Sounds in Silence

Taking a detour from the sound of the engines, we indulge our senses into the sounds of the in-car audio systems with four of the best luxury EVs on sale right now.

Nishant Padhiar 4 Mar 2024 02:56 PM

Few things are inextricably linked to each other like the open road and music. In fact, with rising congestion across the globe, in-car entertainment systems have gained a level of sophistication never seen before in the OEM space. So while we still strive to find that perfect ribbon of tarmac behind the wheel of the perfect car, it’s also important to address the everyday victories. The “stuck-in-traffic-but-headbanging-to-AC/DC” sort of victories. Speaking of AC/DC…EVs incidentally make for the perfect testing bed for the sound quality of stock audio systems. Thanks to the inherently quieter cabins, the vanishingly low NVH levels and their relatively newer system architecture compared to ICE counterparts. This feature focuses solely on the sound quality and sonic characteristics of each car in question and doesn’t delve into their respective infotainment systems or operation. 

Our quartet of Avengers included the Audi Q8 e-Tron, Mercedes EQE SUV, Jaguar i-Pace and BMW iX, all roughly in the similar price bracket but vastly different in their cabin design and system configuration. The task was simple; to ascertain which car could separate the Weeknd from the Milli Vanili based on stringent parameters such as Soundstage, Clarity and Precision, Tonality, Bass Definition, Maximum SPL (sound pressure levels) and Structural Rigidity. Every system was tested with the car parked in Autocar’s very own studio, in controlled conditions that allowed us to maintain extremely low ambient noise levels. This allowed us to pinpoint misgivings more easily than driving around, which would lead to body flex on our battered city roads and incessant honking in the perpetually trafficated Mumbai corrupting our impressions and findings.

Soundstage

Three-dimensional sense of space that allows you to imagine a virtual performance with the instruments and musicians in front of you. 

A fundamental difference between most cars and a live performance or home audio system is that we listen to the sound coming primarily from the front. Not from the sides or the rear like in a lot of lesser car audio systems. While all the cars in this test are equipped with a front centre speaker, some pull off the illusion of placing the vocalist right in front of your eyes a lot better than others. 

Barring the Jaguar i-Pace, every other car here offers some level of surround sound control that affects how much direct sound you’re listening to as opposed to reflected or diffused sound. Surprisingly the i-Pace cleverly manages to circumvent this software limitation by physically placing its tweeters as deep into the A-pillars as possible, increasing the sense of depth. The Q8 e-Tron, despite help from B&O wizards, doesn’t conjure the same effect, the sound never going beyond the boundaries of the cabin.The EQE-SUV and iX on the other hand can really make the cabin sound much larger than their cubic volume would suggest, increasing the immersive effect of a 360-degree sonic bubble while maintaining a strong front and centre image. The EQE-SUV ever so slightly edges out the BMW iX with its accuracy and pinpoint imaging as well. If you’re adventurous enough, the EQE-SUV also offers Dolby Atmos capability via MBUX and its Apple Music integration. The BMW on the other hand, offers sounds and chimes designed by none other than Oscar-winning composer Hans Zimmer and while it doesn’t have any bearing on the overall soundstage per se, it does have an interesting Harman Kardon sample clip built into the BMW OS if you want to show off the sonic fireworks to your friends.

Audi Q8 e-Tron - ★★★✩✩

Mercedes EQE SUV - ★★★★★

Jaguar iPace - ★★★✩✩

BMW iX - ★★★★✩

Bass definition

How low can the bass frequencies go without becoming boomy or getting into distortion.

More often than not the word “boomy” is used to describe a positive bass effect, but in reality, it’s the opposite of what is desirable.  Low frequencies are usually the hardest to reproduce accurately in any car due to a variety of factors that include size of the woofer, enclosure in which it’s mounted, body panels being excited by bass energy etc. The list is long but our objective was clear - to crown a definitive winner when it comes to bass. 

Surprisingly, the BMW iX tied with the Jaguar i-Pace, both showing signs of resonance and some energy-robbing vibration through the door panels. Nothing that can be fixed by taming the bass levels a bit but for the sake of equality, all tests were conducted on flat EQ settings. Moving on the Audi Q8 e-Tron and the bass displayed a lot more authority and presence with a more liberal window to play around with the bass levels, depending on personal preference. But it’s the Mercedes EQE-SUV with its Front Bass concept that bolts the subwoofer to the chassis itself that makes a real impression. The bass is taut, well-defined and never out of sync with the rest of the frequency spectrum, making for an engaging listening experience that sounds more cohesive than any other car here.

Audi Q8 e-Tron - ★★★★✩

Mercedes EQE SUV - ★★★★★

Jaguar iPace - ★★★✩✩

BMW iX - ★★★✩✩

Structural rigidity

Door panel flex, rattles and low-bass induced vibrations in the cabin.

Everyone has experienced at some point or another when we are excited by our favourite electronic music track but the body panels of the car seem to share that excitement too and want to play along.The chink in every stock audio system is the amount and quality of the damping material in the door panels and for obvious reasons, auto manufacturers want to reduce cost and weight, hence skimp on this big time. 

Within the realm of OEM systems, this simple test allowed us to crank up the volume of a bass 40Hz frequency test tone and audibly confirm rattling, squeaking and resonances. Now these being luxury cars, they all proved that their build quality was exemplary and the BMW iX, Mercedes EQE-SUV and Audi Q8 e-Tron all tied with an equal score. Even the Jaguar iPace was just a point down, indicating that overall, these are extremely well-put-together automobiles. One could always achieve a higher degree of performance by strategically adding acoustic treatment to areas of the door cards and subwoofer enclosure if possible, but all these cars proved that the inherently high structural rigidity of premium segment vehicles pays dividends in multiple  areas beyond safety and dynamics.

Audi Q8 e-Tron - ★★★★★

Mercedes EQE SUV - ★★★★★

Jaguar iPace - ★★★★✩

BMW iX - ★★★★★

Clarity

Vocal intelligibility, timbre quality of instruments and high frequency “air” and imaging.

Probably the most important aspect of judging the sound quality of any hi-fi system, home or car, is its ability to resolve detail and microdynamics. Ideally, without turning it up to eleven. It’s easier said than done but the contenders here are all equipped with branded audio systems that have many years of experience building high quality home systems. 

Hence, the critical speaker placement and shaping the crossover has been achieved almost flawlessly on all these cars. With the amount of speakers present in any of these cars, it is imperative that the timing and phase of all the speakers is correctly maintained to ensure maximum resolution from modern recordings. The BMW iX and the Mercedes EQE SUV have a slight edge due to their higher speaker counts though. The BMW also boasts of active drive units in the rear headrests and it aids in adding just the right amount of “fill”, without overpowering your ears with localised sound. If you like to tweak the sound to your Both the Audi and the Jaguar do a fine job in maintaining intelligibility, whether it’s for speech on podcasts or vocals on music.

Audi Q8 e-Tron - ★★★★✩

Mercedes EQE SUV - ★★★★★

Jaguar iPace - ★★★★✩

BMW iX - ★★★★★

Max SPL

The measure of how loud a system can play before audible distortion sets in.

Setting our SPL meter to ‘C’ Weighting and Response to ‘Slow’, we set out to unravel the loudest stock premium car audio system in this group. This should be down to the power ratings of their respective amplifiers, but like with all things audio, it’s rarely an isolation function. Multiple factors like THD (Total Harmonic Distortion), driver excursion (how much the speaker cone moves during loud signals) and protective limiting circuits come into play to determine how loud a particular system will play. We cranked up the volume to the point where audible distortion set in and stopped just shy of that breaking point. 

No surprises here, Mercedes beat the pack with the EQE-SUVs mammoth 710-watts of power on tap. It recorded a seriously loud and clean 105.4dB on the SPL meter, only to edge out the Audi Q8 e-Tron by a 0.4dB! The Audi too comes with almost the same amount of power at 705-watts, so they are matched point for point. The BMW iX’s 655-watts of power gave it the third loudest place in this test at a 101dB and yet again, it correlates with its power of 655-watts. The last, at 400-watts, is the Jaguar iPace that still manages a respectable 100dB, just shy of the iX even with a 200-watt power deficit. Talk about a photo finish!

Audi Q8 e-Tron - ★★★★✩

Mercedes EQE SUV - ★★★★★

Jaguar iPace - ★★✩✩✩

BMW iX - ★★★✩✩

Tonal Balance

Blend of all the speaker drivers around the cabin and the seamlessness from the low to the high frequencies.

Having multiple speakers scattered throughout the cabin of the car has its obvious benefits in terms of output and immersiveness, but it can also rear an ugly head in terms of imbalance. Almost every car made these days has tools for tone control (bass, treble, balance), but we are in search of the best blend without altering any settings.

Unsurprisingly though, our notes can attest that every car in this round-up performed at par, without undue emphasis on one frequency band over another. Using Wish you Were Here by Seguridad Social made for a great test of judging if the treble was out of pace with the mid-bass, but none of the cars showed any anomaly and made for an enjoyable experience overall. Again, the Mercedes EQE-SUV does provide granular personalisation of the sound on every level, be it tonal balance, surround levels, sonic signature and sub-bass oomph so you can extract maximum performance out of it. But having said that, the Jaguar, Audi and BMW were hot on their heels when it comes to maintaining timing and rhythm even despite having at least a dozen speakers each!

Audi Q8 e-Tron - ★★★★✩

Mercedes EQE SUV - ★★★★★

Jaguar iPace - ★★✩✩✩

BMW iX - ★★★✩✩