Time for a New Lifestyle

The amazing Bose Lifestyle 650

Car and Home Stereo have been supplying exceptional Bose music and home theatre systems for over 20 years. I still remember the first time the original Acoustimass speaker cubes were demonstrated to me. Tiny speakers that twisted with a sound that seemed to fill the room, very impressive.

From that day we have stayed with Bose as the ‘Home’ in Car and Home Stereo. Some of the most exciting products have been the Lifestyle range of home cinema systems and over the years we have seen continuous and dramatic advances in technology and performance.

The core design feature of the Lifestyle systems has always been amazing, immersive sound from almost invisible speakers. The latest version, the Sound Touch Lifestyle 650 takes this to another level. Let’s take a tour of the technology and features of this incredible home cinema system.

 

The speaker system is revolutionary. The diminutive OmniJewel speaker houses two drivers positioned at the top and bottom with the sound radiating from the central grille.

 

This allows for complete 360-degree dispersal and creates a huge image stage all around the speaker. If the speaker is wall mounted then the reflected sound adds to the widened soundstage. The result when all five speakers are connected is a truly immersive sound with exceptional image separation, perfect for movies. To make installation easier the rear speakers have a wireless connection to the control unit meaning no more wires to chase around the room.

Of course no cinema system is complete without the woofer. This is what creates the power and excitement in the soundtrack.

 

 

The Acoustimass 300 bass unit

From the cutaway, you can see how the driver is positioned under the sleek glass top for maximum dispersion without rattling the floorboards. The tuned port below the speaker enhances the truly deep tones perfect for when the star destroyer thunders across the sky! Again the woofer connection is wireless meaning it can be positioned anywhere and just needs a power point.

But what if your room is an odd shape making it difficult to install the speakers in the ideal positions? Maybe you have high ceilings and wood floors which can produce odd reflections and ruin the sound. Well, Bose has the answer in their AdaptIQ system. This learns the layout of your room and listening positions and automatically adjusts the sound to compensate for anomalies. This means that every system will sound as good as the showroom and you will not need to carefully position your speakers to optimise performance.

Finally, we come to the gorgeous console.

The sleek Sound Touch 650 console

Available in black or white this sleek, glass topped unit is the brain of the whole system and packs an amazing suite of features and technology. It is designed to be the hub of your entire audiovisual system. There are multiple HDMI ports to accept all your devices such as Sky, Virgin, Blu-Ray player and others. There is a single ARC equipped HDMI port for connection to your television but if your TV does not have ARC then there is a dedicated optical port for the TV sound. The smart Bose remote control can be programmed to operate all your other devices which means a lot less clutter on the coffee table!

That takes care of all your video needs but what about your music? Well, the Lifestyle 650 is equipped with Bluetooth for direct streaming of music from your phone or tablet but more importantly, it has the Bose Sound Touch wireless music system on board. This simple system links the Lifestyle to your wifi network and any connected devices. This means it can see your iTunes or My Music library on your computer or network drive giving you instant access to all your music. If you have a Spotify or Deezer account you can access that from the Bose control app on your smart device and play it through the Lifestyle system. There is also internet radio access giving you just about every radio station in the world in digital clarity.

All this technology is incredibly easy to control either via the Bose Sound Touch app or the system remote control which I think is important as we shouldn’t feel intimidated by an overly complex control system. You barely need to look at the instructions as it is so intuitive to use, the system even talks you through the installation making sure no mistakes are made during setup all thanks to the Unify installation process. System updates are automatic via your wifi connection meaning your system will always be up to date and upgraded as necessary.

And there is so much more to the Lifestyle system that makes it one of the best home cinema systems available today, far too much to talk about here. I would urge you to call in for a demonstration so that you can experience the full power of this magnificent range.

 

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.

Invisible Installations

Following on from last week, I thought it would be good to share some images and details of the parts of an audio installation that you would not normally see.

We are a proud member of the Four Masters network. Four Masters is a national group of independent car audio installers that are committed to producing the finest audio experiences. This can only be done by adhering to the highest installation standards, offering the best equipment and having an in-depth knowledge of our systems and the cars on which we work.

At Car and Home Stereo, we constantly search out the best products that can fulfil our customer’s needs. Brands like JL Audio, Audison, Hertz and Rainbow offer amazing amplifiers, processors and speakers. Dynamat, Skinz and Stinger have sound deadening treatments and high-performance cables. Over the many years that we have been designing and installing audio systems we have developed skills and techniques that will consistently produce great results.

We are proud to have been featured in Driving Sounds, a leading industry magazine as recognition of our dedication to excellence.

So let’s say you have visited our shop on Sunderland Street in Macclesfield and together we have designed a system that will blow you away with its power and precision, you have dropped off your car and the garage door shuts. The next time you see it, your car might not look any different yet it now sounds amazing. Other than the amplifiers and speakers what exactly happens to achieve this and why does it take so long? Well, let’s go through it.

At the first discussion, we will have to sit in your car and listen to it but then we do it all over again, that time carefully listening for any issues. Once satisfied we will start the process of stripping down the parts of the interior we need to access. The door cards will need to come off as well as possibly the ‘A’ pillar trims for tweeters. Great care has to be taken here as there are often airbags incorporated into these areas.

All clips and electrical connectors must be safely disconnected not forgetting any moisture seals that must be retained. Any clips that fail will be replaced from our stocks. There will be mechanical linkages for the door release handle that must also be disconnected taking care not to kink the exposed cable.

Side trims will need to be removed for cable runs along with the back seats if we need to run cables to the boot. If we are upgrading the front speakers of a BMW then the front seats may also need to come out.

Finally, the boot trim and carpet may need to be stripped out to allow for amplifier or processor fitment.

All the trim will need to be carefully stored along with all the removed screws, bolts and clips, don’t want to lose any!

The next step will be acoustic treatment for the doors and other exterior panels. We use a combination of Dynamat Xtreme and Skinz acoustic damping sheet for the best results without adding excess weight. Dynamat eliminates panel rattle and significantly improves speaker performance while the Skinz sheet forms a thermal and acoustic barrier in the door meaning a warmer quieter car.

Any installation is only as good as the interconnects and here at Car and Home Stereo we make sure that everything we install is safe and reliable to ensure a lifetime of great sound. This means soldered joints, careful loom routeing and attention to detail. Details like using appropriately sized and applied cloth loom tape to retain the factory look, proper loom support and separation of cables to reduce interference.

  

Once the cabling is in place it is time to start installing the hardware. Car speakers are usually bespoke to the specific car but our aftermarket drivers are a standard size. This usually means we have to make special mounting collars to achieve a perfect fit. It is vital that the speaker assembly is properly sealed to the door to ensure there are no sound leaks that would ruin the sound and also to prevent water leaks from rain or car washing.

 

We always seal our collars to the door and also seal the speaker to the collar with silicone. This seal remains flexible and still allows removal if the speaker needs to come out. Tweeters will be carefully installed into original locations unless they need to be re-sited for sound stage reasons. Once the door cards and trims go back on there will be no visible evidence of change.

The final part of hardware installation is usually the amplifiers and processors. Some customers want a completely stealthy installation while others may want something to show off, we are experts at both. If the installation is to be stealthy then we have to consider several factors and foremost are ventilation and cooling. If the amplifier is to be hidden then it is vital that it can shed the excess heat generated. If space permits then under a front seat is common, this location is convenient however care should be taken as there can be heating ducts in this area which could compromise the amplifier performance.

 

Other common locations are cavities in the boot area. Behind trim panels and under the boot floor trim are acceptable as they are usually cool being next to the outside of the vehicle. Fortunately, modern D class amplifiers are much more efficient now and make less heat than AB class amps but cooling must always be considered.

We also have to consider access in the event that the amplifier settings need to be altered. Again modern DSP equipped amplifiers can be altered remotely via a PC but if it is analogue then we have to be able to adjust as necessary and that cannot be done easily if the amplifier is buried. All this means that when all is closed, there is no visible evidence of the additions

If we are producing something to show off then there are no limits to what we can do. From simple flat trim rebuilds to complete boot interior remodelling, we have done them all!

 

These show stopping installs can take a week to build but the results speak for themselves.

Finally, it’s time to turn on the system and tune it. This in itself can take several hours and will need to be redone after the speakers and subs have had a chance to run in in a week or so.

Tuning is an art and while there are tools to aid us I still prefer to do the final fine tune by ear. As a musician and electronic engineer, I have a great understanding of sound and I know I can produce a stunning sound. However, the tools are invaluable in initial response tuning. Pink noise generators, spectrum analysers, laptops and sophisticated software mean I have a level of control that is almost mind boggling. Learning your way around these tools is a full-time job and definitely not for the feint hearted. Fortunately, I love all this technology and have spent countless hours learning how to ring every last drop of performance from it.

  

Hopefully, this article demonstrates how we do things and why we are able to achieve such fabulous results. Car audio is our passion at Car and Home Stereo and we like to think our installations are some of the best. Retaining our Four Master status is important to us as it reflects our commitment to excellence as well as giving our customers peace of mind that their vehicle will be looked after and all installation will be to the highest standards. That is why we can offer a three-year warranty on our installed products and a lifetime warranty on all installation.

If you would like to know more please feel free to contact me for a chat or better still call in to our shop @ 01625 432707.