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Recommend new head units...


anglais49

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Afternoon!

 

I'm after a new head unit for my 2003 import. It's got a double din Sony unit in it now which I don't like...

 

A couple of things it must have:

 

-DAB radio

-Bluetooth (Android)

 

- Sat nav & DVD would be cool too.

 

 

I've had a look in a few shops and there seem to be precious few double deck units that can do DAB and Bluetooth. I would have thought there'd be a much bigger market for them these days....

 

This is the only one I've seen so far that fits the bill: http://goo.gl/mVniF

 

 

Anyone recommend any others?

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Does DAB give good sound quality?

 

 

Introduction

 

The marketing people will tell you that DAB gives you 'digital quality' sound. This may be true, but it is also meaningless as digital quality ranges from mobile phone quality, through internet radio, up to CD quality. Although DAB is capable of near CD quality sound, there is a trade-off between the number of stations and the sound quality. UK broadcasters have prioritised station choice.

 

In the UK, DAB sound quality is similar to FM at best and can often be poorer. If you listen on a portable or in-car, you won't notice any difference in most cases, noting that in-car FM sound quality varies with the signal stength. However, on good quality hi-fi or headphones, many stations sound better on FM, subject to the quality of reception and how sensitive the listener is. Note that Radio 4 occasionally broadcasts in mono on DAB. BBC 7 and the Asian Network are permanently in mono on DAB, whilst available in stereo on all other digital platforms. All other speech stations are in mono on all platforms.

 

Radio 3 uses a much higher bit rate than other stations, giving better sound quality. Classic FM and Virgin also use a higher bit rate, whilst Radios 1, 2, 4, 6 Music and 1 Xtra use more efficient audio coders. These stations have a sound quality similar to average FM. Most other DAB stations have a noticeably poorer sound quality than FM. The commercial broadcasters plan to use the new audio coders to increase the number of services instead of addressing the sound quality problem. Sound quality may be improved on a few stations, most likely those that are also available on FM.

 

The sound quality on FM simulcasted stations sometimes sounds poorer than digital only stations due to too much dynamic range compression. A feature of digital radio audio coding techniques is that some types of programming is easier to code than others, so, on a music station, the quality will vary from track to track. Relatively sparse music, such as R&B, soft rock and country tends to code well, whereas busy music, such as loud rock and over-produced pop can present more of a problem.

 

To get the best sound quality out of digital radio on a hi-fi, using one of the digital TV systems is recommended as these use higher data rates than DAB on the main BBC networks and some commercial stations. If you are happy with the programme choice on FM, upgrading your aerial installation or using a better quality phono cable between your tuner and amplifier may improve the sound quality.

 

Technical

 

A CD codes audio at a rate of about 1.2 Mbit/s. Using the same coding standard on DAB would only allow one station per multiplex - not very practical. Therefore audio compression is used to reduce the data rate of each station. Audio compression technqiues all make use of psycho-acoustic coding. This takes advantage of the fact that when a sound on one frequency is heard, the ear is rendered much less sensitive to quieter sounds on nearby frequencies. A psycho-acoustic coder performs a Fourier analysis of the sound to be coded and calculates a noise floor. Sound below the noise floor can not be perceived by the listener, so can be discarded. Only the sound above the noise floor need be calculated and this requires much fewer bits than coding the whole sound, as is done on CDs.

 

The audio coding standard used for DAB is MPEG (Motion Picture Expert Group) 2 Layer 2, abbreviated to MP2. This samples at 48k samples per second (twice the maximum audio frequency). Each block of 384 samples is broken into 32 equal frequency bands of 12 samples each and a separate noise floor and scale factor is set for each band. Noise floor and scale factor information is shared between sets of three blocks to save bits. Stereo stations mostly use a technique known as joint stereo whereby lower bit rate stereo separation data is added to a mono signal rather than coding the left and right channels in full.

 

DAB was designed in the early 1990s and MP2 is now a rather dated coding standard, requiring 192 kbit/s to transmit a high quality joint stereo signal. Its successor, MPEG 2 layer 3, or MP3, only requires 128 kbit/s because it uses narrower frequency bands at for the lower frequency components of the signal, enabling the noise floor to be set much more efficiently.

 

Newer techniques, such as AAC and HE-AAC, are even more efficient. These are used for the new DAB+ standard, which many countries are currently replacing DAB with. A multiplex can carry a mixture of DAB and DAB+ stations. However, an existing DAB radio will only receive the DAB stations. A DAB+ radio is needed to receive both types of station. This will delay the introduction of DAB+ in the UK.

 

Although DAB was designed to transmit stereo stations at 192 kbit/s or higher, the vast majority of stereo stations in the UK transmit at only 128 kbit/s, significantly limiting the sound quality. Only Radio 3 transmits at 192 kbit/s. Classic FM, Virgin and one or two local stations use 160 kbit/s. The mono stations use a variety of bit rates: 48, 64, 80 and 96 kbit/s. The DAB Ensembles Worldwide site lists the bit rates for each station.

 

The bit rate is not the only factor determining digital radio sound quality. A well engineered station at 128 kbit/s can sound better than a poorly engineered station transmitting at 160 kbit/s for example. There are three main factors in addition to the bit rate that affect sound quality. These are:

 

Dynamic range compression;

Studio sound quality and programme distribution;

Coder type and tuning.

Each of these is discussed below. Over the past year or two, the BBC has been making small improvements in each of these areas to try and 'squeeze' the best sound quality possible from a 128 kbit/s channel.

 

Dynamic range compression

 

Dynamic range compression (DRC) increases the amplitude of weaker frequency components of a sound signal. This makes the overall sound seem louder, making a station 'stand out' on the dial and helping to mask background interference on AM and FM. In recent years it has become fashionable, especially amongst commercial broadcasters, to use extreme amounts of DRC. This makes music sound distorted, particularly percussion, on all transmission platforms. On DAB, it creates an additional problem: the DRC brings more frequency components above the noise floor of the psycho-acoustic coder. This means that more bits are required (particularly at the higher frequencies) to encode the sound to a certain standard. Conversely, if the bit rate is fixed, high levels of DRC cause the perceived sound quality to drop. Amongst the national stations, Virgin and Life both use very high levels of DRC. Virgin gets away with it because it broadcasts at 160 kbit/s, though it sounds no better than BBC 6 Music, which broadcasts at 128 kbit/s with very little DRC. Life, on the other hand, sounds distorted on many songs. Turning down the dynamic range compression would be a very simple way of improving the sound quality on many stations.

 

Studio sound quality and programme distribution

 

Many radio stations play music off automated playout systems or mini-discs, rather than CDs. There are good practical reasons for this. CDs skip if not kept clean and automated playout systems enable presenters to record their links in advance, reducing costs. However mini-discs and many automated playout systems use compressed audio. This is not a problem with FM transmission, but with digital radio can cause problems. The radio psycho-acoustic coder has trouble telling the difference between weak frequency components and the noise floor left by the playout system, leading to poorer sound quality than if it had coded the original sound, even if the playout system codes at a higher quality than the radio coder. A good analogy is photocopies - a copy of a copy always looks poorer than a copy of the original. To resolve this problem, the BBC has installed a linear playout system at Radio 1 and is gradually rolling it across the other national networks.

 

In a well engineered DAB system, such as the BBC's, audiocoding is performed once, at the studio, and all further distribution between studio and transmitters is in coded form. However, some broadcasters will code and decode the programme material several times through the transmission chain, a process known as transcoding. This is equivalent to "putting the audio through a photocopier" several times and can significantly degrade sound quality, particularly where low bit rates are used through the distribution chain. Many EMAP stations suffer noticeably from transcoding problems.

 

Coder type and tuning

 

Some MPEG coders are more efficient than others. Research into hearing perception has progressed over the past ten years and faster processors enable more sophisticated audio coding algorithms to be run. New designs are about 10-15% more efficient than the original generation of DAB audio coders. Another issue is that the original MP2 coders were designed to operate at 192 kbit/s, so to get the best performance at 128 kbit/s, a certain amount of retuning is required.

 

There is a limit to how much new psycho-acoustic models can improve on the best coders currently available. However, there may be scope to introduce residual feedback algorithms and to introduce backward-compatible upgrades to the DAB system, such as spectral band replication and multi-layer transmission.

 

 

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http://www.halfords....tegoryId_265865

 

this is just the single DIN of what you posted

 

This is what I have just put in to my car, DAB is good - only problem is that i live in middle of nowhere and signal phases out about 2 miles from my house.

 

It was on offer when I got it so i think it cost me about £270 installed with DAB aerial etc.

 

has bluetooth hands free - its pretty good, not quite to the standard of a parrot etc, but its not bad. has 2x usb inputs as well as bluetooth audio, I have an 03 import as well and it all worked first time, though I would suggest getting the shop to fit it unless you have done many before, I did just as Ive not done an install in years and it took the Halfords guy who does it all day every day about 90 mins to do the install as its a bit of a faf.

Edited by LloydV
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DAB is not worth it trust me, just get a decent headunit and get an add on wirh a cheap aerial just to try it, then you won't have wasted too mucb trying it :surrender:

DAB was going to be the next big thing but as the article above explains quantity has been put before quality, fine for a little radio in the kitchen or at work but play it through a decent set up and its weak and tinny and the bass is awful, it really is like going back to old MP3s of 10 years ago :headhurt:

 

BBC channels are good mostly, a few others are not bad, rest are just awful!

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I have the Pioneer x3500dab fitted

http://www.350z-uk.com/topic/68868-new-hu-arrived/

 

Really like DAB. Had it in my last car and wanted to keep in the zed.

 

Was not impressed with interior aerials, too much burble as the signal dropped.

Replaced with external in place of the FM one.

http://www.350z-uk.com/topic/71434-removing-aerial-to-replace-with-a-dab-one/

 

If you want DAB, go for it but be prepared to try a few aerial options.

 

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I have to agree with SMD - have had DAB in both my cars for a few years now (only for PlanetRock), but recently the sound quality has gone downhill. It used to be 128 kbps in stereo which wasn't brilliant but at least it was listenable, but is now broadcast at 80 kbps in mono :dry: It's like being back in the dark ages.

 

Through a radio in the kitchen it's okay, but through a decent stereo system it sounds awful (got a proper DAB tuner on my home hi-fi as well and it sounds crap now - I use the Sky channel instead). You're better buying a Pure Highway and connecting that through the FM modulator, then you can listen to it in any car and use it as a personal radio as well (and it's cheaper). An external aerial will help the signal, but won't improve the sound quality.

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DAB is not worth it trust me, just get a decent headunit and get an add on wirh a cheap aerial just to try it, then you won't have wasted too mucb trying it :surrender:

DAB was going to be the next big thing but as the article above explains quantity has been put before quality, fine for a little radio in the kitchen or at work but play it through a decent set up and its weak and tinny and the bass is awful, it really is like going back to old MP3s of 10 years ago :headhurt:

 

BBC channels are good mostly, a few others are not bad, rest are just awful!

 

Wow, that certainly was a comprehensive report on DAB! :D

 

I had it in my previous car and had no problems at all. Primarily I had it for the stations that I can't get any other way like 5 Live Sports Extra. I don't mind if it isn't as great as everyone thought, just so long as I can listen to TMS and F1 commentary! :)

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http://www.halfords....tegoryId_265865

 

this is just the single DIN of what you posted

 

This is what I have just put in to my car, DAB is good - only problem is that i live in middle of nowhere and signal phases out about 2 miles from my house.

 

It was on offer when I got it so i think it cost me about £270 installed with DAB aerial etc.

 

has bluetooth hands free - its pretty good, not quite to the standard of a parrot etc, but its not bad. has 2x usb inputs as well as bluetooth audio, I have an 03 import as well and it all worked first time, though I would suggest getting the shop to fit it unless you have done many before, I did just as Ive not done an install in years and it took the Halfords guy who does it all day every day about 90 mins to do the install as its a bit of a faf.

 

Cheers. Oh yeah I'd definitely get someone else to install it. That's been out of my depth since my 1986 Fiesta!

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I have the Pioneer x3500dab fitted

http://www.350z-uk.c...new-hu-arrived/

 

Really like DAB. Had it in my last car and wanted to keep in the zed.

 

Was not impressed with interior aerials, too much burble as the signal dropped.

Replaced with external in place of the FM one.

http://www.350z-uk.c...with-a-dab-one/

 

If you want DAB, go for it but be prepared to try a few aerial options.

 

Cheers for the advice, I'll keep that in mind.

 

Do you have any sat nav set-up with it? I've seen some advertised as 'sat nav ready' whatever that is. But presume you need to set up an add on?

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I have the Pioneer x3500dab fitted

http://www.350z-uk.c...new-hu-arrived/

 

Really like DAB. Had it in my last car and wanted to keep in the zed.

 

Was not impressed with interior aerials, too much burble as the signal dropped.

Replaced with external in place of the FM one.

http://www.350z-uk.c...with-a-dab-one/

 

If you want DAB, go for it but be prepared to try a few aerial options.

 

Cheers for the advice, I'll keep that in mind.

 

Do you have any sat nav set-up with it? I've seen some advertised as 'sat nav ready' whatever that is. But presume you need to set up an add on?

 

 

I don't have satnav as I have the inbuilt one.

 

Assume this is the addon

http://www.pioneer.eu/uk/products/25/111/241/AVIC-F250/page.html

 

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Fair enough if you get DAB to get channels you can't get elsewhere :thumbs:

 

I'm with baggie on Planet Rock, can't believe it has gone to such a pathetic rate and in mono!!!! I have emailed them to say they are pi$$ing on the majority of their audience i.e. DAB listeners, unless they are going to go FM they will be dead in the water before too long :byebye:

 

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internet radio is the way forward, shame we're still way behind the yanks.

 

Could always use in App mode and install an Internet radio app like

http://www.livioradi...neer-appradioâ„¢/

 

Planning on doing that in mine but still not the same as USA car version where a monthly subscription enables great reception in most places. Irrespective of data amount used.

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Fair enough if you get DAB to get channels you can't get elsewhere :thumbs:

 

I'm with baggie on Planet Rock, can't believe it has gone to such a pathetic rate and in mono!!!! I have emailed them to say they are pi$$ing on the majority of their audience i.e. DAB listeners, unless they are going to go FM they will be dead in the water before too long :byebye:

 

Apparently PlanetRock is now on FM in the midlands area; maybe the start of a roll out?

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internet radio is the way forward, shame we're still way behind the yanks.

 

Could always use in App mode and install an Internet radio app like

http://www.livioradi...neer-appradioâ„¢/

 

Have you used internet radio in a car?

 

I can't imagine I'd get any signal for it where I live. 3G is rare on the move and even regular phone signal has its blackspots!

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Fair enough if you get DAB to get channels you can't get elsewhere :thumbs:

 

I'm with baggie on Planet Rock, can't believe it has gone to such a pathetic rate and in mono!!!! I have emailed them to say they are pi$$ing on the majority of their audience i.e. DAB listeners, unless they are going to go FM they will be dead in the water before too long :byebye:

 

Apparently PlanetRock is now on FM in the midlands area; maybe the start of a roll out?

 

Lets hope so :thumbs:

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internet radio is the way forward, shame we're still way behind the yanks.

 

Could always use in App mode and install an Internet radio app like

http://www.livioradi...neer-appradioâ„¢/

 

Have you used internet radio in a car?

 

I can't imagine I'd get any signal for it where I live. 3G is rare on the move and even regular phone signal has its blackspots!

 

I use internet radio as with 3 I get unlimited 3G, it does drop out here and there but if you set thr buffer large enough its ok. The difference in sound quality is massive, there are poor quality streams if your in a poor area but there are much higher quality ones for the good areas :yahoo:

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