How to…….upgrade the stereo in mk.4 Golfs/Boras
And just why would you want to change the OEM fans idea of perfection?
The first reason is the low output power,the stock four channel Gamma or two channel Beta only manage an embarrassing 7 watts RMS/channel,play any piece of music with any real bass in it and they just don’t have enough headroom to hold it all together,most people don’t know that you can do more damage to a speaker by underpowering it than by overpowering it.A small amp driven into severe clipping (where the sound turns fuzzy and distorted) can harm a speaker in a matter of seconds,the fragile tweeter will go first (the voice coil will melt,so it just won’t work),followed shortly afterwards by the mid that will probably survive the torture,but will always sound distorted afterwards.I’ve heard this happen to many more speakers driven by low powered OEM head units than I ever have with ones where a higher powered (25 watts RMS/channel or more) aftermarket unit has been fitted.
Another one (or at least in my opinion) is that you have a unit based around a music storage and playback format that was first used in the late 1960s.Although Compact Cassette was very good in its day,sadly that day has long since said goodbye to us,as have all that use analogue recording techniques,and finally the tape deck in these radios really is truly awful.
THIS thread just about covers everything I can say about the reasons on the grounds of sound quality (or lack of it) to change the stereo in these cars.Another point to add to this is that these units have some fancy EQ (equalizer) curves built into them that are designed to work with the OEM speakers to try and compensate for their lack of output power (bass too bassy,mid too middy etc),and changing them for aftermarket component speakers while keeping the stock radio can lead to a reduction in sound quality.Any aftermarket source unit will have a much flatter frequency response that will work a lot better when you upgrade the speakers.
There a few steps you can take to improve the sound of the stock units that are detailed below.
ADDING AN AMPLIFIER TO A STOCK RADIO
It is possible to increase the output power of these units by adding an external amplifier,luckily we have been given a pre-amp level output that can be found in the mini ISO connector at the back of the radio,top row and the end nearest the middle.We can use a connector as shown below (Autoleads PC3-11) to give us front and rear outputs as labelled,the blue wire is for the remote switching of our amp(s).
We can use this in a number of different ways,we could use a four channel amp to drive all the speakers and nothing else,or we could amp just the fronts and a sub,or just a sub.
If you are amping the speakers up,it’s not worth running new wires all the way to the speakers,and as the standard speaker wiring is of more than adequate thickness then you can make the connections from the amp at the back of the radio in the ISO loom.
The male speaker ISO block is shown below,the easiest and least permanent way to connect to it is with a female ISO,if you don’t have one and don’t want to cut it off then you can splice into the wires just above the connector.
If the ISO block has been cut off already,you will need to refer to the following to know what the different coloured wires connect to.
|
VW wiring colour |
Speaker wiring |
Standard ISO wire colours |
|
Blue |
Rear right +ve |
Purple |
|
Brown/blue |
Rear right –ve |
Purple/black |
|
Red |
Front right +ve |
Grey |
|
Brown/red |
Front right -ve |
Grey/black |
|
Blue/white |
Front left +ve |
White |
|
Brown/white |
Front left -ve |
White/black |
|
Red/green |
Rear left +ve |
Green |
|
Brown/green |
Rear left -ve |
Green/black |
If the power ISO has also been cut off,the following will be needed,but please note that this is only applicable to Golfs & Boras,other VAG cars are slightly different.
|
VW wiring colour |
Function |
Standard ISO wire colours |
|
Red/white #1 |
Permanent live |
Yellow |
|
Red/white #2 |
Permanent live |
Yellow |
|
Brown |
Ground or earth |
Black |
|
Grey/blue |
Illumination |
Orange |
|
Yellow/red |
Ignition/accessory switched live |
Red |
|
Grey/white |
K line diagnostic-DO NOT CONNECT |
|
|
Blue/white |
Speed pulse for GALA function |
|
Don’t worry if you get the pos and neg wires of the different speakers mixed up,it won’t damage anything,but you will lose bass as the speakers will now be out of phase,a quick test would be to balance and fade around the car and if you get the bass come back as you do this,then you’ll have to start swapping wires over to find out which ones are round the wrong way.
Connecting external sound sources,i.e. MP3 players.
The most popular addition to these units has to be that of a portable MP3 player,in particular the iconic Apple i-Pod.As there is no direct auxiliary input as such for external devices,then we have to look to other methods to achieve this.
- FM modulator………………..(i-Trip etc) The audio signal from the player is taken to a low powered radio transmitter that has several preset frequencies at the lower end of the FM radio broadcast band,typically 87Mhz to about 89Mhz that we tune our radio to.The downside to this is very poor sound quality compared to any other method,as it will only ever be as good as the tuner section of our radio,and and will almost always (in about 90% of cases) be accompanied by unwanted noise that originates from the engine such as alternator whine or ignition noise from a petrol engine.At best we can only ever expect the sound quality to be on par with that of an average tape deck.
- If a CD changer is fitted……………..You can use the audio input wires from the changer as shown below,pin #19 and #20 in the blue connector will give you audio of a quality comparable to that of CD,the limitation being the quality that comes down the earphone cable.Please note that a CD changer must be plugged in for this to work,othwerwise the head unit won’t let you select CD if it can’t establish two way communication with an outboard source.
You’ll need to cut the wires so that the CD audio isn’t passed to the radio,and of course you need to have a CD playing all the time you want to listen to your MP3 player.
Audio ground should go to pin #18,but expect the possibility of noise that may need some playing about with earths to get rid of.If you wanted to be adventurous,then you could arrange a changeover switch to re-enable use of the CD if and when needed.
- Aftermarket auxiliary input adaptor………..These work by making the radio “think” that it has a CD changer fitted when there actually isn’t one,all you have to do is plug your MP3 player into it,plug it into the CD port on your Gamma or Beta radio,and finally select CD and listen.
There are different options available whether you have a CD changer fitted or not,and are available from such companies as Dension,Soundlinx and Connects2 amongst others.
- Aux input and control……….As above in part but they treat the i-Pod as a CD changer,meaning it can be remotely mounted out of sight such as in the glovebox,full control is available over track selection without touching the player but with very limited track information being shown on the radios display.
The downside to any of these methods is that unless you are very lucky you will get unwanted noise added to the music,normally in the form of clearly audible alternator whine.
There is no one particular reason why we get this noise that is somewhat random in nature,take two apparently identical cars and one will have it and the other one won’t,or two identical units in the same car where one will have the noise and the other one won’t.
It is sometimes possible to cure this noise by messing about with different earths,sometimes it is caused by not having an earth it needs,and sometimes by having an earth it doesn’t need,this is mostly down to very poor quality control at the manufacturing stage,and doesn’t have one easy cure-all that always works.
Ground loop isolators can actually make it worse in some cases,and they also remove most of the bass which won’t be a problem if you’re using a subwoofer as well,and surpressors also don’t normally work as the noise doesn’t come in down the power wire,but either down the earth or ground connection or it can even be airborn.
A lot of this is also down to incompatibility between different makes of equipment,such as different signal levels and poorly matched input and output impedances,the only way to guarantee that this will not happen is to either make sure that all the various parts come from the same manufacturer,or buy an aftermarket unit that has everything all in one neat box.
You will never be able to overcome all of the problems with stock radios as outlined above,the only way around them is with a change to an aftermarket unit.
INSTALLING AN AFTERMARKET HEADUNIT
The single biggest fallacy of the OEM radios is their very low output power,all we need to do to release the potential of the OEM speakers which are surprisingly good is install a higher powered headunit with the now almost standard single CD/RDS tuner,peak power figures of around about 4 X 50 watts which are still good for about 4 X 25 watts RMS will make the biggest single improvement in sound quality for the least amount of money spent that we will hear in our cars,and all in the space of the ten minutes or so that takes to swap radios over.
Anything from any of the known manufacturers such as Pioneer,Kenwood,Alpine,Sony,JVC,Panasonic etc will always be a guarantee of quality and reliability,avoid any brands you haven’t heard of being sold cheaply on e-bay,if it seems too good to be true as it has a lot more features than other more expensive units,then it almost certainly is,with this cheap gear it’s not a case of if it goes wrong,but when,sometimes within a few hours.
Also if you want to be covered by all the proper consumers statutory rights,always buy from a recognised UK based retailer,and not from someone who’s shop only exists in cyber space,it may well cost you a little bit more money in the first place,but it really is false economy to do it any other way.These traders are NOT normally authorised dealers,and as such you will not be covered by the manufacturers Uk warranty,so if your equipment goes wrong,you may find yourself needing to pay for the repairs.
- WHAT FEATURES SHOULD I LOOK FOR?
It really depends on what you want it for,or what your primary format or sound source will be.
i-Pod COMPATIBILTY
For as little as £50 for a brand new 2008 model you can get a front mounted auxiliary input socket that you can plug any external audio source into such as i-Pods or any other portable MP3 players WITHOUT the noise problems associated with the adaptors that can be plugged into OEM radios.
If i-Pod will be your main source,then it would be a better idea to get a dedicated unit that will give full high speed control of the external player as well as charging it,meaning it can be hidden away in the armrest or glovebox and controlled entirely from the headunit in the same way a CD changer would be.
USB
Even better would be one with front or rear mount USB (Universal Serial Bus) socket that will let you plug ANY MP3 player into and be controlled by it (not just i-Pod),and also any of the ever expanding variety of Flash drives or memory cards (with the appropriate reader of course).Solid state memory such as this is so cheap now that is almost disposable,2Gb Flash drives are now as cheap as £7.99 that can take 500 songs,and still at good(ish) quality.
N.B. USB is available in two different standards,G1 which will only work with solid state memory such as Flash drives,memory cards and small MP3 players such as i-Pod Nano (but not with Hard Disc Drives),and G2 which will work with everything including HDDs and full sized i-Pods,so read the specs and make sure you get the one that is appropriate for your needs.
RCA OUTPUTS
Taken from the initials of the “Radio Corporation of America” and also known as phono leads,but no matter what you call them they are unfortunately the worst possible way of getting a low level audio signal from a source unit to an external amplifier,but as they have now become a world wide standard then sadly there is nothing we can do about it.
To be able to upgrade our system we need at least one RCA output,although we are able to split this into two or more to drive multiple amplifiers,we won’t have the ability to fade front to rear,but will have to rely on whatever we preset the gains on the amp(s) to.
To get the best from any fully amplified system,we could do with at least two RCAs to give us front/rear fade or front and sub with fade,or even better would be front and rear AND sub with non fading to the sub output,that way we can have full control over everything from the front of the car.
DSP/CROSSOVERS
Not really essential,but a very useful feature to be able to give your system that final tweek from the comfort of the drivers or passengers seat.
High Pass Filters (or HPF) if you also have a subwoofer in the car,these cut the bass off to the full range or component speakers,meaning they will play louder with less distortion,possibly with variable crossover points from about 80Hz upwards.
Low Pass Filter (or LPF) to cut off the midrange and upwards to drive a subwoofer,again variable would be nice up to about 100Hz.
A graphic equalizer to be able to compensate for acoustic anomalies in the cars interior,even the very best component speakers will always benefit from a touch of subtle EQ,and if you want to be really posh time alignment to compensate for differing speaker positions.
One thing I don’t think is needed,and one the doesn’t actually improve the sound is the soundfield simulations such as club,stadium,church etc,NO NEEEEDDDDDD!!!!!!!
BLUETOOTH
If you have any portable Bluetooth devices,then you can connect them to any compatible headunits with this feature built in.Your mobile phone will automatically route all incoming and outgoing calls through the cars speakers and display all the information from the phone on the radios display without the need for any external hands free car kits,and if it also supports streaming audio it can play full quality music from your mobile phone through the cars speakers.
DIGITAL RADIO
DAB (Digital Audio Broadcasting) has been set to be the biggest ever change in the history of radio,but it is all a bit indefinite at the moment,it may or may not happen as planned.It won’t be long before we get satellite radio like the Syrius and XM services they have in America (or at least that’s the plan),but at the moment nothing is carved in stone,so don’t buy any equipment based purely on digital radio,as it could all be obsolete in a few years time.
Of course the first thing to do is to remove the OEM radio,don’t try the old trick of cutting up a credit card as all that will happen is you’ll have bits of plastic stuck in the slots,and a radio stuck in the dashboard,instead buy the proper VAG radio removal tools,such as Autoleads PC5-133 from Halfords (Other shops are available).
Pull the old radio out and disconnect all the wiring from the ISO and aerial sockets on the back,where you should see something like this.
The connector on the left is for the speakers as discussed a bit further up,the right hand one is for power and a few other functions such as speed pulse.If we want to connect any standard ISO equipped radio directly to this the easiest way is to buy a plug and play adaptor such as the Autoleads PC2-69-4,if not then we have to do a few wiring modifications first.
The new ISO loom will come with plain red and a plain yellow wire with inline male and female bullet connectors already in place,we have to swap these over so that yellow now goes to red,and red will now go to yellow.If we don’t do this then the unit will still switch on and work ok,but when we switch off then it will lose everything stored in its memory and return to its default settings when we switch on again.
Make sure you don’t have anything connected to the grey/white wire to the right of it,if you do you may find that important functions such as central locking and electric windows no longer work.
There will also be a blue or blue/white wire in the new ISO block connected to the red/white wire shown with the yellow arrow,this is the remote switching wire for electric aerials or amplifiers,if we don’t isolate these two so that they aren’t connected to each other,then there will be a backfeed that could flatten your cars battery,although it will appear that it has switched off,it won’t have done so fully although the display won’t be lit up.The best way to do this is cut the blue or blue/white wire in the new ISO loom,put a female insulated bullet crimp onto the headunit end,and insulate the end that goes to the cars loom.
If you want to listen to the radio,you will also need an Autoleads PC5-90 or equivalent adaptor.Contrary to popular belief this is NOT a booster amplifier,it is a phantom power supply that sends power up the aerials coax cable to the matching amplifier built into the base of the aerial,again this also is not a booster but actually makes the radio “think” that the aerial is lot longer for MW reception (ideally it needs to be about 1.5km long for this).This is built into all the OEM radios,and is only needed on aftermarket radios if you want to listen to MW,or not all if you don’t mind no reception at all on MW,or slight loss on FM where it won’t be noticed if you only ever listen to strong local stations.
You will need to connect the blue flying lead to the blue or blue/white wire as outlined in the last step.
That’s about if for now,you will have your new head unit in and working at last,the next step will be to change the speakers for better ones,and also to add an amp(s) and even maybe a sub.That guide will be along as soon as I’ve written it,so watch this space.
Chris.