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Keys to Proper Car Audio Speaker Installation

Speaker Installation

Over the years, car audio speakers have been installed in seemingly endless combinations of panels, pods and baffles. Some look great, some sound great and some offer both. Sadly, not everyone understands the physics involved in choosing the ideal installation locations for speakers. This article will cover a few of the vital installation criteria that need to be considered when your local retailer is installing new speakers in your car or truck.

Every Speaker Needs an Enclosure

If a speaker were set on a table and music played through it, you’d find it doesn’t produce any bass and very little midbass. This is because there’s a nearly equal amount of sound produced from the back of the woofer cone compared to the front. If you wrap your hands around the speaker, the performance improves. If you mount the speaker in a baffle that separates the two sound sources (front and rear), you’ve eliminated back-wave cancellation.

Speaker Installation
Bass and midrange sound produced by the speaker’s front and rear will cancel each other if the driver is not installed in a proper baffle.

Dash and Door Panel Installations

Of course, one of the most popular locations to mount a speaker is in the factory location in the dash or door of your car or truck in place of the speaker that came from the factory. This location typically provides excellent cosmetics as the vehicle retains its factory-like appearance. In many cases, such as a dash location at the base of the windshield, the speaker’s performance can be such that it delivers excellent frequency response throughout the entire listening environment.

Door Speaker Installation and Sound Deadening

If you have a speaker installed in a door location, your retailer may need to create a set of mounting adapters. A few factors need careful consideration during the design of these adapters. First, they need to be thick enough to ensure that the magnet assembly on the speaker’s rear won’t interfere with the window mechanism or glass. Second, the speaker’s front needs adequate clearance to ensure that the woofer cone can’t come into contact with the grille. Finally, the adapter needs to be made from a material that won’t be damaged by moisture. Most people would be surprised by how much water gets into the door when it rains or when a vehicle goes through a car wash. Common materials for speaker adapters include ABS and expanded PVC plastics. Wood is not a suitable material for use in the doors.

Speaker Installation
Extreme Audio near Richmond, Virginia, created a set of mounting adapters out of expanded PVC plastic to install new speakers in the rear doors of this 2014 Lexus RX350. They applied a layer of sound deadening to the door to serve as a gasket for the adapter.

Most modern vehicles have openings built into the interior skin of the doors. These openings allow technicians to service the door handles and window mechanism. Unfortunately, these openings also allow the sound from the speaker’s rear to mix with the sound from the front. The easiest way to improve the performance of a speaker mounted in a door like this is to add a layer of sound deadening. The dense butyl material and foam will seal the openings and dramatically improve your speakers’ efficiency and sound quality.

Speaker Installation
Perfectionist Auto Sound and Security in Anchorage, Alaska, treated the doors of this GMC 2500HD with a layer of SoundShield sound deadening material before installing new Morel speakers.

A Look at Speaker Pods and Enclosures

A common error we see in custom A-pillars and speaker pods is the use of an enclosure that’s too small for the chosen speaker. Even a 4-inch midrange that will play down to 125 Hz needs a certain volume of air in the space behind the driver so as not to affect the overall compliance of the system. If a speaker pod is too small, the system’s resonant frequency will increase and, beyond a certain point, so will the distortion added to the signal. Let’s look at a few examples.

It’s quite common to see 6.5-inch coaxial speakers mounted in small enclosures in an amp rack or subwoofer enclosure. Let’s look at a speaker like the BLAM Live-Series LW 165 C 6.5-inch coaxial speaker. Based on the manufacturer’s Thiele/Small parameters, the small sealed enclosure that would be acceptable for this driver would have an internal volume of about 0.3 cubic feet. This enclosure yields a system Q (Qts) of 0.707 and a-3 dB frequency of about 90 Hz.

Speaker Installation
Predicted low-frequency response of a single BLAM LW 165 C 6.5-inch speaker in a 0.3-cubic-foot enclosure.

Where we get into trouble is when an enclosure isn’t large enough. We recently saw a post where a fabricator crammed a driver similar to this into a pod that “was just big enough to house the speaker.” Let’s make this an extreme example and say the interior dimension was 5.5 by 5.5 inches with a depth of 2.5 inches. That’s a mere 0.017 cubic feet.

Speaker Installation
Here’s our 6.5-inch speaker now crammed into a tiny enclosure. There’s an almost 4 dB peak at 305 Hz, and the -3 dB point is now close to 190 Hz. The total system Q has a completely unacceptable value of just over 1.4. Not only would this sound terrible, but it would also be nearly impossible to blend into a subwoofer. Sadly, it happens all the time in cars and trucks and even more often in displays.

To prevent this, every speaker larger than about 2.5 inches in diameter should be modeled using enclosure simulation software to ensure that the planned enclosure won’t be detrimental to the system’s overall performance.

System Directivity

The last topic we’ll mention is directivity. Every speaker, from every brand and of every size, is subject to a phenomenon called directivity. In short, directivity describes how directional the sound of a speaker is. At relatively low frequencies, the sound created by a speaker radiates in a sphere from the cone.

Speaker Installation
At lower frequencies, sound emanates in all directions from a speaker.

As frequency increases, all speakers become more directional. The frequency at which this starts to happen depends on the diameter of the speaker cone. The chart below indicates (in green) maximum frequencies that radiate evenly in all directions. Frequencies in the red zone are only audible directly in front of the speaker.

Speaker Installation
Directivity behavior of different size speakers based on frequency.
Speaker Installation
Every speaker from every company experiences a certain amount of directivity.

Knowing about directivity, it’s important to choose speakers that will sound good in your vehicle’s available locations. For example, a component speaker set with an 8-inch woofer and a tweeter that only plays down to 4 kHz may not deliver good audio performance between 3 and 4 kHz if the listening position isn’t directly on-axis with the speaker. If you can add a midrange driver to the system, you may be better off choosing a 6.5-inch set.

Car Audio Speaker Installation Is Crucial

As you can see from the above, working with an experienced specialty retailer is vital to your car stereo system’s performance. Unlike buying home stereo speakers, where the crossovers and enclosures are designed in a controlled environment, car audio installation experts have to use their knowledge and training to create a speaker system from scratch. The tools and training they offer can be the difference between music that sounds realistic and an audio system plagued by distortion and poor frequency response.

Lead-In Image Credit: Musicar Northwest in Portland designed these enclosures to house a set of Morel tweeters in the doors of this 2009 Ferrari F30 Spyder.

This article is written and produced by the team at www.BestCarAudio.com. Reproduction or use of any kind is prohibited without the express written permission of 1sixty8 media.

Filed Under: ARTICLES, Car Audio, RESOURCE LIBRARY

Why Do Some Car Stereo Upgrades Need Load Resistors?

Load Resistors

If you’ve asked your local specialty mobile enhancement retailer about upgrading your car stereo in recent years, they may have told you that they will need to add load resistors. While seemingly new in concept, the purpose of these resistors is simple. They’re often needed to ensure that the factory-installed amplifier in your car, truck or SUV continues to function the way it was designed.

Modern Car Audio Systems and Class-D Amplifiers

Most modern car audio amplifiers, especially those installed by a vehicle manufacturer on an assembly line, use Class-D output circuitry to provide a balance of sound quality and amplifier efficiency. Automakers are fanatical about reducing fuel consumption. If an electronics supplier can deliver an amplifier that draws less current, there’s less load on the alternator, and the engine has to do less work.

All Class-D amplifiers use a filter circuit on the switching devices’ output to remove high-frequency noise caused by the MOSFETs switching off and on. The output of the filter is the original audio signal. These filters typically comprise a capacitor and an inductor. The value of these components is based on the load (speaker) impedance the amplifier is designed to drive. If the values are incorrect, high-frequency audio information may be attenuated, or too much noise might be allowed into the output.

Load Resistors
Amplifiers like this AudioControl D-4.800 use high-quality capacitors and shielded inductors in their Class-D output filter networks.

Upgrading a Mobile Audio System

If you visit a local stereo shop and tell them you want to upgrade your audio system, they’ll likely suggest new speakers and an amplifier. In many cases, the shop will use the factory amplifier’s output to feed to the new amp. All good so far.

Load Resistors
Frequency response of a good-quality Class-D amplifier when connected to a 4-ohm load.

When the speaker is disconnected from the factory-installed Class-D amplifier, the filter circuit that was designed for a 2- or 4-ohm load isn’t going to function correctly. The signal presented to the capacitor and inductor will cause an oscillation, and a great deal of high-frequency noise may be added to the signal.

Load Resistors
Frequency response of the same amplifier when no load is connected to the output.

Another issue is that these oscillations in the output filter network may become quite significant in terms of their voltage. These voltages can damage components in the amplifier. Companies like Dodge, Chrysler and Ram have circuitry in their radios and amplifiers that prevents them from producing any output if their original speaker isn’t connected.

Load Resistors
AudioControl offers several different load generating devices to allow installers to upgrade factory audio systems without running into noise issues.
Load Resistors
All Wavtech line output converters like this Link DQ have 180-ohm resistors on the inputs. If your application needs require a lower impedance, their linkLD modules can be added to present a 36-ohm load to the factory amplifier.
Load Resistors
The Universal Speakers Simulator (USS4) from Audison presents a low impedance to a factory amplifier so that it will function properly. The USS4 can also generate a remote turn-on output signal to activate an aftermarket amplifier.
Load Resistors
Match amplifiers include a high-level input circuit called ADEP.3 that’s designed to prevent the no-output condition common to factory-installed amplifiers when they don’t see speakers connected.

Upgrade Your Car Stereo Today for Better Sound!

If you can’t turn the volume on your factory-installed car stereo system up without the system distorting, drop by a local car stereo retailer and ask about upgrading your audio system with new speakers and a more powerful amplifier. If they mention that the upgrade will require load-resistors to prevent noise or hiss, now you know why.

This article is written and produced by the team at www.BestCarAudio.com. Reproduction or use of any kind is prohibited without the express written permission of 1sixty8 media.

Filed Under: ARTICLES, Car Audio, RESOURCE LIBRARY, Uncategorized

Upgrades for Nissan Skyline, the GT-R and the Z-Cars

Nissan Upgrades

Whether you have a classic 240Z, a 370Z right off the showroom floor or are lucky enough to roll in a Skyline or GT-R, your local specialty mobile enhancement retailer offers a variety of audio, convenience, styling and safety system upgrades. From a technology upgrade like a new radio with CarPlay and Android Auto, a custom audio system that sounds like a rock concert, to a camera system to help you park safely, it’s easy to add improvements to Nissan sports cars. Let’s look at some of the most popular and unique ways to make driving your Nissan more enjoyable.

Nissan Skyline, GT-R and Z-Car Audio System Upgrades

Way back in 1969, Nissan started selling the 240Z in North America under the now-defunct Datsun name. Equipped with only an AM radio built by Hitachi, things couldn’t have been more basic. Fast-forward to 2007, and the latest-generation GT-R rolled off the showroom floor with a multifunction display screen on the dash that was quite literally straight out of a video game. The interface was designed in cooperation with Polyphony Digital – the game development studio behind the incredibly popular Gran Turismo series of video games. With the ability to display such vehicle information as cornering forces, brake system pressure and boost pressure, the difference between these vehicles couldn’t have been more dramatic.

Nissan Upgrades
Designed by Polyphony Digital, the modern GT-R display offers an impressive array of vehicle and driving information. Thanks to Gary Bell from Define Concepts in Orange, California, for the photograph.

Whether you have a classic Datsun or a brand-new Nissan, upgrading the audio in your car will make the drive much more enjoyable. Let’s start at the front with radio upgrades. If you’ve got an older vehicle, you may want to add something with USB support for your smartphone or media player. Having Bluetooth for streaming and hands-free calling is another great reason to buy a new radio.

Thankfully, many Nissan sports cars have come from the factory with ISO-mount radio solutions that can be easily upgraded with a double-DIN multimedia receiver. Aside from options for large touchscreen displays between 6 and 7 inches, these radios open up the options for navigation solutions and backup camera upgrades. We’ll circle back around to safety system options after we finish the audio discussion.

Nissan Upgrades
Mobile Edge in Lehighton, Pennsylvania, upgraded this client’s 2010 Nissan 370Z with a Sony XAV-AX5000 so she’d have Apple CarPlay smartphone integration.

No matter what head unit you choose, picking amplifiers, speakers and subwoofers that deliver accurate sound is crucial to your music’s faithful reproduction. If you want to make your music sound clearer or play louder, you need high-quality products, proper audio system design and a reliable installation. In the images that follow, there’s everything from daily-driven upgrades to show-quality custom installations.

Nissan Upgrades
Jeff Smith from Cars of Atlanta in Georgia shared this photo of a 2009 Nissan 370Z they upgraded with an Audison LRx amplifier and a pair of JL Audio 10W1 subwoofers.
Nissan Upgrades
Taylor Pearson from Phantomwerks Designs & HIFI Mobile Audio in Roanoke, Texas, sent along this photo of a 2019 GT-R upgraded with a JL Audio amplifier and subwoofer system.
Nissan Upgrades
Al Vincent from TiBurnt Design in Ste Anne, Manitoba, built this epic 350Z system with Mosconi and Focal products purchased from Brian Reimer Audio. Colin McAndrew from Brian Reimer helped with the amplifier.
Nissan Upgrades
Adam from Devine Concepts in Naples, Florida, upgraded this 2003 350Z with Audison subwoofers.
Nissan Upgrades
Chris Rogers from Audio Express in Texarkana reached out to the team at Mobile Toys in College Station, Texas, to build these custom pillars and door panels for Audison AP1, AP2, AP4 and AP6 drivers in his 1987 Nissan Skyline.
Nissan Upgrades
Audio Crew from Moncton, New Brunswick, sent this photo of a Nissan 240Z they upgraded years ago with Alpine amplifiers, subwoofers and speakers.
Nissan Upgrades
Our friend Mike Maltais has worked in the car audio industry in the Vancouver area for years. Here’s a shot of the Digital Designs system he installed in his 2003 Nissan 350Z.
Nissan Upgrades
William Coats from Audio X in Florence, Alabama, shared this fantastic photo of an R34 Nissan GT-R they upgraded a few years ago.
Nissan Upgrades
Nissan has had fun-to-drive cars for a long time. Sak Mach from Ralph’s Radio in Vancouver, British Columbia, shared this photo of a Datsun 510 that they upgraded with Helix amplifiers and JL Audio speakers.
Nissan Upgrades
Simplicity in Sound in Milpitas, California, built this show-grade custom trunk installation in a Nissan GT-R for one of their Canadian clients.

There are always a few paths you can take to get better sound in your Nissan. One of the best-bang-for-your-buck upgrades is to add a subwoofer with a dedicated amplifier. Having a sub means that the small speakers in your car don’t have to work as hard. Your local specialty mobile enhancement retailer should have a variety of options for subwoofer upgrades for your car. They can build a custom enclosure like the those in the photos above or set you up with a prefabricated enclosure. Of course, make sure you pick a high-quality amp and choose good power cables to feed it.

Nissan Upgrades
The JL Audio SB-N-370/10W3v3 Stealthbox for 2009 and newer 370Z’s features a pair of 10W3v3 subwoofers to deliver great bass output.
Nissan Upgrades
The Audison APBX 10 DS is a compact subwoofer enclosure that features a 10-inch subwoofer.
Nissan Upgrades
The Match PP 8E-Q from Audiotec-Fischer includes a single 8-inch subwoofer with a unique quad-3-ohm voice coil design that works perfectly with its Match amplifier solutions.
Nissan Upgrades
If space is at a premium but you still want to add some bass, check out the Sony XS-AW8 powered subwoofer system. At only 3.125 inches thick, this amplified subwoofer system will fit into even the tightest of spaces.

Speaker and Amplifier Upgrades

Once you’ve got some solid bass in your Nissan, it’s time to upgrade the speakers and add an amplifier to power them. Good quality speakers are crucial in improving the realism and output capabilities of your sound system. Think about it – you could have the best radio and amplifiers, but if your speakers don’t perform well, your music won’t either.

Aside from choosing the right speakers, make sure you are investing in proper installation. The addition of sound deadening to your doors will make a world of difference in what you hear. If your installer needs to create adapters to allow new speakers to fit, make sure they’re constructed of something other than wood. Wood will get wet and warp or become moldy. Finally, if you’ve opted for a set of component speakers, make sure the technician is going to mount the tweeters on-axis with the listening position or place them at the edge of the dash, so the sound bounces off of the windshield.

Nissan Upgrades
The Hertz Energy ESK 130.5 speaker set combines a large soft-dome tweeter with a woofer that uses a treated paper cone and rubber surround to deliver impressive clarity.
Nissan Upgrades
The new BLAM 165-ES is a component speaker set that combines a set of 6.5-inch woofers with compact 20 mm soft-dome tweeters to deliver your music with that classic French sound.
Nissan Upgrades
The ARC 602 6.5-inch coaxial speakers from ARC Audio feature a cast aluminum basket, a glass fiber woofer cone reinforced with Rohacell and a soft-dome tweeter. These features combine to recreate your music with impressive accuracy.
Nissan Upgrades
Adrenaline Autosound in Clayton, North Carolina, stripped the interior out of this 2005 350Z to treat it with a layer of Focal sound deadening material.

To get the most out of a new set of speakers, you’ll need a good quality amplifier to power them. Shopping for an amplifier can be tricky since it’s challenging to audition different options under controlled conditions. For a set of high-performance speakers, you’ll want at least 75 watts of power. For a subwoofer, as little as 300 watts may be enough, but some high-power subs can handle 500 or 750 watts. Stick with the name-brand amplifiers, and you shouldn’t have any issues with background noise.

If you want to extract the most out of your audio upgrade, then you’ll need a digital signal processor. The acoustics of a vehicle are, quite simply, atrocious. Compensating for different pathlengths between speakers and the reflections caused by all the glass, vinyl and plastic close to the speaker location is crucial to hearing your music the way it should sound. As we’ve said a few dozen times, ensuring that your processor is calibrated properly is key to the upgrade being worthwhile.

Nissan Upgrades
ARC Audio’s latest generation of ARC Series amplifiers is available in two-, four- and six-channel configurations that can produce as much as 500 watts per channel. These amplifiers can be upgraded with their IPS-8.8 digital signal processor so your technician can fine-tune the performance of your mobile audio system.
Nissan Upgrades
The Sony XM-GS6DSP is a six-channel amplifier rated to produce 45 watts of power to the front channels and an impressive 600 watts to a subwoofer. The amp can be used without a source unit by installing the Music Center app on a Bluetooth-equipped smartphone.
Nissan Upgrades
The Helix V Eight DSP MK2 is an eight-channel amp that offers 75 watts per channel into a 4-ohm load. The amp includes a powerful digital signal processor that can be used to calibrate your audio system’s output.
Nissan Upgrades
The Audison AP F8.9 bit amplifier includes a digital signal processor with powerful features to make integrating it into a factory audio system reliable and efficient. The amp can produce 85 watts per channel into 4-ohm loads.
Nissan Upgrades
Adrenaline Autosound in Clayton, North Carolina, modified the Bodysonic amplifier knobs to serve as the master volume control and subwoofer level controls for a Bluetooth-only audio upgrade in a 1984 Nissan 300XZ.

Lighting Upgrades for Style and Safety

Headlights are an essential and often overlooked safety feature. Being able to see clearly while not blinding oncoming drivers is crucial to driving safely once the sun sets. If your car came with incandescent halogen headlights, then you might want to ask about an HID or LED upgrade. The style of light you have (reflector or projector) will determine which upgrade works best for your application.

Nissan Upgrades
Companies like Lumens have LED upgrade bulbs explicitly designed for projector or reflector headlight housings. LED lights reach full output very quickly and can also be used in high-beam applications.

If you want to add a little extra style to your Nissan, RGB LED lighting is a great choice. LED lighting has replaced the unreliable and often-dangerous neon lighting that was popular many years ago. With RGB lighting, you can change colors using a wireless controller or a smartphone app to personalize your vehicle’s look.

Nissan Upgrades
Audio Garage in Fargo, North Dakota, added RGB LED lighting to the interior and exterior of this client’s cool 370Z coupe.
Nissan Upgrades
This 2012 Nissan GT-R was upgraded with under-vehicle LED lighting by Tunes-N-Tint in Lakeland, Florida.

Backup Cameras and Safety Systems

If you own a 350Z or 370Z, then you know how difficult it is to see behind you when parking. Adding a backup camera system to these vehicles makes backing up and maneuvering safer. There are many options for cameras and displays. If you want to maintain your car’s factory look, then a replacement rearview mirror with an integrated display is a great option. If you’ve upgraded the radio with a multimedia receiver, most camera solutions will work with the touchscreen.

Nissan Upgrades
California Car Sounds and Tint in Campbell, California, added a flush-mount backup camera to the rear of this 2013 Nissan 350Z. The camera image is displayed on a new Pioneer multimedia receiver.
Nissan Upgrades
Audio Garage in Fargo upgraded this Nissan 370Z with a Sony multimedia receiver and a backup camera that makes parking much safer.
Nissan Upgrades
Safe Drive Solutions near Vancouver, British Columbia, installed a Thinkware U1000 dual-camera dashcam in this 2017 Nissan GT-R to monitor everything happening around the vehicle while it’s in motion.

Remote Car Starters the Drive More Comfortable

Of course, the options to make your Nissan sports car more comfortable include a host of remote starter options. If you live somewhere that’s cold in the winter or hot in the summer, then starting your car a few minutes before it’s time to leave is a great way to make the interior more comfortable. There are car starters that include safety features to make them safe for manual transmission vehicles.

Nissan Upgrades
Remote car starters like those from Compustar include safety and interlock features that allow them to work with manual transmission vehicles.

Upgrade Your Nissan Sports Car Today

If a feature is missing from your car, or you’d like to enhance its looks or audio system performance, drop by your local specialty mobile enhancement retailer today. They can make your music sound amazing, make your car more comfortable or make it look even better.

Lead-In Image: A huge thanks to Robert Kelly from The Car Clinic in Fort Smith, Arkansas, for this great shot of this 2014 370Z Touring Sport. The car features a laundry list of upgrades that include a Stillen front bumper, Z1 intakes and test pipes, Eibach sway bars, Koni struts with Swift springs and Power Stop rotors. He’s added a JVC head unit and dB Drive speakers to make sure it sounds great while cruising.
This article is written and produced by the team at www.BestCarAudio.com. Reproduction or use of any kind is prohibited without the express written permission of 1sixty8 media.

Filed Under: ARTICLES, Car Audio, RESOURCE LIBRARY

Dual Bluetooth Phone Support Makes Communicating Easier

Dual Bluetooth

In recent years, car radio manufacturers have added simultaneous dual Bluetooth phone support. At a quick glance, the ability to connect two phones to a single radio seems like a great solution for a family where the parents will be travelling in the vehicle at the same time. With that said, depending on the brand of radio you choose, that’s not necessarily how dual Bluetooth or dual phone support works. Let’s look at this subject with a little more detail.

Phone Pairing Options

For many years, car radios have offered the ability to pair with at as many as five Bluetooth devices. The pairing process involves establishing an initial connection between your radio and your phone. In most cases, this step involves going into the Bluetooth menu of your phone and looking for the radio. Years ago, this was a complicated process that involved putting the radio into “paring mode.” Now, the Secure Simple Pairing (SSP) interface makes this process much simpler and eliminates the need to go through complicated steps on the radio.

Dual Bluetooth
Pairing your phone to a new car radio is as easy as searching for it in the Bluetooth menu.

When the radio boots up, it goes through this list of paired devices and searches for them to re-establish a Bluetooth connection. Depending on the radio, users can set a priority so that a preferred device is always connected first. As an aside, the radio may check the contacts in the phone and automatically download new names and phone numbers right after the connection is established. If you’re making calls using the phone list on the screen, this is a great feature.

Dual Phone Support Options

There are two types of “dual phone support” systems on the market. The first type allows two devices to share the hands-free capabilities of the radio. As such, the system allows the driver to answer calls received on either device by pressing the Send/End button on the radio face or the steering wheel.

The second type of “dual phone” connectivity pairs one phone as a hands-free device and a second phone as an audio source to be used for playing music. The driver may not be able to answer calls on the second device, but can stream from such sources as Pandora, iHeartRadio, Spotify or Apple Music.

Let’s be clear: Two phones are always better than one. We are simply establishing a distinction between the way different source units work.

Always Try a New Radio Before You Buy It

If there’s ever been a message that’s crystal clear to our readers, it’s that you should try the radio you want to buy on a display board at your local specialty mobile enhancement retailer before it’s installed into your vehicle. If support for the simultaneous use of two phones is important, bring both phones and pair them both to the radio. Cycle the power to the radio to see how the phones reconnect. Test to see how the radio responds when a call is received on each device. Also check to see how the radio behaves if only one of the two phones is paired. Since the firmware on radios is often updated at least once or twice after being launched, ask the product specialist you are dealing with if everything is up to date.

Dual Bluetooth
Retailers such as Westminster Speed and Sound in Maryland have fully interactive displays that allow you to test the features of the radio you are considering.

You may want to check out BestCarAudio.com’s 2020 Car Radio Buying Guide for a few more items you might want to check on the display before buying. There’s even a handy downloadable checklist.

A Quick Reminder about Bluetooth Terminology

Most consumers think Bluetooth is a wireless phone connectivity solution. While this is true, Bluetooth is actually a low-power, short-range digital communication standard that was created to replace serial cables. How Bluetooth is implemented varies by device. For example, controllers for your Xbox or PlayStation use Bluetooth to communicate with the console to transmit button and joystick commands and receive instructions to activate the vibration functions.

Of course, wireless computer keyboards and mice use Bluetooth. The Apple Pencil that works with the iPad uses Bluetooth. Other applications for Bluetooth include communication between street lights that lets them turn on or off at the same time. There are also car alarms that communicate with a siren under the hood using Bluetooth instead of wires, and smartphone remote control options that let you unlock or remote-start your vehicle using your smartphone. The remote that comes with an Amazon Fire Stick also uses Bluetooth.

Dual Bluetooth
Modern video game controllers use Bluetooth to communicate with the main console.

Upgrade Your Car Radio for Dual Phone Support

If you find there are often two of you in your vehicle at the same time, and both want to be able to receive phone calls or serve as the disc jockey for your next trip, drop by your local specialty mobile enhancement retailer and test drive a new car radio with dual Bluetooth phone support.

This article is written and produced by the team at www.BestCarAudio.com. Reproduction or use of any kind is prohibited without the express written permission of 1sixty8 media.

Filed Under: ARTICLES, Car Audio, RESOURCE LIBRARY

Proper Size Is Key for Subwoofer Enclosures

Enclosure Size

When it comes to subwoofers or speakers, they need to be installed in a correctly sized enclosure to deliver accurate performance and useful bass extension. Speakers are complex devices that rely on their suspension components and the enclosure they are installed in to determine how they perform at lower frequencies. When the product specialist you’re working with is designing your sound system, he or she needs to balance many criteria to ensure you get the sound you want. In this article, we’ll look at the importance of installing subwoofers in enclosures with enough internal air volume.

How Enclosure Volume Affects Speaker Performance

Every speaker of every size is affected by the volume of air in the enclosure behind the driver. Even large tweeters are often designed with cavities behind the diaphragm that can change their performance down near the crossover point. For this article, we’ll focus on midbass subwoofers and look at several real-world examples and application comparisons.

Lately, we’ve seen several instances where multiple subwoofers have been crammed into incredibly small enclosures. The most common example of this is in pickup trucks. The space under the rear seat of your truck is limited. In most cases, there is less than 1.6 cubic feet of air space for the woofers to work with. Physically, you can easily install a pair of woofers, and some custom solutions allow for as many as four drivers under the rear seat. Let’s look at how a popular shallow-mount subwoofer like the JL Audio 10TW3-4 behaves in this space.

Let’s start with a single subwoofer in 1.5 cubic feet of space. Our enclosure simulation software predicts a -3 dB frequency of 45.95 Hz and a total system Q of 0.483. This low Q tells us that it is likely too large of an enclosure for this driver. Thanks to the impressive excursion capabilities of the TW3 subwoofers, things will work fine.

Enclosure Size
Predicted frequency response of a single JL Audio 10TW3 in a 1.5-cubic-foot enclosure.

Now, let’s say we want more bass. The seemingly logical move would be to add another subwoofer, right? If we ask our technician to install two drivers in this 1.5-cubic-foot enclosure, the -3 dB point raises to 47 Hz, and the Q increases a bit to 0.643. Based on the shape of the graph and those numbers, this combination looks like a great solution.

Enclosure Size
1.5-cubic-foot enclosure. Single 10TW3 in red, dual 10TW3 in orange.

Thankfully, JL Audio knows how to design a subwoofer to work in a small enclosure. The response of these systems is smooth. Now, let’s double down again and see what happens when we use four woofers in this 1.5-cubic-foot enclosure. Our software says the -3 dB point is now 50 Hz, and the Q is 0.738. Both are great numbers.

Enclosure Size
Single driver – red; two drivers – orange; four drivers – yellow.

With that said, we need to look carefully at where the increase in output happens. The single-driver solution predicts an output of 106.4 dB, the dual driver system predicts 109.4 dB, and the quad-sub solution says 112.4 dB at 60 Hz. As science indicates, that’s a 3 dB increase for every doubling of cone area for a given power rating. But does that mean more usable bass? Let’s look at what happens down at 35 Hz. The single driver enclosure is predicted to produce 102 dB of output. The dual-driver enclosure should produce 104.4 dB. Finally, the quad-driver enclosure should offer 105.9 dB at 35 Hz. We saw a gain of 2.2 dB from the single to dual increase and only 1.5 dB from the dual to the quad system.

Why? Because the volume of air in the enclosure limits cone excursion at lower frequencies. More specifically, the ratio of the available airspace to the driver’s equivalent compliance (this specification is called the Vas) decreases as the effective enclosure volume decreases. In this example, we get more upper bass around 60 Hz with four subwoofers, but beyond two, we don’t get much more deep bass.

Extreme Cases Result in No Bass

As we mentioned, JL Audio did a great job designing its TW-Series subwoofers to work in very small enclosures. Not every subwoofer on the market is designed this way. Balancing the design of a subwoofer trades efficiency for low-frequency extension. Let’s look at an example that doesn’t work. In this case, we have a very shallow 8-inch driver that’s been crammed into a tiny enclosure in the door of a car. The enclosure has a net volume of 0.15 cubic foot. The enclosure fits, but does it work?

Enclosure Size
Predicted frequency response of an 8-inch subwoofer in a very small 0.15-cubic-foot enclosure.

As you can see, this is a disaster. There’s a huge peak at 450 Hz and barely any output below 100 Hz. Given that most subwoofer systems operate below 60 Hz, this doesn’t work. Oh, the system Q is 1.79. Target Q-factors are typically in the 0.6 to 0.95 range. This would sound unpleasant in every way.

Does this make this a bad subwoofer? We modeled the driver in a 1-cubic-foot enclosure and it still didn’t make much bass. It’s clearly designed for an infinite baffle application.

Enclosure Size
8-inch subwoofer in 0.15 cubic foot – green; 8-inch subwoofer in an infinite baffle installation – teal.

A better solution for this ultra-small enclosure would have been a high-quality 6-inch subwoofer. The graph below shows the aforementioned 8-inch sub and a 6.5-inch sub in the same 0.15-cubic-foot enclosure. The 6.5-inch sub is 12 dB louder at 40 Hz.

Enclosure Size
A comparison of the 8-inch sub to a 6.5-inch sub in a similar 0.15-cubic-foot enclosure. The 6.5 is louder at all frequencies below 125 Hz.

What About Vented Enclosures?

Let’s circle back to the beginning and look at how a vented enclosure might change our subwoofer system performance. We’ll remind you that we want the subwoofer to be able to produce lots of energy between 30 and 60 Hz for deep bass.

The graph below shows our 1.5-cubic-foot truck enclosure’s performance with subwoofers in sealed (acoustic suspension) and vented (bass reflex) designs.

Enclosure Size
Single 10 – red; dual 10 – orange; quad 10 – yellow; single 10 vented – violet

As you can see, between 20 and 50 Hz, the single subwoofer in a vented enclosure is louder than four subs in a sealed design. At 25 Hz, the vented design can produce 106.9 dB, whereas the four drivers are only making 100.7 dB. That’s a HUGE difference! The vented enclosure would cost less, sound better and require less power from your amplifier to recreate the lowest notes in your music. Your installer will also have an easier time blending the system’s output with the midbass speakers in your truck because there’s less of a peak in the response at the crossover point. It’s a complete win-win!

Enclosure Size
Brian Mitchell from Liquid Trends in Modesto, California, built this custom subwoofer enclosure to house a quartet of ARC Audio ARC 8 subwoofers.

Picking the Right Subwoofer Solution

When it comes time to shop for a subwoofer upgrade for your car or truck, be sure to ask the specialty mobile enhancement retailer you are working with about your options in terms of the enclosure. It’s pretty common to see a single subwoofer in a vented design deliver significantly more output than multiple drivers in a sealed enclosure.

Lead-In Image: Thanks to Jim Skaggs at the team at MTI Acoustics for the lead-in photograph.

This article is written and produced by the team at www.BestCarAudio.com. Reproduction or use of any kind is prohibited without the express written permission of 1sixty8 media.

Filed Under: ARTICLES, Car Audio, RESOURCE LIBRARY

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