Talking about the performance of audio equipment without objective measurements is like describing the taste of food without eating it. Maybe that’s a bit over the top, but the concept is accurate. You’ll hear many folks into high-end audio describe listening experiences that are sweet or emotional. However, those adjectives do very little to describe the physical characteristics of the performance.

Where in the world are we going with this? A combination of several listening tests and lab measurements got us thinking about the Hi-Res Audio product certification. We’ve tested many source units, amplifiers, signal processors, and Bluetooth interfaces that bear this accreditation. What does Hi-Res Audio certification mean? Further, does it mean a product will sound great?

High-Frequency Audio Reproduction

The first part of the certification attempts to correlate extended high-frequency performance with audio resolution. The standard requires amplifiers, signal processors, audio interfaces, source units, speakers, earphones, and microphones to record or reproduce audio frequencies up to 40 kHz.

The inference is that extended frequency response somehow correlates to resolution. In reality, bit depth, in theory, has more to do with resolution than high-frequency performance.

Ask anyone over 30 if they can hear audio frequencies above about 16 kHz, and most will tell you no. Those who think they can ought to have a formal listening test performed. We believe they will be surprised. Most adults we know can’t hear much over 14 kHz.

The argument for capturing audio frequencies above 22.05 kHz (the upper limit of a compact disc) is that harmonics present in the audio change the audible frequency region. While possible, those harmonics will also be present in the recording at audible frequencies. Reproducing them offers no benefit if they can’t be heard. Bats, dogs, cats, rats, mice, owls, and reptiles might appreciate the extra effort and storage bandwidth, but humans won’t.

Benefits of High-Resolution Audio Recording

The most significant benefit of recording higher-frequency content is the overall quality of the recording equipment. A recording studio might have a Universal Audio Apollo audio interface capable of sampling analog audio at 192 kHz with 24 bits of depth. However, those details alone don’t describe the true performance capabilities of the device. The Apollo X8 boasts 130 dB of dynamic range and a THD+N specification of -127 dB. The latter is equivalent to better than 0.0000446% Total Harmonic Distortion and Noise. To put it subtly, that’s ludicrously impressive.

What does this mean for the recording? The recording only captures the audio signal from the microphone at the interface, as the harmonic content added to the signal is imperceptibly low. An order of magnitude worse performance would still be imperceptible. You will get an incredibly clear recording when the engineer mixes dozens of tracks at this quality level.

Actual Bit Depth Comparison

The image below, and dozens like it, are misused in hundreds of applications to infer different quality levels based on bit depth.

The second part of the Hi-Res Audio criteria refers to handling audio files with 24 bits of depth. A common misconception about bit depth is that it also correlates with resolution. In reality, it doesn’t. The benefit of additional bit depth is reducing the noise captured in an audio signal.

Here’s a very real-world example. The image below shows the spectral content of a 1 kHz tone recorded at -80 dB FS, then saved as a 192 kHz, 24-bit file in red. The yellow trace is the same test tone but is saved as a 16-bit file.

When we open the file and check the spectral content, we see that a lot of noise has been added to the 16-bit track. Yes, the information is at a very low level of -98.13 dB for the 16-bit file. Crucially, it’s something that wasn’t in the original recording.

When a music producer creates a modern rock or pop song, they might combine 50 to 80 different tracks or samples. Let’s assume it’s only 60 tracks with 16 bits of depth. After typing a really long equation into Microsoft Excel, we get a noise floor of -90 dB FS. With playback levels of 100 dB SPL, which is easily possible from even modestly robust audio systems, the noise in the recording would be audible during quiet passages.

A 24-bit audio file has a noise floor of around -160 dB FS. I won’t bother doing the math, as no source units or amplifiers perform anywhere near that level. Okay, I lied. That’s about -152 dB of noise with 60 tracks combined. Like I said, it’s not audible.

Sound Quality

Unfortunately, for the Hi-Res Audio designation, the most easily perceptible degradation in audio quality is associated with distortion. Harmonic distortion is far more prominent than noise or high-frequency extension. As we’ve explained repeatedly, distortion is the addition of unwanted harmonic content due to nonlinearities in a speaker, amplifier, signal processor, or source unit.

The Japan Audio Society ignores this significant factor in its Hi-Res Audio certification. Their exact statement regarding audio quality is based on a “hearing evaluation” that is “implemented according to each company’s regulations.” Given that few products publish distortion specifications, it’s concerning that a label intended to designate a product as high quality leaves out this critical consideration.

Hi-Res Audio Wireless

What got us all riled up about the Hi-Res Audio designation? It was a culmination of several listening tests of Hi-Res Audio Wireless products. While the efforts put into optimizing wireless audio transmission over Bluetooth are commendable, the degradation the process causes is significant.

Based on our hands-on experience, playing a Hi-Res Audio Wireless format like LDAC or aptX on a premium-quality source unit degrades the performance to well below what you’d hear with a regular run-of-the-mill solution. Nevertheless, we understand the concept and goal – the execution fails miserably.

If you think for a moment that Bluetooth “sounds awesome,” then it’s time to play some music directly from a USB memory stick. The same goes for wireless connections used in Apple CarPlay and Android Audio. Switch to hi-res tracks you’ve purchased and stored on a USB memory stick. If your system can deliver, the difference will blow your mind! If you don’t hear a difference, it’s time for an upgrade.

Hi-Res Audio Isn’t Necessarily High-Fidelity Audio

We’ve been incredibly fortunate to have the opportunity to measure and audition audio solutions from all the top brands in the car audio industry. Indeed, many solutions sound magnificent. Unfortunately, many make quality and clarity claims that the hardware can’t substantiate. Some of these products bear the Hi-Res Audio logo.

When it’s time to upgrade your car audio system, drop by a few local specialty mobile enhancement retailers and audition the solutions they offer. If you’ve done some research and listened to the same music in the demo vehicles and on the display boards, picking out what sounds terrific is easy.

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

A while back, we examined the difference in sound quality between wired and wireless Apple CarPlay. Now that many Android-based smartphones have access to additional audio streaming codecs like LDAC and aptX, it’s time to check out how they perform in terms of signal accuracy and frequency response. We’ll use the Sony XAV-9000ES digital media receiver we tested in May 2024 for the test. Let’s see what happens!

The Test Criteria

The most important consideration in determining sound quality is frequency response. To evaluate this, we’ll conduct two tests. First, we’ll play a five-minute-long white noise track from an Android smartphone while it’s connected to the Sony radio’s USB port. We’ll use the averaging capabilities of our QuantAsylum QA403 to analyze the result. We are looking for as flat a response as possible here.

Next, we’ll connect the phone to the radio wirelessly and repeat the measurement. The frequency response results for an iPhone were similar over either connection.

The second test is to evaluate signal quality. We’ll play a 0dB 1kHz test tone for this test in both wired and wireless configurations. We’ll examine the harmonic content to evaluate how each scenario performs regarding purity. Perfect performance would mean that no additional harmonic information is added to the 1 kHz tone. In the case of the iPhone, the wireless connection couldn’t hold a candle to having the device hardwired to the source unit.

For reference, we’ll include measurements of the white noise and 1kHz test tone tracks played back from a USB memory stick. With an Apple iPhone as the source option, playing your music from a USB memory stick was hands down the best choice.

Frequency Response Testing

We should have mentioned that we are using a Samsung S9 running Android 10 for the testing. Yep, it’s a bit old, but it has LDAC. Should we stumble on a more recent model, we’ll repeat the testing and update.

Let’s dive right into the frequency response results, shall we? First, let’s look at the performance when using a wired connection to the smartphone.

Up first, we have the analysis of the white noise track played back from a USB memory stick. We’ve zoomed in so you can see if there is any roll-off.

Overall, the response looks just as we expected—flat out from 10 Hz to 96 kHz. Now, let’s switch to a wired connection while using Android Auto and see if that affects anything.

It’s clear that the audio signal starts to roll off at about 14 kHz, and it appears to be about 20 dB down by 22 kHz. There’s no audio information above 22 kHz, so the signal is not considered hi-res. Now, let’s switch to a wireless connection and measure the white noise track again.

In this test of the Sony radio and Samsung S9 phone, we can see that nothing above approximately 17 kHz is passed from the radio. We’d really like to try a new phone, though, to confidently assert that the wireless connection is this bad in all cases.

Signal Purity

The next test is to evaluate how the different playback options affect signal purity. In a perfect world, no additional audio content would be added to the test tone. However, every audio device adds some amount of harmonic content. The less added, the more precise and accurate the system will sound, assuming the frequency response remains unaltered.

First, we have the distortion performance when playing our test tone from a USB memory stick.

Overall, the Sony performed well, with a THD+N specification of 0.00581% and an output right around one volt. This would be considered excellent performance. Now, let’s see what happens when we play the same track from the Samsung phone using a wired Android Auto connection.

There’s a little more low-level noise below the 1 kHz tone, but overall, the performance is quite similar. Measured THD+N came in at a still respectable 0.01029%. Finally, let’s try this with a wireless connection.

Just as we saw when using an iPhone, the wireless connection adds a lot of low-level noise. While the graph looks much worse, the 3 kHz, -91 dBV spike remains the primary factor in determining total harmonic distortion. As such, the measured performance only decreases slightly to 0.01139%. This is still considered to be a good distortion number.

Conclusions on Wired Versus Wireless Android Auto Sound Quality

From the standpoint of our 1 kHz signal purity test, it remains clear that a USB connection outperforms wired or wireless connections. This is especially true regarding frequency response. The Android Auto connections would sound duller and less detailed than playing music from a USB memory stick.

If you’re after the best sound quality possible from a premium multimedia receiver, then put your music collection on a USB memory stick and connect that to your radio. If your radio doesn’t support the latest high-resolution audio formats, drop by a local specialty mobile enhancement retailer to see what they have to offer to upgrade the clarity of your mobile audio system.

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

It wouldn’t be an exaggeration to say that we’ve seen dozens of posts asking about dash cameras that are easy to install and don’t cost much. We’ve all but beaten the topic of dash camera quality to death and have reviewed and analyzed several solutions from Momento and Thinkware. Based on the results of our testing, the words “inexpensive” and “dash cam” don’t belong in the same sentence.

Looking at the installation side, an easy installation would have the camera suction-cupped to your windshield and the power wire hanging down and plugged into the cigarette lighter socket—by the way, the proper term is now “Power Outlet.” From the standpoint of integration, this solution isn’t integrated at all. The wire is a safety hazard as it can be distracting. Trusting the camera mounting to a suction cup isn’t ideal either. Notably, no rear camera is present to capture what happens behind your vehicle. Not all accidents are going to happen in front of you.

We have decades of experience upgrading audio systems in cars and trucks. As such, we are more than capable of installing a modern dash camera system to a level that matches our standards. However, Ben and, more specifically, Ted from Safe Drive Solutions volunteered to handle the installation and permit us to document the process. Let’s check it out!

Pre-Installation Vehicle Preparation

Whenever you take your vehicle to a mobile enhancement retailer for upgrades or a service center for repairs, clean it out. Ensure there is nothing on the floor, in the cup holders, the back seat, or the cargo area/trunk. Anything left there must be moved, wasting the technician’s time. The goal is to clean the interior so the technician doesn’t have to deal with spilled coffee or stray french fries. Though this should be common courtesy, it often isn’t, so please heed this reminder.

Second—and this is something we obsess about—ensure your battery is fully charged. The technician will need a few hours to route wiring from the rear camera to the front unit and from the camera to a power source. The doors will be open most of this time. A battery that isn’t fully charged may not start the vehicle after the work is complete. We left our CTEK MUS7002 battery charger connected to the battery while Ted worked his magic.

Some shops have battery chargers for each vehicle they are working on. Ask the shop if they charge the vehicle battery while the doors are open.

Vehicle Protection Prevents Disasters

Most insurance policies don’t allow consumers to access the vehicle while work is underway. Having the vehicle owner hovering around the car during the work is a colossal distraction and liability.

When shopping for the best shop to work on your vehicle, you should ask whether they use seat, fender, or other protective covers while working. Accidents happen, and having a cover over the seats, steering wheel, and center console can prevent costly repairs. This is the attention to detail you want to see in every step of the upgrade process.

Pick the Right Dash Camera

Finally, make sure you’ve picked the camera you want. There are dozens of considerations when choosing a dash cam. What resolution are the image sensors? How does Parking Mode work? Does the camera offer HDR? How much current does the camera draw? What’s the image compression method? How large of an SD card will the camera accept? What is the field of vision? Does the camera have an LCD screen? Does the camera have Wi-Fi connectivity? There are probably another half-dozen essential questions you’ll want to ask the Product Specialist before you agree to the installation. Ensure the camera will do what you want and behave how you want before you consider booking the installation appointment.

Rear Camera Installation

Let’s dive into the nitty-gritty of this installation. Ted started with the rear camera. In this case, the rear camera in the kit is water-resistant and has an IP67 rating. Even though it would survive on the vehicle exterior, we wanted the camera mounted inside the rear window to keep the lens clean. Mounting it externally would be ideal for a delivery or cargo van without a rear window.

Front Camera Installation

The next step is to pick a location for the front camera. We wanted the camera hidden from view, so we chose the passenger side of the windshield. This location conceals the camera behind the rearview mirror. While we can set the display to turn off to reduce distraction, this location also prevents the camera from blocking any of our field of vision.

Someone at Kenwood put more than a moment of thought into the design of the connectors on the side of the camera. They are both low-profile right-angle units, which reduces the camera’s visual footprint compared to something with a power cord that sticks straight out. Nice work!

Ted bundled the power harness and the rear camera cable together using automotive-grade cloth tape. This makes the installation much neater than using zip-ties or electrical tape. He has small wire-routing tabs he can stick to the windshield or trim if needed, but the wiring naturally stayed right up against the rain sensor and Lane Keep Assist camera pod at the top of the windshield.

Perhaps one of the most important aspects of a dash camera installation is how the wiring is routed down the A-pillar. Most vehicles have a side-curtain airbag. You don’t want any wiring to interfere with this safety device. As such, the wiring should be installed with the factory wiring that runs behind the bag.

Dash Camera Electrical Connections

We could write a full essay on the benefits and drawbacks of how electrical connections for the camera are made. In this instance, Ted had already researched where to get constant power, accessory, and ground wires in the factory wiring. As any good technician should, he used a high-quality multimeter to test that the wires functioned as he expected before going forward. Once satisfied, he stripped the jacket off the wires and soldered the connections from the Kenwood hardwire kit to them. The connections are protected with automotive-grade tape. No wiring should ever be visible around the fuse panel, around the door seal or A-pillar trim, or across the top of the windshield.

The Kenwood dash camera has a color display on the back and can provide a real-time view on a smartphone using the Kenwood Dash Cam Manager app. We looked at the image on our smartphone as we picked a final installation location for both the front and rear cameras. Once chosen, he thoroughly cleaned the glass using alcohol wipes to ensure the two-sided tape would remain secure.

Camera Configuration

Wiring and mounting a dash camera are only three-quarters of the project. Ted set the time and date on the camera and turned on the date stamp feature. We then discussed whether we wanted parking mode enabled and reviewed the different configuration options in the smartphone menu. It was clear that he’d done this hundreds of times.

Even though we have extensive experience with dash camera configuration and testing, he offered to explain how the sensitivity settings are adjusted for impact detection. Furthermore, he ensured we could connect the phone to download videos. We had it covered, but these processes separate the paid amateurs from the true professionals.

We finished by ensuring the camera powered up and down correctly as the ignition was turned on and off. Ted mentioned that the wire color codes on some wire harnesses don’t match industry standards, so he always tests the system thoroughly before he calls the job done. We know for a fact many shops overlook this simple step.

After-Installation Clean-Up

What impressed us the most was that Ted went through the entire working area with a damp cloth and interior detailing cleaner to ensure there wasn’t a speck of dust or fingerprints left behind. He also ensured there were no wire jacket strippings or zip tie ends on the floor where he worked. He also repacked the camera boxes so we had all the owner’s manuals and warranty information in one place. He finished the project by presenting his business card and letting us know he was available for any questions or concerns.

Professional Dash Camera Installation

The camera installation and configuration took about two hours to complete. Ted says that’s pretty much normal for modern vehicles. Systems with only a front camera take less time, and systems with three or more cameras are more involved. Adding an external battery like the Thinkware iVolt Xtra can also add time to the project. We are considering a battery pack upgrade in the future.

As we have repeatedly harped on, shopping for a professional to work on your vehicle is no easy task. We’ve known Ben at Safe Drive Solutions for decades and knew that if he was confident enough to partner with Ted, his attention to detail and processes would meet our high standards. He delivered in spades. This article should provide a good set of questions to ask when shopping for someone to integrate a dash camera system into your vehicle. Please don’t skimp on the quality of the camera you choose or who installs it.

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.