Head Unit

Head units

Like your music? Whether you store your music on CD’s, mp3, iPod, phone or any other form, if you want to have full control and to play your music in your car the way you like, you need a stereo. This is a great way of improving the detail and clarity from your music so you will have a higher quality of bass, midrange and high end when compared to your factory fitted stereo. It should be noted however that headunits do come with a amplifier built in which although is able to send a cleaner signal to your speakers when compared to the factory one if you are after a loud sound you will need an external amplifier. However head units come in a variety of forms and as a result there is a large range in functions but all aim to make your music sound as good as possible which is why, you NEED a head unit. Due to the vast range of features and options that head units have, it can be a daunting task to find your ideal head unit, I know that for me personally, when first starting out I was unclear on which head unit would be best suited to my demands, however after a lot of research I have been able to find my ideal stereo solution and I hope that I can pass on the knowledge that I have found on to you! And so here comes the big question;

Are you confused at the vast choice of stereo?

Then look no further, over the next few weeks, I hope to give you all the knowledge required so that you will be able to pick your perfect stereo and as an added bonus understand why certain units would be better than others, so be sure to read on and keep checking for the next few updates on stereos!

If you remember the post on Speakers, the Head Unit is the other piece to the puzzle when you're going about ensuring that your car audio system is able to produce sound to the highest quality that you can feel that you have the artist singing live next to you!

What are head units?

Head units are also known as car stereos. They are used as a means to allow the user to have control over what is played and at what volume. Most modern head units have a built in CD player to play CD’s as well has having the ability to equalise as well.

Types of head unit

The technology used in most aftermarket head units allow for a range of features available to the end user. There are two sizes that are universal to most cars. Single din or double din radios. There are many reasons however that even though someone would have the ability to install a double din unit, they may wish to add a equaliser to their car audio system to increase the voltage being sent to the amplifiers and thus delivering a cleaner signal. I always had the intention of using an equaliser however I was able to house my equaliser somewhere that would be convenient to use as well as looking aesthetically pleasing. However do not get me wrong, the stereo systems employed in cars such as Mercedes Benz and the like are of high quality too as well as some people do not want to swap their stereo based on personal reasons as well as with some cars, it is nearly impossible, without serious modification to be able to change a head unit and for those reasons, there are alternative methods to be able to improve the sound quality which we will look at later on in this blog.

Single din head unit

Single din head units are half the size of double din. They due to their space confinement they can be used where it is not possible to install a double din. The single din units vary in price, ranging from the basic units offering a CD player all the way to the high end head units offering a greater control of equalisation (control over the different frequencies) as well has having connectivity for amplifiers. There is also the option, should you wish/your budget allow, to get single din head units with motorised screens. The benefit of this sort of setup would be to have the full functionality of a double din head unit but with half the side, and some people think the motorised mechanism looks cool!


single din head unit with a pocket in a double din area

Double din head units

These are double the size of single din units and due to their size; many units are touch screen operated. This allows for additional features such as satellite navigation as well as the ability to watch movies and videos while also including convenience features such as a reverse camera. Such as this Pioneer Double Din head unit which will automatically switch the display to the reverse camera without the need to change anything manually. There are also double din head units available without the features of a screen and are similar in function to a regular single din head unit however you may, should your car allow for a double din stereo, to have a stereo that takes up all the available space so that you are not left with a compartment underneath as shown in the picture above taken in a Vaxhaul Corsa.


double din head unit in a VW Golf

Facias

For some cars however, the standard stereo does not confirm to the standard DIN (Deutsches Institut für Normung) sizes the need for a facia comes into play. The facia will make adapt the car to be able to accept standard din sizes. These are the little things that will ensure that not only will your car audio system sound good, but will also look great! However, if you are lucky enough to not need a facia then your head unit will literally replace your old one.

Alternatives to head units

You may decide however to install an in car computer for example and as a result it is not uncommon to choose to to bypass a head unit and therefore connect the computer directly to the amplifiers. This method can result in poor sound quality at high volume levels and as a result, a signal processor can be used to not only control the equalisation but to also process the signal, such as the Rockford Fosgate 3.sixty.2
. The advantage of using this, is that the unit will increase the voltage being sent to the amplifiers and coupled with the fact that it will process the sound over many bands of equalisation, will be ‘cleaner’ and will have less distortion being sent, as playing distortion through any type of speaker will damage it.

Some people may find that a signal processor such as the Rockford Fosgate 3.sixty.2 are not within their budget, they may choose a signal line to RCA adaptor. The problem with using this adaptor is the quality of signal being sent to the amplifers, as the main goal is to send the cleanest signal to the amplifiers, which is something that the line to RCA adaptors do not do. I would personally avoid the use of an adaptor and use a line driver or a signal processor if possible.



So what do I need?

Well, after looking at what car you have (as this will define what type of head unit you require) you need to think about what features you want too. If you wish to have satellite navigation as well as to watch DVD’s etc for example, but do have space for a double din head unit, then there is the option of using a single din head unit that features a motorised screen. This will offer all of the benefits of a double din unit but in a single din unit.

I hope that this has given you an insight into all the different alternatives available to you, however if you are still undecided, do not hesistate to contact me and I will be more than happy to help you in any way that I can. Either send me a facebook message directly here or send an email to info@sound-evolution.co.uk stating you're enquiring about a stereo solution after reading this blog entry.

And now a bit on my car. For my car, I had the option to go for a double din head unit, while this would have looked better; my plan was to install a car computer. Therefore I wanted to run a separate screen and the only way was to use a single din head unit and a single din motorised screen designed specifically for in car computers so that it would be easy to use the features of the computer without the need of a mouse which would be difficult to use while driving.



Due to the nature of this area of car audio, without a doubt head units is one topic too vast in size to cover without going into much detail however I hope this has given you food with regards to choosing a stereo. In the next few weeks, look for future entries that will focus on more specific aspects of car stereos. These will go into detail regarding the type of products if you’re weather you’re looking for a new stereo, thinking of a new one or just reading for curiosity, watch this space for the next installment!

Neil Patel

Wires!

Wires and Wiring Kits
WIRES... everywhere! The boot of your car is full of them! They’re coming out from under your carpet, visible by your footwell, tangled, messy, abstract, annoying bundles of utter confusion!!! Sound familiar...? Here is how to keep them simple! Read on...

K.I.S.S

For a car audio system, the wires are one of the most crucial parts of the system (apart from the components themselves!) This is why it is important to use decent cabling in your system, but at the same time, to keep the layout as simple as possible to minimise any potential interference and should anything go wrong, it will be easier to diagnose the problem. There are many different wiring kits available on the market; the difference in price is respectful to the gauges and the quality of the cables.

If you plan to run two amplifiers or more, it is advisable to use a distribution block. This will make the wires look neat and tidy whilst giving you the option should you wish, to have some of your wires on display. Distribution blocks come in many different variations by many different manufactures and whilst some people are happy to chain the power wire from amp to amp, I personally think that the use of a distribution block is quite a nice touch and will make your installation a lot simpler and more pleasing to look at. For my car, the distribution block I chose was able to be used as for both the power and ground, and due to the location of my amplifiers, this was the most ideal solution.



What type of cabling do I need?

The power and ground wires come in different thicknesses or 'gauges' (the term coming from the American Wiring Gauge or AWG for short) The lower the gauge, the more current can flow through, so for example 0AWG wire would allow the most current through. The thicker the wire the more current that is able to flow through. For a car audio system that has several amplifiers or a very high power amplifier, you need as much current as can be delivered. This is coupled in with the fact that as electricity flows through a wire, the voltage will drop, this poses a problem, one which can be remedied by, for example carrying out 'the big three' upgrade, upgrading the alternator or using a higher gauge wire.

"Trying to power a high current amplifier using thin wire would be like trying to suck water out of a lake using a chain of McDonald’s straws."

The overall idea to use a thicker wire is to effectively reduce the resistance that the electrical current has to go against. From a number of sources, I have also found that it is recommended that wire no thinner than 12 gauge is used, due to a number of reasons, the obvious being the higher resistance as amplifiers have a rated power input, usually, but not always around 14.4v, if the voltage were to drop too much then potential damage could occur to the components as well as the rated power output of the amp being higher than the actual output. Trying to power a high current amplifier using thin wire would be like trying to suck water out of a lake using a chain of McDonald’s straws. It would be like trying to empty a huge swimming pool with a pipe the thickness of a straw, replacing the pipe with a much thicker one will allow for more efficiency and thus a greater flow.

If you buy a wiring kit, inside you will have everything you need to be able to wire up your amplifier into your car. You will have a piece of grounding wire, a positive wire as well as a fuse holder and the RCA cables required by the amplifier to deliver the signal from the head unit to the amplifier. You will also find a thin piece of wire (usually, but not always blue). This wire is what is used as the remote to turn the amplifier on and off in conjunction with the state of the head unit. It may be possible however that the head unit does not have the facility to accommodate a 12v switched signal. If this is the case it is up to you where to find another source of 12v switched power as having the amplifier on even when the engine is off will reduce the voltage of the battery and potentially, if enough current has been drawn, render the battery indefinitely useless. www.the12volt.com have a guide to the ideal gauge wire used depending on what size of length wire is required, however if you, like me have a specific wire gauge in mind, that is higher than what is recommended, from my research I would strongly recommend that it is better to go for the thicker option.

For my car, I opted to use a 4 gauge wiring kit. I felt that this would be the best option as the wire wouldn’t be too thick that it would be resulting in bulges from the carpet while also being too thin that I would encounter a serious voltage drop as my plan was to be running 2 amplifiers and I can confirm that the voltage is kept at about 13.8 volts. Should I wish to undertake ‘The Big Three’ upgrade, the voltage will be increased.

Fuses

As Steve Meade would say

"use FUSES - they are your friend and prevent Car- B-Q's"

This is true. A fuse is effectively the lowest common denominator in the circuit, therefore should the rated power exceed what the fuse is able to handle it will blow. Fuses should not blow on a regular basis, if they do, it indicates there may be a serious underlying problem and to just keep replacing fuses when the blow does not solve the problem. there are different types of fuses, the blade fuses, AGU fuses, while the more expensive ones are ANL fuses. the difference being the range of amps each type of fuse is able to handle.

Types of Kit

There are many different types of Kits to choose from, however there is a lot of talk of Stinger Wiring Accessories being one of the top brands. I came across one on a forum, a rave review about a Stinger kit that he purchased.

The Earth Wire

Earthing the amplifier is the most important part of powering the amplifier and your car audio system. It is important to keep the ground wire as short and thick as reasonably possible. As the wire is not directly connected to the battery’s negative terminal it is important not to forget that the signal will have to travel throughout the entire car till it can reach the battery negative. For this reason, being able to use the shortest ground lead possible will help reduce the chance of obtaining feedback, without the use of a ground loop isolator. The isolator is seen by some as a quick fix for the grounding problem, however if the amplifiers are grounded properly, then strictly speaking there should be no need for ground loop isolators. However it is important to not forget that although there are measures to reduce grounding issues each car varies in design and some cars even with the utmost care taken, may still encounter grounding issues.

Conclusion

"It could be like the difference between slapping an orange hard enough for a bit of juice to spray out, or squeezing the life out of that orange and drinking every last drop of sweet OJ..."

At the end of the day, no matter how much you are willing to spend on the other components such as amplifiers, subwoofers, speakers or head units, the best way to ensure that you get the most out of whatever you have installed, and are able to use them to their full potential, is if you spend the right amount on high quality wires. It could be like the difference between slapping an orange hard enough for a bit of juice to spray out, or squeezing the life out of that orange and drinking every last drop of sweet OJ...
Once again hope you have enjoyed reading this week’s blog and have found it useful and informative. Stay tuned for the next update very soon!

Neil Patel

Speakers

After the response from the power capacitor article, there have been many requests for an article on speakers and which ones are the best to have as well as how to choose the speakers for your ideal car audio system. So if you want to know the basics behind creating a car audio system so great that it almost feels as if Linkin Park are rocking out in your back seats while jay z is sitting next to you telling you about his 99 problems, then you’ll want to give this a read... just my 2 cents...

Speakers

Speakers (drivers) are a vital part of car audio systems. They take charge of reproducing the sound from electrical to audible. They work by vibrating the air around the speaker when an electrical current is passed through them. This is why it is important to choose the best speakers that your budget will allow. This will give you end impression that you would feel that you were in a live concert hall; with the artist next to you actually singing live!

Types of speaker

There are usually four types of speaker used in car audio set ups. For the low end of the sound spectrum, subwoofers and mid-bass drivers are used; the middle of the sound spectrum is taken care of by the mid-range drivers while the high end is reproduced by tweeters. There are also speakers such as 6x9’s that are able to produce a broader spectrum of sound than a standard midrange driver on its own for example and also the design of the speaker varies depending on the intended use.

Tweeters

Tweeters are used to play the high end of the sound spectrum. Due to the nature of the speaker, either an inline capacitor or a crossover is used to filter the sound out to ensure that only the frequencies that the tweeter is designed to play are sent to the tweeter. The crossover may also aid in reducing damage to the tweeter, as well as increasing efficiency of the speaker. With my car, I chose to install a separate pair of JBL GTO-18T tweeters that are running directly of the head unit. This is purely to aid my pursuit to produce a special sound in the car as opposed to just sound coming directly from the speakers.

Midrange speaker

The midrange is a vital part of a car audio system. It is in theory possible to run a car audio system solely of midrange speakers however for someone wishing to recreate sound at a high level, it is unheard of. The midrange speakers come in a variety of sizes to fit the different door panels. Unlike subwoofers for example, midrange speakers are able to run directly off the head unit however it is common to see that if the head unit is turned too high, then distortion can be heard (clipping). This is why many people choose to add an amplifier to amplify the signal sent to the midrange speakers so that at high volumes, a cleaner signal is being sent to the speakers. Again some will choose to use a crossover system to limit certain frequencies to be reproduced by the midrange speaker. There are two types of midrange speaker, component and coaxial. The difference between component and coaxial is design. With a pair of component speakers, the tweeter is separate to the main driver whereas with a coaxial speaker, the design is of an all-in-one nature. The difference is in the type of sound produced. As coaxial speakers are all in one, the sound comes from one location, however with component speakers, the tweeter is separate thus it is able to achieve a more spatial sound. Due to the benefits offered with a set of component speakers, in my car, I have chosen to use one pair of JBL component speakers to act as the ‘front speakers’ as well as a pair of JBL coaxial speakers as ‘rear speakers’ even though they both have been installed in the door. The reason for this is that my car, out of the factory only has 2 speakers, one in each door. This left me with the problem of how I was going to achieve a spatial sound. To go about this, ideally I needed to have another pair of speakers acting as the ‘rear’ speakers. This is why I had chosen to use a set of coaxial speakers for the rear speakers and a set of component speakers for the ‘front’ speakers. The idea of this would be to achieve a surround sound from the system while inside the car, and given the conditions I had to work with, I’m pretty happy with the turnout of the overall system.




Mid bass

Mid bass drivers produce frequencies between the subwoofer and the midrange speakers. Some people argue that they are not a vital part of a system while others swear by them. For some simple systems, the mid bass driver can be a vital tool if someone is aiming to achieve clarity over loudness, as again, it would be separating the sound spectrum even more to each of the components so that fidelity will be increased. For my project, I had decided against the use of mid bass drivers purely dude to space confinements of my project car.

Subwoofers

Subwoofers come in a variety of sizes usually 8, 10, 12, 15 and 18 inches. They are used to produce the low frequencies. Almost all subwoofers are amplified due to their demand for high power; however a few head units and subwoofers from pioneer are able to work together without the use of an amplifier. Some subwoofers require an enclosure, this may be a sealed or vented enclosure with some subwoofers being free-to-air, i.e. they will work without the use of an enclosure, and however these subwoofers on average require more power than a subwoofer of equivalent sound output that requires the use of an enclosure. Free-to-air subs have also been commented on by many people who say that they find that type of bass that is produced is not of the same standard or quality even though they are rated at the same power. There are also active bass boxes where the amp, subwoofer and the enclosure are all built into one unit however they, on average tend to have a lower power output than say a separate sub/amp combination. This is why many people will choose an enclosure type subwoofer. The presence of a port will adapt the type of bass produced. With a port, many people find that there is more bass produced (as the subwoofer is moving the air through a tuned port, however there is less definition in terms of the sound. With a sealed enclosure however, the bass produced can be described as more of a tighter sounding bass as the air is moved inside the box, however the use of a sealed enclosure will also put more strain on the subwoofer, due to the pressure levels built up inside of the enclosure.

While doing some research for my enclosure, I found that the size of the enclosure makes a massive difference. After choosing the Kicker L7, I had two options for my enclosure, to either use a sealed box that would be very small (the benefit would also be to save space) or if I wanted to use a ported box, then the size would be much larger and the effect of the bass would be different as greater pressure levels could be built up inside the car with a slot ported box, which is why I chose the ported box.

Power ratings

Power ratings determine what power each component is able to handle at continuous and at maximum. For example, a speaker may have a rating of 45w RMS and 135w MAX. The RMS indicated is the maximum amount of continuous power that can run through without bringing about damage to the component and the max is how much power the component can handle for a short period of time this is why it is important to ensure that the components are not supplied with too much power. Most head units are capable of producing 50Wx4 max on average however some amplifiers are able to produce 50Wx4 RMS and upwards. For my set-up I went for a system what would be able to output 50Wx4 rms. I felt that this would result in a small enough amplifier as well as giving me the midrange punch that I desired.
Other speakers

Traditionally speakers come in round shapes. However there are speakers that come in different shapes and sizes. For example, recently, companies such as Kicker and Sony have released subwoofers that are different in size to the traditional round subwoofer. There are also oblong shaped speakers such as the popular 6x9’s, as well as 4x6, 5x7 and 6x8.

There are tweeters known as super-tweeters. They are similar to tweeters in the sense that they produce the high end frequencies however they able to produce frequencies that are beyond that of conventional tweeters. Bullet tweeters are a type of super tweeter. They are called bullet tweeters due to their name. They usually work by having an inline capacitor when connected to a signal. Some people choose to use piezo electric tweeters in their cars in addition to conventional tweeters. The piezo electric tweeters, like the bullet tweeters are known as super-tweeters and are chosen due to their high power rating and their durability. The piezo tweeters do not require anything to limit the frequencies that are delivered to the component due to the way they are manufactured, their high impedance acts as a filter. Some people however find that the sound they produce is not of very high quality however I’m yet to test out a pair of piezo tweeter in my system, but it is one of the next additions I am looking to install.
Bullet Tweeter Piezo Tweeter

Conclusion

At the end of the day, it is important to keep in mind that if you’re looking for that full bodied sound that you ensure that your system is able to reproduce the whole sound spectrum, this will include a subwoofer of some sort for the bass, usually many people bypass the mid-bass drivers and will use midrange drivers as well as tweeters and this will be enough to produce a full sound. I personally have a pair of coaxial and component midrange speakers, a pair of bullet tweeters and a Kicker L7 to the end result being enough to bring a smile to my face every time!
Hope this was helpful...

Neil Patel

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Power Capacitors

Power Capacitors

What are they?

Power capacitors work by acting as a reserve power bank; they store the charge rather than being the source of power such as the battery. When you are listening to your music, and playing a heavy sub-bass note, the power will draw from the capacitor rather than from the battery so to ensure that the rest of the car will not be starved of power i.e. the headlights dimming. It will act as a buffer so that that the power being delivered to the amplifiers will not drop below the recommended voltages and be steady therefore reducing the risk of damage to the components.

So what power capacitor to choose?

After doing a bit of research, the general rule seems to be 1 farad per 1000 watts of power that your system is running at. So using that, a 1.5 farad power capacitor should be ideally suited to a 1500 watt system. There is a large selection of power capacitors available out there, for example, this power capacitor is a 2 farad power capacitor designed for smaller systems, this is not to say however that it will have a reduction in performance, however for those systems that require more power, a power capacitor with a higher farad will be able to deliver for longer and will usually be of a higher build quality. For a high quality power capacitor, I would recommend high quality car audio brands such as Rockford Fosgate. For example there is a selection of Rockford Fosgate series digital capacitors that are available in either 2 farad power capacitor or 10 farad power capacitor options that are well suited for highly demanding systems and as an added bonus, some might even say they look the business!

How to install the capacitor

Ideally the capacitor needs to be installed as close to the amplifiers as possible. The capacitor requires a 12 volt positive from the battery and a separate ground, to the amplifier; so that the 12 volt positive is 'inline' with the terminal from the battery and the amplifier. The amplifier 12 volt positive is then taken from the capacitor while the amplifier is usually grounded separately as it is important to use as short a ground cable as possible to reduce any potential ground interference.

When you need to consider other alternatives

Power capacitors will not always be of help when you are listening to music, if the lights for example dim down, and stay dim, this indicates there is a deficiency of power and there are other methods of solving the problem, it could potentially be that the battery is not able to generate a charge sufficient enough to meet the demands, so installing a higher cranking battery is usually the common solution however it is possible that upgrading "The Big Three" may also solve the issue(see below for more details). It is also important to check that the current alternator can produce a charge that will be sufficient with a larger battery.

'The Big Three'

The big three is a popular upgrade. It consists of upgrading three wires in the car to ones that are much thicker. As a result of using much thicker wire, more current is allowed to flow through; hence the overall effect seen will be that the voltage running through the car will be higher. The three wires that are upgraded are the wire from the alternator to the battery, the engine ground to the chassis and the battery ground to the chassis. It is common, but not always, that people will choose 0 gauge power wire when going about the big three upgrade. This is vital again to ensure that the voltage delivered to the amplifiers does not drop so low that the risk of damage is possible.

Conclusion

So in conclusion, there is no hard or fast answer to if a capacitor is necessary or not. However capacitors may have benefits if used appropriately. There are large selections of capacitors; some come with digital volt meters, distribution blocks etc, while others are purely chosen for aesthetic pleasure, I myself went for a 4 farad power capacitor with a built in digital volt meter with an LCD display so that it was something I was able to display and looks pretty damn cool.

Neil Patel

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