Speed of Sound Technologies

Mobile Enhancement Experts in Milford CT

55 Woodmont Rd., Milford, CT 203-954-0066
  • Home
  • About Us
  • Services
    • Car Audio
    • Custom Installation
    • Driver Safety
    • Radar/Laser Detectors
    • Remote Starters
    • Truck Accessories
    • Vehicle Security
    • Window Tint
  • Location and Directions
  • Contact Us
  • Facebook
  • Instagram

Product Spotlight: Sony XM-1ES Mobile ES Mono Power Amplifier

Sony XM-1ES

The team here at BestCarAudio.com has been privileged to follow the introduction of new, high-performance car audio components in the Sony Mobile ES line. From their impressive speakers and subwoofers to the genuinely outstanding XAV-9500ES source unit, each solution has delivered exceptional performance and value. For 2022, Sony has added three amplifiers to the Mobile ES line. The first model we’ll spotlight is the XM-1ES monoblock subwoofer amplifier. Let’s dig in!

Sony Mobile ES XM-1ES Amplifier Specifications

The XM-1ES is a monoblock car audio amplifier designed to power subwoofers with up to 1,000 watts of power. Specifically, Sony rates the amp as capable of producing 600 watts of power into a 4-ohm load with specifications that fall under the CTA-2006-C guidelines for noise, distortion and supply voltage. When driving a 2-ohm load, power output increases to 1,000 watts while remaining under the 1% THD+N limit. Sony specs the distortion as being 0.05% or less at 100 Hz. Though it’s uber-geeky, I’m happy to see that the 77 dB signal-to-noise ratio specification is also CTA-compliant. Everyone at BestCarAudio.com is fanatical about proper specification qualifications, and Sony isn’t playing any games in this regard.

Sony XM-1ES
All connections are along one edge of the amplifier for a clean and tidy installation.

The amplifier measures 10.63 inches wide, 8.46 inches deep and 2.36 inches tall. This is small enough to fit under the front seats of many vehicles or in a storage compartment under the floor of a cargo area. Sony has done something unique with the chassis and bottom-plate design of the XM-1ES that I’ve never seen from any other amplifier manufacturer. The high-mass cast-aluminum extrusion has been optimized for a resonant frequency that is well out of the region where most of the vibration energy from the vehicle and subwoofer system occurs. This will contribute to product reliability and could easily improve the amplifier’s sonic performance. It’s also worth noting that the center trim panel on the top of the amp can be rotated 180 degrees, so the Mobile ES logo aligns cosmetically with your installation. This is impressive attention to detail.

Sony XM-1ES
The chassis of the XM-1ES is designed to be damped better than other amplifiers on the market to improve reliability and performance.

In terms of electrical connections, all signal, power and speaker terminals are along the front edge of the amplifier. All the speaker and power connections are made via heavy-duty terminal blocks with hex-head set screws accessible from the top of the amp. Even better, the same size hex key is used for every screw on the amplifier, from the top trim cover to the beefy 1/0 gauge power terminals. Fuses, the connection for the very handsome remote level control and an input voltage selection switch round out the end panel features.

Sony XM-1ES
The remote level control included with the XM-1ES will allow you to adjust the output of the amplifier quickly and easily from the front of the vehicle.

Removing two screws on top of the amp gives your installer access to the amplifier’s configuration settings and controls. RCA input jacks will accept 0.2 to 8V in low-voltage mode and 3 to 16 volts in high-level mode. This switch implies that the inputs on the amp feature a differential design that will help eliminate the presence of induced noise. The low-pass crossover is adjustable from 50 to 500 Hz and has a slope of -24 dB/octave.

The XM-1ES has remote signal detection turn-on capabilities when using the high-level input setting, so it can be used with a factory source unit without needing external hardware in most applications. The infrasonic filter is adjustable from 5 to 50 hertz with the same attenuation rate.

Sony XM-1ES
The center trim piece on Sony’s new Mobile ES amplifiers can be rotated to suit your installation layout.

A look inside the amp shows a modern design, using surface-mount components almost exclusively. Surface-mount parts, which can be placed on the board robotically instead of by hand, offer exponentially better value to consumers. These parts also typically offer higher precision than their through-hole brethren. High-quality capacitors, shielded output filter chokes, lots of energy storage and good input filtering are clearly evident.

A small variable-speed fan in the back left corner helps ensure that the amp will continue to function reliably, even when installed in a space with limited ventilation. This durability is part of why Sony can back its Mobile ES amplifiers with a three-year manufacturer’s warranty.

Sony XM-1ES
A solid design executed with good-quality components should ensure that the Sony XM-1ES sounds great and operates efficiently

Check Out the Sony XM-1ES at Your Local Authorized Sony Retailer

We plan to get one of the new Sony XM-1ES amplifiers to our lab for a full BestCarAudio.com Test Drive Review shortly. If you’re shopping for a high-quality, full-featured subwoofer amplifier for your vehicle, visit your local authorized Sony Mobile ES retailer. You can learn more about this amp and its two brethren (the XM-4ES four-channel and XM-5ES five-channel) by visiting the Sony Mobile ES website, their Facebook page, Instagram feed or YouTube channel.

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, PRODUCTS, RESOURCE LIBRARY Tagged With: Sony

What Is An MP3 File?

MP3

You cannot have talked about audio and computers any time in the last 15 years and not have heard of an MP3 file. MP3 audio files and websites, like the original Napster, started a shift in where, how and when people acquired music. If you are on the older end of the spectrum, like many of us in the mobile electronics industry, then you bought your CDs, cassettes and maybe even your vinyl at a record store. Computers and the Internet changed that. You could go online after dinner and download an illegal copy of a song in a few minutes. It was wrong, but people acquired tens of millions of songs this way.

In the 1990s and early 2000s, accessing the Internet was slow. We started connecting to the Internet using phone lines and modems. Each byte of information took time to transfer to your computer, so anything that would speed up the process was a treat. Downloading (stealing) music using the Internet is where the popularity of the MP3 audio file met its calling.

A Primer on Digital Audio

MP3We could write 10 articles about digital audio – and we just might. For now, we are going to look at the basics and use the compact disc (CD) as our reference. CDs store digital audio sampled at 44.1 kHz with a resolution of 16 bits. These numbers mean each sample can have an amplitude that is a single value within a range of 65,536 different levels (2 to the power of 16). The information is sampled 44,100 times a second. Sampling at what is known as 44.1/16 allows capturing the audible range of audio (considered 20 Hz to 20 kHz) with good detail and accuracy.

To store 1 second of audio at this resolution, we need to store 1,411,200 bits of information. Anyone who has played with audio transcoding software may recognize 1,411 kbps as a standard data rate. This number is calculated by multiplying the number bits per sample (16) times the number of samples per second (44,100) times 2. The times-2 factor is because we record in stereo – which is two channels. So, a 3-minute long song is 254,016,000 bits or 31,752,000 bytes.

Let’s round it off to 31 megabytes of information. Can you imagine how long it takes to download that with a dial-up modem running at 14,400 baud? The answer is at least 3.5 minutes – without error checking, line noise and other factors that slow the real download time to about 5.5 minutes.

Data Compression

What if someone found a way to shrink the size of the audio file to speed up download time and reduce bandwidth usage? The caveat is that the audio still sounds essentially the same on most basic audio systems, such as a TV, computer speakers or a 1990s factory car radio. In 1991, a group of companies, including the Fraunhofer Institute, France Telecom, Philips, TDF and IRT, started working on a way to reduce file size while maintaining relevant information. That is the key to how file size is reduced using MP3 compression.

The MP3 file format is a “lossy compression” algorithm. Lossy compression means that information is thrown away to reduce file size. The development team worked on a compression method called perceptual encoding to decide what information to remove. Perceptual encoding is based on how we hear sounds relative to other information, and the limits of our hearing.

What MP3 Files Throw Out

We are going to analyze the information that MP3 files remove to reduce file size. One of the easiest ways to cut back on information storage is to reduce the highest frequency that will be reproduced. If we analyze a 128 kbps MP3 file, we see that the highest reproduced frequency is just below 16 kHz. If that were the only information that was removed, our new bitrate with 16-bit samples in stereo would be about 1,004,800 kbps instead of 1,411,200 kbps for 20.05 kHz.

MP3The next part of the compression process analyzes content that is common to both channels. It is common for some parts of a recording to be virtually in mono. The encoding process removes duplicated information from the file and adds code to copy the opposite channel. If the audio track were purely mono, the file size would be divided in two. Few tracks are completely mono, but we can see more space saving from this process.

Subsequent processing looks at low-level information during high-amplitude passages. Let’s use the example of a song with a lot of bass in it and some very quiet harmonic midrange information. Perceptual encoding processes like MP3 will remove this low-level information from the audio track. This process is called audio masking. There is enough audio information at other frequencies to distract you from hearing what is removed.

Can You Hear the Difference?

Dozens – nay, hundreds – of tests have compared MP3 files to full CD-quality audio tracks. Are there differences? There most certainly are. One thing became apparent during our research: How an MP3 file is created is crucial to its subjective sound quality. Different encoders work in different ways with different results.

Perhaps the best way to describe the difference between a CD-quality recording and an MP3 file is to look at the difference between the two. I wish we could share some samples here for you to listen to, but that would break copyright laws. What we can do is visually show you the difference.

We took a 3-second sample from Daft Punk’s “Give Life Back to Music.” We chose this track because of Daft Punk’s clear and conscious effort to make a high-resolution version of the album commercially available. We want to thank them for that! The sample is from 31.5 seconds to 34.5 seconds into the song.

This Spectrogram shows the frequency content of the sample. The horizontal scale is time. The vertical scale is frequency. Finally, the color intensity shows the amplitude.

MP3
This is the original sample.

You can see that there is frequency content up to 30 kHz, clearly demonstrating the high-resolution nature of this track. Each vertical color band represents a drum machine beat – more or less.

128 kbs MP3 File Analyzation

MP3
This is the sample converted to a 128 kbps MP3 file.

It is clear that audio information above 16 kHz has been removed. Infrasonic frequency content is clearly different as well. There is more information in the MP3 file below 30 Hz compared to the original. This increase in information will, however, present itself as less-dynamic range.

MP3 Vs Original File

MP3
This is the difference between the Original sample and the MP3 Sample.

We inverted the MP3 file and added it to the original sample to make the image you see here. The net result is the difference between the two tracks. You can see the high-frequency content that was removed above 16 kHz. In fact, information was removed at all frequencies, and that information follows the intensity pattern of the audio file.

The original file has a peak amplitude of -0.1 dB for both channels and an average amplitude of about -14.2 dB. The removed information has a peak level of -10.9 dB and an average amplitude of -37.01. The removed information is buried deep below the peak amplitude information.

MP3What does the removed audio sound like? We would describe the clip as the sound of a distant marching band. The audio is mostly high-frequency information. The track has a decidedly warbled texture to it as well: The drum machine beats are clear and present, but they sound like distorted cymbal hits.

Even with a high-end headphone preamp and studio grade headphones, the difference is hard to perceive when switching between the original track and the MP3 file. In a listening environment with a larger soundstage, it may be more apparent.

Conclusions about MP3 Files

Purists will tell you that you should have the highest-quality recordings available. There is no fault to this logic. Why skimp when you can have it all? High bitrate MP3 files, like those at 320 kbps, for example, are excellent in quality. Repeated testing has shown that when created with quality compression algorithms, the sound difference between a CD-quality recording and a 320 kbps MP3 file is almost impossible to detect. Lower bitrate MP3 files start to dispose of more information, and the differences become bigger.

The latest source units on the market are capable of playing WAV and FLAC audio files of great resolution and bit depth. Shortly, we will see units that will play MQA files over digital connections. Almost every source will handle MP3 and WMA files.

Drop into your local mobile electronics specialist retailer today, and bring along some music to enjoy. We think you will be impressed – no matter what format you choose.

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

Product Spotlight: Sony Mobile ES XS-690ES and XS-680ES Speakers

Mobile ES Speakers

Consumer reception of the new Sony Mobile ES speakers has been incredible. These solutions were designed to offer benchmark performance at very accessible price points. A while back, we looked at the 6.5-inch component set and coaxial speakers. In this BestCarAudio.com spotlight, we’ll check out the features of the XS690ES 6-by-9 and the XS-680ES 6-by-8-inch speaker sets.

Sony Mobile ES XS-690ES

Mobile ES Speakers

The XS-690ES speaker set is a drop-in replacement for the most popular speaker size of all time – the ubiquitous six-by-nine. Sold in pairs, the set includes mesh grilles for custom installations. These two-way speakers feature a 1-inch soft-dome tweeter and a mica-reinforced cellular aramid fiber matrix woofer cone. The tweeter uses a synthetic fiber diaphragm that balances mass and rigidity to deliver excellent clarity and extension to an as-claimed 40 kHz. The woofer cones are well-damped and rigid to ensure uncolored midrange performance and great bass production. The rubber surround features Sony’s Separated Notch Edge Surround design that helps to damp unwanted oscillations that add distortion at high excursion levels. In addition, Sony notes that the progressive spider is designed to deliver “rapid and precise” control over the woofer for crystal clear performance.

Mobile ES Speakers
Staggered notches molded in the surrounds help eliminate unwanted resonances and deliver precise audio reproduction.

Physically, the speakers are based on a five-beam composite basket that offers both rigidity and excellent damping characteristics. This construction allowed Sony to integrate a cooling system around the ceramic magnet that they call the Dynamic Air Diffuser. As a result, hot air from the voice coil can escape from under the spider to optimize power handling and reduce compression and rarefication at high excursion levels.

In terms of specifications, the XS-690ES speakers are rated to handle 110 watts as per the CTA-2031 specification and efficiency is specified as 90 dB at 1-watt, 1-meter, with a tolerance of 4 dB. When choosing these speakers for upgrades in vehicle doors, note that the mounting depth is 2.875 inches with a protrusion height of just 0.50 inch from the mounting surface. Last but certainly not least, the speakers have a nominal impedance of 3.2 ohms.

Mobile ES Speakers

Sony Mobile ES XS-680ES

Mobile ES Speakers

The XS-680ES speakers are explicitly designed as an OE speaker upgrade solution. These drivers share the same five-spoke composite basket with their integrated Dynamic Air Diffuser cooling technology. The woofer cones feature the same balanced-performance mica-reinforced cellular aramid fiber matrix construction. It’s worth noting that the mica mineral not only improves damping but it also increases thermal stability. This physical robustness is crucial around the joint with the voice coil.

Mobile ES Speakers
The XS-680ES and the XS-690ES feature Sony’s Dynamic Air Diffuser design to improve linearity and power handling.

Sony has done its homework in terms of delivering smooth output between the midrange and tweeter. Aside from the high-quality polypropylene capacitor that serves as the crossover, the XS-162ES 6.5-inch coaxial speakers and these XS-680ES six-by-eight drivers use the same 13/16-inch (2.0 cm) tweeters. The XS-690ES uses the larger, more efficient 1-inch design used with the XS-160ES component set. The crossover in the component set includes attenuation circuitry, so the output efficiency matches that of the woofer while offering improved low-frequency output.

In the case of all three coaxial driver solutions, the tweeters are mounted atop a custom-tooled composite post that extends up through the center of the driver. The post features a smoothly tapered shape and finned outer edge to help control midrange-information reflections. Likewise, the top of the tweeter is positioned so that it doesn’t extend past the front edge of the woofer surround. Other drivers aren’t always like this, and their tweeters can present issues when mounted behind factory grilles. It’s clear that every square inch of these drivers is optimized for the best possible performance.

Mobile ES Speakers
The smooth shape of the tweeter mounting post helps manage reflections from the woofer for surprisingly clear sound.

The XS-680ES drivers also use a progressive spider at the base of the driver and Sony’s new Separated Notch Edge Surround for compliance at the top of the cone. In terms of specs, power handling is rated at 75 watts (CTA-2015 compliant), efficiency at 89 dB with a tolerance of 4 dB, and nominal impedance at 3.2 ohms. The mounting depth for these six-by-eight speakers is 2.125 inches.

Mobile ES Speakers

Distortion-Reducing Shorting Ring

With respect to both the XS-680ES and XS-690ES, we’ve already mentioned the woofer cone material as well as the notched surround as crucial factors in delivering clear sound at high volume levels. However, another vital feature that Sony included is an aluminum shorting ring inside the motor assembly. This seemingly simple addition helps damp unwanted magnetic fields that are created as the voice coil moves forward and rearward from rest. Those fields would oppose the efforts of the fixed ceramic magnet and dramatically reduce output at the top end of the midrange and add distortion. The aluminum shorting ring, quite simply, acts as a short-circuit to those unwanted high-frequency magnetic currents, allowing the drivers to deliver uncannily clear midrange clarity.

If you haven’t heard car audio speakers with this technology, it’s well worth making a special trip to audition them. Quite simply, they sound different and better than speakers that don’t include this technology. Oh, and most products that include shorting rings cost at least twice as much, if not three times.

Experience Sony Mobile ES Speakers Today!

If it’s time to upgrade the audio system in your car or truck, drop by your local authorized Sony Mobile ES retailer and audition the new XS-690ES and XS-680ES. Be sure to bring your favorite music with you and give the volume on the display a good crank. You won’t believe how great they sound!

For more information on Mobile ES products, visit the Sony website. Be sure to follow Sony on Facebook, Instagram and YouTube to stay on top of future additions to the Mobile ES line.

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, PRODUCTS, RESOURCE LIBRARY Tagged With: Sony

Product Spotlight: Sony Mobile ES XS-160ES and XS-162ES Speakers

Sony Mobile ES

In the first week of May 2021, Sony Electronics introduced its new Mobile ES series of speakers and subwoofers. If you’ve been into the car audio industry for a while, then you’ll recognize the Mobile ES (Elevated Standard) name from classic products like the CDX-X90 CD player. The new Mobile ES speakers include 6.5-inch coaxial and component sets, a set of 6×8 and 6×9-inch coaxials and a 10-inch subwoofer. Let’s dive into the 6.5-inch sets and explain what makes them an excellent solution for an enthusiast wanting amazing sound from their car audio system.

Sony Mobile ES XS-162ES Speakers

Sony Mobile ES

The XS-162ES is a 6.5-inch component speaker set that includes a pair of woofers with removable grilles, a set of 1-inch tweeters and a pair of passive crossover networks. The woofers are based on a proprietary lightweight composite material, designed to integrate cooling vents around the perimeter of the magnet to help keep the motor assembly cool. Sony calls this its Dynamic Air Diffuser. The five-spoke baskets also include venting under the spider mounting plateau to increase linearity at high excursion levels. There are 10 mounting holes in the thick upper flange to accommodate three-, four- and six-position fastener locations. A phase plug in the center of each woofer is supported by a finned aluminum bobbin with its own Dynamic Air Diffuser for added cooling.

Sony Mobile ES
The Dynamic Air Diffuser design helps remove heat from the motor assembly to increase power handling and reduce thermal compression.

The woofers are formed using Sony’s third-generation Mica Reinforced Cellular (MRC) cone material. The mixture combines mica mineral powder to increase damping and thermal stability with aramid fibers to provide good strength and rigidity. Sony reports that this new material helps suppress cone resonances to deliver improved bass and midrange performance. The cone is suspended by a progressive spider that helps control motion at extreme excursion levels. The design of the Separated Notch Edge Surround at the top of the cone, with its curved grooves, reduces distortion by equalizing compliance for inward and outward motion and damping the synthetic rubber material’s resonances.

Speaking of distortion reduction, Sony has included an aluminum shorting ring around the inside of the magnet to help control unwanted magnet flux in the motor assembly. This feature results in a significant reduction in speaker inductance and smoother upper midrange performance.

Sony Mobile ES
The Separated Notch Edge Surround of the new Mobile ES speakers.

The set of tweeters included in the system uses a soft-dome design with a large surround. The voice coil is connected directly to the base of the diaphragm. A large neodymium magnet slug serves as the motor for the tweeter. The voice coil is immersed in a magnetic fluid that improves power handling, increases efficiency and damps unwanted resonance.

Sony claims these tweeters deliver output to 40 kHz. As such, they are ideal for Hi-Res source units that can play FLAC and DSD files. The tweeters can be flush-, surface- or angle-mounted using the included hardware.

Sony Mobile ES
The large mounting ring around the 1-inch tweeter serves as a waveguide to increase efficiency and allow for a lower crossover frequency.

The passive crossover networks each feature high-quality mylar capacitors and an air-wound inductor. There’s an output level control switch that will allow your installer to attenuate the tweeter by 3 dB to balance the system.

Sony Mobile ES
The bi-amp capable crossover networks include high-quality components and a tweeter output attenuator for easy system calibration.

XS-160ES Coaxial 6.5-inch Speakers

Sony Mobile ES

The XS-160ES is the coaxial version of the XS-162ES drivers. They share the same basket and woofer design but feature a 13/16-inch soft dome tweeter instead of the 1-inch driver found on the component set. The tweeter is mounted on top of the composite center post and, just like its big brother, includes an integrated waveguide to help increase efficiency. The tweeter crossover capacitor is mounted in the center of the pole extension for a clean and tidy appearance.

Sony Mobile ES
A cutaway view of the XS-160ES highlights the unique cooling features of the speaker and the proprietary mounting post for the tweeter.

An important consideration in choosing a coaxial speaker for your car or truck is to ensure that the tweeter doesn’t protrude too far out the front. The product development team at Sony took this into account and made the top edge of the tweeter even with the top of the woofer surround so it won’t come into contact with the stock grille in your car or truck.

Mounting Requirements and Specifications

Both the XS-160ES and XS-162ES have a mounting depth of 2.125 inches and require a 5-inch cutout diameter. When installed, the grilles stick out 29/32 of an inch. The tweeters in the XS-162ES require a 2.128-inch mounting hole and need 0.75 inch of depth when mounted flush. The overall outer diameter is 2.5 inches. Both speakers are rated for up to 60 watts of continuous and 270 watts peak power handling as per the IEC 60268-5 spec. The CTA-2031 spec is 90 watts per driver. Efficiency is specified at 89 dB with a tolerance of 2 dB at 1 W/1M. The frequency response is 45 Hz to 40 kHz for the XS-160ES and 40 Hz to 40 kHz for the XS-162ES system with no specified tolerance.

Upgrade Your Car Audio Experience with Sony Mobile ES

Based on the feature set alone, the new Mobile ES speakers put themselves in competition with products costing two to three times as much. The new Sony speakers are available to audition and purchase from authorized Sony Mobile ES retailers across the U.S. and Canada. If you’re looking for a way to improve the audio system in your car or truck dramatically, the XS-162ES and XS-160ES speakers are a great option.

You can learn more about Sony Mobile ES car audio products by visiting their website or visiting an Authorized Sony Mobile ES retailer near you. Of course, be sure to follow Sony on Facebook, Instagram and YouTube to stay on top of future additions to the Sony Mobile ES line.

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, PRODUCTS, RESOURCE LIBRARY Tagged With: Sony

Amplifier Classes: Making Sense Out of Class AB and Class D Amps

Amplifier ClassesAmplifiers have a very tough job. They have to take a very low voltage signal and increase it in amplitude so it can drive a speaker. In this transformation, we expect the signal to remain pure – no distortion or no noise should be added. We also want significant amounts of power to drive our speakers, even though we only feed our amplifiers with a measly 12 to 14 volts of electricity. The laws of physics seem to want to work against us at every turn – but we prevail! Modern car audio amplifiers are amazing feats of engineering and design. This article looks at the two main types of amplifier classes used in the car audio industry and the benefits and drawbacks of each. Welcome to Class AB vs. Class D.

The Math behind how Amplifiers Make Power

No matter how we configure the components inside an amplifier, the goal is the same: Increase the voltage of the preamp audio signal so it can drive a speaker. Because the speakers we use are low in impedance (2 or 4 ohms for most midrange speakers), we need to be able to provide a significant amount of current to the speaker as well. This delivery of current to the speaker is the second task an amplifier has to undertake.

By way of some quick math, if a 4 ohm speaker is getting a 12V RMS signal, we can make a few calculations. To calculate the current flowing through the speaker, we divide the supplied voltage by the impedance of the speaker. In this example, we have 12 divided by 4, so 3 amps of current are flowing through the speaker wires and the voice coil. An easy way to calculate the power going to the speaker is to multiply the supplied voltage times the supplied current. The product of 12 times 3 is 36. This speaker is receiving 36 watts of power.

Let’s look at the same example as though this were a subwoofer amplifier. In this second example, we will assume we have a Dual 2 Ohm voice coil subwoofer with both coils wired in parallel to produce a 1 ohm load. If we supply this speaker with 12 Vrms of signal, then 12 amps of current flow through the speaker wire and the subwoofer. To calculate power, we multiply 12 times 12 to get 144 watts. 144 watts is a lot more power and current for the same amount of voltage.

General Amplifier Function Overview

Most amplifiers are composed of three or four key sections (or stages), depending on their design and complexity. The input stage is the portion of the amp where the low-level preamp audio signal enters the amp and receives any processing in the form of equalization or filtering.

An amplifier has a power supply. The power supply converts the supplied 12 to 14 V of direct current to positive and negative rail voltages. Let’s say, for example, a theoretical amplifier has +25 and -25V rails, relative to our ground reference. Depending on the size of the amp, there will be a driver stage. The driver stage is responsible for increasing the low-level audio signal to a higher voltage. How much the driver stage increases the voltage depends on how much power the amp will be making.

Amplifier Classes
Mosfets have shrunken in size over the years to the minuscule size now available (right).

Finally, we have the output stage. The output stage is relatively simple – it does not significantly alter the signal coming from the driver stage, but the devices (MOSFETs or transistors) used to provide the output signal with the current the load requires. The power supply and the output stage are the two portions of the amp that do the most “hard work.” That is to say, they are the stages that pass a lot of current.

In almost all amps on the market, we use dedicated devices for the positive half of the waveform and separate devices for the negative half of the waveform. To clarify , if we measure the output signal of the amplifier about the vehicle ground, we will see that it swings back and forth above and below 0V. Think back to our +25 V and -25 V power rails. Speakers don’t care about the value of the signal being sent to them; all they care about is the difference in voltage from one end of the voice coil to the other end.

Class AB Amplifiers

Amplifier ClassesFor this article, we are going to generalize Class AB amps into an Analog, Amplifier model. In our analog amplifier, we have large transistors in the output stage of the amp. When we want half of the positive rail voltage at the output, we feed half the voltage to the positive output device. When the signal goes negative, we turn off the positive device and start using the negative device only. Looked at a different way, the audio signal from the driver stage controls the resistance of the output devices and, subsequently, how much current can flow to the speaker.

In an Analog Amplifier, the output devices can be “turned on” in varying amounts about the audio signal. This means the output devices are often acting as resistors. Power is wasted as heat when we pass current through a resistor. Keep this in mind as part of our comparison later in the article.

Class D Amplifiers

Amplifier ClassesIn a Class D amp, the output devices receive a control from a Controller Integrated Circuit (IC). This controller sends out a variable duty cycle square wave. The square wave amplitude is high enough that it turns the output devices all the way on or off. The output devices spend very little time operating as resistors and act more like switches.

The logical question is, how in the world do we get music out of a square wave? If you thought that, good for you! The frequency of the square wave is much higher than the maximum frequency of our music. In fact, some modern Class D amplifiers switch the output devices at frequencies as high as 600 kHz.

Amplifier Classes
An additional benefit of class D amplifiers is the potential for extremely compact size.

To recreate music, the Class D controller sends out a signal that is Pulse Width Modulated. The amount of “on” time about the “off” time determines the output level of the signal. As a very general analogy, if the positive output devices were sent a square wave with a 50% duty cycle (on for as much time as it was off), then the average of the output would be 50% of the positive rail voltage. If the square wave is on for 75% of the time, then off for 25%, then we would get 75% of the rail voltage at the output.

As you can imagine, the signal from the Class D controller is quite complex. It has to modulate the duty cycle of the square wave going to the positive and negative devices fast enough to accurately recreate the audio signal. It also has to control both the positive and the negative output devices separately.

Benefits and Drawbacks of Analog Amplifiers

Because the audio signal in an analog amplifier is never chopped up into tiny pieces, analog amplifiers can remain faithful to the original signal. The best-sounding amplifiers in the mobile electronics industry are analog. Analog amplifiers are, historically, given a reputation for accurate high-frequency response.

The drawback of an analog amplifier is its efficiency. Efficiency describes how much energy is wasted as heat as compared to the energy sent to the speaker. Because of the output devices in an analog amplifier work as variable resistors, they get hot. Typical analog amplifiers operate in the 70-80% efficiency range regarding total efficiency, while operating at full power. That missing 20-30% is released as heat. At lower output level, the efficiency drops even more.

Benefits and Drawbacks of Digital Amplifiers

Amplifier Classes
The integrated circuit of the class D amplifier controls the switching.

Modern digital amplifiers switch at extremely high frequencies. We see amps capable of audio frequency response beyond 50 kHz, and some that exceed 70 kHz. This performance is a long way from the first Class D amps that were only for subwoofers and struggled to produce audio above 5 kHz. That said, because digital amplifiers require filter networks at the end of the output stage, they still cannot quite match the performance of a premium analog amp. With this information in mind, consider that there are some good digital amplifiers that sound better than many poorly designed analog amplifiers.

Because the output devices of a digital amplifier rarely operate in their resistive range, these amplifiers can be very efficient. A well-designed Class D amp can have an efficiency around 92%.

Another problem with Class D amplifiers is noise. Because the output devices are driven by a square wave, there is a lot of high-frequency energy in the output signal. The filter network we talked about removes much of that from the output signal, but that energy can still have detrimental effects on other systems in the vehicle. An unfortunately common trait for many Class D amps is that they cause interference with radio reception when in operation.

Choosing Between Amplifier Classes

Amplifier ClassesIt would be nice if we could formulate a set of hard-and-fast rules for choosing the right amplifier for your system. With so many variations on each kind of amp at so many different price points, that is truly impossible. We strongly suggest that the only way to pick an amp is to compare one to another under controlled conditions: Use the same music and the same speakers, and listen at the same volume. You will hear differences in frequency response and dramatic differences in imaging and staging capabilities.

Is one kind of amp better than the other? For an installation dedicated purely to sound quality, the choice is clear. For an installation where power delivery is limited or massive amounts of power are required, the choice is clear there as well. In the middle, it depends on your application and budget.

Drop in at your local mobile electronics specialist retailer to find out about the latest amplifiers on the market. They would be happy to help you choose one that meets your application and works with your budget.

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

  • 1
  • 2
  • 3
  • …
  • 13
  • Next Page »

Recent Articles

Product Spotlight Sony XM-1ES Mobile ES Mono Power Amplifier

Product Spotlight: Sony XM-1ES Mobile ES Mono Power Amplifier

August 11, 2022 

The team here at BestCarAudio.com has been privileged to follow the introduction of new, high-performance car audio components in the Sony Mobile ES line. From their impressive … [Read More...]

smiling woman lying on carpet and listening to music

What Is An MP3 File?

August 7, 2022 

You cannot have talked about audio and computers any time in the last 15 years and not have heard of an MP3 file. MP3 audio files and websites, like the original Napster, started a … [Read More...]

Product Spotlight: Sony Mobile ES XS-690ES and XS-680ES Speakers

Product Spotlight: Sony Mobile ES XS-690ES and XS-680ES Speakers

August 4, 2022 

Consumer reception of the new Sony Mobile ES speakers has been incredible. These solutions were designed to offer benchmark performance at very accessible price points. A while … [Read More...]

Product Spotlight: Sony Mobile ES XS-160ES and XS-162ES Speakers

Product Spotlight: Sony Mobile ES XS-160ES and XS-162ES Speakers

July 28, 2022 

In the first week of May 2021, Sony Electronics introduced its new Mobile ES series of speakers and subwoofers. If you’ve been into the car audio industry for a while, then you’ll … [Read More...]

Testimonials

Will be going back for sure!






Very happy with how the tint came out. Professional and friendly. Will be going back for sure.




Jonathan P.

Speed of Sound Technologies
5
2016-09-27T02:18:41-04:00

Jonathan P.

Very happy with how the tint came out. Professional and friendly. Will be going back for sure.
https://speedofsoundtech.com/testimonials/amazing-customer-experience/

I recommend then to everyone!






Super great place to get lots of custom things done. Very nice, very knowledgeable and very fare prices. I recommend to everyone I know.




Jonathan L.

Speed of Sound Technologies
5
2016-09-27T02:12:51-04:00

Jonathan L.

Super great place to get lots of custom things done. Very nice, very knowledgeable and very fare prices. I recommend to everyone I know.
https://speedofsoundtech.com/testimonials/i-recommend-then-to-everyone/

Very Friendly Staff






Very friendly staff, knowledgeable group . Needed help on my remote starter, they got me back up and running in no time . They also do amazing tint jobs!!




Todd D.

Speed of Sound Technologies
5
2016-09-27T00:49:55-04:00

Todd D.

Very friendly staff, knowledgeable group . Needed help on my remote starter, they got me back up and running in no time . They also do amazing tint jobs!!
https://speedofsoundtech.com/testimonials/very-friendly-staff/
5
3
Speed of Sound Technologies

Subscribe to Our Website

Enter your email address to subscribe to our website and receive notifications of new posts by email.

Location


Get Directions to Speed of Sound Technologies

Address

Speed of Sound Technologies
55 Woodmont Road
Milford, CT 06460
Phone: 203-954-0066

Connect With Us

  • Facebook
  • Instagram

Services

  • Car Audio
  • Custom Installation
  • Driver Safety
  • Radar/Laser Detectors
  • Remote Starters
  • Truck Accessories
  • Vehicle Security
  • Window Tint

Store Hours

MondayClosed
Tuesday9:00 AM - 5:00 PM
Wednesday9:00 AM - 5:00 PM
Thursday9:00 AM - 5:00 PM
Friday9:00 AM - 5:00 PM
Saturday9:00 AM - 5:00 PM
SundayClosed

Copyright © 2022 Speed of Sound Technologies · Privacy Policy · Website by 1sixty8 media, inc. · Log in

 

Loading Comments...