Digital Radio

The opposite. SCA trying to not allow community broadcasters on by stealth, tho that’s not the case.

I’m still confused - SCA using their own bandwidth allocation for their own stations is stopping stealth community stations? Huh?

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Nothing says music passion like an automated stream running at 48kbps :heart_eyes:

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Exactly.

I’d prefer some sort of Triple M Talk digital station.

For example play the Grill Team into Melbourne and Hot Breakfast into Sydney live at breakfast. Chaser into Melbourne and JB and Billy Rush Hour into Sydney live in the afternoons. Then play some sport documentaries such as Mark Howard’s Howie Games. Best of Roy and HG, Tom and Olly and Luke Bona at other times during the day.
Also an opportunity to work out the mess that is NRL and AFL coverage that clashes in Sydney. NRL on Triple M DAB+/FM, then put the AFL on Triple M Talk .

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I’m a little surprised none of the station operators have ever launched a hard rock and metal station. It seems like such an obvious hole in the analog and digital lineups in all capital cities.

I’m thinking it could be popular with tradies, delivery drivers, people that spend a lot of time on the road but not necessarily in a continuous block, who may refresh their vehicles more often and may be more likely to have DAB+ on board.

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I agree. I think the biggest mistake they’ve made with DAB is not opening it up to some new entrants. If they had I’m sure formats would be more adventurous.

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iHeartRadio Australia has two heavy metal stations, AndrewHaug.com and The Faction Radio. I wonder if ARN would think to put one of them on digital radio if the streams were attracting enough listeners to make it worthwhile?

Here’s the current DAB+ configuration in Sydney.

Station name, PTY, Codec, Stereo/Mono, Bitrate, Protection

9A
104.1 2DayFM, No PTY, HE-AAC v1, Stereo, 56 kbps, EEP 3-A
2OOO Languages, Culture, HE-AAC v1, Stereo, 64 kbps, EEP 3-B
2RPH Digital, Information, HE-AAC v1, Stereo, 64 kbps, EEP 3-B
2SM Talk & Sport, News, AAC-LC, Mono, 64 kbps, EEP 3-A
2UE LIFESTYLE, News, HE-AAC v1, Stereo, 80 kbps, EEP 3-A
BUDDHA HITS, No PTY, HE-AAC v1, Stereo, 48 kbps, EEP 3-A
Dance Super Digi, Pop Music, HE-AAC v2, Stereo, 48 kbps, EEP 4-A
EASY HITS, No PTY, HE-AAC v1, Stereo, 48 kbps, EEP 3-A
Fine Music, Serious Classical, HE-AAC v1, Stereo, 64 kbps, EEP 3-A
FUN Classic Hits, No PTY, HE-AAC v2, Stereo, 48 kbps, EEP 4-A
GorillaDanceHits, No PTY, HE-AAC v2, Stereo, 48 kbps, EEP 4-A
Kinderling Kids, No PTY, HE-AAC v2, Stereo, 48 kbps, EEP 3-A
Koori Radio, Culture, HE-AAC v2, Stereo, 48 kbps, EEP 3-A
MMM CLASSIC ROCK, No PTY, HE-AAC v1, Stereo, 48 kbps, EEP 3-A
MMM GREATEST, No PTY, HE-AAC v1, Stereo, 48 kbps, EEP 3-A
MMM MODERN, No PTY, HE-AAC v1, Stereo, 48 kbps, EEP 3-A
News Talk Sport, Sport, HE-AAC v1, Mono, 32 kbps, EEP 3-A
OLDSKOOL HITS, No PTY, HE-AAC v1, Stereo, 48 kbps, EEP 3-A
Sky Tbred Cent, No PTY, HE-AAC v1, Mono, 32 kbps, EEP 3-A
SkySportsRadio1, No PTY, HE-AAC v1, Stereo, 64 kbps, EEP 3-A
SkySportsRadio2, No PTY, HE-AAC v1, Mono, 32 kbps, EEP 3-A
Triple M, No PTY, HE-AAC v1, Stereo, 56 kbps, EEP 3-A
ZOO MusicVariety, Pop Music, HE-AAC v2, Stereo, 48 kbps, EEP 4-A

9B
2CH 1170, No PTY, HE-AAC v1, Stereo, 128 kbps, EEP 3-A
2GB 873, No PTY, AAC-LC, Stereo, 128 kbps, EEP 3-A
2MFM Muslim DR, Religion, HE-AAC v2, Stereo, 48 kbps, EEP 4-A
2SER 107.3, Education, HE-AAC v1, Stereo, 64 kbps, EEP 4-A
Coles Radio, No PTY, HE-AAC v1, Stereo, 40 kbps, EEP 3-A
CW Remix, No PTY, HE-AAC v2, Stereo, 48 kbps, EEP 3-A
FBi Radio, Other Music, HE-AAC v1, Stereo, 64 kbps, EEP 3-A
Hope 1032, Other Music, HE-AAC v2, Stereo, 48 kbps, EEP 4-A
Inspire Digital, Religion, HE-AAC v2, Stereo, 48 kbps, EEP 4-A
KIIS 1065, No PTY, HE-AAC v2, Stereo, 48 kbps, EEP 3-A
Koffee, No PTY, HE-AAC v1, Stereo, 40 kbps, EEP 3-A
MMM COUNTRY, No PTY, HE-AAC v1, Stereo, 48 kbps, EEP 3-A
Nova 969, Pop Music, HE-AAC v1, Stereo, 112 kbps, EEP 3-A
smooth fm 95.3, Easy Listening Music, HE-AAC v1, Stereo, 64 kbps, EEP 3-A
The 80s, No PTY, HE-AAC v2, Stereo, 32 kbps, EEP 3-A
The 90s, No PTY, HE-AAC v2, Stereo, 48 kbps, EEP 3-A
The Edge, No PTY, HE-AAC v2, Stereo, 48 kbps, EEP 3-A
WSFM 1017, No PTY, HE-AAC v2, Stereo, 48 kbps, EEP 3-A
Zed, Other Music, HE-AAC v2, Stereo, 48 kbps, EEP 3-A

9C
ABC Classic FM, Serious Classical, HE-AAC v1, Stereo, 80 kbps, EEP 3-A
ABC Country, Country Music, HE-AAC v1, Stereo, 80 kbps, EEP 3-A
ABC Extra, Varied, HE-AAC v1, Stereo, 72 kbps, EEP 3-A
ABC Grandstand, Sport, HE-AAC v1, Mono, 40 kbps, EEP 3-A
ABC Jazz, Jazz Music, HE-AAC v1, Stereo, 80 kbps, EEP 3-A
ABC NEWS, News, HE-AAC v1, Mono, 48 kbps, EEP 3-A
ABC SYDNEY, News, HE-AAC v1, Stereo, 64 kbps, EEP 3-A
ABCRadioNational, Current Affairs, HE-AAC v1, Stereo, 64 kbps, EEP 3-A
ABC-SBS EPG, none, Data, N/A, 8 kbps, EEP 3-A
Double J, Other Music, HE-AAC v1, Stereo, 80 kbps, EEP 3-A
SBS Arabic24, News, HE-AAC v2, Stereo, 48 kbps, EEP 3-A
SBS Chill, National Music, HE-AAC v1, Stereo, 56 kbps, EEP 3-A
SBS PopAsia, National Music, HE-AAC v1, Stereo, 64 kbps, EEP 3-A
SBS PopDesi, National Music, HE-AAC v2, Stereo, 48 kbps, EEP 3-A
SBS Radio 1, none, HE-AAC v2, Stereo, 40 kbps, EEP 3-A
SBS Radio 2, none, HE-AAC v2, Stereo, 40 kbps, EEP 3-A
SBS Radio 3, National Music, HE-AAC v2, Stereo, 40 kbps, EEP 3-A
SBS Radio 4, National Music, HE-AAC v2, Stereo, 48 kbps, EEP 3-A
triple j, Pop Music, HE-AAC v1, Stereo, 80 kbps, EEP 3-A
triplejUnearthed, Other Music, HE-AAC v1, Stereo, 72 kbps, EEP 3-A

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Thanks for posting that list.

Wow, never realised 2GB were at 128 kbps.
And 2SM at 64 kbps even though it’s only mono.

They seem like a waste when there are music stations running at a piddly 32 kbps.

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Best ever.

In order to get the some balance between quality and quantity given the limited spectrum on digital radio, I would like to see the stations follow some guidelines regarding bit rates

Talk stations = maximum 48 kbps
Music stations = minimum 48 kbps

In the case of 2GB, I would like to see them reduce the main channel as above, and commence a second station OR sell the other 80 kbps (or unused bits) to another operator.

WTF would they let 2GB at 128kbps. Just sounds like someone has more control of the mux then needed.

Some questions for the techies on Mediaspy following TVCL’s post:

  • What is the difference between HE-AAC v1, AAC-LC and HE-AAC v2. I understand they are different signal encryption methodologies, but are there pros and cons for each codec - or is it like running on an old version of Windows (ie IT department too busy to upgrade)?
  • How does the codec interact with the birate - ie is HE-AAC v2 @48 kbps better than HE-AAC v1 @ 40kbps?
  • Ignoring the obvious sexually innuendo, what does “Protection” do? And similar to the first question, what is the difference between EEP 3-A, 3-B and 4-A?

:

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Thanks posting the list . I still have the annoying glitch on the Mazda 3 dab radio, mostly on 9B these days but 9A still glitches. Noted ABC does not use AAC-LC where 2GB and 2SM do. Also the EEP is consistent with 3A(on channel 9C). I wonder if this what screws my Mazda dab radio to glitch and unable to scan 9A and 9B first go. Or it could be the repeaters. ABC still transmit at lower power from the repeaters, except for Winmalee?

They’re not different encryption methodologies; rather, different audio compression codecs.

The ‘LC’ in AAC-LC stands for ‘low complexity’. This is the standard version of AAC which gives good quality audio at 128 kbps, but starts sounding a bit shabby below this bitrate point.

HE-AAC v1 (or AAC+) is a newer version of AAC that is optimised for low bandwidth applications. It employs spectral band replication (SBR) to compensate for the lower bitrates. With HE-AAC v1, essentially the upper half of the frequency response is discarded (i.e. above about 11 kHz). These upper frequencies (approx. 11–22 kHz) are then simulated/interpolated based on harmonics from the lower frequencies.

HE-AAC v2 (or eAAC+) is a further development on HE-AAC v1 meant for use in even lower bitrate applications (around 32 kbps and lower). HE-AAC v2 uses SBR, but it also uses parametric stereo (PS). Given that the bitrate is very starved at this point, the true stereo information is also discarded and instead, there’s some data in the audio stream that says pan to the left and this point in time or pan to the right at this point in the audio track, to give an illusion of stereo.

To my ears SBR is immediately obvious even if I’m listening to it for about a second and even if it’s just speech. The trebles just sound fake and tinny. Perhaps older people can’t tell how fake SBR sounds given that with age, you lose the ability to hear higher frequencies. To me, analogue FM sounds much better than anything with HE-AAC.

As for how codec interacts with bitrate, each of the aforementioned codecs are optimised for a different bitrate range and each codec would give the best results at its optimal range. Roughly, this would be:

  • 128 kbps and above: AAC-LC
  • 64 kbps to 96 kbps: HE-AAC v1
  • Below 64 kbps: HE-AAC v2

It doesn’t make sense for 2CH to be using HE-AAC with a 128 kbps because that configuration actually sounds worse (or less realistic) than using an AAC-LC 128 kbps stream. This is because by employing HE-AAC, they are discarding the actual high-frequency information and simulating it, whereas by using AAC-LC, the original high-frequency information would be retained.

As for protection (EEP stands for Equal Error Protection), the higher percentage of bitrate that goes to protection (or error correction), the more likely the stream will be glitch-free at marginal signal levels. Some stations are using less protection in order to be able to fit more stations in. Basically, it’s a continuum between little correction and more data or more correction and less data.

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That’s an awesome explanation. I hope you don’t mind a couple of follow up questions…

  • I presume (maybe incorrectly) that FM transmissions have a cut off on the frequencies sent (hence my LPs and CDs sound better than radio). Accordingly at what point does the kpbs/AAC combo begin to exceed FM. Is it only 128/AAC-LC?

  • When you talk about the “illusion of stereo” for AAC v2, it sounds similar to an explanation I was given once about AM Stereo. Is it a similar approach, albeit different technologies?

Theoretically, for a mono signal, FM could go beyond 150 kHz in frequency response. Given humans can’t hear up that high, the upper portion of the response has been repurposed for other things.

For a stereo FM signal the very hard limit of frequency response is just below 19 kHz, but usually, it’ll be a bit lower than this (15–18 kHz). This is because of the stereo pilot signal at 19 kHz (this is a sine wave at 19 kHz to indicate to radios that the broadcast is in stereo). So 0–15 kHz is the monaural audio (L+R) and between about 23 kHz and 53 kHz is the stereo difference channel (L-R).

Above this, you have Auxiliary Communication Services (ACS). One such example is Radio Data System (RDS) at about 57 kHz which gives station name information, alternate frequencies, genre, song title, etc.

Other ACSs can be found even higher up. At 67 kHz or 92 kHz, there can be a secondary audio programme. I believe that 2MBS (102.5 MHz in Sydney) has an Indian radio station broadcasting at 92 kHz. This is essentially hidden to normal FM receivers and you would a special radio to be able to receive this signal. Other uses of ACS can include telemetry or paging services.

Back to your question, my personal opinion is that 128 kbps is the point at which digital sounds comparable to FM because that’s the point at which AAC-HE is supposed to stop being used (and along with that, SBR). If the source audio’s sampling rate is 48 kHz as it is with DAB+, with SBR, anything above 12 kHz is discarded and instead simulated. FM retains the actual high-frequency audio up to around 15–18 kHz. With AAC-LC, theoretically, up to 24 kHz of the actual high-frequency audio can be retained.

Having said that, it should be noted that, in practice, AAC-LC encoders often discard audio above about 15–19 kHz to improve compressibility (some encoders, such as FFMPEG, will let you specify the point at which the cutoff occurs).

AM stereo is a bit before my time, so I’ll let someone else here cover that one due to my limited knowledge in how it works.

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Out of curiosity, is it just me that can hear the fakeness/tinny-ness of the higher frequencies in DAB+? Or can others here notice it as well? With speech, SBR sounds to me like the person is speaking with a lisp.

I’ve heard from a few sources that Mazda haven’t got DAB right in their car yet. They seem to be the only ones. I’ve got no complaints in my Ford and also heard Mitsubishi and Honda are fine. Not sure what it is the Mazda, it shouldn’t be that hard.

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