Whether it’s Black Friday, Christmas, Back to School or just a regular sale, many car stereo shops around the country offer subwoofer system upgrade packages that let you add bass to your stereo at an affordable price. These packages typically include a 200-300 watt amplifier, a single subwoofer, an enclosure and an installation kit. We’ve noticed a trend in the choice of enclosure included in these systems. We want to offer some advice on an upgrade that will dramatically improve performance and value.

Sealed Versus Ported Subwoofer Enclosures

The goal of these car audio subwoofer upgrade packages is to deliver an affordable way to add bass to your vehicle. As such, the products these systems include are typically chosen based on their price rather than their combined performance. Most options include a 12-inch subwoofer and a sealed enclosure. While this combination works well, it might not offer the best bang for your buck. Let’s look at an example.

Let’s use an ARC Audio X2-Series X2-12D4 12-inch subwoofer as an example. It’s not an entry-level subwoofer compared to some of the low-cost options on the market, but its performance, build quality and capabilities make it worth every penny. The sub is rated to handle 250 watts of power. Let’s model it in a sealed enclosure with a net internal air volume of 1 cubic foot.

As you can see, the response curve is nice and flat. By way of specifications, the system has a Qtc of 0.894 and an F3 frequency of 42 Hz. These numbers are ideal terms of delivering clear and accurate bass.

Less Subwoofer, More Enclosure

What if we switch things up a bit and go with a 10-inch subwoofer in a vented enclosure? This cost of the system might go up a little bit, but is it worth it? Let’s model the 10-inch version of that subwoofer in a vented enclosure with the same net 1-cubic-foot internal air volume. For this simulation, the enclosure has a tuning frequency of 33 Hz.

You’d think we knew what was going to happen before we started writing, wouldn’t you? The 10-inch sub in the vented enclosure is louder at all frequencies between 20 Hz and 75 Hz. How much louder? We made this chart below to show you.

If the two systems’ differences were less than a decibel, the comparison would be a wash. The 10-inch sub in the vented enclosure produces around 3 dB more output from 40 to 50 hertz. This increase in output level is significant.

System Efficiency and Power

Aside from getting more output for a similar investment, there’s another way to look at this. Let’s say you want to listen at a specific volume level. The subwoofer in the vented enclosure can produce that output with less power. This means the amp won’t run as hot, the subwoofer won’t heat up and the amp will draw less current from the vehicle electrical system. We’ll add a power comparison to our graph above to show you just how much less is required for the same output.

In the chart above, we compare the output of the 12-inch driver with 250 watts to the amount of power the 10-inch driver in the vented enclosure requires to produce the same result. At 45 hertz, the requirement is less than half the power. This equates to much less current draw on the electrical system in your car. It also means the voice coil of the subwoofer won’t heat up as much. This reduction in power to the sub can help reduce power compression and further improve the efficiency of the subwoofer system.

If you are wise with your purchasing strategies, you might ask if there are any drawbacks to using a vented enclosure instead of a sealed one. So long as the enclosure has a large enough vent and includes a smooth radius around the vent opening, there aren’t any issues. In addition, you can see that the overall shape of the response curve is similar to that of the sealed design, so the system will sound similar. In all honesty, it’s a win-win situation.

Upgrade Your Car Audio System with a Subwoofer

One of the best upgrades you can make to your car audio system is to add a subwoofer. So drop by a local specialty mobile enhancement retailer today to find out what’s available for your vehicle. If they have a subwoofer system package available, ask about upgrading to a vented enclosure. The improvement in efficiency will be worth every penny.

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.

A while back we published an article that discussed why aiming speakers in a properly designed car audio system was futile. As usual, we received a good deal of feedback about the piece. The comments ranged from the typical “that’s not how it works” to more scientific discussions about how even minor changes in placement had significant effects on imaging and soundstage position. So let’s dive deeper into this discussion to flesh out some of the finer details in speaker positioning.

Proper Audio System Design

The first thing we need to discuss is proper audio system design and component selection. To deliver the most realistic listening experience possible, you need to choose high-quality speakers. Speakers that add significant distortion will lack clarity and detail and render all other efforts futile. Forget the hype about anti-resonant baskets and fancy cones – the technologies that dramatically reduce distortion are motor upgrades like shorting rings and copper inductance-reducing caps.

Next, the speaker system needs to be designed and integrated into the vehicle in a way that ensures the even distribution of sound through the listening environment. This typically involves using a subwoofer, a set of woofers or midbass drivers, midrange speakers and tweeters. As our article on directivity explained, below a frequency where the effective circumference of the cone is equal to the sound wavelength, the sound is emitted evenly in all directions — as such, tilting a speaker up or down won’t change its perceived frequency. Keep this in mind, as we’ll circle back to it shortly.

Lastly, the speakers need to be chosen so that the high-frequency driver operating in the adjacent frequency range can play low enough to ensure that directivity doesn’t become an issue. Unfortunately, this statement confirms that using a two-way front stage with a 6.5-inch woofer is difficult, as most tweeters bundled in component sets can’t play low enough.

Speaker Placement Matters

When we talk about speaker placement for the front stage of our vehicles, the options are typically a stock location in the lower part of the front door, a location in the middle or upper portion of the door, the dash or in a custom pod on the A-pillar. It should come as no surprise that every location has a benefit and an equal number of drawbacks.

For midbass drivers used in a three-way front stage, the door location often works well. Some will go further with the installation and have custom mounting solutions created in the kick panels. If this driver is going to play up to 400 or 500 Hz, this “farther away” position can help with the perceived depth of the soundstage.

The same concept applies to midrange drivers. If they are installed in the doors, as would be found in many Porsches and BMWs, the soundstage can appear to span the car, but comes from a position that’s in line with the steering wheel. Mounting the speakers in pods on the A-pillars can move that soundstage deeper into the dash. Finally, speaker positions in the corners of the dash, right at the base of the windshield, are about as far away from the listening position as is possible and help to create a soundstage that seems to come from the rear edge of the hood. Some listeners don’t concern themselves with the sound source, while others weigh it heavily in their system design considerations.

The angle at which tweeters are aimed matters. Suppose you want to have any chance of hearing the highest of frequencies. In that case, tweeters need to be aimed toward the listening position or pointed up into the windshield so their output can reflect off the glass and “spray” into the vehicle interior. Tweeters mounted in sail panels can help to increase the perceived width of a soundstage – another consideration in where the music seems to come from.

What About Fine-Tuning Mounting Angles?

Much of the feedback on our article about speaker directivity was targeted at the fact that car audio system performance changed based on the angle at which the speakers were mounted. We don’t dispute this for one second. How a speaker performs in terms of directivity is a constant. How sounds reflect off of nearby surfaces plays a huge role in what we hear, even after setting signal delays and calibrating the system with an equalizer.

Let’s say you have a speaker mounted in an A-pillar, and it’s aimed directly across the vehicle. There will be immediate reflections off the windshield and, a moment later, off the side windows. Given their proximity to the speaker, these reflections may be almost as loud as the sound coming directly from the speaker cone. Another moment later, there may be a reflection off the roof and the dash. Vehicles are very complex and behave differently than a listening room or recording studio.

If we tilt the speaker in or out, up or down, we can change the path lengths from the edge of the speaker to the surfaces off of which the sound will reflect. Even a fraction of an inch will change how the sound these speakers produce interacts with these surfaces.

Let’s Look at An Example

Let’s say you have a Porsche 911 or Boxster with a midrange speaker location in the middle of the door. A number of 2.5- and 3-inch midrange drivers will perform excellently in that location. On the inside of the car, there is almost nothing near the speaker that will cause a significant reflection, other than the smooth surface of the door panel itself. In terms of delivering a predictable performance that won’t require significant equalization, this is as close to an ideal mounting location as is possible in a car or truck.

Is this the perfect location, though? What if you like the sound to appear to come from the windshield or dash of the vehicle, or even out on the hood? Will this speaker location offer that? It isn’t very likely. The soundstage is apt to seem very shallow. Tonally, the system may sound excellent, and the lack of nearby reflections should offer impressive clarity.

If we put those same speakers in small enclosures up on the dash, just as we described above, the sound will reflect off of every surface imaginable. We can make the system sound good with an equalizer, but the interaction of multiple reflections won’t deliver the same amount of clarity.

Balance the Benefits and Drawbacks

The goal of any speaker system design (i.e., the placement and configuration of the drivers in a listening application) requires balancing the benefits and drawbacks of each location. The specialty mobile enhancement retailer you are working with can help explain each location’s benefits and disadvantages. Together, you can choose a solution that will deliver the sonic performance and aesthetics you want from your upgrade.

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.

Have you ever looked at something and thought you were only getting part of the story? Many previous articles have discussed amplifier distortion at length but haven’t delved into how power output levels and frequency affect distortion measurements. If you’re looking for the best amplifier for your car audio system, especially for midrange drivers and tweeters, this information should be crucial to your purchasing decision.

Amplifier Distortion Specifications

If you’re browsing a car audio amplifier manufacturer’s website, you’ll see a single specification that’s intended to quantify the amount of distortion an amplifier adds to the audio signal. The CTA-2006-C standard requires that the total harmonic distortion and noise added to the audio signal be specified at an output level that is 50% of the maximum rated output for the amplifier. Of course, that power rating needs to comply with the CTA-2006-C standard as well.

Measuring Amplifier Distortion

When an amplifier is being tested for distortion, the technician or engineer will typically look at the harmonic information and noise added to a single test tone.

In the measurement above, you can see the test signal at 1 kHz at a level of 2.0 volts. The second harmonic (labelled with the pink 3) is at a level of -77.10 dBV, or 83.15 dB below the 6.03 dBV (2.00V) test signal. The third-order harmonic (labelled with the pink 1) is louder at an absolute level of -68.18 dBV and a relative level of -74.23 dB. You can see the pattern of even and odd harmonics continue well past 20 kHz. It’s worth noting that this is a good Class AB amplifier and not a poorly designed, inexpensive unit.

Sadly, this single specification is quite incomplete in terms of telling the whole story. Audio measurement and analyzer devices like those from Audio Precision and QuantAsylum can generate distortion graphs across a range of power output levels and frequencies. So let’s characterize this amplifier in terms of the amount of distortion it adds to an audio signal based on the amount of power it produces.

Before we dive into analyzing the data, we should explain that the horizontal X-axis scale is in decibel volts, known as dBV. This way of looking at voltage represents the amplifier output level using a decibel scale with 1 volt as 0 dB. Thus, the equation to convert dBV to a voltage is 10 ^ (dBV/20).

The output level of 6.03 dBV, where we measured %THD+N in the first chart, would be 2.00 volts. At the low level, distortion is at 0.075%. At an output level of 22.6 dBV, you can see that the distortion increased. This level is the point where the amplifier started to run into clipping. Maximum power output measurements are specified at the output level that corresponds to a THD+N of 1%. For this amplifier, that would be about 24 dBV, or 63 watts into a 4-ohm load.

At the other end of the scale, you can see that distortion increases as output power decreases. This performance is very typical for a Class-AB amplifier. At very low levels, the harmonic distortion content is buried in the noise created by the amp, which for this unit is at about -105 dBV. Crossover distortion at very low volume levels plays a significant role in adding unwanted information to the audio signal. As the output level increases, the audio signal passes through the transition between the positive and negative output devices at a steeper slope, reducing the time the signal spends in this transition region. As such, distortion decreases relative to the output level.

The CTA-2006 THD+N specification for this amplifier would be 0.02% at the output level of 21 dBV (-3 dB from the maximum power output level). This information doesn’t do a good job of describing how well the amp performs in a real-world application since most of the time, we’re only using a fraction of the power available to drive a speaker. For example, if we have a midrange speaker or a tweeter in a three-way system, we may only need 1/10 to 1/20 of the power a midbass speaker would need, or even less than a subwoofer. Played at high volume levels, a tweeter rarely needs more than a few watts.

So far, in all the TestDriveReview product evaluations we’ve published, the distortion has been specified at the same level as the signal-to-noise ratio. This would be at an output level of 1 watt in a 4-ohm load or 2.00 volts. From now on, we’ll include the Power versus THD+N graphs as shown above so readers can see the entire picture of how the amplifier behaves.

Distortion Versus Frequency Response

Another characteristic often overlooked is the amount of distortion an amplifier adds relative to different frequencies. We ran another test on this amplifier to characterize this. We used an output level of 1.95 volts (very close to our 2.00-volt number) and measured distortion at frequencies from 20 Hz to 20 kHz.

While the numbers don’t vary as much compared to output level changes, you can see that there’s more distortion added at higher frequencies compared to midrange levels.

In an upcoming article, we’ll start all over with a new set of measurements with the three amplifiers we used in the What Do Better Amplifiers Sound Like article a few years ago. We’ll throw in a Class-D amp or two to round out the mix, so you’ll have a benchmark from which to compare solutions.

In the meantime, if you’re interested in purchasing an amplifier for your car or truck, drop by your local specialty mobile enhancement retailer today and ask them about a high-performance solution that will make your music sound amazing!

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.

More and more companies are offering motorcycle audio system upgrade solutions. Bikes like Harley-Davidson Road Glide and Street Glide can sound so much better with proper speakers and a high-power amplifier. In this article, we’ll cover four things you need to keep in mind when shopping for new tunes for your touring bike.

1. Installation Is Crucial to Performance and Reliability

How the new speakers, amplifier and perhaps a new radio are mounted, wired and configured plays a considerable role in the performance and reliability of your motorcycle audio system. New speakers are often much more substantial than the factory-installed products they replace. The speakers need to be mounted securely with corrosion-resistant fasteners. Of course, the speakers need to fit perfectly and seal tightly against the faring face for optimum performance.

Amplifiers can draw a lot of current from the battery and charging system when the volume is cranked. High-quality, appropriately sized wiring with solid electrical connections is mandatory to get the most efficient delivery.

2. Buy from a Brick-and-Mortar Retailer

If you’re going to have work done to your motorcycle, make sure that it’s by someone who will be available to support the products and services they sell you. Many bike enthusiasts buy audio upgrades at shows and rallies. If you have problems or need adjustments weeks or months after the purchase, you’ll need to find someone else to help and you’ll have to pay them for their time. Dealing with a local shop that specializes in motorcycle audio can save you a lot of headaches. A deal at a show isn’t a deal if you have to invest more money down the road.

3. Choose Premium Products

Face it: Your motorcycle is likely worth a lot of money. Inexpensive speakers and amplifiers aren’t apt to perform well or last as long as products from reputable companies. A motorcycle presents a challenging environment for audio equipment. Vibration is a huge factor, and when poorly designed audio components are used, they often fail in a few months.

Amplifiers need to be designed so that they are efficient and reliable — the fragile components inside need to be secured so that nothing will break. Speakers need to be weather-resistant in case you get caught in the rain. You also want a solution that is designed to handle prolonged UV exposure without drying out, chalking, cracking or fading. Woofer cones that fade or change color after prolonged exposure to the sun may become more brittle and eventually crack and fail. Regular car audio speakers simply aren’t a reliable option.

If you’re upgrading the radio on your bike, be sure to choose something that is weather resistant. You want a bright screen that’s easy to see in direct sunlight. You will also want something that can integrate with the handlebar stereo controls, if your bike has them.

4. Audio System Upgrades Need Tuning for Accurate Sound

We may have beat this topic to death, but it’s worth stating at least one more time. The factory-installed radios in 2014 and newer Harley-Davidson touring bikes have a slew of signal processing built into them. If you don’t address this tuning when upgrading the bike with a new amp and speakers, the system likely won’t sound right, and you could damage the new components. A reputable mobile enhancement retailer should have the tools to check the output of the radio on a Honda, Yamaha or BMW bike before they dive into an upgrade.

Your best bet is to purchase a digital signal processor (DSP) from the shop installing your equipment. They can use their audio test equipment to smooth the EQ curve in the radio and fine-tune the system to sound the way you want. Having the radio flashed to reduce the equalization settings is another option, but this process could be undone if you take your bike in for service. Likewise, there may be concerns about your warranty when you make alterations to the software.

Upgrade the Audio System on Your Motorcycle Today!

If you can’t crank the stereo on your motorcycle to the point that it gives you goosebumps, drop by your local specialty mobile enhancement retailer today and find out about the upgrades that are available. Don’t be afraid to research the suitability and reliability of their suggestions before you make a purchase. In the end, a little planning will keep your investment sounding great and last for years.

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.

There seems to be some misunderstanding about the relationship between subwoofer mounting depth requirements and performance relative to enclosure volume. We constantly see enthusiasts talk about having a 10-inch shallow sub mounted under a car or truck seat. Their expectation is full-size subwoofer performance without the need for a large enclosure. Let’s do a few simulations to see if they have any hope of getting the bass they want.

What Is ‘Great Bass’?

In our opinion, the purpose of a subwoofer is to extend the low-frequency output of an audio system such that the entire audio spectrum is covered. Unless they are massive (which causes other problems), the speakers in your doors or dash won’t play much below 50 Hz at high volume levels. The addition of a dedicated subwoofer with a dedicated amplifier can easily play to 20 or 25 Hz and relieves the smaller speakers of the task of playing these frequencies. As a result, the smaller speakers will sound better, and the subwoofer will give you the impact you expect from your audio system.

When quantifying bass performance, we talk about output capability and extension. Quantifying these characteristics is tricky, as the numbers depend on the vehicle into which the products are installed. Instead, we’ll use simulations from the BassBox Pro software to give you an idea of how different subwoofers perform in compact enclosure volumes. While not absolute in terms of in-car performance, the relative differences will be demonstrated clearly.

Sample 1 – Rockford Fosgate Subwoofers

Rockford Fosgate has dozens of differently sized subwoofers in their product line. Their solutions range from affordable entry-level products in the Prime Series to competition-grade Superwoofers in the Power Series. For this comparison, let’s look at a Punch P3 shallow 10-inch subwoofer and compare it to a full-depth version at the same feature level. The two subs will be the shallow-mount P3SD2-10 and the full-depth P3D2-10.

Because space is usually at a premium for shallow subwoofer installations, let’s take a look at how each of these subwoofers performs in a compact sealed enclosure with a net internal volume of 0.5 cubic foot. If you want to picture that enclosure, it might have a width of 13.5 inches, a depth of 5 inches and will need to be 22 inches long if constructed from ¾-inch-thick material (as it should be).

It would be easy to think that the shallow sub plays louder, as the peak output is 109.7 dB at 106.7 Hz compared to 109 dB at 75 Hz for the big driver. However, in almost every application, your subwoofers will be used with a low-pass filter that’s set somewhere around 60-70 Hz. As such, it’s the system efficiency below 70 Hz that will determine how much bass the sub produces for a given power level.

The P3D2-10 simulation predicts 103.2 dB of output at 40 Hz and 101.8 dB from the shallow sub at the same depth. In this case, the big woofer will be louder for a given enclosure size.

Sample 2 – JL Audio Subwoofers

Another company with a great selection of full-depth and shallow subwoofers is JL Audio. Let’s look at the big 10W3v3-4 to the shallow 10TW4-D8 driver. The big sub needs at least 5.93 inches of mounting depth, while the shallow TW3 driver requires only 3.25 inches. Let’s look at both of these drivers in a half-cubic-foot enclosure and see which is louder.

Here we see that both subwoofers are very similar below our crossover frequency. The big W3 sub is producing 102.9 dB at 40 Hz, and the shallow TW3 driver offers 102.6. In our opinion, that’s pretty much the same.

Sample 3 – Kicker Subwoofers

Let’s run these calculations one more time with a pair of Kicker subwoofers. This time, we’ll compare the 10-inch square dual-4-ohm L7R sub to its shallow-mount L7T brother. Both drivers are rated for 500 watts maximum power handling. The L7R requires 6.125 inches of mounting depth, while the L7T needs only 3.75 inches.

Just as with the JL subwoofers, the output of the shallow subwoofer is very similar to that of the big sub when driven with 300 watts of power. The L7R’s predicted output is 103.7 dB at 40 Hz, with the thinner L7T is calculated to produce 104.3 dB. You might be able to hear the difference, but not likely.

Are Shallow Subs the Same as Deep Subwoofers?

As one of our readers asked on Facebook, “So, the benefit is only shallow mounting depth, not a change in enclosure requirements?” He is right. The physics that govern output and low-frequency extension don’t change with a shallow subwoofer. Their benefit is minimized mounting depth, not magical deep-bass from microscopic enclosures. Your installer can create unique low-profile enclosures with a shallow sub, letting them mount them in spaces where a full-size sub doesn’t fit.

One thing to keep in mind is that shallow subwoofers may not have as much cone excursion capability as their full-sized brethren. The Kicker L7R has an Xmax spec of 13.9 millimeters, where the L7R is only 9.2 mm. The full-depth Rockford Fosgate P3D2-10 has an Xmax of 15.2 millimeters versus 8.4 mm for the shallow P3SD2-10. The chosen JL Audio subwoofers are the exception here. The TW3 has a rated Xmax of 15.2 millimeters, where the W3v3 sub is 14.0 mm. Both are good numbers, so it’s not a concern.

Do Shallow Subs Work in Small Enclosure?

The answer to this is that every subwoofer needs a certain amount of air volume behind the cone to perform. Subwoofers with shallow designs don’t produce more deep bass from a small enclosure. We’ve heard both deep and shallow subs in 0.2- and 0.3-cubic-foot enclosures. They sound terrible. Our take-away from this series of simulations is a recommendation to resist asking the local specialist mobile retailer you are working with to design and fabricate an enclosure that doesn’t provide the subwoofers you’ve chosen with adequate space. You’ll likely find that you’ll get more deep bass by using fewer subs in a properly designed system.

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.