Car Radios

Can you expand on what you mean by interference - is it static or something to do with FM stations breaking through on the AM band?

Electrical static. Like putting your mobile phone against your portable am radio.

@Laoma I’m very pleased to report the DAB reception and sound quality in the Focus is fantastic. I’ve only been driving within 20km of the CBD but it hasn’t dropped out once, no interference, and is crystal clear. It’s a Sony system in the Focus with 9 speakers and just sounds great. The only way you know you’re on DAB rather than FM is a slight half-second or so delay when you change stations. But even that varies and is hardly noticeable on some changes. Very happy with it. The only other niggle is that they don’t have DAB repeaters in the tunnels - and the tunnels in Brisbane are quite long! The cross river tunnel is 5km and the airport link tunnel is 7km so back to FM in those. As for FM DX’ing, it’s not quite as good as my previous 2008 Focus unfortunately. I can still pick up Rebel, Breeze, River and Mix Sunshine Coast with RDS where available, but there is a little bit more scratchiness occasionally than the old one which really sounded like “local” stations. Anyway, I couldn’t be happier with the DAB. There is also a DAB-1, DAB-2 and DAB-3 pre-sets so 18 stations to store. My DAB-1 is: Smooth FM, More 80s90s, Triple M Classic Rock, Pure 80s, Pure 90s and Double J.

Pleased to hear that re your car radio.

Given the rather average sound quality on DAB+ (re the low bit rates of most stations) … so you don’t find that gets magnified in comparison to FM or CD given the high sound quality?

The Sony systems as used in the upper spec Focus/Mondeos seem to get good reviews from Wheels… they seem to be held in better regard than the Bose set ups in the Mazda 3 and 6.

Is the aerial an in-glass one?

@Radiohead Even with the low bit rates I find the sound equal to FM in most cases. Perhaps FM sounds a bit “louder” on some stations but I haven’t even done any tweaking on the sound settings (base etc.), it just sounds great to me. Also a big benefit in getting AM music stations (4KQ and Magic) in DAB. So no complaints from me at all. No, the aerial is just a normal spike one on the roof. The Ford dealer reckons the only complaints they’ve had with DAB is no coverage in the tunnels. As mentioned I haven’t been beyond 20km of the CBD yet so can’t comment on outer suburb reception as yet.

@Laoma yes I definitely agree more problems with AM reception in metro areas than 20 years ago. AM reception is lost completely in some streets in downtown Brisbane (e.g. Elizabeth Street).

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Thanks Brian. I will consider the focus when the time comes. Save my pennies. I dont like the space saver tyre though as I got a flat a couple of weeks ago and was happy my getz had big size tyre.
With my dab radio low bit music stations sounds horrible. First world issue :blush:

For me, I can hear a huge difference between FM and DAB+, with FM sounding vastly superior, in my opinion. On DAB+ the trebles/higher frequencies sound very artificial, tinny and inaccurate compared with the original audio. I can easily tell within a few seconds if I’m listening to a stream encoded in AAC+, which is what DAB+ is encoded with. Regular 128kbps AAC sounds fine to me, but anything AAC+ sounds terrible, in my opinion.

Perhaps those who can’t tell the difference between FM and AAC+ are those who are of an older age, as with age, we gradually lose our ability to hear high frequencies.

Hey I’m only 47! :slight_smile:
I seriously can’t tell much difference.
I notice More Digital sounds better than Pure 80s and Pure 90s but hey it’s nitpicking and worth the perceived drop in quantity from FM (arguable) to get the variety of formats.
There’s a bit more of a treble sound perhaps .But there’s a button to adjust treble and base. Crisis over.

I don’t think AAC+ is THAT bad, 2CH Sydney sounds pretty decent at 128 Kbps.

I thought AAC+ was used for DAB because it was more efficient than AAC …
A bit like the DVB-T MPEG4 vs MPEG2 debate, but not as marked as that.

Not sure if this hotlink will work: http://www.roger-russell.com/hearing/hearing4.jpg

But even at 45, there is considerable loss of hearing in the high frequencies – and that chart only goes to 8 kHz. The treble distortions I’m talking about would be higher in frequency than that.

Once audio bitrates reach 128kbps, AAC+ is generally no longer used as it brings no benefits. I don’t think 2CH’s audio is actually 128kbps. That 128kbps figure incorporates programme associated data (PAD) also.

AAC+ is basically optimisations to fake the treble at low bitrates. One of the key components of AAC+ is Spectral band replication (SBR). From Wikipedia, SBR “reconstructs or adaptively mixes in noise-like information in selected frequency bands in order to faithfully replicate signals that originally contained no or fewer tonal components.” (i.e. there’s not enough bitrate to actually carry the treble data, so we’ll have a guess at it).

At lower bitrates, Parametric Stereo (PS) is also used, which is essentially the same thing as SBR, but done to the channel separation – “An AAC HE v2 bitstream is obtained by downmixing the stereo audio to mono at the encoder along with 2-3 kbit/s of side info (the Parametric Stereo information) in order to describe the spatial intensity stereo generation and ambience regeneration at the decoder.” So it’s just an approximation of the stereo information.

Essentially, AAC+ is about faking the information in situations where there’s not enough bandwidth (i.e. streams below 128kbps).

It is, but only at low bitrates. At bitrates above 128kbps, it doesn’t help. If anything, using SBR on 128kbps+ audio might make it sound worse.

Thanks for the explanation re AAC+ vs AAC…

Re 2CH … yes, you’re right… the 128 kbps would include the overheads… but the ‘pure’ audio feed would make up the vast majority of the 128 kbps (maybe 112 kbps or so??).

I think 2ue sound better than 2ch. Is 2ch using aac+ and 2ue using aac?

On Monday night, I took the entry level 2015 Subaru Impreza 2.0i (all-wheel-drive hatchback hire car) to a mountain west of Brisbane to test the touchscreen radio. There was slight tropo enhancement from the Northern Rivers as 99.9 BAY was crystal clear driving home on non-elevated roads. (This signal can be received on the Tecsun PL-300WT in the bedroom at home during moderate tropo. Funnily enough, it’s audible right now!)

At the mountain, peak elevation is 229 m ASL. Mt Coot-tha FM broadcasts are 19 km away.

RDS decoded as would be expected. I took some photos, otherwise this post has the potential to be incredibly boring to those unfamiliar with FM reception in SE QLD. :laughing:

97.9 HOT 91.1 Tewantin. (Identical to 91.1 decode).
99.4 REBEL Tamborine. (Scrolls with Logan & Gold Coast frequency information).
100.5 ZINC 96.1 Doonan. (96.1 is blocked).
101.9 SEA FM Hervey Bay. (Can be quite ‘the bastard’, due to PARADISE FM interference. Took several attempts!)
102.9 HOT TOMATO Tamborine. (Very detailed temperature & traffic information).

RDS sensitivity seemed above average. Stereo signals were heard but RDS did not decode on the Bundaberg SEA & HITZ signals (Bundy faded whilst driving) or the Hervey Bay MIX FM. Nor did Gold Coast’s GOLD, SEA or RADIO METRO. However, the Toowoomba 100.7 HOT FM did decode, as would be ordinarily be expected driving west of Brisbane. [With various Blaupunkt SHARX receivers used for over a decade now, RDS should ordinarily decode up here on BREEZE 88.9 FM].

Sensitivity seemed above average. Strong signals were received from the Mt Moombil broadcasts, Byron 99.9 BAY & occasionally weak 99.1 Mt Dowe. On 88.9 MHz, RICHMOND VALLEY RADIO & BREEZE were mixing. On 93.7 MHz, 4ABCFM Cooroy & REBEL were mixing. Over the weekend, there was no problem hearing Mt Moombil 99.5 2ABCRN frequently just driving around the suburbs.

Average selectivity. No problem differentiating strong signals on 99.3, 99.4 & 99.5 MHz. 99.3 is 4JJJ Biggenden.

No problem with THE NEW 104.7 Grafton adjacent to 104.5 TRIPLE M. No problem with 93.1 SEA FM adjacent to 93.3 SBS RADIO. No problem with weak 106.7 REBEL FM or 107.1 4GY Doonan, both adjacent to NOVA 106.9 FM.

Spillover from 98.9 FM when Mt Dowe wasn’t audible. On suburban streets 104.7 also was not a clear frequency. There was permanent bleedover from TRIPLE M. [There is never spillover onto the adjacents with SHARX in these suburbs. In suburbs 2 km from Mt Coot-tha, even 107.1 4GY Doonan is often audible adjacent to NOVA 106.9 FM].

The ability to cope with strong FM signals was not tested due to lack of time.

However, the 2015 Subaru Impreza radio could be improved in some areas. The manual tuning knob (top left in photograph) needed to be turned painfully slowly for accurate 100 kHz increments. This makes it unsuitable for tuning in weak signals whilst driving. Distortion seemed evident on some weak stations. For example, Byron 99.9 BAY seemed distorted adjacent to 99 7 Redcliffe. The physical media drive is CD compatible only, there is no provision for DVD playback. On balance, quite a difficult radio to use for weak signals. Although to be fair, the radio was only used for about three hours during the hire period.

Respectable FM reception for a $27,000 hatch? Yes, that’s my view, considering the significantly inferior factory radios that I’ve used in the last few years!


Moving away from that specific radio & to a general discussion of today’s car radios in general terms… Manufacturers use inexpensive DSP integrated circuits usually made by either NXP (Philips) or STMicroelectronics. It is often suggested that quality analogue tuners have become too expensive for car audio manufacturers to design… or there is little incentive to do so! NXP calls their dynamic/variable IF bandwidth functionality Precision Adjacent Channel Suppression (PACS). These chipsets are in use by JVC, for example. STMicroelectronics tend to be in use by Pioneer & Sony.

I do wonder will there be a discernible difference between the FM performance of a current aftermarket car radio made by JVC, Pioneer or Sony for example, as a result of widespread adoption of these chipsets by manufacturers?

Listed on Ebay is another example of a third party multimedia unit with a STMicroelectronics based tuner. There are dozens of manufacturers using this chipset listed on Ebay!!!

From my limited observations with these inexpensive DSP chipsets (including the Impreza radio) the adjacent channel selectivity tends to be asymmetrical, with high side rejection typically noticeably worse. (This can also be observed with the Silabs or Frontier Silicon based portable DAB/FM radios using DSP).

On the other hand, the strong signal handling is often better than (the 10.7 MHF IF based) analogue tuners they replaced. In addition, the specifications of the current Sony models suggest significantly better stereo separation & slighter better sensitivity performance than their previous analogue models. Whilst audio reproduction of strong FM broadcasts may be improved, actual reception of weak signals may not necessarily be superior than predecessors.

Prestige German manufacturers Bosch & Becker remain notable exceptions, bucking the above trend. These manufacturers generally don’t use the widely used inexpensive chipsets in their OEM European factory radios. These manufacturers pioneered automotive tuners in Europe so their previous research & development likely remains relevant. SHARX is still incorporated into many expensive OEM European factory radios made by Bosch Car Multimedia. Harman Becker also collaborate with former rival Bosch to maintain innovations within their OEM European factory multimedia systems.

Good to see the new Honda Civic lists DAB included, at least for the upper end models. I’m thinking this is the first Honda with DAB? Finally some inroads are being made. I’m in love with the DAB in my Focus - I spend 80% of my time on DAB around Brisbane - flawless reception and great sound. Took a trip up to the Sunshine Coast a few weeks ago and the reception was absolutely impeccable all the way up to the Caloundra exit and then all of a sudden, gone :slight_smile:

Hi All,

This is my first post so please be kind to me! :sunglasses:

I would like to find out what after-market double-DIN car radios people might have that cover the AM Expanded Band in Australia. The AM Expanded Band extends the top frequency of the AM broadcast band from 1602 kHz to 1701 kHz and is used for Narrowcast broadcasting.

I have a 2015 Holden Commodore Evoke which covers up to 1710 kHz but I would like to find an after-market radio for a 2003 Toyota Corolla. All of the main manufacturers have models that seem to cover up to 1710 kHz but only in 10 kHz steps - this is what the US uses. In Australia we use a 9 kHz spacing.

If people know of a double-DIN car radio/CD player which covers the Australian AM Expanded Band and has good quality AM reception, that would be awesome.

Thanks guys.

Shane,

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Welcome - I would think that anything sold in Australia would use the 9kHz spacing - and if they use it for 531-1600 then it would definitely extend to 1710. If a model looks like it is 10kHz, there is probably an simple way to switch to 9.

(PS - post moved to this thread as it is the most appropriate area to discuss).

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Thanks TV.Cynic. The problem seems to be that most of the after-market car CD/radio receivers for sale seem to operate to 1710 kHz when set for 10 kHz spacing but when they are set for 9 kHz spacing they only operate to 1602 kHz - because that’s what the original AM band in Australia used to stop at…

Yes - you are right - I have come across that.

As I mentioned in the DX thread, I now have a shiny new Lancer with the stock Mitsubishi system installed.

It is nice having a DAB+ radio within the car. I have a bit of an issue with the sound quality on DAB, it sounds quite ‘trebley’ compared to FM and some of the stations really don’t come out clearly (though that may be a bitrate issue rather than receiver issue).

Coverage isn’t bad - it seems to be largely on parallel to FM. For instance, driving down the coast, I generally keep a solid signal until around the Smith St exit, when it starts to dip. That’s about the same as the Brisbane FM stations which are starting to struggle by the time you get near Nerang.

The FM itself isn’t too bad, despite the car only having one of those low profile antennas mounted on the rear windscreen. RDS selectivity is average, and sometimes on a weaker signal it will lock on the PTY display but not be able to show the station name (so I will have the second line of the display showing ‘ROCK MUSIC’ but the first line still only showing 104.5 MHz).

The tuner goes ok, struggles with the big boys on adjacent frequencies but otherwise is pretty selective. I haven’t really given it a proper test yet other than yesterday’s quick run, but it’s better than I expected it to be. It really does seem that the stock tuners now are of a better class than they used to be in years gone by, which is convenient given that it’s infinitely more difficult to replace them now than it used to be.

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