Wirez Signature amp kits include full-size ODC copper power and ground cable, as well as speaker cable and premium RCA interconnects. Accessories like spade terminals, wire ties and a grommet are included in all.

Text by Dave MacKinnon, Photos by the Manufacturers

I was just trolling the 12V Insider forums when I stumbled across a discussion of mobile electronics installation wiring guidelines. I have to admit, this is one of my favourite topics, and one I have spent some significant time researching. It is also critically important to the performance, reliability and safety of car audio products.

The Bassworx BSAK5 kit includes 17 feet of power and ground cable, along with speaker wire and an RCA interconnect. Accessories to complete the install, like spades and a fuse holder, are included.

Modern car audio amplifiers are capable of consuming significant amounts of power, as are devices like high-wattage lighting and winches. Because cars operate on a low voltage (~12V) direct current (DC) electrical system, these large power requirements coincide with large amounts of current being drawn. To explain this, let’s dive right into some math. Don’t worry, it’s not hard.

Power can be calculated many ways, but in this case, we are going to look at the product of Voltage (V) and Current (I). The equation is Power = Voltage x Current, or P = E x I. Let’s say we have a pair of headlights that consume a combined total of 110 Watts. We will also assume for this example that the car’s voltage is 12V (it should actually be closer to 13.6 when everything is running properly). We know P and we know V, so we can determine I. I = P ÷ V, or I = 110 ÷ 12, or 9.167 Amps of current.

When it comes to audio, things are worse than you think. Let’s say you bought a big amplifier to run a pair of subwoofers. These days, 1,000 Watts is not unreasonable. Where it goes south is that the amp consumes more power than it produces. We’ll assume a good quality, high-efficiency Class D amp in this example, with an efficiency rating of 83 percent. If it were a Class AB amp, we’d assume efficiency around 55 percent. So, to get 1,000 Watts out of this amp, we need to feed it 1,204.82 Watts. Next, we calculate how much current that amp draws by dividing 1204.82 by 12 to get 100.4 Amps of current. To keep life simple, we’ll call it 100 Amps even.

The iConnects i4600K 4-gauge kit includes 18 feet of power cable, 3 feet of ground, 30 feet of speaker cable and a 16-foot RCA. They rate the kit as being compatible with systems up to 600W, and use 100-percent OFC cabling.

This seems relatively simple, except that most cars have alternators rated for 65-85 Amps, small batteries and small wiring. The result is an inability to supply the amplifier with the power it needs to produce the power you want.

Streetwires ZeroNoise5 Amp kits are 100-percent OFC copper and meet CEA-2015 guidelines. The super flex jacket allows for easy cable manipulation for easy installation and excellent reliability.

You have to know I am setting you up for something – it’s just my way. Flowing 100 Amps of current through a conductor can cause problems. Why? Because all conductors have resistance, and when current flows through something with resistance, power is wasted. That leads us to our second equation. Power (P) is the square of Current (I) times Resistance (R), or P = I² x R. Now, just how important is the size and quality of the wire you use in your installation? Let’s let the math decide.

If we try and power the above amp with a 17-foot length of good-quality Copper 8AWG power cable with a resistance of 0.0007162 Ohms per foot, let’s see what happens with respect to the math. That resistance number, by the way, is the maximum allowable resistance per foot for a piece of 8AWG cable as per the CEA-2015 Mobile Electronics Cabling Standard document. So P = (100 x 100) x 0.0007162 x 17 (feet). That works out to 121.75 Watts of power wasted in the cable. Want the bad news? You need a ground, or return path to the battery, and there are connections to fuses and so forth along the way. For the sake of this example, we’ll just double the cable length. So now we have 243.51 Watts wasted in the power cables.  If you want to put that into a number you can relate to, go put your hand on a 100W light bulb and get back to me.

We can also calculate how much voltage drop that represents at the end of the cable. We know the current is 100 Amps, the resistance is 0.000716 Ohms/foot and we have 34 feet of cable. If we multiply all those numbers together, we get 100 x 0.000716 x 34 = 2.435 Volts. So now, our poor 12V electrical system is only supplying 9.56 Volts to the amp because of cable losses. Think you need bigger cable? The recommended minimum cable size to handle 100A of current is a real 4 AWG cable.

Stinger amp kits are available in a multitude of configurations with 8, 4 and 0 gauge cables. Stinger uses premium nylon braiding instead of split loom to protect the power cable for a very clean and professional look in its 6000-series kits.

The maximum allowable resistance for a 4 AWG cable as per CEA-2015 is 0.0002835 Ohms per foot. I’ll save you the trouble of dropping that back into the equation and just do the math in a spreadsheet for you. Our power wasted in the 4 AWG cable drops to 0.963 Volts total, so we have just over 11V at the amp. If you are like me, and are now a bit obsessed by the math, a worst-case 0 AWG cable has a voltage drop of only 0.38 Volts, and that’s my idea of good power delivery.

We’ll revisit this another time, but let me leave you with this scary thought. Not all cables are created equally in terms of size and material. Copper Clad Aluminum conductors are less expensive, but have about 30 percent more resistance. Add to that the fact that some companies don’t manufacture cables to meet the AWG (American Wire Gauge) size guidelines, and the resistance of the cable can go up even more.

The impressive 1/0 AWG Premium Power Connection System from JL Audio is rated for 200 Amps and includes 20 feet of 1/0 power cable, a distribution block and 4AWG power and ground cable – enough to install two amplifiers. JL extends the warranty on its amps by a year when installed with these kits.

No matter what accessory you are installing in or on your vehicle, please do it with good-quality cables and good-quality connections. The performance and reliability will pay off in spades!

Text by Dave MacKinnon, Photos by the Manufacturers

It’s getting cold outside and we in Southern Ontario are scheduled to get our first snow flurries of the season in the next few days. Typically, this would be the perfect introduction to a piece on remote start systems – but it’s not; we are saving that for the next issue. What got me thinking about the topic for this issue was my recent introduction to the intricacies and availability of aftermarket seat heater kits, something that, for some reason, is not popular here in Eastern Canada. We’re going to check out heated seat kits, as well as several other cool functionality upgrades your local mobile electronics specialist can set you up with.

Adding heated seats to your car is actually a relatively simple process – most kits come with a pair of seat pads, a control switch and a wire harness. If you want to do two seats, then you use two kits as one pad is intended for the bottom of the seat and one for the lower back. Good quality heating pads will have flexible carbon fibre strands that run across them that are connected to flexible conductors along the edges. When current is passed through these carbon conductors, they warm up. It’s so simple! Good quality seat heaters also include a built-in thermometer to regulate the maximum temperature and likely a three-position switch with off, low and high settings. Ensure the kits your installer is using have reasonable gauge wiring; some kits cheap out on the wiring and the size of the heating pad. As always, you get what you pay for. Lastly, ask if the kits are made to modern OEM production tolerances and guidelines, and if the kits are insured; they are heating elements, and although I don’t know of ANY failures, you want to be covered and have confidence in the product.

How does it all come together? Your installer simply removes your seats from the car, removes the covering on the seats (leather or cloth), trims the heating pad to fit for length and around any connections, then reassembles the seat covering. He may require some special tools such as hog ring pliers to complete the task properly. Make sure your installer is using genuine metal hog rings and not plastic zip ties – you want the seat covering to remain in place when you are getting in and out of the car so it always looks good. Plastic ties can and do fail over time.

Another fantastic and popular mobile electronics upgrade is a backup camera. The price of backup cameras varies dramatically – and don’t think they are all created equally. The best cameras are built around a cast aluminum housing and feature o-rings to seal out water. A glass lens is another sure sign of quality in a camera. The device used to capture the picture – called an image sensor – is the heart of the camera, and its ability to produce a clear, focused, high-contrast image under all types of lighting conditions is what separates the good ones from the cheap ones. Yes, those all-in-one systems from the local auto parts store do work, but I am not going to comment on their reliability or image quality. Same goes for the cheap wireless systems; I have heard many stories about them not working when cell phones are turned on, not an issue you want to deal with.

Finally, look for a camera with an extremely wide field of vision – at least 115 degrees horizontally. Also watch for low-temperature operation capabilities. You want to be sure it’s going to work on a frosty winter morning; -20C is a good starting point. Small size and solid mounting, along with quality water-resistant cabling, are also key features.

What you connect the camera to is the next option. I am, of course, going to suggest going all-out and replacing your radio with a quality in-dash video source unit that has backup camera capabilities. But if that’s out of your budget, or you can’t replace the radio in your vehicle, then there are a multitude of quality head restraint monitors that can be installed overhead. Ultimately, you want the image to appear when you put the car into reverse, without touching any buttons. Make sure your salesperson and installer understand that.

Another option is the installation of an aftermarket ultrasonic backup sensor kit. This is the same concept that many factory installed systems use, including my ‘07 Grand Cherokee. These kits include sensors (typically four) that are to be installed in your rear bumper. A module inside the vehicle beeps, and on some better systems, a display indicates your distance from an object. Though not as informative as a back-up camera, they are indeed better than nothing.

Moving on, I am reminded of the work I did to my first new car, a 1991 Mazda 323 hatchback. We built a moderate audio system in it that included four 10-inch JL Audio 10W1 subwoofers, two PPI Art Series amplifiers, an AudioControl 24XS and EQS, and custom door panels with a 3-way MQ Quart speaker set, and fed it from an Alpine or Clarion source unit (the head unit changed often.) To mount the speakers in the door the way I wanted, we had to remove the manual window cranks and install a power window kit.

Again, the process was relatively easy as the aftermarket offers several solutions. The kits come with a pair of motors, adapters, switches and wiring. The hardest part of the installation in many cars is running control wires into the doors through the factory grommet / wire boot. Good kits include overload sensing to ensure their safe operation.

If you have added power window control, or if your car was built with power windows, then adding a window control module to your alarm or remote start system is also a great idea. I did this on my ‘02 Subaru Impreza WRX. I could roll down either front window from the remote, and both rolled up when I armed the security system, a real convenience since I love driving with the windows down in the summer. You can similarly control a sunroof in the same way.

While you are thinking about upgrades to security or convenience systems, the addition of power locks and power trunk control is a no-brainer. Even if your car has manual locks and a cable trunk release, adding actuators to the locks or a solenoid to the trunk is an easy and common upgrade. Adding parking light flash is also very common when remote starts and security systems are being installed. This really helps make it easy to find your car in a congested parking lot.

When I was in high school, I became notorious for leaving the headlights on in my car, so thanks to a few relays tied to the key detection sensor, I eliminated that problem for good. Your local mobile electronics expert can do the same. This reminds me, if you are importing a car into Canada and it doesn’t have daytime running lights, they can fix that problem too!

Adding accessories like the ones I have mentioned above make using your car safer, more enjoyable and more convenient. I have owned everything from the above list, and the money spent was well worth it. Visit your local mobile electronics expert to see what they can do to really accessorize your car – and I’m not talking about LED washer sprayers.

Twenty-two years ago, when I got into the mobile electronics industry, everything was relatively simple. The most complex part of a radio installation was making sure the cage for the pull-out tape deck was secure in the dash and that you had correctly connected the dimmer lead to the headlight circuit. Now, cars are far more complex. Advanced data bus communication, GPS antennas, satellite radio and more have turned the common deck install into a university engineering project worthy of a doctorate – or has it? Companies like Pacific Accessory Corporation are in business to make the lives of installers and consumers easy and pain-free when it comes to integrating aftermarket products into our vehicles. Follow along as I install a Kenwood DNX9960 into my 2007 Grand Cherokee SRT-8 with the help of the Pacific Accessory Corporation’s (known as PAC) C2R-CHY4 OEM Data interface and SWI-JACK steering wheel interface as well as an American International BAA20 antenna adapter and CDK650 mounting bracket kit.

Before you rush out and buy a whole pile of adapters and accessories, I’d like to clarify a few things. My Jeep is very easy to work on, at least with respect to changing the radio, but not all vehicles are this cooperative. I also have extensive resources at my disposal in terms of connectivity information and decades of installation experience under my belt. While this step-by-step looks simple, time was spent researching what products I wanted to use, as well as ensuring all the connections I made were correct. You will notice the instruction manuals for the adapters are visible in most pictures as I referred to them frequently for wiring and programming reference.

This project may not be something the average DIY enthusiast is capable of, and definitely not something someone with no experience should undertake. The intent is to show that you can indeed replace and upgrade that feature-limited terrible-sounding factory radio in most vehicles – and the pay-off in terms of sound quality improvement and new features is well worth it. If you are not absolutely, 100 percent confident in your ability to perform a task like this, please have the installation completed by your local car audio shop. They have the experience and knowledge to do the work quickly and safely.

Text by Dave MacKinnon Photos by the Manufacturers

Last month, we took a look at marine electronics including head units and amplifiers. It was a good primer to get into this cool mobile electronics category, but it’s also only half the story. I have said a million times – if you don’t have good speakers, all the expensive electronics in the world will still sound terrible. As you can guess, we are going to talk about marine speakers in this issue.

The job of any speaker is to convert an electrical signal into sound. Better speakers do this more accurately, better recreating the original sound of a recording. These guidelines hold just as true in your living room as they do pounding across the waves. But those waves pose a challenge, as does the harsh and unrelenting sun.

Marine speakers need to be designed to take punishment. They have to withstand being wet. Not damp, not splashed – flat-out wet. Something to look at when you are intending to buy a set of speakers for a marine application is to ensure that they feature a rubber mounting gasket to give a tight seal against your boat hull. Further, in a coaxial design, you need to ensure there is a secondary flexible seal at the base of the tweeter pedestal that keeps water from entering the motor structure. Without this secondary seal on the midrange cone, your speaker will likely fail within a year or so.

The ability to properly handle water means that marine speakers should have provisions to allow water that does get splashed on them to evacuate properly – this can be as simple as a small hole or channel in the bottom of the grill. Whatever it is, you don’t want water pooling behind the speaker grill.

The sun is a harsh mistress. Sure, she keeps us warm and lets us see, but she also burns our skin (when we aren’t careful) and can wreak havoc on anything else left exposed to her all day. The plastics that are used to construct marine speakers need to be chosen to be able to handle the effects of UV rays and not chalk, fade or crack. Many manufacturers, like JL Audio, Clarion and MTX offer ASTM D4329 certification, which means the device in question has been exposed to high levels of UV exposure without failing – something to look for in a marine speaker.

So, how do you buy a marine speaker? Listening to them on a display board is one way. But I suggest you step way back – about half way across the store and listen to them at many angles. You aren’t likely to be sitting in front of these speakers on your boat; in fact, in most applications; they are going to be playing music facing your legs. So, walk around the room, and listen to see if the sound changes drastically. Also, make sure you are listening to the type of music you like; I suggest bringing your own. And lastly, listen to them at the volume level you expect to use them. If you are looking for something to keep you from getting bored while fishing, then sheer volume might not be a concern, but if you are water-skiing or wakeboarding, then output and efficiency are critical.

Tower speaker systems are another beast altogether. They really need to be able to take a beating as it’s rarely the people in the boat that are trying to enjoy the music, but the person being pulled through the water behind the boat that is trying to get their groove on. For tower speaker systems, you have all sorts of options – large cone area drivers, up to and including 8-inch midrange and woofers. There are systems with horn-loaded compression drivers that are great at projecting large amounts of sound. You can also find countless accessories and options when it comes to tower speaker systems. My favourite are the LED lights – how cool would that look at dusk?

What it all boils down to is that your time on the water is your time to relax, and you should enjoy yourself. So whether you are listening to your favourite jazz music during dinner or cranking tunes while skiing – having music with you on the water just makes everything better.

Text by Dave MacKinnon, Photos by the Manufacturers

I’ll be straight up about this issue of Plugged In – we aren’t going to talk about anything related to cars. When I started writing Plugged In, it was my goal to never beat any single topic to death, and to expose the readers of RPM to as many diverse aspects of the mobile electronics industry as I could. So, given that Mother Nature is doing her thing and warming things up, we thought it might be fun to take a look at marine audio.

A few decades ago, there were very few companies that offered products designed specifically for the marine environment. The first marine-specific product I recall seeing was heavy aluminum-cone subwoofers from a company called BABB in a shop in Ft. Myers, Florida when I was in high school. Things have changed, and now almost every major car audio manufacturer has a line of marine products. In this issue of Plugged In, we are going to look at the electronics behind entertainment on the water.
You might think that almost any source unit would do when it comes to enjoying your music on your boat, and in essence, this is very true, but the marine environment poses its own special challenges on an electronic product, many of which are amplified ten-fold when you expose these electronics to salt water.

Now, if you happen to be able to spend your weekends on a 100-foot yacht, your needs may vary a little, but for us normal folk, our boats are weekend toys or week-long vacation destinations for the summer. Quality marine electronics take into account that devices may be exposed to very harsh conditions, not just in terms of water exposure, but also heat, humidity and vibration. If you are looking at marine electronics, look closely at the design of the chassis, wiring connections and mounting. It’s often more than just regular use that challenges these products. For example, water dripping on the rear of a source unit behind the scenes can wreak havoc.

Source units don’t differ much when it comes to features – AM/FM receivers, CD playback with MP3 and WMA compatibility, iPod and USB connections and what is important for marine applications, the availability of satellite radio as an option. Many boaters travel well out of range of their favourite radio station on a good cruise, so having Sirius or XM on board means you can enjoy your music almost anywhere. Given some of the geographic challenges our terrain imposes, make sure the satellite radio provider you choose for your boat will work where you want to use it.

Entertainment systems on boats often need to be operated from multiple locations. A radio may be installed up at the helm or down in the galley, so most radio manufacturers offer various options in terms of remote controls. Many include an IR remote that functions in a line-of-sight application. You also have the option of wired and wireless remotes. Some of these remotes have displays on them, so you are essentially looking at the same information as is being displayed on the face of the radio.

Marine amplification is a necessity and a challenge at the same time. Amplifiers are historically large and inefficient, but recent advances in high-speed computer processing has allowed digital amplifiers to dramatically shrink in size to that of a textbook, while providing great efficiency. While my personal preference is for purely analog amplification, digital amps sound better than they ever have and the increase in efficiency, especially on a boat, is worthwhile. I mention that amplifiers are a necessity, because the background noise level on a power boat can be very high. Combine that with wind noise and the spray of the water and you will easily need several hundred real Watts to ensure you can hear your music loud and clear. The paltry 18-20 Watts built in to a radio is fine for eating dinner when you are docked or at anchor, but when you are pounding the waves, it’s just not enough.

There are standards for everything in life, and when it comes to marine entertainment products, manufacturers spend lots of money to test their products before they sell them to make sure they will be reliable. The design stage of any product helps to ensure reliability; for example, most quality marine electronics will feature a conformal coating on the main circuit board to prevent humidity from corroding the tiny connections between components on the board.

Another consideration on a boat is safety. There are standards for devices installed in environments that may be exposed to fuel or cooking gas vapours. You don’t want your boat to blow up when you turn your radio on, do you? Look for marine electronics (including battery chargers, inverters, battery switches and so on) that are Ignition Protection Certified. These devices have been tested to ensure they will not ignite a flammable air-fuel mixture, ensuring your safety.

One thing that is hard to address on a boat is security. Really, you could just back a trailer up to a loading dock, undo some ropes and steal almost anything. BlackLine GPS has a solution for boat owners called Harpoon GPS. This is a GPS-based tracking system that uses cellular communication to let the boat owner know instantly should the boat be moved without the provided key fob present. You can even track the boat’s location, speed and heading via a dedicated website that uses Google Maps, so if the kids are out playing, you know where they are and what they are doing.

I’ll stop somewhat abruptly at this point, but in the next issue, we are going to look at marine speakers and accessories, as well as touch briefly on some installation issues specific to marine installations.

Text by Dave MacKinnon, Photos by the Manufacturers

It wasn’t long ago that automakers phased out tape decks in new cars in lieu of CD players. In the past couple of years, most of them have caught on to the iPod revolution and now include either a USB port or dedicated iPod connection to let the latest generation of music enthusiasts bring their collection with them.

As the mobile entertainment aftermarket is typically one step ahead of the OEM guys, there is another change on the horizon, which will include only digital media source units in a car. What is digital media you ask? In this context, it is any device that can store computer recognisable files, such as an SD card or USB memory stick. So what makes a digital media deck different? It’s not what it’s got, it’s what’s missing – a CD transport. Some manufacturers refer to these decks as ‘mechless’ in that they don’t have a CD mechanism.

So, why would you want a digital media deck? Given the current availability from the top manufacturers, digital media decks are poised to increase in popularity because of the features that have been included to replace the CD mechanism. These include high resolution and colour displays, enhanced compatibility for different media formats and often a unique look that differs from the rest of the company’s product offerings.

Okay, so you have finally sold the last of your 45s and the neighbour is rocking your old eight-tracks. It’s time to go digital – so where do you get your music? The answer is, of course, the Internet. No, I am not talking about illegal downloading from Napster, Kazaa and Bit Torrent; there are lots of places to buy music quickly and legally, the best known of which is iTunes. Here, you simply set up an account, click on the song you want, and in seconds, you are listening to your favourite track or album.

What was once the biggest thorn in the side of music companies has reinvented itself on the right side of the law – Napster is now a great resource for music and makes it really easy to copy and paste downloaded music to a USB memory stick or similar.

Another option is to convert your existing CD collection into a digital format (MP3 or WMA). If you are running Windows (XP, Vista or Windows 7), then converting an entire CD to a collection of WMA files is as easy as inserting the CD into your computer and using Windows Media Player to rip it. Ripping is the act of converting the contents of a CD to a collection of digital media files.

So, why do we want our music in digital format? The best reason is that we can take a large collection of music with us in a very small package. Take, for example, the Apple iPod series of digital media players. Even the tiny little iPod Nano with 4GB of storage can give you an impressive 2,000 songs. Stepping up to the big 160GB Ipod Classic means you can have 40,000 songs. That’s like 4,000 entire CDs, right in your pocket!

The first digital media decks were designed around the concept of bringing your digital music with you. They all tended to show a preference towards the Apple iPod in terms of compatibility and interface. The newest generation of digital media decks now includes provisions for video playback. This was a logical extension as more and more people are converting their DVD collections to digital formats.

So, what should you look for when shopping for a digital media source unit? Since the price, features and capabilities of the decks differ from one manufacturer to another, this can get tricky. First and foremost, though, is to ensure that the music or videos you have plays on the unit you buy. Try this in the store on their display board. You should also ensure that the deck has the audio features and capabilities you want. These include preamp outputs, crossovers, high-quality D/A converters and more.

You should, of course, ensure the unit will fit in your vehicle and that the interface is easy to use and intuitive. A provision for factory audio control integration would be nice.

Since many of these digital media units represent premium products, it is likely you will find many of them with Bluetooth hands-free and audio streaming built in. Try your phone with the deck on the display board of the store you are purchasing from. Ensure it functions the way you want and has the capabilities you desire.

Text by Dave MacKinnon (www.osmlabs.com), Photos by the Manufacturers

Last year, we took a look at how speakers worked, then at what separated the also-rans from the truly great products. In this installment of Plugged In, we are going to delve into the topic of subwoofers.

If you ask the average guy or girl on the street what a subwoofer is, they’ll tell you one of two things – it’s either a smart answer something like “Oh, that’s the bass part in my home theatre” or something less flattering like “those darn kids boomin’ down my street at all hours have those.” While both are right, they are far from a technical answer – which, of course, is where I come in.

A subwoofer is a speaker, typically fairly large in size, that is designed to reproduce the bottom two octaves of the audible spectrum. If we consider the audible range of sound to be 20Hz to 20kHz, then a subwoofer covers 20Hz to 80Hz. In a later issue of Plugged In, we’ll look at high-end subwoofers and explain how some, combined with their use in a car, can play down another octave.

So, then, is a subwoofer important to accurately reproducing music? It most certainly is – high fidelity means that we want to reproduce music as accurately as possible with respect to the original recording. I did a quick dig on the Internet to get some backup. For those of you with an orchestral background, then there are a few instruments that would be lost in a performance without a quality subwoofer. The contrabassoon, for example, plays down to an impressive 29.1Hz, and a Harp (which I didn’t know) plays down to 30.9Hz. The lowest A note on a piano is 27.5Hz, and a Bosendorfer Imperial Grand Piano and most quality church pipe organs will play to a bone-rattling 16.35Hz. Mmmm, I get shivers of delight just thinking about it!

So, what differs in the design of a subwoofer as compared to a regular speaker? Other than their physical size, the key change is the distance the speaker cone must move to do its job. For every octave lower a subwoofer must play, cone excursion quadruples. So, if a subwoofer must move 1mm back and forth to play 80Hz at a specific volume level, it has to move 4mm to play 40Hz at the same level, and a whopping 16mm to play 20Hz. Which is why some won’t play 20Hz very well – they can’t move that far.

A key and critical factor with respect to subwoofer performance is the enclosure in which it is installed. Because the cone moves quite far, the air inside the enclosure is pressurized and then put under vacuum. So the amount of air inside the enclosure has a dramatic effect on the subwoofer cone’s ability to move. We won’t get into the math behind that right now, but know that the design of the enclosure you choose and the quality of its construction is as critical to its performance in your car (or home) as the design of the subwoofer itself.

Since we know it takes lots of cone excursion to move a subwoofer, and we know that it takes lots of power to make a speaker cone move, then we can quickly surmise that subwoofers need to handle lots of power. Foolishly, people continue to rate speakers based on their power handling capabilities. It would be like rating a car’s handling based on its top speed capabilities – fine for a Veyron, but the plan falls apart when John Force deep stages his Mustang in front of your house but plans on making a U-turn at the end of the street and coming back.

The problem with putting lots of power into a speaker is that, sadly, speakers are really inefficient. Most subwoofers convert about one percent of the energy you put into them into sound. This means, a sub getting 100W of power is making 1W of musical energy and is heating the car with 99W of thermal energy. When things get hot, they fail. So, the parts used to build a subwoofer need to be able to withstand a great deal of heat. Most subwoofers are designed to allow air to flow in and around the voice coil to help move heat away from it, so it won’t overheat the varnish that keeps it neatly wound together.

What separates one subwoofer from another? Its design. Most are made of good materials and most can move back and forth well, to some extent. Where one subwoofer differentiates itself from another is in the speed at which it can respond to an input signal, how fast it stops moving once the signal is gone, how accurately it tracks the input signal (linearity), how far the speaker cone can move and the frequency response (output level) of the subwoofer in a given enclosure.

We’ll save subwoofer enclosure designs and construction for a later installment, but let’s look at a few numbers that you should understand when you go subwoofer shopping. The first one to know (to make you sound smart) is Xmax. Xmax is the distance the cone of the subwoofer can move forward or backward from its rest position before the voice coil comes out of the magnetic gap. It can get more complicated, but really, it tells you how much air the cone can move, and given the correct enclosure application, how loud the sub can play. More is better – to a point.

Efficiency is the next specification to talk about, but this one gets tricky, since the number specified is typically in the 85 to 90dB range. This refers to how much sound the subwoofer will produce when powered (typically) with 1 Watt. It’s often written as 89dB 1W/1M – which reads 89 Decibels with 1 Watt measured at 1 Metre. The problem with this specification is that it doesn’t tell you at what frequency it produces this output, and it’s often derived mathematically.

Getting a little more technical, we should discuss ‘low frequency cut-off.’ This specification is 100 percent dependent on the enclosure you use and describes how low (or deep) a subwoofer will play. For example, a ported subwoofer enclosure for most cars with the speakers I am going to highlight here, should play down to 35Hz or so. Sadly, as an enclosure allows a subwoofer to play lower, you typically lose more efficiency. There are dozens more, but we’ll get into those next time – sorry for the tease.

So what about all the fancy materials and designs you see out there? Flat-cone subwoofers? Square, hexagonal and triangular subwoofers? These are just variations on a theme. Sure, some let the designers cram more cone area into a smaller space (both in terms of cone surface area and driver depth), but if done properly, that’s the extent of the benefit. No fear though, that can be worth the ‘price of admission’ and they are well worth checking out for specific applications.

I’ll wrap things up by saying that the choice of one subwoofer over another should be done by listening to them. Ideally, if you can try the subwoofer you want in your car, that would be best – each and every subwoofer from the hundreds of companies out there sounds a little different than another. Some play really low, some are very tight and controlled, some are boomy and loud. Let your local car audio shop know what your needs are in terms of a subwoofer and they should be able to offer you something that really brings some emotion and realism to your music – be it the 1812 Overture, Money for Nothing, Down in It or The Real Slim Shady!

Text by Dave MacKinnon (www.osmlabs.com). Photos by the Manufacturers

Back when I got into the industry, a mere 22 years ago, the car alarm installed in my 1982 Dodge Aries (sedan version, don’t you know) included an impressive two wires and a knob to adjust the shock sensor sensitivity. We have come a long way, and now have security and convenience systems that can tell us the location of a vehicle, allow us to remote start a car from more than a mile away and even let us use our cellular phone to activate functions from another town, province or continent. In this issue of Plugged In, we are going to look at modern security and convenience systems for you car.

It used to be easy, installing a car alarm that is. Mount the brain and siren, tap into the door pin wires and install a relay to cut the starter wire if the alarm was set off. Now, we have cars with complicated data bus systems that use digital communications to activate door locks. We have keys with built-in transponders that must be present for a car to start. And scariest of all, the wiring in cars has become so complicated that what was once a simple skill of a good installer has turned into a specialty talent that has been perfected by only a select few.

Most of us think of these systems as car alarms. You push a button, the siren chirps and the car is protected from damage or entry. The evolution of the convenience system began with the ability for the car alarm to lock the car doors. Quickly following that was trunk-opening ability and then came remote start systems. Early remote starts weren’t overly complicated and their reliability (actually starting the vehicle and keeping it started) took off once all the cars on the road moved from carburetors to fuel injection.

Modern remote start systems are very intelligent. They are connected to not only your ignition and starter circuitry, but to the engine as well. They are capable of monitoring engine RPM and will shut down if the engine speed is too high, or attempt to restart the vehicle if the engine doesn’t stay running.

The next evolution in security and convenience came with the battle for long range communication. Being able to be further away from your car, and still start it, is one of the key marketing features of every system in the industry. Entry-level and basic systems often claim a range of 300 feet, the better ones are 500, and with the use of the 900 MHz and 2.4GHz spectrum, computer-controlled communication allows for one mile of range. Like any feature or specification that the marketing guys focus on, these numbers are based on ideal conditions – your performance may vary by as much as 50 percent.

Once we had the ability to communicate reliably with the vehicle, the next step was to allow for the vehicle to communicate with us. Fifteen years ago, I had a pager for my car alarm that I wore on my belt. It had two lights to tell me if the shock sensor had gone off, or if a door had been opened. Now, the keyfob that you have attached to your keychain can include an LCD or, in some cars, colour OLED display that will confirm that your car is locked, tell you once it’s started or, in the event of foul play, tell you what zone is being affected (doors, shock sensor or trunk). Remember the good old days when a cell phone only displayed phone numbers? The epitome of two-way transmitters is the new full-colour OLED unit from Clifford in their Responder HD systems.

So, what’s next for security and convenience systems? Companies are always adding features that make them easier for installers to integrate them with your complex vehicles. For example, Fortin Electronic System of St. Leonard, Quebec offers an extensive line of programmable data interfaces for vehicles that have their accessories on the CAN data bus. These modules allow a security or convenience system to monitor door, hood and trunk pins, lock and unlock doors, arm and disarm the factory security system and even provide an engine rpm signal to the system to ensure the engine is running. These modules do this all digitally via the data bus. Most importantly, these interfaces allow installers to remote-start vehicles that have transponders built into their keys.

What is a transponder? It’s a small RFID chip embedded in the head of your car key. When you start your car, a code is read from this chip and compared with what is in memory in your vehicle’s engine management system. If the codes match, the car starts. If they don’t, even if the key is cut identically and you can turn the ignition barrel on, the car won’t start, or won’t continue to run. The implementation of this technology has dramatically reduced auto theft, since it is very difficult to bypass.

Many remote start systems now include logic to allow them to be installed in vehicles with standard transmissions. In the past, crude designs that included micro switches were the only way to detect if your car was in neutral. Now, when you want to remote start a vehicle with standard transmission, you simply need to go through a quick procedure before you turn the car off the night before. For example, DEI (best known for its Viper and Clifford products) requires that you set the parking brake, activate the remote start then leave the vehicle and close the doors. The remote start system will then shut down the engine. If a door is opened before you remote start the car, it exits remote start mode, as someone may have put the transmission in gear. Simple, yet very effective.

Another cool new technology I found is from Zenesis Electronics Corp. Its ZN-502, ZN-302 and Z-101 systems come with a new feature called Z-Pass TOUCH. This is a small touch-sensitive pad that is installed on the inside of your windshield. You can use this pad to page the person with the keys to the vehicle, or in the unlikely event you have lost the keys, you can disarm the vehicle by simply typing in a preset code. If you want to see it in action, head to YouTube and search for Zenesis Zpass. VERY cool!

The last item of interest is the new Text Start system from Titan Innovations. Using cellular phone text messaging, the TMS100 Vehicle Messaging system can provide you status updates from an OEM or aftermarket security system. You can send commands to the system (also via text message) and have it unlock the doors or remote start the vehicle (if you have a remote start installed). The system will even tell you if someone has disconnected your battery. Now, you can be on the beach in Mexico and keep tabs on your Hot Rod in Kelowna via your cell phone.

You might be thinking to yourself – why should I install an aftermarket system in my car? I already have keyless entry. Like anything aftermarket, it’s all about performance and convenience. With an aftermarket system, you get increased range, so you can start your car in the underground parking lot of your apartment building. If you choose a two-way system, you can keep tabs on your vehicle when you are in the movie theatre or at the mall. Finally, you may get some cool add-ons like an integrated turbo timer, or a headlight car-finder. Ultimately, you need to decide your goal for the system, then have a qualified shop integrate it into your vehicle for you.

by Dave MacKinnon (www.osmlabs.com)

What if your car could call for help? Imagine a scenario where a thief decides that no matter what you have done to protect your vehicle, they absolutely have to have it? Does this sound like Gone in 60 Seconds to you? It absolutely happens – specific make, model, trim level and colour vehicles are targeted all the time by theft rings because they are wanted by chop shops. Why so specific? Shops often buy a car that has been written off in an accident, then steal an identical car and transfer the VIN numbers to the stolen car and sell it to unsuspecting and seemingly innocent buyers. Unfortunately it happens all the time.

So what can you do to protect your pride and joy when a thief pulls up with a flatbed and drags your car away? You have the police simply go and retrieve it thanks to the marvel of modern GPS and cellular technology. Products from companies LoJack, Boomerang, Titan and BlackLine GPS allow you, to varying degrees, to know exactly where your car is and what it is doing.

For example, the GPS Snitch from BlackLine GPS is designed for convenient consumer use. Once placed in a vehicle, you can visit the GPS Snitch website and see the location, heading and speed of your vehicle. It’s convenient because it can operate via an internal battery for up to a week. For basic operation, there is no installation required. The GPS Snitch is also a great way to keep track of the kids when they borrow the family car.

Moving up in complexity and features is the TT3000 from Titan Tracking Systems. This system adds features such as over-speed alerts, low or disconnected battery, excessive idle time and many more tools that are not only convenient to nosy and cautious parents, but can be beneficial to fleet operators or rental companies. With the TT3000, you know what the driver is doing all the time. The TT3000 also features five inputs and seven outputs, so you can monitor zones such as doors, seatbelts, the parking brake and more, while having control over door locking, parking lights, trunk release and starter disable all via a convenient web interface. The TT3000 is a product that would be professionally integrated into your vehicle.

LoJack is one of the oldest companies in the vehicle tracking industry. They focus primarily on theft recovery, and their vehicle tracking is performed by law enforcement agencies. LoJack and Quebec-based Boomerang operate together in Canada. If and when your vehicle is stolen, you call the police and they deploy a tracking team to get your car back. Often, your car can be found within hours or even minutes. To date, Boomerang tracking devices have aided in the recovery of more than 6,800 vehicles with an approximate value of more than 300 million dollars. Boomerang and LoJack disguise their hardware and make its installation locations difficult to detect, adding another level of security and reliability to their products. You must seek professional installation for either LoJack or Boomerang.

All of these devices use a high sensitivity GPS receiver to locate themselves, then communicate that information back to a central location via cellular technology. This means that these systems carry a monthly charge for the cellular service, as well as the original cost of the product and its installation. That being said, knowing that you can find out where your car is at any time, or have your car let you know that someone is messing with it, is priceless!

Text by Dave MacKinnon (www.osmlabs.com) Photos by the Manufacturers

By now, all of you have seen car audio installations that incorporate what seems like large-diameter power wires. These cables can be nearly a half-inch in diameter for systems under 1,000W and nearly an inch in diameter for systems rated more than that. This may seem like overkill, but in fact, it’s just adequate for most systems.

The size of the wire you use to power up your amplifiers and other high-current devices (lights, winches, etc) is called its gauge. If you are using good-quality wire, you will see a size printed on the jacket such as 8 AWG or 4 AWG. AWG stands for American Wire Gauge and it is a universal standard for determining the size of a conductor. We’ll talk more about this at the end of the article.

Unfortunately, our cars run on a 12V electrical system. Optimistically, we might see 13.6V to just under 14V at the battery when the car is running. The problem is that we need to draw massive amounts of current from this low-voltage electrical system to produce large amounts of power. Why? Because the laws of physics state that power is the product of voltage times current. If we want to power a 100W light bulb from a 13.6V electrical system, that light bulb will draw 7.36 Amps of current.

When we start to talk about car audio systems and large amounts of power, we also need to take into account the efficiency of the amplifiers. Most Class AB amplifiers operate between 60 and 75 percent efficiency at full power, and at less than half that at lower power levels. Class D amplifiers increase this up to around 90 percent for some of the best designs. So, let’s say you want to install a 1,500-watt amplifier, and the amp in question is 80 percent efficient, you need to supply the amp with 1,875 watts of power. At 13.6V, that’s an awe-inspiring 137.9 amps of current. That’s way more than a piece of 4 AWG cable is rated for – they max out their effectiveness at about 100A.

What happens when a conductor isn’t large enough? Its resistance causes the voltage at the end of the wire to be too low to allow the load device to operate properly. For most car audio amplifiers, this means that the amp won’t make as much power as rated. For example, the CEA-2006 amplifier specification states that amplifiers tested to this standard are to be supplied with 14.4V; unfortunately, that is a number rarely achieved in a car, but at least the standard makes amplifier ratings comparable.

Another issue with respect to power distribution is that people forget that current must travel in a loop – from one terminal of the battery and back to the other. I see countless audio system installations where a large 4 AWG or even 0 AWG power wire has been run from the battery to the amplifier, but the negative terminal of the battery remains a tiny piece of 8 AWG cable. It’s no wonder these systems often suffer from headlight and dash lights that dim with the beat of the music.

Speaking of dimming lights, there are some great solutions to this very common problem. The first is to ensure you have adequately large power wire for the size of system you have installed. You cannot have oversized wire, so get as much as you can afford. The second step is to complete what is known in the industry as the ‘big three’ connections. This refers to the connection of the positive terminal of the amplifier to the positive terminal of the battery through an appropriately sized and located protection device (fuse or circuit breaker). The other two connections are to ensure there is an additional, equivalent-sized ground wire running from the negative terminal to the chassis. The removal of all paint and primer at the chassis connection is critical. Finally, you need to do the same for the negative terminal of the amplifier. The same size wire should be run from the negative of the amp to the chassis, with all paint and primer removed.

The next step in upgrading your audio system would be to include an upgraded battery or a stiffening capacitor. Both of these devices store electrical energy. A battery stores a significant amount of energy, but the rate at which it is released is limited. A cap can store a small amount of energy, and release it very quickly. Caps can help stabilize the voltage of a car’s electrical system when you are playing very dynamic music at high listening levels. A cap, however, does nothing to increase overall system volume (output) or its available playing time. If you want more power or longer play time, a larger battery or a secondary battery are your only solutions.

It is absolutely critical that proper fusing is used any time you connect a wire to a power source such as a battery. Fusing not only protects the device you have connected (such as an amplifier), but protects you as well. Imagine the scenario where you have installed a large 0AWG conductor in your car and it runs from the front to the back to feed a large amplifier. If your car were to get into an accident such that this large wire was pinched and shorted out, without proper fusing, the battery could easily explode, and at the very least, you could prevent a fire.

I mentioned earlier about wire sizing. This is a case where you can’t judge a book by its cover. Although the American Wire Gauge standard is the most common way of describing wire size, it appears that many wire manufacturers have taken liberties with the naming, and sell undersized wire in an oversized package. It’s like a small hot dog in a big bun, and unfortunately, it just doesn’t have the current carrying capacity of real cable. The other thing to look for is the material that the power wire is made of. Pure copper is ideal, as it conducts well. However, a lot of inexpensive cables use copper-clad  aluminum. Aluminum is less expensive, but it unfortunately has about 30 percent more resistance than copper. This means, for the same size wire, less power is actually getting to your amplifier. I recommend going up at least one size in cabling when using CCA cables. So if you needed an 8AWG conductor, use a 6AWG. If you needed 4AWG, then use 2AWG… or just use good copper conductors.

Finally, if you are running multiple amplifiers in a system, there are nearly an endless combination of power distribution blocks available, many with fuse holders built in. You can select the size of the cable going into the block, and the size and quantity of cables exiting. Companies put significant effort into the design of these blocks, and some are very cool looking.

Don’t overlook proper size wiring, no matter what you are hooking up. As I mentioned, anything that draws current – auxiliary lights, power inverters, air conditioners in campers, winches and so forth –  can present a significant load on your factory electrical system. Feeding them all properly will help ensure they operate reliably and to their maximum capacity.