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?

Say Hello To The Future!

JL Audio are a renowned American manufacturer of the highest quality subwoofers, amplifiers and speakers. Some of our best sounding installs have been based around JL Audio products and it is true to say that there is something for everyone within the range.

I was lucky enough to attend a training day with JL Audio’s head of training, Steve Turrisi in March 2017 where, without exaggeration, I was shown the future of car audio. This year JL are launching a fabulous new range of products so let me describe what I was shown.

In June we will see a new entry level speaker range designated C1. These look set to clean up on the simple speaker upgrade market. They are robust, great sounding and very easy to fit as they come with installation collars to cater for different vehicle apertures.

 

 

I am sure I will be fitting a lot of these in the near future.

As mentioned there will also be a new ultra high-end speaker set, the C7. This speaker has been designed from the ground up to be the absolute best. Drawing from JL Audio’s many years of experience this will be a milestone in audio performance. It will not be cheap but the best never is.

Expect a price tag in excess of £2000 for these magnificent drivers but I am sure we will not be short of takers when these launch in summer 2017.

Already available are the new RD series of amplifiers which fill the gap between JX and XD. Boasting huge power output from a small chassis I have installed quite a few now and they are extremely impressive.

The RD amps are extremely well priced for the level of performance they deliver, the build quality is amazing and of course, they have the legendary JL sound. Available in mono, 2 channel, 4 channel and the incredible 5 channel every application is catered for.

As if this wasn’t enough I’ve saved the best till last. Available now are the stars of the show. JL Audio’s new line of digital processors the FiX and TwK.

With these products, we will no longer have to endure the sound supplied by factory head units that cannot be swapped out. The BMW, Ford, Audi and VW factory radios can be made to sound amazing. Couple this output to a great amp and speakers and there are no limits to how good your car could sound. This is thanks to the amazing TuN software developed by JL and an installers dream come true.

As can be seen, the software gives me complete control over every aspect of the audio system. There is nowhere near enough room here to describe all the features but trust me, this is a game changer. Car audio will now take the next great performance leap.

For details of all these great new products call me on 01625 432707 or better still call into our shop on Sunderland Street in Macclesfield.

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.

 

Vehicle Specific Systems: BMW E90

This car is a firm favourite of ours especially in the M Sport however, the stock audio is nothing short of terrible. There is a distinct lack of any real bass and even with the optional stock tweeters there is no sparkle or liveliness in the sound. A lot of owners are unaware that there are bass speakers are located under the front seats as the low-frequency performance is so bad. There are of course many options to improve the audio but perhaps the simplest is to replace the speakers. The BMW speakers are a unique size and fitting a standard set can be difficult, fortunately, there are several companies now making BMW specific replacement speakers. Foremost amongst these are Rainbow, a German company specialising in some very high-end speakers.

The Il-c8.3 kit is suitable for all BMW E9x and F series and comes complete with all OE style connectors. All speakers will fit in the standard location with the minimum of modification. What’s more, all the original speakers can be re-installed when the car is sold or returned.

The difference between the Rainbow and the stock speakers is astonishing even without fitting an upgraded amplifier. The sound stage is better with vocals being presented cleanly, the mid range is much less confused and at last, there is a decent bass response. It is possible to just change the door speakers but I would highly recommend replacing the whole set.

Another popular vehicle with an underwhelming audio system is the VW Golf. Like the BMW the stock system has no sparkle and again a poor bass response. Once again Rainbow step in to provide a direct replacement speaker set, one for the VW Golf Mk5 and one for the Mk6. Available in three and two-way, this upgrade immediately lifts the whole audio soundstage to a new level. The kit comes with all fittings and collars required so it is possible to fit yourself if you wish.

Of course, you may be looking for a complete upgrade for your Golf Mk6 or 7 and here we can turn to the masters of car audio Audison. They have designed a specific system for this car that replaces the speakers as well as adding a custom tuned amplifier and a  super slim sub enclosure designed to seamlessly fit the car.

 

This system brings a whole new dimension to the audio system with a full digital signal processor that is built into the compact amplifier that sits discreetly under the seat. It has been developed from painstaking testing and tweaking to make sure that it both integrates perfectly with the stock car and provides the best possible sound. Again this kit comes complete with everything you will need to install it but unless you are comfortable removing the trim and panels from your car we would recommend letting us install it.

Of course, not all cars are covered with a ready made upgrade kit and this is where Car and Home Stereo can really help. Over the last thirty years, we have seen almost every type of vehicle and our comprehensive knowledge allows us to design and install audio systems that will delight. We strive to design systems that will blend perfectly with your car whatever your requirements may be. From the simplest speaker upgrade to a complete multimedia systems our aim is to put a big smile on your face every time you listen to it and that is what music should be about.

 

If you are ready to start your journey to better sound then please call Tim on 01625 432707 or better still call into our shop on Sunderland Street in Macclesfield for a chat and a demonstration of the best that car audio can be.

Perfect Timing

Let’s talk about sound and specifically how we perceive a sound’s location, (we’ll come back to the elephant in the room). To do this we need to understand what sound is and how it travels.

In its basic form sound is a compression wave propagating through a medium. Think of ripples in water travelling away from where the stone hit. The sound is exactly the same but travelling through air. Travelling very quickly by the way at over 700 miles an hour.

The defining characteristic of a wave is the fact that it has high and low points.

 

Points along this wave are known as the phase and describe whether the wave is positive or negative and by how much. Now for the clever bit. Consider a listener sat in a chair with their eyes shut, someone off to their left claps. Of course, he can tell it was to his left but how? We all have two ears so it might be true that we can detect the time difference between the sound reaching our left and right ears. But at 700 miles an hour this is a VERY short difference and if true it would mean that all frequencies could be located but as we know the lower the sound the harder it is for us to locate the source.

What we are predominantly detecting is the difference in the phase of the wave between our ears. By measuring the difference between the high and low points on the wave our brains can very accurately calculate sound location and create our spatial awareness. That is why we cannot locate very low (very long wave) sounds as the difference in the phase between our close set ears is minimal (think about thunder).

So now we know this how can we use it in the car audio environments?

One of the big problems in the car is that we are always sat closer to one speaker than the other, therefore the stereo effect is foreshortened to one side. A very crude way to combat this is to put the balance off to one side to compensate but that does not enhance the stereo performance. What we really need to do is place the speakers an equal distance from the listener. Difficult if you are not in a McLaren but we can fool our ears into thinking the sound is coming from somewhere else using phase.

By carefully manipulating the phase of the sound from the speakers we can create the effect that the close speaker is actually further away which leads to a much wider stereo field. This manipulation is very delicate as you can imagine but as a member of the FourMasters network, we are equipped with a sophisticated range of tools and software to achieve this.

The difference between a standard setup and a phase aligned one is astonishing. The whole soundstage comes alive with instruments and vocals spread across the car in a very lifelike and live performance. It is possible to compensate for difficult speaker positioning (BMW) or over separated speakers (VW).

Of course, you will need to have the products to permit this tuning and fortunately, there is a range of sophisticated processors from Audison and Hertz that offer these features. Products like the astonishing Bit family from Audison. These devices give me the capacity to completely shape the acoustic performance in your car which means you will have a completely bespoke sound that perfectly complements your car and your personal tastes.

We have a demonstration vehicle always available at our shop on Sunderland Street in Macclesfield. In this we can demonstrate the difference between a standard and phase aligned sound, we would love to show it off if you want to pop in for an audition.

Oh and the elephant? Elephants communicate their location by stamping on the hard ground. This creates a very low-frequency sound which can travel a great distance. You or I could not locate this low sound but elephants can, why? Because their ears are much further apart and can detect the phase differences!

Simplicity Wins

At Car and Home Stereo we regularly install very high performance, in-car audio systems. It is intensely satisfying to build these systems as the musical performance they deliver is breathtaking. These systems do of course come with quite a high price tag so what can we do if the budget is a little more modest?

Let’s meet ‘James’. He’s 22 and just bought his first new car, a Ford Fiesta ST.

ford fiesta st

He loves music and thinks the standard sound system is OK especially since the car is equipped with Bluetooth so he can stream from his phone. After owning it for a while he starts to think about improving the sound but after lease payments and insurance he’s not got a lot to play with.

The first thing we will ask when he calls in to the shop is what type of music he listens to and what sort of sound he likes. The next step is to sit in his car and listen to the sound, often we will find the tone controls have been set to max bass and treble in an attempt to get a better sound. This usually just has the effect of making the sound muddy as the speakers cannot cope.

Now we know he would like a better bass performance for his music and more clarity from the main speakers. We need to add a subwoofer and better speakers to achieve a complete improvement. James has a limited budget and wants to get the best performance boost for the money.

We have a wide range of products available to suit all requirements but in this case an ideal solution would be the Rainbow Intellisub 8 and a set of JL Audio TR650 CSI components for the front doors. Total cost installed of £500. This very simple system would transform the performance of the audio and give years of pleasure.

But what if the budget will not stretch to £500, should we find cheaper products? The answer is always no. It is never worth compromising performance for price. There are cheaper products out there but they are always inferior and will not stand the test of time. The best option is to split the installation and have one part now and the next when funds allow. So which part first?

Simple, the sub. By adding the extra bass system there are two immediate benefits. First and most obvious is the bass improvement with greater depth and punch. The second improvement is more subtle, as there is no need for the main speakers to produce bass they start to sound a lot better. Certainly good enough while you save for the speakers!

I give this advice on an almost daily basis and it’s worth has been proved time and again with customers who have simple audio systems that far exceed their expectations. We have an in store demonstration stand that shows this off beautifully so please feel free to call into our shop on Sunderland Street in Macclesfield and we can start your journey to a better sound.

Demonstration of Distortion

An interesting situation occurred at Car and Home Stereo recently that I would like to share. It highlighted a phenomenon that is quite counter intuitive and led to some interesting discussions.

We have a demonstration Land Rover Discovery that has a simple, high quality audio system installed that is tuned to perfectly suit the interior acoustics. We always encourage our customers to sit in and experience it as it shows what can really be done with car audio. The amplifier that powers the system is the magnificent Audison 5.1K which develops a true 1650 Watts.

There is one pair of component Hertz Mille Legend speakers in the front doors and a Hertz Mille subwoofer in the rear.

A customer recently auditioned the system and we spent a good hour playing different types of music with a view to producing something similar in his car. He was completely blown away with the sound, couldn’t believe the clarity and how the sub blended perfectly with the whole system. And then he said ‘I love it, but it’s not very loud is it?’. In fact he reckoned his standard Ford system was louder!

Now I know just how loud our system is and the odd thing is that the cleaner the sound the less we perceive volume. Since we had some time I decided to run a little proof experiment with my customer’s car.

As part of our equipment set we have an industry standard spectrum analyser which is also equipped with an SPL meter. It was a simple task to set this up in the Discovery first and then the Ford to compare. As expected our Discovery hit 126dB easily, the Ford however struggled to hit 110dB. In real world terms this equates to a perceived doubling of power (a true doubling is 3dB but we don’t really hear it that way). The next test was the distortion level. By plugging an oscilloscope into the amplifier output we can measure the clipping levels. Unsurprisingly the Discovery registered less than 5 percent distortion at full volume as this was how it was set up. However the Ford reached 5 percent at a little over half volume and climbed to over 25 percent.

There is no arguing with the figures so what is going on? Simply that the higher  distortion levels were being registered as unpleasantly loud and our brains are trying to get us to turn it down! Distortion is the quickest way to destroy a speaker or indeed your hearing.

At Car an Home Stereo we value our customers and hope to be providing high quality audio systems for many years. A distorted sound system will very quickly do serious harm to our hearing and that is why we only choose the best equipment and like to carefully set these up to give the best possible sound. Brands such as JL Audio, Audison, Hertz and Dynamat may not be the cheapest but certainly are amongst the best. The fact that when installed correctly they can deliver an amazing sound makes them excellent value for money.

As to my customer with the Ford, he now has a fabulous system based around a JL Audio amp and speakers with a Rainbow active sub. He loves to play it loud and I know it will give him years of pleasure without doing any harm.

If you want to experience the Discovery sound system or would like to discuss how we can improve your car please all us on 01625 432707.

What To Look Forward To In 2017

It’s good to be back after the festive break and there is a lot to look forward to in 2017.

World renowned audio manufacturer Audison have just announced their new Thesis speaker range. The Thesis amplifier represents the absolute pinnacle of performance without compromise and now there is a speaker set available to match. If you are looking for the absolute best possible sound then this is it.

adison speakers

Staying with Audison, the new slimline Prima subwoofers and enclosures offer stunning bass performance from a very compact form. These will appeal to anyone who does not want to sacrifice much boot space but still demands a Hi-Fi response.

audison prima subwoofers

 

There will also be a new Prima Pack custom installation kit for the BMW 1 series. This car has always had a very disappointing standard audio system and the Prima Pack is a tailored solution comprising the stunning AP amplifier, a custom Prima speaker pack and compact subwoofer. As with all the Prima Pack systems the factory head unit remains unchanged but the audio performance is greatly enhanced by the AP amplifier. The speakers fit perfectly into the factory locations and the sub is designed to blend seamlessly with the factory trim.

bmw1 car

On the other side of the Atlantic, JL Audio have released their amazing new processors, the new Fix and TwK.

jl audio

The FiX range is simplicity itself to use and automatically deals with all the anomalies inherent in vehicle factory head units. Building on the success of the CleanSweep processor, the FiX can automatically de-equalise audio streams and can even remove spurious time alignment errors giving  a flatter, more open sound from which we can build a better audio system.

The new TwK processors take this a huge step further by allowing access to a vast range of processors via the JL Audio software. From input/output configuration to full spectrum equalisation, this product means that every installation can be tuned to perfection.

Over the break we have been busy building new demonstration stands to showcase some of our best car audio equipment as well as tweaking our Land Rover Discovery demonstrator. This simple car audio system still astonishes me with its clarity and power showing what can be achieved with just one pair of speakers, a subwoofer and amplifier. If you haven’t heard it and can come down to our shop on Sunderland Street in Macclesfield I would encourage you to do so, it is sure to impress.

Our focus, as ever is on installation of the highest quality whether it is a simple dash cam or a full blown custom audio system. We are proud to be a part of the national FourMasters group offering the highest installation standards and a three year warranty on installations.

Please feel free to pop in or give me a call on 01625 432707 to discuss ideas and start your journey towards better sound!

Wishing you a happy new year!

We hope your 2017 has got off to a good start!

Here, at Car and Home Stereo we already have some exciting, new products coming through the door. Come to our shop on Sunderland Street, Macclesfield, and see what we can do for you.