The final article in our series on understanding high-end car audio systems moves away from the need for accurate system design, integration, configuration and calibration to discuss audio product quality. If you’ve been a long-time reader of the articles at BestCarAudio.com, you know that we put a significant emphasis on identifying car audio products that perform well. Importantly, those solutions aren’t always the most expensive options. Let’s discuss what higher-quality audio products sound like and how they should behave.

What Is Car Audio Product Quality?

Depending on your point of view, audio product quality can have a lot of different meanings. From the perspective of the retailer you’re working with, it might mean that a particular brand is incredibly reliable. For example, we’ve tested amplifiers from Rockford Fosgate and ARC Audio that can run at their maximum rated power for at least 20 minutes without any issues. In contrast, in the same tests, we’ve tested other amps that overheat and shut down in under three minutes. If you play your music at high volume levels or live somewhere that’s hot in the summer, picking an amplifier with a functional heatsink design will help keep your music playing without interruption. An amp with better cooling capabilities will likely last longer than one that overheats its internal components frequently.

Another consideration in audio product quality is noise. Many low-priced source units use low-quality preamp output stages and even more amplifiers that produce audible amounts of hiss while they make a lot of power. Listen to almost any motorcycle audio system with super-small amplifiers, and you’ll hear the system hissing when no music is playing. Audible noise like hiss isn’t acceptable in a high-end car audio system. During the system design stage, part of the product selection process is to audition the products you want to use. This might be on the store’s display board or a demo vehicle. It’s crucial that you listen for absolute silence between tracks. One note: Every piece of electronics adds a tiny bit of noise. If you put your ear up to a tweeter, you’re going to hear something. That’s OK. When the noise is loud enough to be heard at the regular listening position, then it’s a problem.

Speaker Quality Characteristics

When it comes to all-out audio system performance, the difference between regular consumer-grade speakers and those that sound truly magnificent comes down to frequency response and linearity. Both are relatively easy to distinguish. Once again, part of the purchasing process is to audition the speakers before you purchase them. As we’ve mentioned, you’ll want to bring along your absolute favorite music and listen to it on several speaker options. We recommend starting with a speaker that might even be slightly above your price range. This “should” set a benchmark for how accurate your music can sound. However, there’s a problem. There are several “boutique” or “luxury” brands that, while they are expensive, don’t offer genuinely high-end performance. As such, the key to getting the most bang for your buck will be to visit several retailers and audition as many speakers as possible. After a few visits, you’ll be able to pick out the designs that offer truly accurate performance.

Here are a few tips for auditioning speakers for linear frequency response. Start with the easy stuff. Listen for unwanted emphasis in the high-frequency region. The letters S, T and P might be too loud if there are issues with a midrange or improper level-matching of a tweeter. Listen to music that doesn’t have too many instruments. We hear people talk all day. So listening to voices is a great way to audition speakers. We know a few people actually listen to movie soundtracks rather than music, as the vocal recordings are sometimes less processed. We recently started using “Into My Arms” by Nick Cave & The Bad Seeds for this very purpose. “Spanish Harlem” by Rebecca Pigeon is another track that will make any frequency response issue stand out. No, neither of these is a fun audio system demonstration track. They are, however, a great way to assess the quality of the speakers.

You want to listen for dynamics at lower frequencies, as would be produced by woofers and subwoofers. This is the second characteristic of speaker quality. Listening at lower volume levels doesn’t tell you much because the speakers aren’t working very hard, and, as such, the cones aren’t moving much. Inexpensive or low-tech speakers can sound fine when loafing along at these volume levels. Where features that improve linearity come into their own is when you start to really turn up the volume. First and foremost, the music should just get louder. There shouldn’t be any change in frequency response or tonal balance. Bass frequencies, in particular, should remain tight and dynamic.

If things get sloppy or boomy, the speakers you’re listening to have linearity issues. The problem could be a simple excursion issue where the speaker has run out of voice coil length. The issue could also be more complicated. Some speakers, especially larger woofers like a 6.5-inch, change frequency response depending on the cone position. When the voice coil is in its most outward or forward position, less of the voice coil is in the magnetic gap, so there is less inductance. When the speaker moves rearward, the opposite happens. With more of the voice coil wrapped around the T-yoke, there is more inductance and, as such, less upper midrange output. These position-based issues are surprisingly common in mid-priced speakers and those expensive speakers that are just overpriced mid-quality solutions. While not a guarantee of performance, woofers and subwoofers that include copper or aluminum shorting rings or a copper T-yoke cap typically exhibit less change in performance as the cone moves inward or outward.

Amplifier Quality

Sadly, there are no specifications available from reputable manufacturers that completely describe an amplifier’s sound. Of course, frequency response is a factor, but nobody provides measured frequency response under a reactive load. Further, there is no standard for a reactive load test. As such, predicting their performance is impossible, particularly in the case of Class D amplifiers.

Second, relevant distortion measurements or specifications are also difficult to interpret. Some companies that offer great-sounding amplifiers say that their amplifiers operate at less than 0.1% THD+N. I would hope so, as that’s a pretty lousy distortion specification. Others that provide really low distortion specifications, like 0.002%, aren’t clear about how they measured that number. Was it at a particular frequency or output level? Based on our extensive experience with reviewing amplifiers, it appears that intermodulation distortion performance is more relevant to the “sound” of an amplifier than harmonic distortion. Even fewer companies even test for IMD or publish relevant data.

As an aside, the lack of accurate and detailed quantification of amplifier performance allows these boutique and luxury brands to proliferate. Consumers are often misled by the higher prices, thinking that they are buying something truly magnificent. Often, the reality is that these solutions are inexpensive products with strong marketing programs. See “Lipstick on a Pig” for reference. But we digress.

So how do you pick an amplifier that sounds good? Once again, it would be best to listen to as many as possible under controlled conditions. This means using the same speakers and volume levels. Making this happen is extremely difficult, as very few retailers match the amplifiers on their displays so they all produce the same output. We have decades of experience in auditioning amplifiers, and we can pick out the ones that sound bad, good or great, often in different systems. However, expecting anyone to devote thousands of hours over decades to establish this experience is unreasonable.

The answer remains: You have to listen. Dynamics are once again a good tell. We recently reviewed a small amplifier. It sounded pretty good at lower volume levels. The reduced energy storage (because of the small size) made the amp sound softer when pushed harder. The attack of a kick-drum was mushier. A rim shot on a snare didn’t make us wince. Now, it’s really difficult to separate the difference in amplifier performance at low versus high output levels from the same changes in performance from speakers. As such, you want to audition amplifiers with genuinely high-quality speakers, even if they are better than what you plan to use.

What Does Audiophile-Grade Car Audio Sound Like?

The point of building any audiophile-grade sound system is to extract the most accuracy possible from a recording. As the previous articles have detailed, the frequency response, sound source and imaging are crucial to presenting the music accurately. Those characteristics are primarily focused on audio system design, installation and calibration.

The difference between run-of-the-mill audio equipment and those components that sound truly exceptional is revealed as accuracy. Does a performer’s voice sound authentic or like a very good audio system? Realism is the next level. When it doesn’t sound like you’re listening to audio equipment, and it sounds like the performer or instrument is out in front of you, you are experiencing something truly exceptional. Of course, it takes a complete system to make this happen. A great source unit, a high-quality digital signal processor, excellent amplifiers and truly amazing speakers are all necessary. It all needs to be installed, configured and calibrated correctly, too!

A while back, we were rewiring the test bench in our lab. We use an ARC Audio PS8-50 to power the audio system on the bench and the nearby computer. The main computer’s TOSLINK digital output feeds audio to the amp. We also use the test bench computer’s analog output. After completing the rewiring, we tested everything to ensure that it was all working. We played the same song from each computer. There was an audible difference between the two sound sources. We fine-tuned the output levels to make sure it wasn’t a psychoacoustic trick and repeated the comparison.

The TOSLINK connection sounded better than the line output on the lab bench computer. Tonally and spatially, they sounded the same. The difference was in the clarity or transparency. There was less “other stuff” on the signal from the main computer. Think of it as hearing less static from a radio station. Better, think of it like less grain in a printed photograph. The image was identical, but it was clearer. Another example we use is the difference between driving with a spotless windshield and one that needs that annoying greasy film that builds up on the inside removed. Of course, you can see where you are going through both. However, the difference is clearly visible when you get that just-slightly-dirty window clean.

Wait, I Like My Music LOUD!

So far, this series of articles on audio quality hasn’t talked much about those who want their audio systems to play louder. Now, unfortunately, there are a lot of people who think loud doesn’t sound good. More people don’t know how good loud can sound. One of the best things about an excellent car audio system is that you are welcome to play it loud. You aren’t going to bother the rest of your family or the neighbors if you crank the volume while driving to work. You are in your own little entertainment cocoon.

A well-designed audio system should sound great at background levels and at concert levels. All the features that make a speaker great also allow them to play loudly. This wasn’t the case 20 or 30 years ago. High-end speakers of that era were fragile. They used tiny voice coils that didn’t weigh much. An audiophile-grade 6.5-inch woofer might have more output capability than some entry-level 8-inch subwoofers. If the SPL guys heard what great speakers sounded like, they’d ditch that pro-sound stuff in a heartbeat. We’ve converted a few folks over to using an audiophile-grade front stage for their systems that are capable of over 150 dB SPL. Their music stays clear and detailed, even at volume levels that blur your vision and rattle your fillings.

The Four Stages of Truly Audiophile-Grade Car Audio

Well, there you have it, a series of four articles that explain what to expect from a genuinely audiophile-grade car audio system. If you are a true music lover who cares about the quality and accuracy of what you are listening to, take a drive down to a local specialty mobile enhancement retailer and start the process of designing a genuinely high-end audio system. Do your work beforehand to choose a shop that has the skills to properly execute the system design, integration, installation and calibration. Be sure to shop around. Many shops with great reputations can’t deliver on what we’ve talked about in these articles.

Associated Articles:

The Four Stages of High-End Car Audio – Frequency Response
We explain why proper system design and calibration are crucial to recreating music with realistic tonal balance and frequency response. (https://www.bestcaraudio.com/the-four-stages-of-high-end-car-audio-frequency-response/)

The Four Stages of High-End Car Audio – Part 2: The Soundstage
At a concert, the music you hear should sound like it’s coming from the performers on the stage. This article explains what to listen for to determine the accuracy of the soundstage in your car audio system. (https://www.bestcaraudio.com/the-four-stages-of-high-end-car-audio-part-2-the-soundstage/)

The Four Stages of High-End Car Audio – Part 3: Imaging
Once you’ve established a good soundstage, an audio system with precise imaging will provide the sensation of real live performers out in front of you rather than a blurred wall of sound. (https://www.bestcaraudio.com/the-four-stages-of-high-end-car-audio-part-3-imaging/)

The Four Stages of High-End Car Audio – Part 4: Product Quality
One of the most crucial components in designing a truly audiophile-grade car audio system is using excellent equipment. We explain what to look for in terms of speakers and amplifiers and why the performance difference is crucial.

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.

The third article in our series on understanding high-end car audio systems delves into the fascinating world of imaging. In essence, imaging is the ability of an audio system to recreate the precise location of a performer or instrument on a soundstage. While not all recordings excel in this aspect, some are genuinely awe-inspiring. Let’s explore this captivating facet of music reproduction.

What Is Imaging in a Car Audio System?

As mentioned, a truly high-end audio system, be it in your vehicle or at home, should be able to accurately present each performer’s position on the soundstage. This sounds similar to our previous discussion about the source of your music. That is the soundstage. The soundstage defines where the music is coming from. Imaging describes the positional accuracy of the sounds on that soundstage.

When two audio signals are the same in amplitude and phase in a recording, they should be reproduced from the exact center of the soundstage.

For example, let’s say we have a recording of a four-piece band. The drums are centered on the stage and are located at the back. The bassist is on the right, a few feet back from the front edge of the stage. The guitarist is on the left side of the stage at a similar distance. Finally, the lead singer is center-stage, right at the front edge.

Whether or not a recording has imaging cues depends on how the performance is captured. For this initial discussion, let’s assume the microphones on a drum kit are mixed into a single mono channel. Each performer has a microphone for vocals, and the guitar and bass also have a single audio channel. If all of these are brought into a mixer, summed together at appropriate levels to produce good tonal balance, and then recorded, all the music would seem to come from the center of an audio system’s soundstage. Why? There is no left or right information captured in the mix. All the music should seem to come from that single blue dot in the center of the soundstage.

A Stereo Microphone Mix

What if the drum kit is mic’ed with 10 microphones, and the floor tom and the ride cymbal on the left of the stage are panned left, and the hi-hats and crash cymbal are panned to the right? The snare might be panned a moderate amount to the right, with the high tom panned slightly right and the mid tom panned slightly to the left. The kick drum mic is likely to be in the center. Further, a pair of overhead microphones placed 5 feet above the drum kit might be dedicated exclusively to left and right channels. The map might look something like this.

The exact amount of panning depends on the drum technician and the recording engineer. If they want the drums to stay relatively focused in the center of the soundstage, perhaps they should be panned no more than 25% to the right or left. They’ll fine-tune this in the studio.

Next, the guitarist and bassist might have their mics panned to the left and right to separate them from the lead singer.

The image below might represent what you’d hear with some panning added to the microphones on the drums, the bassist, the guitarist and the lead singer.

Would this sound the same as what you’d hear if you stood in the studio with the band? Absolutely not. Would it sound better if all the microphones were mixed into a mono signal? Most definitely.

For a genuinely realistic stereo recording that captures more of a sense of the room, the engineer might use more audio information from the overhead microphones. Some performances, like a choir or an orchestra, might be recorded with fewer microphones. When done accurately, capturing the reverberations in the room can add a fantastic sense of realism to the listening experience. The art of creating a recording is equal in skill and talent to that of the performers themselves.

What It Takes to Create Excellent Car Audio System Imaging

For this discussion, let’s consider a stereo sound system. The alternative would be something with an upmixer that adds a center and possible side and surround channels. For a stereo system to provide pinpoint imaging, the signals from the left and right channels must arrive at the listening position at the same amplitude and at the same time. This concept can be expanded by considering that all frequencies must arrive at the same time as those from the opposite channel. Likewise, all frequencies must be at the same amplitude.

Connect a set of headphones to your smartphone and play some music. You’ll likely find that the lead performer’s voice appears to come from a spot in the center of your head, as if they were singing from the middle of your brain. Now, go into the phone’s settings and adjust the balance about 75% toward the left. All the music will seem to come from just inside your left ear. This is a perfect example of how signal level affects imaging.

Now, if one frequency is louder from one side of the car compared with the other, the source of the music that contains that frequency will seem to move its position on the soundstage. We call this phenomenon frequency steering. This is undesirable because the sound source shouldn’t move based on frequency, only amplitude and phase.

Imagine if a stage is recorded with a high-quality stereo microphone, or better yet, a binaural mic placed exactly in the middle of the stage. If the performer is directly in front of the mic, audio signals will simultaneously arrive at the left and right recording elements. Now, if the performer walks to the right side of the stage, the audio signal will arrive at the right microphone element just before the left one and be slightly louder on the right. If the playback system is truly symmetrical in its ability to recreate the recording, we’ll hear the performer move to the right.

How Human Hearing Detects Sound Sources

Our ears work the same way as a pair of microphones to detect the source of a sound. We can triangulate the arrival time and slight differences in amplitude between one ear and the other to locate a sound source. We are accustomed to the changes in frequency response that occur as sound wraps around our heads. This is how we know whether something is in front of or behind us. We can also detect reflections off adjacent surfaces to correlate height. A bird in a tree sounds different from one standing on the ground.

Companies like Harman International have invested a great deal of time in measuring how we perceive sounds from different locations. They’ve used that data to create stereo headphones like the JBL Quantum One that can recreate surround-sound effects from movies and video games. Using only two speakers, you can hear if a bad guy is walking up behind you in Halo or Call of Duty. Yes, it sounds like the person is just behind you. How do they do it? They adjust the frequency response of the sound to mimic what the helix, antihelix, antihelical fold and antitragus do to sounds. This takes some serious math, but it works surprisingly well. The headphones also include head tracking, so if you turn your head to the side, the source of sounds changes. It works so well; it’s almost creepy.

Tips for Excellent Car Stereo System Imaging

To create a car audio system with excellent imaging and a soundstage that is well out in front of the listener, there are a few items to consider. The first is speaker placement. If you want the stage to be on the dash, you’ll need the tweeters to be in line with the dash. This might require a mounting position on the dash or in the A-pillars. It’s better if you can get a small midrange driver onto the dash; this will help solidify the soundstage position at that depth. Many new cars and trucks have midrange speaker positions at the base of the windshield. This works great for depth. Combining that with tweeters in the sail panels or pillars can increase the system’s perception of width.

Next, you’ll want the tweeters installed within 15 to 20 degrees of being on-axis with the listening position. If you use a three-way speaker set with midrange and midbass drivers, angling these speakers only changes the reflections or equalizes the signal.

Next, you need a way to control the output amplitude of each speaker in the audio system. This means that you’ll likely want a fully active system where each speaker has a dedicated amplifier channel.

Next, your system must have some sort of stereo equalizer that’s precise enough to ensure that the signals from the left and right speakers are the same in amplitude across a wide range of frequencies and with enough bands to make sure nothing goes unchecked.

Finally, from a system design and hardware perspective, you’ll need a way to delay the signals going to the speakers closest to the listening position. Your system will need a digital signal processor or a source unit with signal delay features.

Finding a technician who is well-versed in calibrating digital signal processors in vehicles is the most critical aspect of creating a sound system with exceptional imaging. There’s a big difference in a vocal that sounds like it’s the size of an umbrella in the center of the car compared to a softball or even a golf ball. Once the system is calibrated precisely, you’ll hear additional information being revealed. An accurate sense of room ambiance is, for example, often only audible when the system’s imaging is excellent. You’ll start to hear reflections from the ceiling and back of the recording venue, assuming they’re in the recording at all. If the system is calibrated precisely, this information becomes confusing and unrealistic.

Center Image Position

There is one last point of discussion before we wrap up. There are two common options for where the center image should be on the soundstage. Most professionals like the center to be located equidistant from the left and right boundaries of the soundstage itself. In most cases, this would put the center in the middle of the windshield under the rearview mirror.

With that said some people like the center position to be in front of the driver’s seat. Based on our experience, this is a bit more common for factory-installed systems. We won’t say that your preference is wrong, if you enjoy this “right in front of you” calibration. However, we find that it compresses the size of all the instruments on the left side of the soundstage. If the lead vocals are in front of you, the system might have 12 inches of width to the left boundary to place all the performers on the left side of the stage. Conversely, you might have three feet on the right side. It’s your choice, and you should discuss this with the person configuring and calibrating your car audio system before work begins.

Single-Seat System Calibrations

So far, we have discussed audio systems designed, configured and calibrated to provide an exceptional listening experience from the driver’s seat. However, whoever sits in the passenger seat will likely hear all the music coming from the right side of the dash or the door. Why? The speaker will be louder and sounds from the opposite side of the car are delayed. Sadly, when it comes to listening to the music, it’s not very enjoyable to be a passenger in a vehicle with an audio system set up for a single-seat calibration.

Currently, very few digital signal processors on the market can properly extract a center channel signal from the left/right channels and feed it to a discreet output. This feature, called an upmixer, is the only option for creating a detailed soundstage for the vehicle’s driver and passenger. Your installer and the calibration technician might be able to create something that works satisfactorily using all-pass filters. Still, it might lack the precision of a truly amazing single-seat system. Make sure the signal processor you choose has several preset options. You can have an amazing single-seat calibration for those times when you are alone in the vehicle, then a two-seat tune when someone is in the car or truck with you.

Upgrade Your Car Audio System Today for Excellent Imaging

If you want to improve the realism and detail of your car audio system, visit a specialty mobile enhancement retailer with extensive experience calibrating digital signal processors. Audition several vehicles they configured and calibrated to ensure that they can deliver an experience that matches your expectations.

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.

Every speaker, be it a tweeter, midrange driver, woofer or subwoofer, will have a sensitivity rating. Sensitivity ratings attempt to describe how much sound a speaker will produce for a given amount of power from an amplifier. There’s a common misconception that more efficiency is better. Longtime readers of BestCarAudio.com won’t be surprised to learn that multiple standards are used to describe speaker efficiency. It’s time to break speaker sensitivity specifications down to eliminate the confusion.

Understanding Efficiency

Efficiency in a mechanical or electrical system describes the amount of energy or work put into the system compared to how much you get out. To be clear, nothing is 100% efficient. A flashlight might waste 50% of the electricity from a battery as heat. An alternator might only convert 80% of the mechanical energy from a vehicle engine into electricity. Even an automobile engine might only convert 20% of the energy in the fuel that powers it into mechanical energy.

Calculating efficiency is theoretically simple. You divide the power out of a system or device by the power put in, then multiply by 100. For example, a high-quality car audio amplifier might consume 1,075.3 watts of power to produce 1,000 watts of output at the speaker terminals. This would represent an overall efficiency of about 93%. A poorly engineered amplifier might consume 1,750 watts to produce 1,000 watts to drive a subwoofer. That’s an efficiency of only 57%. In terms of the performance and longevity of car audio amplifiers, efficiency is an essential factor.

What Is Speaker Sensitivity?

We need a way to describe how much sound the speaker produces for a given signal from an amplifier. We’ll clarify that speaker efficiency numbers are, at best, horrible.

Let’s look at the two standard specifications used to describe speaker sensitivity. First, we have the 1-watt/1-meter standard. This should be the reference for all car audio speakers, as it negates concerns over speaker impedance. If you have a midrange speaker with a 4-ohm voice coil, a 2-volt signal from an amplifier will deliver 1 watt of power to the speaker. If the speaker has a 2-ohm voice coil, it only takes 1.414 volts. A 1-ohm speaker only needs 1 volt of signal to deliver 1 watt of power.

The second standard is the 2.83 volt/1-meter standard. This is a holdover from the old days of home audio. A signal with an amplitude of 2.83 volts would deliver 1 watt of power into a speaker with an 8-ohm impedance. Connecting a 4-ohm speaker to a 2.83-volt signal gives you 2 watts. That same voltage connected to a 1-ohm load delivers 8 watts of power.

Using the Efficiency Comparison Chart

The chart below shows how much higher a 2.83-volt efficiency rating is than a 1-watt rating. For example, if you have a specification of 82 dB @ 2.83 volts/1-meter for a 4-ohm speaker, the 1-watt/1-meter rating would be 3.01 dB lower at 78.99-dB SPL. If you were given a 2.83-volt rating on a 1.5-ohm subwoofer of 85 dB, the 1-watt/1-meter rating would be 77.71 dB @ 1-watt/1-meter.

If you’re looking at speaker efficiency numbers, make sure you know whether they’re using the 2.83-volt or 1-watt standard.

Sound Level and Distance from the Sound Source

Before we examine the benefits and drawbacks of each specification method, we’ll discuss what’s common to both: the 1-meter measuring distance.

If you live in the U.S., it’s worth explaining that 1 meter equals 39.3701 inches, or 3 feet and 3.3701 inches. Using either the 1-watt or 2.83-volt speaker efficiency specification method is equivalent to a microphone or listener 1 meter from the speaker cone. If you are 2 meters away, the amplitude will be 6 dB lower. The sound level will be 6 dB higher if you are at half the distance, 50 centimeters or 19.685 inches. Pay close attention to speaker efficiency specifications; some companies provide 1-watt at 0.5-meter numbers.

Speaker Sensitivity Measurements

Car audio manufacturers use two methods to generate speaker sensitivity specifications. The simplest is to place a microphone 1 meter from the speaker and perform a frequency response sweep at a specific voltage level. This will produce a chart that shows the driver’s output at each measured frequency. However, this doesn’t produce a single efficiency number. That said, the information is much more helpful in determining the suitability of a speaker for different applications. We’ll dive into extracting data from frequency response measurements another time. Most manufacturers will average the output of the above measurement to provide a single efficiency number.

The second method for specifying a speaker’s predicted efficiency is based on a formula using Thiele/Small parameters. The formula calculates the reference or “power available” efficiency, represented by the lowercase Greek letter Eta (H), which looks like an n with a longer right-side tail, and the subscript 0.

As you can see from the above formula, a higher equivalent compliance (Vas) value will increase efficiency. A higher electrical damping factor (Qes) reduces efficiency. Importantly, even a slight increase in the driver’s resonant frequency (Fs) dramatically increases efficiency as the value is cubed.

The graph above shows the predicted frequency response of a high-quality 6.5-inch car audio woofer in red. The orange graph is the same driver with a 10 Hz higher resonant frequency and a lighter cone. The yellow trace is the same driver with a 20 hertz higher resonant frequency, and so on. As you can see, the efficiency increases significantly, but the amount of bass the driver produces relative to the midrange decreases.

Subwoofers and Efficiency Numbers

It’s absolutely crucial to understand that a subwoofer’s efficiency number doesn’t directly correlate to the amount of bass it will produce. For example, if you cram a 12-inch subwoofer into a 0.85-cubic-foot sealed enclosure, an 8-inch subwoofer in a 0.6-cubic-foot ported enclosure is louder from 25 to 45 hertz with the same power. Comparison of subwoofer efficiency numbers is misleading, so simulation software is required to determine whether it will produce more output.

Should We Compare Speaker Efficiency Numbers?

In many cases, comparing the efficiency of similarly sized speakers based on efficiency is more likely to provide information about how little bass they produce than how loudly they can play. If your application doesn’t need much output below 200 hertz, a more efficient speaker is likely a good choice. However, there is a lot of crucial audio information below 200 hertz. Most male voices extend to 100 Hz, with some like Johnny Cash, Leonard Cohen and David Draman of Disturbed being much lower. If you want to hear their voices clearly, you need speakers that play lower frequencies louder.

Every specification in a speaker design interacts with all the others to produce a specific end product. When it comes to efficiency, the trade-off is typically bass performance. Shopping for speakers based on their efficiency parameters might not yield the desired results. When it’s time to pick speakers for your car, truck, boat or motorcycle, drop by a local specialty mobile enhancement retailer and talk to them about your expectations for the system. You might find that a driver with a lower efficiency specification sounds much better than one with a higher number.

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.

We recently witnessed a discussion on social media in which someone said that two 16 AWG wires could do the same work as a single 8 AWG wire. Unfortunately, the American Wire Gauge standard for stranded conductors isn’t intuitive in helping determine how multiple conductors can pass current. So let’s get geeky and do the math on how much current different-sized or multiple conductors can handle. We know it’s not something that comes up daily, but it’s an interesting topic.

The American Wire Gauge Standard

The American Wire Gauge standard for describing the cross-sectional area of a conductor was created in 1857. Knowing the area of a conductor is crucial to picking the correct size wire for a specific current-carrying application. For example, a small wire, perhaps one with a diameter of 0.1 inch, won’t be able to handle 50 amps of current without going up in smoke.

The AWG standard has a direct diameter-area relationship between one size and the next. For example, the diameter of a 10 AWG wire is 1.1229322 times the diameter of an 11 AWG Wire. The exact ratio applies to any two adjacent wire sizes. As such, the ratio of wire size to diameter is logarithmic, as the size doesn’t increase linearly. The chart below plots the data.

Given that the relationship is logarithmic, it’s tough to determine an equivalency between conductors. For example, if you have an 1,800-watt amplifier installed, it will need more current carrying capacity than a single 4 AWG conductor can provide. Does it need a full 0 AWG conductor? Well, it can’t hurt. But would two 4 AWG wires work? That’s what we have set out to determine.

Metric Wire Sizes

Just so you’re aware, Europe and Asia use metric wire sizes. While they use metric for most things, Canada still uses the AWG standard. For example, a 4 AWG power wire is sold as a 25mm2 wire across the ocean. It should come as no surprise that calculating equivalent current carrying capacities using the metric system is very simple.

There seems to be a discrepancy, however. If you look up 4 AWG in the above chart, it has an area of 0.03286 square inch. That’s equivalent to 21.2 square millimeters. An area of 21.2 is a lot less than 25 square millimeters.

Let’s look at another size. Most charts specify that a 10 AWG is equivalent to a 6-square-millimeter conductor. However, the American Wire Gauge chart lists it as 5.26 square millimeters. Clearly, some averaging is done at some point in the process. Even when trying to be accurate, it seems someone has taken a lackadaisical approach to math.

Power Wire Current Carrying Equivalency

One accurate fact we have is a resistance measurement for the different AWG sizes of copper wiring. This specification is part of the American Wire Gauge standard. We can compare the resistance of differently sized wires regarding their current carrying capacity. We’ve created a chart that compares standard wire sizes from 20 to 0000 AWG to other sizes.

Using the chart is simple, though perhaps not intuitive at first. Let’s start with some simple observations. Any cell with the same wire size will have a number 1. This indicates that the resistance is equivalent, which, of course, makes sense.

Let’s say we have a 4 AWG conductor and want to know its resistance compared to a 2 AWG conductor. Start by looking across the top row for the 4 column, then look down at the row represented by the 2. We see a number of 0.625. This means a single 4 AWG wire can carry 62.5% of the current of a 2 AWG conductor for the same voltage drop.

We can compare them the other way by looking across the top for the 2 column and then comparing it to the 4 row. Here, we see the number 1.6. This means a 2 AWG conductor can carry 1.6 times as much current as the 4 AWG for the same voltage drop.

Multiple Conductor Evaluation

The table also gives us information on how much current multiple conductors might handle to be equivalent to something more significant. So, how many runs of 4 AWG are comparable to a single 0 AWG cable? Look across to the 0 column, then down to the 4 row. We see the number 2.514. This means we need 2.514 runs of 4 AWG to pass the same amount of current as a 0 AWG cable with the same voltage drop.

A better example would be comparing a 6 AWG cable to a 0 AWG. Here, the ratio is 3.971. So, effectively, you need four runs of 6 AWG to equal a single 0 AWG.

Now, let’s get back to what started this discussion. How many 16 AWG wires are required to be equal in current-carrying to a single 8 AWG wire? If we go to the 8 column and then down to the 16 row, we see the number 6.389. This means you need more than six runs of 16 gauge to pass the same current as a single 8 AWG conductor. Six would have more resistance, and seven would have less than the 8 AWG.

Voltage Drop Look-Up Table

While understanding how much current a single or multiple conductors can pass, we need a standard for an acceptable voltage drop. This is a bit complicated as it considers conductor size, current requirements and the length of the wire. The ANSI/CTA-2015 Mobile Electronics Cabling Standard uses a voltage drop of 0.25 volt. For an electrical system providing 14.4 volt, that’s a drop of 1.7% across a single run of wire. We’d likely see the same drop along the ground path.

Please refer back to our article about conductor ampacity (how much current a wire can handle) to determine what’s suitable for a specific application.

Not All Wire Is Created Equally

Before we close out, we should remind our readers that this chart only works for all-copper, full AWG-spec conductors. The resistance will be different if you are looking at a tinned wire. If the wire is copper-clad aluminum, the chart doesn’t apply. If the wire label says gauge instead of AWG, it’s likely not full AWG sizing.

Be wary of these shortcuts and differences. You are buying something unique. Though the tinned wire might be a much better choice for marine applications, tin has only 15% the conductivity of pure copper. You may want to go up a wire size in a marine application to ensure reliable power delivery.

Be Sure To Get The Right Size Wire For Your Car Audio System

Be sure to discuss with the product specialist or technician designing the audio system for your vehicle what size wire they’re using. Before the project starts, understand whether it’s a single run of wire or multiple. This handy chart and a basic understanding of electrical theory from high school will ensure that your audio system performs reliably. Or, at the very least, you won’t make a statement that two 16 AWG wires are the same as a single 8 AWG.

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.

We’re back with the second of four articles discussing the listening experience of truly high-end car audio systems. In our first article, we discussed the importance of accurate frequency response. This second article will discuss the soundstage, provide a definition for it and explain why it’s crucial to recreating a recording accurately.

What Is a Car Audio Soundstage?

We need to define what a soundstage is before we get into describing the intricacies of how to evaluate one. Essentially, we’re talking about where the sound comes from in a vehicle. In a poorly executed system, the music might appear to come from each speaker. This is likely because of a lack of level adjustment, improper signal delay settings in a signal processor or a difference in frequency response between one side of the vehicle and the other. Most basic car audio systems with a radio and one or two pair of speakers deliver sound that seems to come from the speaker closest to the listening position.

As a system’s quality improves, the attention to detail in configuring and calibrating the equipment should also improve. Proper calibration will yield the best performance possible from even the most modest audio products.

We’ll be clear in saying that finding a mobile electronics retailer that is experienced and proficient in designing, integrating, configuring and calibrating an audio system so that it delivers what we’re describing is no easy feat. Some retailers still think digital signal processors are magic black boxes filled with voodoo. If accuracy, realism and detail are the goals of your car audio system, you’ll have to visit many retailers and audition their demo vehicles to find one that can deliver the performance you want. Don’t trust statements. Listen to their work and judge for yourself.

Soundstage Options

Before describing what to listen for in the perfect audio system, we should clarify that listening preferences play a significant role in system design and calibration. The standard for the ideal audio system is to recreate what seems like a live performance in front of the listener. This applies to both home and car audio systems. Many car audio enthusiasts prefer to be immersed in the center of a listening experience. This would replicate a listener’s experience at a dance club or when wearing headphones. The music is all around them, and while there are well-defined left and right channels, it fills the listening space. There is no right or wrong in terms of a client’s preference.

Many car audio retailers fail to qualify their clients’ expectations in this regard. Do you want the music to sound like it’s coming from the front of the vehicle or from all around you? Harman International includes an option in some factory-installed sound systems that allows the listener to switch from an “in audience” to an “on stage” experience. While the concepts are similar, we’ll refer to that in-audience experience for this discussion.

Music Source

In an audio system that is designed, integrated, configured and calibrated perfectly, all the music should seem to come from a well-defined location in front of the seating position. In most cases, this can be described as the windshield, as though it had speakers built into it. Some genuinely magnificent systems can create a soundstage that extends beyond the physical limits of the vehicle. We’ve heard cars that present sounds that extend beyond the left and right speaker positions and others that made it sound like Neil Young was standing in front of headlights.

What’s key is that the sound source is coherent. If your music comes from the dash or windshield, all the music should come from that location. The midbass shouldn’t seem to come from the steering wheel or the footwells. The bass shouldn’t come from the back of the vehicle. Specific frequencies shouldn’t move up or down. Think of it like having a set of high-end, full-range speakers in front of the vehicle, positioned so the left speaker is aligned with the left A-pillar and the right speaker is aligned with the right A-pillar.

Delivering Amazing Audio Performance

The key to achieving the goal of delivering an accurate sound source starts with the system design. If all of the speakers are behind the listener, it will be impossible for the system to sound as though the music is coming from in front of them. This overly dramatic statement gets at the core of proper system design.

Next, the speaker selection must deliver smooth dispersion through the listening environment. Let’s say you have a set of 6.5-inch component woofers mounted in the doors and a set of 0.75-inch tweeters on the dash. In this case, the system will be sensitive to the listener’s location because the woofers must play to frequencies well beyond where it becomes directional. This is why higher-end speaker manufacturers offer large-diaphragm tweeters that can play to lower frequencies.

Managing directivity is only the first part of the component selection process. The second involves choosing products with features that minimize distortion. As we demonstrated in our series about speaker performance, some drivers add significant second- and third-harmonic distortion. If the door speakers are playing up to 2 kHz, the harmonics could extend to 6 kHz, resulting in the soundstage being pulled down to the footwell.

The same concern goes for subwoofers. Imagine a crossover frequency of 75 hertz. This means the second-order harmonic is 150 hertz, and the third is 225. If you choose a subwoofer without a low-distortion design, you might have issues creating a stable and coherent soundstage. Few car audio companies focus on linearity and distortion in their subwoofer products. Do your research and choose wisely.

Car Audio System Calibration

You will need a digital signal processor if you want a car audio system with a well-defined soundstage. A few source units from Sony include enough processing to handle proper configuration. Alternatively, you can choose an amplifier with a built-in DSP or a stand-alone DSP that will work with your existing amplifiers.

Three features in the DSP require proper calibration to align the output of all the speakers in the vehicle. Of course, this only works if all the speakers have dedicated amplifier channels assigned to dedicated channels on the processor. If you have a component set on a single channel with a passive crossover, the ability to fine-tune the system will be diminished. Ideally, the tweeters and the woofers need dedicated processing and amplification channels.

The technician calibrating the system needs to set delays, output levels and equalization properly for each channel. The delays and levels compensate for the different distances to each speaker in the vehicle. The equalization compensates for resonances and cancellations in the vehicle because of reflections off various surfaces. In this context, equalization isn’t intended to improve frequency response, though proper settings simultaneously handle staging and system tonality considerations.

Table for One, Sir?

We skipped over another consideration when creating a soundstage: Do you want the system optimized for the driver or for everyone in the vehicle? The latter is often referred to as a two-seat tune.

If you listen to an audio system configured for a single seat, the location and size of the soundstage, as perceived from the front passenger seat, often suffer. The resulting sensation can vary from being slightly compressed to sounding like all the music comes from the far-right speaker location. Creating a two-seat calibration is time-consuming and often doesn’t sound as coherent as a single-seat tune. However, if you always have someone in the vehicle with you and they care about how the music sounds, it’s worth requesting.

This request might involve using or adding a center-channel speaker. If the signal processor has dedicated center-channel processing, this can work well. However, be sure to ask whether the center-channel signal contains any information found in the left and right channels. If it does, the effect usually narrows the soundstage significantly. Very few processors have full up-mixing capabilities for a center-channel output.

Soundstage Problems – Bass in the Back

Here are a few common problems with the soundstage in car audio systems. The most prevalent issue is not getting the bass to mix with the front-stage speakers. Your system might have a good soundstage for midbass through high-frequency information, but the deeper bass seems to come from the trunk or cargo area.

This issue can sometimes be solved by better calibrating the crossovers and delays between the midbass drivers and the subwoofer. Sometimes, though, this is a distortion issue with the subwoofer(s); the only solution is to upgrade them.

Soundstage Height Issues

Another common problem is that different frequency ranges come from different heights. If the vehicle has a two-way speaker system and the tweeters can’t play low enough, the midrange and midbass sounds seem to come from the lower part of the dash, while the higher frequencies come from the windshield.

Improving this with a steep filter and a lower crossover frequency on a tweeter might be possible. However, the proper solution is a much larger tweeter, or better yet, switch to a three-way system that uses a midrange up high on the dash or in the A-pillars.

Compressed-Width Soundstage

You might also experience a soundstage that’s much narrower than the vehicle width or where one side doesn’t extend as far to the opposite side. This can make the stage seem unrealistic in relation to the vehicle boundaries. It’s akin to the band congregating on the left (or right) side of the stage but never spreading back out.

The solution to this issue could be complicated. It might be level or delay-related. It can also be a speaker placement issue, which makes it harder to resolve without revisiting the installation.

Drooping Soundstage

Though it’s less common now that kick-panel speaker locations are less popular, another possible soundstage issue is a rainbow or drooping stage. In this case, the center image might be in the middle of the windshield under the rearview mirror. However, the left and right extremes might drop into the kick-panel area. The solution is similar to the fix for frequency separation.

No Sense of Depth

This last issue is a mix between a soundstage issue and an imaging problem. Imaging refers to the placement accuracy and size of instruments on the soundstage. Does the singer’s voice sound like it’s the size of a pizza pan, or is it more like a tennis ball? Are all the instruments placed in accurate and precise locations on the soundstage? The issue we’ll discuss is a soundstage with no sense of depth. You might see why this is a staging and imaging issue.

Not all recordings contain a sense of depth or layering. If you listen to a purely electronic recording, you will likely hear a wall of sound unless they’ve done some fancy tricks with phase adjustments. If the recording is of a band, choir or orchestra, and stereo microphones are used to pick up the space in the hall, a good car audio system should be able to recreate this sensation. If your system doesn’t present any sense of depth, it’s usually an issue with the channels not being calibrated equally.

Experience Your Music Like Never Before

If your car audio system doesn’t have a solid soundstage, drop by a local specialty mobile electronics retailer today. Start by auditioning their demo vehicles to see whether they can create an experience you will enjoy. Bring along your favorite music and listen to a half-dozen tracks. Pay close attention to where the music is coming from. Everything should seem to come from the windshield. The bass, vocals, guitars, drums – all should be coherent and realistic. If the vehicle doesn’t deliver, don’t fret. Find another shop and audition their work. Even once you’ve found what you think is the perfect solution, it’s often a good idea to listen to as many vehicles as possible to get a reference for tonal balance, soundstage, imaging and dynamics. Imaging will be the next topic in this series. Stay tuned!

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.