Life In The Loud Lane

At Car and Home Stereo we are dedicated to getting the best possible sound in your car. We will carefully match your needs to the best equipment and electronics to achieve that goal. We have access to a vast range of products so that we can tailor a system that is perfectly suited to you and your car. Of course what everyone wants is different and two extremes were both in the workshop at the same time recently.

If you have read the Lotus Evora blog you will know that the emphasis was on a stealthy install with the aim to produce a highly detailed soundstage. This was achieved with a full Audison system using the amazing AP8.9 Bit amplifier, Voce speakers and Prima sub, a simple system boasting 520W, more than enough power for the small cabin of the Evora. The final tuned sound of this car was fantastic. The music was surrounding with detail and punch where it needed it.

In the adjacent workshop bay at the same time was a Vauxhall Astra van and the brief for this one was very different. This had to sound good but most importantly it needed the ability to crush you with bass! Being a van we had plenty of space to work with but on the down side all that metal was a prime candidate for epic vibration. Power supply was always going to be an issue from the standard battery and of course with the power we were going to need, the standard wiring would not be adequate.

How we did it:

The first job would be to strip the vehicle for acoustic treatment. Every panel had to be coated to make sure all the enormous energy of the subs was retained inside. There’s no point in installing a 3000W system if 1000W gets out, it might sound good to passers-by but if you’ve paid for all that power, you want to hear it all. Once treated, tapping on any metal panel sounded like tapping on wood. There was no resonance and as a bonus road noise was reduced to almost nothing. The doors were treated with more Dynamat Xtreme to improve the acoustic response of the front speakers and again reduce road noise.

What next?:

The power supply was upgraded with two auxiliary Optima yellow top, deep cycle batteries with a split charge system. Even though the MTX bass amps are ‘D’ class they still draw a significant current and it was important to make sure this would not drain the vehicle battery. This kind of power has to be made safe and that means fuses on each battery and on each supply to the amplifiers, there may only be 12 Volts but the current capacity on the Optima batteries is more than enough to melt any cable and incorrect fusing could cause a fire if short circuited.

Once the power supply was installed we could mount the amps on the forward bulkhead. As this was destined for the show scene we made sure that everything was as neat as could be.

The eagle eyed of you will spot the cut outs for the MTX 6×9 speakers below the amps. This is an unconventional position for speakers as they are behind the seats but they will add a much needed boost to the low mid-range to complement the component speakers in the doors.

The three main amps are MTX RT1000.1Ds, These develop 1000W each at 2 Ohms which is why they need 50mm sq. power cable! The rest of the speakers are powered by a JL Audio XD400/4 and everything is kept under control by the Audison Bit 10. The front speakers were mounted in the standard location on custom collars and the tweeters were mounted into custom ‘A’ pillar pods.

This improved the staging for the front and solved the problem of the size of the tweeter being too large for the factory location.

So what about the subs I hear you cry!

Well this had to be the show stopper so we knew we would have to build something a bit special. The MTX TX612 is a beast of a sub.

With its awesome power handling capability we knew we could really push this speaker. It has incredible excursion and that red, double stitched hinge is not just for show. We wanted to get the most from this driver so we opted for an optimised slot ported enclosure, one for each sub. As you can imagine there is a significant amount of weight here so we also had to make sure that there was no possibility that any of this structure could move. Safety is always prominent in our minds when designing any system.

This is the finished enclosure although there will be trimmed wheel arch boxes either side for storage.

The auxiliary batteries and fuses are located behind the enclosure and are accessible by removing the top trim panel. There will be a voltage display mounted in the right hand arch box so battery condition can be monitored. The main fuse and Stinger 500A peak split charge relay are mounted in the bonnet with the vehicle battery.

Did we fulfil our brief?

And then some! With the tailgate open the bass completely dominates and you can feel the sound waves pushing your chest. If you dare to put your head inside the boot you’re immediately disorientated by the sound pressure level. When sat in the front you can hear the rest of the music as well and now that awesome bass complements rather than overpowers. Of course there is a level control for the bass but the temptation is to turn it up for the biggest smiles!

At Car and Home Stereo we know that this sort of system is not for everyone and we always ensure you get exactly what you need so regardless of what vehicle please give us a call and we can start your journey to a better sound.

 

Stealth Installation: Audi Edition

At Car and Home Stereo, we have been installing high-performance audio for over 40 years now. As I’ve said before we have seen a continuous change in vehicles, equipment, and technology but one very noticeable change has been the drive to take up less space. Amplifiers have shrunk in size and subwoofers can operate in smaller enclosures, the ‘stealth’ install if you like.

I can clearly remember the 1990s when there were queues of Golf GTis waiting for subs and amps. One of our popular installs would be a Phoenix Gold Ti 600 amp and a pair of JL Audio 15w3 subs, what a sound! Of course, it filled the boot space and you couldn’t lift the sub box to get to the spare wheel but who cared when you could feel the bass right through to your bones.

It is true to say that these days our customers are more reluctant to sacrifice all their boot to amplifiers and speakers and as I said earlier, manufacturers have been working hard to reduce sizes without compromising performance but sometimes it’s nice to install a proper ‘muscle’ system and recently  I did just that in an Audi, let me take you through it.

The vehicle is an Audi S3 with the B&O sound system. The owner was reasonably happy with the front speakers but was completely disappointed with the bass performance. When we sat in it together the first thing I noticed was the huge gap in the midrange, quite an achievement considering there are 10 speakers, and of course, the sub bass was nonexistent. Looking in the boot we found the B&O ‘sub’ which was no more than a 6-inch paper cone speaker in a plastic box, awful! The Audi speakers are heavy, low sensitivity drivers which is why the midrange was so poor. So what should we do?

We wanted bass, lots of bass, so the obvious choice was the magnificent JL Audio 12w6 or rather two of them.

This is easily one of my favourite speakers of all time with masses of punch but with a sensitivity to play the fastest of bass lines cleanly.

Of course a sub like that wants lots of power and the perfect match is the JL Audio XD1000/1v2, one for each sub.

With 1000W on tap, this amplifier certainly has the drive but it also boasts a high damping factor to help keep control over that 12-inch cone. When a speaker is played loud the cone has to move a large distance, the 12w6 has a peak to peak maximum excursion of nearly 40mm! That cone builds up a lot of inertia and it is down to the amplifier to keep that under control. Damping factor could be considered to be the brakes of the system and without good brakes, the cone is just going to flop forwards and backward leading to a loose bass performance. It is the damping factor that helps keep everything tight and punchy.

I couldn’t allow this level of bass performance to be added to the car without dealing with the front end which I felt was completely inadequate. Nothing crazy. Just a simple front speaker upgrade with a 4 channel XD amplifier to power it. We settled on the super smooth JL Audio C5 650 component set and the XD 400/4v2 to power them. By using a 4 channel amp I could run the mids and tweeters fully active to eliminate the passive crossovers.

The next challenge is how to connect our system to the factory head unit. The Audi, like many other modern cars, uses the fiber optic MOST system to deliver audio from the entertainment and vehicle alerts to the amplifier. In order to retain this audio feed, we have to retain the B&O amplifier. The trouble, of course, is that the amplifier performance is hopeless. If  I connected my new amplifiers to the audio output of the B&O the sound would be almost as bad as before. Fortunately, we now have an arsenal of tools from JL Audio to remedy this. The simple but powerful FiX automatic processors and the incredible TwK audio processor.

The FiX processor is designed to connect directly to the factory amplifier speaker outputs. It can determine the issues in that speaker feed and automatically correct them. It is capable of accepting multi channel inputs and creating a pair of high quality pre amp outputs, it can even detect phase and time delayed signals and correct them.

With this connected to the B&O we now had a very clean audio feed that retained all of the vehicle and entertainment information and in reality we could have just connected this feed to our new system, but we weren’t finished yet! This system needed to be amazing so step up the JL Audio TwK88. This small but powerful device allows me to create virtually any system configuration I want. I have full control over every aspect of the the audio spectrum, I can control frequency, phase, time correction, equalisation and level. Every output can be fine tuned for the absolute best sound possible so I can take account of annomolies in the sound stage.

Although we left the rear speakers as standard they are faded almost completely off but they are adding a small amount of presence to the rear seats. The small mids in the door and the centre dash speaker have been disconnected as they only muddied the sound which is now wonderful. The sound stage is high and clear, right across the dashboard, the mid range has returned and the bass can go from subtle to armageddon!

So what does all this look like?

Even Henry looks impressed!

Once the boot floor cover goes back none of the electronics are on show, the sub box moves into the load space and surprisingly there is quite a lot of room left. Certainly enough for the shopping.

This system is massively impressive, it might not suit everyone from a size point of view but the sound quality would blow you away.

If you would like to know more about how Car and Home Stereo can improve the sound in your car please call me on 01625 432707 or better still call into the shop on Sunderland Street in Macclesfield.

 

A, AB, D or All Three? Pick Your Amp!

Amplifiers, such a range but which is right for you? I’d like to discuss amplifier types and applications.

As a Four Master, Car and Home Stereo are recognised as one of the leading car audio installers in the country. Our knowledge and experience mean that we are ideally placed to choose the right equipment and install it to the highest standard.  We offer a no pressure approach and are happy to offer advice on choosing the right equipment; just recently I had a great conversation over Facebook with an enthusiast in Australia over the benefits of the magnificent Rainbow Profi speakers.

Commonly I am asked “how many Watts is it?” but there is so much more to an amplifier than that. In reality, the Watts figure is often not the most useful specification when choosing between amplifiers. True it gives a simple indication of power but all too often that figure is heavily massaged to look higher. I have tested some so-called 3000W amplifiers to discover that they only made 200W at the terminals into a speaker load. Still an impressive output but certainly not 3000W as claimed.

But I digress; we are looking today at amplifier types and their uses. There are three types of amplifiers in main use today they are classed as A, AB and D. Although they all have the same purpose there are some fundamental differences between them that make them suit different applications.

At the heart of an amplifier are the power transistors, these are responsible for taking a small signal and making it larger, the classification describes how the transistors are used. Of course, there is a massive range of qualities and performance variations related to each type but we will stick to classes.

Class A, a typical sound wave.

As we know, Sound is an oscillating wave. This wave has a positive and a negative component but is symmetrical about the ‘t’ axis. So all we need is one big transistor that can amplify the whole signal to whatever power we want right? Well yes and this is the ideal solution for sonic accuracy; the high output signal is an exact copy of the small input signal. The best amplifiers I have ever heard have all been A class with a sound that is open, transparent and simply a joy to listen to.

The magnificent Audison Thesis Venti

However, all this purity comes at a price; huge power consumption. Those massive transistors are switched on all the time regardless of whether there is a signal there or not or how loud it’s playing. This means heat and lots of it which has to be dissipated. So we need massive power supplies and large heatsinks which make the amplifier large and somewhat inefficient, typically around 20%. That’s why we need to use such large power cable!

So how do we get better efficiency? Class AB.

 

There are many considerations here but in very simplistic terms it is possible to use one transistor to amplify the top half of the wave and another matched transistor to amplify the bottom half. This means that smaller transistors can be used and they are only on for half the time leading to efficiencies of 50 to 70%. This means less heat and smaller power supplies which help to keep the cost down.

The JL Audio JX360, a mainstay of many audio systems

There are some drawbacks to class AB, principally of which is crossover distortion.

As a matched pair of transistors has to amplify the whole wave it is essential that they turn off and on at exactly the right moment (the class B part). Imagine two people writing the letter S where one person only writes one-half and the other person completes it, there is bound to be a little error. The same is true in the amplifier leading to a very slight distortion of the output wave but in truth, modern design can almost eliminate this meaning we can have a really great sounding amp that is pretty efficient. This has meant that AB design has dominated the market for decades.

The highest efficiency is class D.
Let’s get something straight, D does not stand for digital. Class D is just another design type, a really clever one. This design uses pulse width modulation to generate the amplified output which involves switching the output transistors on and off at a very high rate typically around 300 kHz. This High switching frequency means any noise is well above our audible range and the PWM leads to astonishing efficiencies of around 95% or higher. So, at last, we have a very high power, high quality and very efficient amplifier. It is fair to say that most mainstream car amplifiers today are D class as they are smaller, lighter and generate less heat than their A or AB counterparts.

The JL Audio XD400.4, small but powerful

As with almost everything, there has to be a downside and with D class their Achilles heel is radio interference. The switching frequency mentioned might not be audible but it can do a fine job of broadcasting in the FM radio range. This can lead to reduced radio reception at certain frequencies, of course, modern design does mitigate the problem but nevertheless, it can still be an issue.

So to sum up, Class A for the best possible sound (ideal for tweeters), Class AB for improved efficiency (ideal for midrange) and Class D for maximum power from the smallest chassis (ideal for subwoofers). Wouldn’t it be great if there was an amplifier with all three? Well, there is and it is called the 5.1K from Audison.

 

The superb and versatile Audison 5.1K

This is one of my all-time favourite amplifiers and it is the amp that powers my own personal system. The detail of the class A front stage is phenomenal while the AB class mid-stage offers an amazing amount of punch. The D class sub stage has enough power to rattle the windows but offers a fidelity that allows a seamless blend with the rest of the audio stage. This unit never fails to impress and is not too big to make it impossible to fit. It does get hot if driven hard but does not require special cooling if mounted sensibly.

 

If you would like to hear what the 5.1K can do then please feel free to call into our shop on Sunderland Street in Macclesfield and I would be pleased to demonstrate it in our Discovery or on the demonstration stand in store. If you would like any more information on amplifiers in general please call me on 01625 432707.

 

 

Gain An Advantage: Amplifier

Anyone who has dabbled in car audio will have come across an amplifier at some point. They come in many shapes, sizes, and outputs but from the cheapest eBay special to eye wateringly expensive European exotica they all have one purpose, to get the musical signal to the speakers. The amplifier is, therefore, sat between the CD player and the speakers accepting the low-level input signal and converting it to a high power speaker output. I don’t want to get too bogged down in technicalities but let’s discuss the different types available and the controls we are given.

The JL Audio RD900.5 is a perfect example. This 5 channel, D class amplifier is capable of running a complete car audio system with front speakers, rear speakers, and a subwoofer. Alternatively, it could run a pair of front speakers bridged for enormous power plus a subwoofer once again. So, the RD900.5 is a very high performance, a flexible amplifier with a pretty small footprint making it easy to install.

The input stage is on the far left of this amplifier and comprises the usual red and white RCA connectors. There are 3 pairs that equate to the front, rear and sub input. Above these are three switches that allow for hi or low-level input, auto turn on mode and input channel selection (2, 4 or 6). Not all amplifiers are equipped with these selectors but these add to the RD900.5 flexibility.

The next stage is what interests us here, the frequency filter and the gain controls. The RD 900.5 is nonsymmetrical meaning that all channels are not identical. Channels 1 to 4 are for main speakers while 5 and 6 are for subwoofers. Therefore there is a variable high pass filter for 1 to 4 and a low pass filter for 5 and 6.

What is the filter for you ask? It is used to remove frequencies that are not required by the speaker on that channel. If we know we have a subwoofer fitted then it makes no sense to send the very low frequencies to the door speakers. Sub frequencies require a speaker cone to move a great distance and most door speakers simply cannot achieve this without distortion, I’m sure you have all heard a speaker trying too hard causing the classic ‘burping’ sound. In extreme cases, the speaker coil can be heard crashing into the back plate creating a clapping noise. Either situation is undesirable so to prevent these from occurring the frequency filter is applied to restrict the low tones.

The cutoff frequency is variable to suit different speakers and installations and setting it correctly requires the use of a signal generator. If you do not have access to one of these then it is possible to do roughly by ear, simply play music and slowly raise the filter frequency until there are no very low sounds in the speaker. The result will be a much clearer sound with no distortion. The mid definition should be greatly improved meaning vocals will cut through better. Typically the filter control is graduated and a very rough initial setting for a typical door speaker would be around 80Hz but you should experiment either side of this to find the best setting.

The subwoofer (low-pass) filter is the opposite of the high pass filter as it removes the higher frequencies sent to the sub. This ensures it only gets useful frequencies and we do not waste amplifier energy trying to make it play the higher tones.

Again the cutoff frequency is variable but what we want is to blend the sub with the main speakers so it is important to find a filter point that complements the high pass filter for the speakers.

So now we come to the input sensitivity, perhaps one of the most misunderstood controls. First and foremost it is not a volume control. Sure, it does increase the volume as you turn it but that does not mean it is increasing the amplifier power. Let’s consider what an amplifier is doing, it is taking a small signal and making it bigger. That signal is very dynamic meaning it is made up of loud and quiet parts, an extreme example could be Tchaikovsky’s 1812 Overture. Not something we listen to every day but it serves our example very well. If you are not familiar with the piece it starts very quietly and builds to a crescendo of orchestra and cannons. A more modern piece would be Warriors Dance by Prodigy but with fewer cannons!

The most important thing to consider when setting the sensitivity is that the amplifier only has a finite amount of power, let’s say 100Watts. That is represented by the upper dotted line on the graphs above. Our goal is to get the maximum, undistorted output.

If we look at a typical input sound wave it is obvious that there are loud and quiet parts. As we stated the amplifier is there to make this signal louder. Now let’s add the maximum amplifier power to the input signal graph.

As we increase the sensitivity we increase the size of the input signal at the input stage to the amplifier and remember there is a finite amount of power available. So what happens if we go too far?

As can be seen the nice smooth curves at the top and bottom of the loud spikes have been flattened which is clipped distortion. So yes we have a loud sound but it will be fuzzy and unpleasant. It will also damage speakers as the flat tops of the wave are a DC signal that will only induce heat into the voice coils. So if we take our example, the 1812 Overture, with the sensitivity set as above the quiet passages will sound good but the loud sections will be badly distorted and this will get worse the louder we play it.

For the best sound and maximum output, it is imperative that the loudest sounds are not clipped. Normally this would be set up with an oscilloscope but it can also be done with a voltmeter by measuring the output for maximum unclipped voltage as long as you know the true output power.

Fortunately, the JL Audio RD amplifiers have a brilliant feature, a clip indicator. This will light up if the signal is distorted by over ambitious sensitivity meaning setting up is made much easier.

At Car and Home Stereo, we want all our installations to give the best possible sound and that is why we carefully set up each and every one.

If you would like to have your system checked for any problems and to find solutions to these we would love to measure your car using our state of the art test equipment. These can highlight deficiencies in the sound stage that are difficult to locate just by listening.

As usual, I have run out of space so I’ll leave amplifier types and their best application for another time. But please don’t hesitate to call on 01625 432707 if you have any questions.

Why Does Installation Matter?

At Car and Home Stereo we have been installing exceptional car audio for over 40 years, in fact, when we started there were barely the beginnings of in-car entertainment. Over those years we have seen a tremendous amount of change in the products we use to create outstanding audio experiences. From 8 track cartridge to CD to full digital audio, graphic equalisers to digital signal processors and all the other innovations that have come along we have embraced and utilised these to realise the best possible sound for our customers.

All these fabulous products are available to everybody, there has never been so much choice but all this technology will not guarantee a great sound. That will only be possible with the correct installation and careful setup. Many times I have had a car in that has had a lot of money spent on it yet still sounds bad. From buzzing door panels to downright dangerous wiring I’ve seen it all. Usually from DIY installations but not always. It’s not necessarily the fault of the equipment but rather a combination of poor choice and skimped installation.

It is true that the majority of my work is completely invisible but makes such a massive difference to either the finished sound or the reliability of the whole system.  Application of sound deadening material inside doors will improve the acoustic performance, soldering all connections may take longer but will improve reliability, looming cable runs with fleece tape is expensive but will eliminate any cable rattles and retain the OE look.

It is also important that equipment and wiring are installed to the highest standards to maintain vehicle warranties and safety standards. I have seen microphone cables wrapped around airbags, power cables attached to car batteries without a fuse and any amount of speaker wires dangling over brake pedals. At Car and Home Stereo, we take installation very seriously and we never rush. The best results are not achieved by racing to finish and I would rather spend an extra hour or two to get the best possible sound. After all, you would want your £1000 Rainbow speakers to sound their best.

Of course the same care and attention is applied whether we install top of the range JL Audio speakers or entry level Audison upgrades and in fact, the performance boost from proper door treatment at the lower price range is more apparent.

We will always recommend appropriate enhancements and best installation practices are rigorously followed which may take a little longer and cost a little more but will ultimately lead to a far better sound and is that not what we all really want?

coil

Practicing Safe Sound

There are many ways to upgrade your car audio system and let’s face it, most cars need it. I’m looking at you BMW, VW and Porsche in particular! It is not always possible to upgrade the head unit but it is always possible to improve the speakers. At Car and Home Stereo, we carry speakers by JL Audio, Audison, Hertz, Rainbow and others. This means we can choose the right speaker to suit the car and the customer. We will carefully install your speakers with custom built collars and fittings as well as add sound deadening in the door to improve its acoustic properties. The end result will be a vastly better sound without any cosmetic changes to your car.

And that is where we are finished but before you leave, a word of warning. Please take the time to run your new speakers in. The running in period varies for different speakers but generally, we recommend around 10 hours play time. Running in means keeping the volume at a sensible level without any large bass settings and we will always advise what should be the maximum volume for this period.

If this procedure is not followed your speakers may not fail but they will not reach their full potential, let me explain why.

A speaker is a transducer that converts electrical energy into sound and at the heart of the speaker is a coil of wire sitting inside a magnet. It is bright, shiny copper.

coil speakers good copper

It’s not necessary to know how it works but the important point is that when you pass electricity through a wire heat is generated and the higher the electrical current the more heat is generated. Now, this coil of wire is crucial to the accuracy of the speaker and it is protected by a thin coating of lacquer. This lacquer is quite soft when new and easily damaged by heat but if it is gently warmed over a number of hours the lacquer will harden.

I bet you can see where this is going! If a new speaker is subjected to a lot of power and played loud the voice coil lacquer will boil causing short circuits. Now while this will not necessarily cause the speaker to fail it will mean that the voice coil is not a single continuous wire which leads to a ‘lumpy’ effect within the magnetic gap. This, of course, means that the reproduction of sound is not linear and your investment will not reach its true performance capability. In extreme circumstances, the lacquer is burnt and expands into the magnetic gap which will cause a scratchy sound. These failures are non-reversible, cannot be repaired and are not covered under any warrantee.

 

coil bad burnt copper

burnt copper coil

So that is why we advise the running in period, to gently warm the voice coil lacquer causing it to cure. This hardened lacquer can now stand the heat of high power and your speakers will really perform as the designers intended.

I cannot overstate the importance of running in, a speaker is more likely to be damaged in the first few hours of use rather than over the rest of its life. At Car and Home Stereo, we want you to get the best possible sound from our expert installation so just hold back on the volume for a few hours, you’ll be glad you did.

 

Simon Says? Speakers Please!

For this instalment let’s look at speaker installation. The speaker is the last piece of hardware between your music and your ears and as such has an awful lot to do with the sound you hear.

The science behind the speaker is extremely simple; pass an electric current through a wire that sits inside a magnetic field and the wire experiences a force, vary that current and you vary the force. Of course this demonstration produces no sound but if we attach the wire (or coil) to a diaphragm (or cone) we have the nucleus of a working speaker. The electronics in the amplifier produce the varying electrical current and the speaker responds, creating the highly complex vibrations in the air that we hear as music.

The above description is of course highly simplified and in reality there are many more aspects to speaker design. We have to consider the weight of the moving parts, the resistance to movement within the materials themselves, the linearity of the magnetic field, the quality of the coil wire, the damping to prevent uncontrolled excursion, stability of the frame and so on and so on! Fortunately all of these considerations are engineering problems and this means that better engineering will lead to a better product.

pic-of-rainbow-tweeter

When Mr. Ford or Mr. Audi or even Mr. Porsche are told that they have to put speakers in their cars their first consideration is not about quality even when they enlist the help of respected Hi-Fi companies. Their overriding concern is one of reliability. A blown speaker is a warrantee issue and that costs money. The trouble is that a speaker that can survive heavy metal hard core country rap at full volume has to be made super resilient. This speaker is not going to be able to respond to the subtle nuances of any quality musical performance.

pic-of-sam-bad-sound-face

At Car and Home Stereo we are always going to install a high quality speaker, carefully selected to match the vehicle and musical tastes of the customer. This is where our installation skills are needed. The average car door is a challenging place for a speaker. It is a steel box that is often wet inside, can be freezing one day and very hot the next. There are moving parts within it and it is subject to a large amount of vibration and noise. Let’s look at a typical installation addressing each point.

First of all we carefully remove the inner trim making sure that all clips and seals are retained. After this the next job is to treat the metal skin with sound deadening material which will absorb road noise and any vibrations within the door.

dsc_0002

Particular attention is paid to directly behind the speaker as this will absorb the sound generated by the back of the cone and prevent reflection back into the door panel.

Once the outer skin has been treated we apply a foam barrier to the inner skin. This forms a watertight seal and acts as a thermal and acoustic barrier. This keeps the car warmer in winter, cooler in summer and again reduces road noise. The difference these treatments make to a car is astonishing.

dsc_0003

Now we come to installing the speaker. The factory units are often built to fit so we must make panels and collars to allow a perfect fit to the door.

dsc_0004

It is very important that no moisture gaps are left as it may come as a surprise to know that doors are designed to let rain flow through them. Any gaps could lead to a wet floor so we make sure everything is sealed with high quality silicone, both the collar and the speaker, this also ensures no air gaps to compromise the speaker performance.

dsc_0006

Quite a lot of work but absolutely worth it. These Audison APK speakers sound great anyway but by treating the door they are at least 30% better.

If you would like to know more about how we can improve the sound in your car please call Tim on 01625 432707.

Why Sound Deadening?

In the pursuit of great sound it is essential to consider all aspects of audio reproduction. JL Audio, Audison and others make tremendous speakers which have been carefully designed for accurate music reproduction, unfortunately we have to fit them into less than perfect environments!

The average car door is an acoustic nightmare. A thin, unsealed metal enclosure fronted with hard plastic fittings, often with a loose polythene moisture barrier as well.car-door- explodedCrucially, we want the full, uncoloured response from the speaker we are installing. Unfortunately the design of the door is working against us. Fundamentally, a speaker is a transducer converting electrical signals into pressure waves. Sound is generated from the front of the speaker and from the back.

This is important as the sound from the back of the speaker is playing into the car door. Some will be reflected back into the speaker cone causing distortion of the front signal. Some will be reflected into the door card creating unwanted resonance and annoying vibrations. The louder you want to play it, the worse it will be. speaker distortion

 

Some car manufacturers do apply a token amount of damping but this is just to prevent the panel from rattling, we want to optimise the enclosure for sound reproduction.

The answer is sound deadening. Quite different from sound proofing, sound deadening is about the control of pressure waves inside the door. By applying special materials we can eliminate unwanted resonances and reflections.

There are lots of different products out there but by far the best are Dynamat and Skinz. Dynamat Xtreme is the lightest and most efficient panel treatment I have ever used. It’s damping properties are second to none meaning less needs to be applied. All sound being radiated from the back of the speaker is absorbed and converted into low level heat. This of course stops unwanted vibrations and ensures that you only hear the sound from the front.dynamat door A liberal application of Dynamat behind the speaker prevents reflections.

I believe that it is essential to consider sound deadening whenever a speaker upgrade is installed. Otherwise you will never achieve the full benefit.