How To – Evaluating Car Audio Systems

You can spend a lot on a car stereo, but how do you know if it's any good?

Upgrading the audio system in your swanky British luxo-sedan to “Naim for Bentley” could set you back over $8,000. Now if you're about to write a check for a quarter mill or more that might seem trivial, but when the “base” audio system is doubtless pretty good, how much better can it be for that extra green?

The same question applies to the audio system in your Toyota, Honda or Chevy. Every manufacturer offers an upgrade from the base unit installed. But what is “better”? If beauty is in the eye of the beholder, sound quality must depend on the listeners ear. In other words, it's personal.

Learn how to compare audio systems

Car audio quality is, or at least should be, an important topic. We spend a lot of time in our cars and have more options than ever for playing music. Car audio systems have come a long way since the cassette player and FM radio. Now we can add in satellite plus CD's and MP3s tracks played from our portable electronics along with various streaming services. With all these options, shouldn't you be hearing your music the way the artist intended?

Here we're going to explore the complex, subjective topic of evaluating car audio systems. We'll address:

• The complexity of getting quality sound in a small space
• Where to evaluate car audio systems
• How the pros do it
• What to listen for

Finally, we'll wrap up with some suggestions for tunes to soothe your ears while taxing your sound system. When you've finished reading you'll be ready to go out and upgrade!

Quality sound, small space

All that music you hear is nothing more than changes in air pressure, rippling out from the loudspeakers. Think of waves of water, but in 3D if you can imagine that.

Soft surfaces absorb that wave energy but harder surfaces, like glass, reflect it back. Surfaces that have some flexibility tend to vibrate like the skin on a drum, a behavior termed “resonance” that's accentuated by particular frequencies.

The interior of your car contains all these materials, so sound reflects and disappears and makes panels buzz or even rattle from time to time. On top of this, tires create a low frequency hum or drone as you travel down the road. Even in the quietest car, at highway speeds that becomes loud enough to drown out low frequencies, a.k.a. bass, that give your tunes their distinctive sound.

In other words, your car isn't a great place to listen to music. However, there is an upside. Unlike designing an audio system for your front room, the car audio engineers know exactly what they're up against. With that knowledge they can try to optimize speaker location, within the constraints of the body structure, (thin doors, crowded dashboard layouts and so on.) That's one reason why high-end car audio systems feature a dozen or more speakers.

Where to evaluate car audio systems

Go shopping for an aftermarket car audio system in a store and you'll likely be invited into a cozy demo room. That's guaranteed to make almost every system sound great, and the problem is, it'll sound different in your car. The number one issue is speaker placement. In the demo room they'll be arranged differently to how they are in your car. And second, the room will probably have lots of soft furnishings and little glass or other hard surfaces.

The best place to listen to car audio then, is in a car. Some stores may have installed systems you can listen to, although speaker placement may still be an issue. Obviously if you're in the happy position of buying a car and want to tell if the audio is up the scratch that problem goes away. Don't try evaluating while driving though, not to start with anyway.

First, you should listen to music with your eyes shut – we'll explain why in a moment – and hopefully you wouldn't try that while traveling at 35 mph or more. Second, there's that bass masking effect from the road and tires. So the parking lot or showroom is the place to start your evaluation.

How the pros do it

Assessing sound quality is a little like tasting wine: in the end it comes down to what you like. But that said, it's still helpful to learn what the experts look for.

Back in 2016 Automobile and Sound & Vision magazines teamed up to review high-end car audio systems. Their process was to combine science with a trained ear, (and some great musical choices!) In summary, here's what they did

1. Play some “pink” noise
2. Think of “pink” noise as static. It's basically all frequencies, at the same intensity. They capture this with a microphone and an iPad app that gives a visual display of what the audio system is broadcasting. The more even and uniform the distribution the better the system is at turning signals from electronics into sound.
3. Scan for resonancesAs with “pink” noise, this needs a special recording, in this case a descending, bass tone. This flushes-out any resonances in the vehicle structure.
4. Baseline the road noiseDrive the car without any music, and measure just how much noise gets through the vehicle interior.
5. Listen to quality recordingsListening is the subjective portion, and as with wine-tasting, there's a long list of points to consider. The key though is the quality of the music source. The MP3 format, which most of us use, is not particularly good. (Technically, it's considered a “lossy” format because of how it's compressed.) CDs provide higher quality, although not every car audio system has a CD player these days. The alternative is to use music recorded in WAV or FLAC formats.

What to listen for

Let's start with where to sit. Most listening is done from the driver's seat, so that's where you start. Unless you're completely indifferent to your passenger's audio experience though, it is important to try every seat in the vehicle. And as said before, do your listening parked-up and not on the road.

The audio experience depends on what's called the “soundstage.” This is the listener's perception of where the music is coming from. Modern car audio has moved on from the simple left-right of stereo and the better systems give a really three dimensional impression of a stage. With your eyes closed it should seem that the music is coming from performers arrayed in front of you.

Ideally, the singer or lead performer should seem to be just above the center of the dashboard, with the other musicians arranged around them. There should also be a perception of depth, with the performers not too close, or too far away. It's also important that no single instrument or sound be localized to a single speaker. You don't want Norah Jones coming at you from just the left door pocket!

Then there's the question of reproduction. This really gets into wine-tasting territory with audio experts using an incredibly wide range of terms in an attempt to describe how it sounds. The key though is that every note should be clear. Try to pick out instruments like drums, cymbals and violins and get a sense of how realistic they seem. The same goes for the performer's voice. With the volume cranked on a really good system, and with a high quality recording, you should even hear them breathing!

Top tunes for car audio evaluation

For the Automobile/Sound & Vision study the editors included among his choices: Bill Berry and his Ellington All-Stars' “Take the ‘A' Train”, Michael Ruff's “Wishing Well” and several Pink Floyd tracks such as “Money” and “Time.”

When Road & Track conducted a similar test their editors put together a play list that included Stevie Wonder's “Superstition along with instrumental pieces like Philip Glass' Etude No. 2. A good reason for listening to instrumental works is that it prevents any distraction from the voices. For a similar reason it's also a good idea to listen to some spoken word recordings.

Upgrade for more listening pleasure

If you spend a lot of time in your car you probably listen to music. You know those artists, not to forget the recording crew, went to great lengths creating the precise sound they wanted. Don't you owe it them to listen to it reproduced as closely as possible to their original intent?

Many of the base systems auto manufacturers install today do a good job of producing quality sound, but people who care about music often yearn for something better. If you're buying a new car it's usually possible to upgrade, and the guidance given here should help in evaluating competing systems. Alternatively, you may be planning to install a quality aftermarket system, in which case you know know how to evaluate its performance.