https://en.wikipedia.org/wiki/Digital_Radio_Mondiale

I guess depends on your definition of "crap". In practice, my city has some hills, and none of the half-dozen FM stations I listen to in my car come in without static in some places in the city. Whereas the single HD Radio station has perfect reception, all the time. Plus the sound quality is noticeably better.

They do its called 5G broadcast. No, this doesn't require point to point connections.