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Audio Upgrades


How do i upgrade my car audio system?

Every standard factory audio system I have ever heard suffers from the same thing. Lack of clarity! You need a Car Audio sound upgrade.

Once you sit in a properly set up sound challenge vehicle and experienced the clarity and staging where if you shut your eyes, you think the sound stage is right in front of you and outside the front of the car with rich bass sounds and not or rattle from a panel. You won’t want anything else in a car Hi-Fi system.

This is easily achievable in your car.

How much does it cost to upgrade car audio?

The car salesman will tell you the branded twenty speaker setup in your car is the best but I can assure you we have built sound systems consisting of no more than a pair of front door mids with tweeters in the A-pillars and a sub in the back driven from a good quality amplifier and it would blow the doors of any new showroom car. The ridiculous factory price looks even worse when compared to good aftermarket products. You can start your sound upgrade from below one hundred pounds and the sky is the limit on top end Hi-Fi sounds. Fitting Options.

The problem with standard sound systems.

The main problem with factory radios is the output is coloured to suit the crappy speakers and there is usually an artificial hump in the lower frequencies. There are two ways to fix this, either dump the factory unit in favour of an Alpine aftermarket one or if this is not possible use a “Bit” product to de-equalise the output so you are starting with clean signals.

Good Vibrations.

The next essential is to kill the resonances and rattles in the vehicles body panels with sound deadening material. Once you have dampened the car and made a clean signal you can begin upgrading the sounds.

From there you simply decide on how far you want to go. We can upgrade with a budget from a few hundred pounds to thousands.

Bit Tune.

We love to use Audison Prima products because of their unique ability to integrate with factory equipment and their amplifiers with inbuilt computerised signal processors make setting the system up using the bit play computerised hardware (a big financial investment for us) a breeze.

When the computer is checking speaker phase and time alignment correction as well as optimising the frequency response and amplitude to each active speaker you just can’t go wrong and the results are always fantastic. I love watching a customer’s face when they play their new system for the first time.

Not many specialist dealers have made the investment in the Bit Tune system, we find it invaluable.

If you would like to talk to us about an upgrade for your car give us a call on 01368 860800 or if you would like a written quote click here…

CarAudioStuff showroom

So, you’re unhappy with the sounds in your car, where do we go from here?

How far do you want to go?

An inexpensive speaker upgrade is where you could start; however, I am assuming the desire is for a full audiophile upgrade, so this is everything you need to know. You can do as little or as much as you wish, the following will help you decide.

There are some fundamental “must have” essential thing that is common to all audio systems (more on this later) but we should start with “what is the vehicle”?

Why? Because many cars already have so-called manufacturers upgraded sound systems and it is important to understand a few things about these.

The average car salesman really believes that dozens of speakers all over the car from a brand name like Bose/Sony/Burmester/Harman Kardon etc. must be good, and certainly, they may be an upgrade to the standard junk that’s fitted to these cars but “Quality sound”, they are not.

Why not? Because the brand name is just a badge on the speaker grill to give credibility. The product is still manufactured down to price for the mass market and to make a profit on the car, not give the best sound results. Not to say the brands are rubbish or that they can’t produce quality products.

For example, let’s take Bose. Have you ever walked into a public place like a cafe or shop and being the kind of person that can appreciate good sound, thought to yourself, yes that sounds good?

So, have a look around and see what is happening. Lots of small cubes boxed speakers up high and pointing directly at you (on axis). Making for a very dynamic sound in the vocal range (No highs and no Lows) it must be Bose! Great products, great headphones.

All this is fine for noisy coffee shops but no good for cars. Speakers on the axis are important for efficiency (I’ll explain why later) but difficult to achieve in a vehicle. One solution that Audison have is to time-alignment which adjust the timings when each speaker sound reaches your ears. A feature best left to a specialist for setting up.

So, the car makers have fitted all this cheap plastic, paper cone speakers, how can they make them sound better?

What they do is play around with the signal coming out of the radio head unit. An artificial hump at a certain frequency will make a more bass sound through the speakers; then they attempt to make it have a loudness control which changes everything with variations in volume and road speed.

All this messing around makes any added quality components like amplifiers and speakers impossible to control properly. So, ripping out the factory head unit in favor of a decent Alpine, Pioneer or other aftermarket radio would be the preferred option but not always possible, so what’s the answer?

Thankfully a forward-looking Italian company has invested in technology to overcome the shortcomings of the standard factory equipment.

If it is not possible to carry out the preferred option of a replacement head unit (before you decide it’s impossible, check out the amazing range of fitting adapter kits that are now available), You need to de-equalise and flatted out the signal coming from the factory radio. How?

Using one of the Audison Bit products to modify the factory output signal is the first stage in creating an amazing sound system for your vehicle.

Here are a couple of unusual options if you decide to change the head unit:

  1. Alpine Halo9 – This unit gives you a fully featured nine-inch screen on a single din aperture.
  2. Retrosound San Diego – Yes this may be the only Classic XJ6 show car in the UK with a full Audison Prima Bit Tuned “stealth installation” with eight speakers.

Having decided whether to keep or change the head unit for one with more features like Car-play etc. or even to miss out altogether and go straight to the next stage, you are now ready to start the process of improving the sound quality in your car. What’s next?

Speakers, subs and amps come next but what decisions do you need to make before you start?

I said at the beginning of this article that there were some fundamental “must have” essentials

The first and most important thing to consider before you go on is “Volts”!

Not something to bother you if you have a simple speaker upgrade but any serious sound system will consume a lot of current, and the power supply should be planned before anything else.

Voltage, Current, Resistance and Capacitance will be explained fully later, and when you understand a bit about the importance of ohms law, it should all fall into place but for now, trust me the power supply is a crucial part of any sound system upgrade.

Before we go on to speakers, you have a decision to make.

What type of music are you into? The answer to this question will govern the speaker choice. There are three considerations.

  1. Budget – How much of your overall budget should be spent on speakers?

Your budget should be divided equally between, speakers (inc subs), amplifiers & installation parts. These components are like a chain, each only as strong as the individual links.

A mega expensive set of Hi-Fi car speakers driven by a cheap low output amplifier will distort and damage the speakers with clipped, distorted square wave output from the amp.

Cheap speakers overdriven by a powerful amplifier will distort and destroy themselves in no time.

Good quality speakers and well-matched amplifiers powered by poor cheap wiring will distort and may cause a fire if not fused properly. Each link of the chain has the same importance in the budget.

  1. SQL or SPL? – Are you looking for Sound quality (SQL) or has it just to be the loudest on the block (SPL) Sound Pressure Level?

A good Sound Quality Level upgrade is what we do best. I love to see the customers face at handover. We play a demo track, and with eyes closed from the driver’s seat (optimum position) you can imagine the individual musical instruments right in front of you with right and left sound stages appearing to be way outside of the vehicle and on a strong transient when the bass comes in, wow! You are simply blown away. All of this is no happy accident. We have set up the system with Bit tune hardware and software to get this effect.

Using Audison signal processing, we first de-equalise the car, and the final setup entails the use of an omnidirectional saucer-shaped microphone array which gets strapped to the driver’s headrest.

The computer is connected to the Bit tune hardware and after speaker phase checking the system automatically injects a sweep signal through each speaker in sequence until the final file is saved to a memory stick so it can quickly be installed if needed.

The actual speakers used here, of course, depends on the individual vehicle speaker dimensions. We always try to use Audison Prima components (Speakers/subs/ amps & cables) which are so well matched and efficient that there is usually little need to upgrade the vehicle power supply.

SPL is a completely different ball game and to get this right; you should be prepared to double your budget or even more. High power speakers and especially subwoofers are big, heavy and expensive; they need to be, to deliver the insane amounts of power the whole installation needs to be beefed up with lots of sound deadening and extra batteries or mains power supply systems and large capacitors.

SPL builds and some SQL ones usually also need lots of fabrication work. Special tweeters on A-pillar fabrication, Door panel built out for oversize speakers, and sub-woofer box boot builds are the norm.

We recommend Hertz subs and speakers for SPL builds

  1. Pro fit or DIY? If you are looking to fit your own, then easy fit or Plug & Play might be for you.

1 & 2 above explain options that the professionals will do. Although there is nothing stopping anyone handy with fabrication and wiring doing the same, although proper setup may be difficult if not impossible in the case of the bit tune equipment (unless they have a spare £3k and the will to learn to drive it ?

The installation of good quality sound upgrade components can now be made easier with a dedicated vehicle specific plug and play kits. The speakers drop in, and the wiring exactly matches the factory kit, exactly what the DIY market needs. Especially if you are not close to a specialist installer like one of the Four Master dealers in the UK.


So, we know the choice of speakers is dependent on what you expect from them but what other factors are important when choosing speakers? Obviously, they need to be the right size to fit the car but is it simply bigger the better or are there other things to consider?

A speaker is simply a coil of copper wire wrapped around a tube over an iron core attached to a magnet and a diaphragm or cone fixed to the tube supported by a stiff basket. The edges of the cone have a soft, flexible suspension between the cone and basket and when modulated electrical current is applied to the coil the cone moves in sympathy to the modulations. So why do all speakers not sound the same?

All the individual components, voice coil, magnet, cone, suspension, and the basket can be different grades of material thus making a vast difference in sound quality and power handling.

Companies like Elettromedia (Italy) spend millions developing products inside expensive anechoic chambers that produce the purest of fidelity and some factory in China can mass produce cheap lookalike products, but they are no comparison when it comes to sound quality.

So, buy the best you can afford.

Should you have lots of speakers in your car, does size matter?

The size of the cone governs the frequency range the speaker can achieve. A small 10cm cone can not produce a deep bass sound, and a 15-inch cone isn’t good at very high frequencies, so you need a mix of all in your vehicle to cover the full range.

The question is, how many? The optimal would be a pair of six or eight inches in the front doors (space permitting) with tweeters mounted as high as possible (A-pillars) and a single or double sub-woofer either in the boot or under the seats if boot space is not available.

Rear door infill speakers may be added but not essential. That’s it, stop, no more speakers. You gain nothing from filling every space with a speaker and trying to acoustically setup multiple cones is a nightmare. New car manufacturers need to learn this lesson.

The only case when multiple speakers is better than a single is with Sub-Woofers. A single giant cone may move a lot of air, but because the piston effect of the centre of the cone is moving faster than the outside of the cone, distortion may ensue. Four eight-inch sub drivers move more air than a single 15” and will be much punchier; they might not get down to that church organ bottom note but not too many people listen to that stuff anyway.

As with everything, sound in a car is a compromise, and if you can’t afford the space or the finances to a full system, there are other options.

Full range speakers with a tweeter build inside the main cone are called coaxial speakers. They are less expensive and if mounted as near to on-axis as possible can be quite effective. They are generally more efficient and don’t always need an extra amplifier so are budget friendly.

What does on-axis actually mean?

If I were to shine a torchlight directly into your eyes you would squint and find it uncomfortable, If I move the torch a couple of degrees, either way, the light would appear to dim, and you could now stare directly at it.

Speakers on or off-axis have the same effect sonically to your ears. You will be able to appreciate more of the music if they are on-axis.

Most cars have the speakers pointing at the side of your leg, so angling them up if possible (usually by fabrication) or using separate component speakers well positioned is the answer.

In conclusion (about speakers) you should now be better placed to decide as to what kind of speakers to go for in your sound upgrade although I should mention a couple of special types just in case you fall into this category.

99% of car speakers show a 4-ohm load to the amplifiers. However, there are exceptions. Specialist Sub-Woofers at 2-ohms are available so they can be wired in series to have more cone area for a 4-ohm load or the amp may be bridged to drive 2 ohms. What’s the difference?

2 x 2ohm driven at 4ohm will be quieter that being driven at 2ohms but the later will have more distortion. Some of the SPL boys don’t care about distortion, so the louder, the better for them.

The other special type of car speaker is DVC (Dual Voice Coil). A DVC sub can be driven from a stereo amplifier. We also supply lots of DVC speakers to Classic car owners so that the single center dash speaker in their vintage vehicles can be driven by both right and left channels of their stereo radio.


What is an amplifier and why do I need one?

The amp sits between the head unit and the speakers and basically provides all the power for the system. You don’t need an amplifier if you are simply upgrading the speakers in your car as long as you match the new speaker’s power handling to the power output of the head unit.

Better quality speakers generally need an amp, and Sub Woofers certainly do.

Which Amp, how do you decide?

Since all the parts that make up the cars sound system are like a chain (only as strong as the weakest link) you need to decide on which amplifier at the same time as the speakers and also the wiring grade.

To put it another way. In a plumbing scenario, if the loft tank was the car’s battery, water pipes the wiring and a Tap or valve was the amplifier. If you had a huge tap or valve fed from drinking straw sized pipes, how much water would you expect to flow out?

If you had big pipes and big tap but small sink (speakers) you would soon overflow the water and very quickly empty the tank. So, if you want a big powerful system, it makes sense to up-size all the parts.

This all may be starting to sound like you need to spend thousands to get a good result, which may be true if you are building competition or show car, however, if you follow the basic rules, you can have a great sound upgrade at a modest cost.

Audison Prima range of amplifiers and speakers are perfectly matched to each other and with the signal processing Bit technology built into some Prima amps you can achieve remarkable results. With the addition of decent wiring kits and signal phono cables along with some Skinz sound deadening you can transform your car sounds for a reasonable budget.

What should I be looking for in a good car amplifier?


Output Power is measured in watts, and some amp vendors have been known to exaggerate.

If it’s printed on the box it must be true, how can they get away with telling lies with all the modern laws and consumer safeguards?  I could tell you that an Isetta bubble car can reach 100 mph and that would be true if I throw it over a cliff.

As a car amplifier manufacturer, I might be able to measure 1000 watts for a split second at 15.5 volts with 90% total harmonic distortion and could repeat this test to a trading standards officer, so my product gets to boast 1000 Watts boldly on the box. Rubbish!

Don’t get fooled. I have heard 20-watt amps sounding much better and louder than some cheap so-called 500-watt amps. The important number you should be looking at is THD (Total Harmonic Distortion) this should be as low as possible.


How fast is your amplifier is not a term you hear every day. I am referring to the ability of the amp to waken from its slumber when a big transient signal comes along. Imagine you are at a concert, and you are sitting close to the band or orchestra, you get a start when the big bass drum strikes up or something similar. You can rarely get the same dynamic hair standing to feel in a car, why?

To get the same effect in a car would take a ton of power delivered very quickly to enough speaker cones that only the finest demo show cars can normally achieve. You can get close with a good fast amp and a Power stiffening Capacitor.

Frequency response.

Once again the cheapo amp suppliers will Bragg frequency responses of DC to light, please avoid.

A full range amplifier will attempt to cover the full audio spectrum, and a look at the figures might imply that the amp is capable of going much higher than the human hearing range. Although you can’t hear these frequencies, a good amps ability to hit them means you will appreciate the difference because of harmonics, trust me.

Next is inputs and outputs.

Multi-channel amps as the name suggests will power many speakers. At one end will be all the speaker connections and the other the signal inputs. The inputs can be low-level signal or high-level speaker inputs so you can simply connect your head unit speaker outputs straight to the amp inputs.

A high level may be more convenient, but any distortion in the radio head unit will be transferred to the amp. Low-level signal (if available on your head unit) will be taken after the pre-amp stage and before the main unit’s amp so the better choice for better fidelity.

A low-level signal will need to be well screened from spurious (RF) radio frequency signal interference, and so the best RCA (Radio Corporation of America – the inventor) phone leads that you can afford should be used.

There may also be the various adjustments available on the input side, like frequency filters tec.

Mono amplifiers are usually less sophisticated than full range since all they have to do is thump bass through a sub, but they always require a much bigger power supply meaning power and earth cables.

Why not get rid of all this extra wiring and bulk by putting the amps directly on the speakers because it doesn’t work. That is what Bose and some of the branded factory systems do. Yuk!

Oh and yes we also can do Plug and play amps for certain applications, Ask us!

So, you have chosen your amplifiers to match the speakers, and now you are ready to install.

First things first.

A car is a hostile environment for audio sounds, there is too much glass, and nearly every single body panel rings like a bell. There is not much to be done with the glass but using Skins sound deadening material, you can make a vast improvement in killing all other resonances in the bodywork.

Even just doing this and nothing else will improve the sonic properties of the car, and your stock factory system will be improved.


Don’t spoil the ship for a ha’porth of tar. Good quality wiring may look expensive, and you may be tempted to cut corners here. Don’t!

OFC (Oxygen Free Copper) is a great conductor and shows the least electrical resistance to the audio signals. High-density coax and gold plated plugs are good for keeping the noise out too.

So, there you have it. In all the years that my company has been building car audio upgrade systems, we have used those same principals.

  • Kill the vehicles body resonances as much as possible.
  • Try to swap out the head unit if the budget
  • Use a bit product to modify factory head unit output (if not swapping it)
  • Respect the battery and upgrade if necessary.
  • Sympathetically choose speakers and amplifiers to suit.
  • Use the very best wiring kits and signal cables at all times.

Every install is different, and after you have done all the hard graft, and you switch it on for the first time, the initial reaction might not always be great. There can often be a period of tweaking the amps and filters etc.

We recently did a stealth install (a stealth install is where all the speakers and amps are hidden or in original positions) in our Classic demonstrator car, a Jaguar XJ6. My expectations for this car was not great. The thirty-five-year-old front door speakers were too low down, and I wondered how good a modern but classic looking radio was going to be a source for all the signals I had planned.

The Retrosound San Diego has a front and rear low level and a dedicated sub out. It plays full-fat flak music files and has an inbuilt equaliser, and it turned out to be a gem of a head unit.

The front and rear door speakers were replaced with Audison coaxial drivers since there is no room for tweeters on the ancient thin A-pillars (and I didn’t want to modify it). Eight-inch full range Audison speakers housed in hand made boxes under the front seats, and a couple of ten-inch subs in boxes fitted in the boot facing the back seats.

We drove the subs with a Hertz Mono-block amp and used the AP8.9bit multi-channel DSP (Digital Signal Processor) Amplifier to drive all the other speakers.

Needless to say, we wired it all up with the best stuff and killed all the body resonances (and there were many on this old girl) but when I first switched it on it sounded dreadful.

With such sophisticated equipment, you always have the potential to make an awful sound, however, once we hooked up the “Bit-Play.” and let the automatic EQ, and time alignment do its magic, the difference was staggering.

All of a sudden the low down tinny sound was transformed, and when I close my eyes the sound stage is right in front of me. How it did that is staggering, given the speaker position restrictions.

To believe this car, you have to hear it. ?



Earlier we hinted we would discuss the relationship between Voltage, Current, Resistance and Capacitance.

I could just point you at this Ohms Law calculator ,and explain that Ohms law is a three part equation where, I (current), V (voltage) & R (resistance) all have an effect on each other, and you would be none the wiser..  

Let me try to explain a different way.

Voltage (V)

The car battery is made up of galvanic cells. A single cell which is made of two or more dissimilar plates in a dielectric solution produces a potential difference (voltage) of 2.1 volts.

If the plates are small or large they will still only produce 2.1 volts but the bigger ones will deliver more current for a longer period of time. Ampere-hours (A-h), is a unit related to the energy storage capacity of the battery.   

So, six cells are needed in a 12 volt battery and it basically provides all the power for your car audio sound system.

Current (I)

The symbol for current is I, which originates from the French phrase intensité du courant, (current intensity).  Current is the flow of electricity in a circuit and a circuit is made when you switch something on in the car and current flows from the battery through whatever it was you turned on then back to the negative side of the battery through the vehicle earth or chassis.

Resistance (R)

When you switch something on in the car, it will show a resistance to the circuit, Interior lights will be a fairly high resistance and draw a little current. The headlights will be a lower resistance and draw more current.

When you crank the starter about 500 amps will be required from the battery and the starter motor resistance is almost like a short circuit which is why it will flatten a battery very quickly.

This I why a standard factory car radio will happily play in a car with the engine off for quite a while but a proper sound upgrade with multiple speakers, subs and amplifiers will last only minutes without the engine running and the alternator pushing current back into the battery.

Unwanted resistance is the enemy of sound upgrade systems which is why only the best cable with the lowest resistance should be used.


The book says: Electrical impedance, the ratio of the voltage phasor to the electric current phasor, a measure of the opposition to time-varying electric current in an electric circuit.

What does that mean?

In relation to car speakers impedance is usually 4 ohm and means this is the average resistance shown to the amplifier when audio signals are flowing through it. Unlike straight resistance which can be measured with a multi meter, you would need an oscilloscope to measure true impedance of a speaker.

Why does this matter?

most power amplifiers are designed to work into a 4 ohm load so one 4 ohm speaker hanging off each output channel is best, but what if you want to run more speakers off one channel?

You could wire two speakers to one channel in two ways (one correct and one not).

Resistors in series multiply resistors in parallel divide. So if you wire two 4 ohm speakers with the + on one going to the – on the other and connecting the amp to the – on one and the + on the other (Series) you get 8 ohms which will result in a quieter output but less strain on the amp so (Good)

If you connect the amp to the + and – on one speaker and then link the positives and negatives together  (Parallel) you will get 2 ohms which will result in a louder but more distorted output at the amp (Bad)


Once you have wired up all your speakers and made sure all the positive terminals on the amplifier match the speaker’s connections you should have everything in phase which means all the voice coils in the speakers are pushing out the cones in unison.

One speaker out of phase will cancel some of the output and make the sound thin. This is a very important part of any installation and the first thing the Bit Tune equipment does is a phase test.

You would be surprised how many times a piece of equipment is manufactured out of phase. Its worth testing first.

Capacitance (Farad)

Capacitance has many properties; I will explain one method for the purpose of explaining Power Caps in sound upgrade applications.

Much like a battery a Power Capacitor has two plates separated by a dielectric. The plates take the form of very long thin strips of flexible flat tinfoil like material wound over each other in a tube with positive and negative connectors at one end.

Like a battery, a cap holds a charge to maintain a steady voltage which can be delivered much faster that a lead acid battery can.

Because of Ohms law the resistance that the power amplifier shows to the circuit can change very quickly when a very strong fast note in the music comes along like a drum beat (attack).

When this happens the voltage drops because the current went up (it had to because the resistance dropped) and the amplifier drops its volume for a split second until the attack has passed. To the ear this can sound like distortion or a softening of the music.

If you bolt a power cap close to the amplifiers positive terminal when the transient (attack) comes along the capacitor reacts faster than the power supply (battery) and provides the voltage to keep the fidelity of the sound output.


Ray Smith from memory wrote this article and the contents are accurate to the best of his knowledge. After over fifty years in the car auto electrical and car audio industry he may forget what he had for dinner but all this stuff in ingrained and learnt by study and experience. He hopes you enjoyed it.

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