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2020 Chevrolet Corvette does a sound check around Thunderhill West

Mild cabin noise turns into controversy over augmented exhaust frequencies

Road & Track has been deep into parsing data gathered for its annual Performance Car of the Year extravaganza. During testing at Thunderhill West, the mag included a pre-production 2020 Chevrolet Corvette among the luminaries. Guest judge Matt Farah from The Smoking Tire ran America's now-mid-engined sports car around the two-mile track, and took video of two laps. An embargo on driving impressions until October 16 meant he couldn't discuss the Z51-equipped coupe's behavior or any other driving impression, but the video does clue us into the cabin sound coming from the 6.2-liter LT2 V8 with 495 horsepower and 465 pound-feet of torque.    

The first word that could come to mind while listening is, "Mild;" a C8.R this is not. Even during the portions when it's clear Farah's muscling the throttle, cockpit ambiance never rises above burbly restraint. We don't know what kind of sound equipment Farah had set up, but the aural reserve shouldn't be surprising. When Motor Trend tested a C7 Corvette Grand Sport at Laguna Seca in 2017 for its Best Driver's Car competition, and pro shoe Randy Pobst was hard on the throttle, the 460-hp Corvette doesn't sound much more rorty than Farah's easier run in the 495-hp C8 Corvette. Even so, at one point in the video Pobst says, "Wow, this is not a Z06? Sure sounds like one." When it comes to getting goosebumps in a Corvette, well, guess you have to be there.

At least one comment Farah got about the C8 Corvette sound compelled Farah to tweet, "The new Corvette has fake engine noise from the speakers. This is not a driving impression, it is a specification fact, so I can say it." This fact has caused a touch of stir, enthusiasts treating any enhancement like devious chicanery. But there's a difference between "fake engine noise" and exhaust note "frequency augmentation." As Motor Trend writer Frank Markus put it after enjoying a pre-production ride-along, "the active noise-cancellation sound system does a tiny bit of frequency augmentation, as well—primarily of exhaust sound, because the pipes are now muffled by a luggage area and the engine. They're also positioned way behind our ears, and sound pressure drops with the square of distance."

Yet Chevrolet didn't add this only to make up for the new engine placement — the C7 used the same system. When Motor1 asked the carmaker for clarification on Farah's tweet, Chevrolet responded, in part, "The car actually uses the exact same strategy and execution as all seventh-generation Corvettes, including the 2019 ZR1. It’s important to note, nothing coming out of the speakers would sound like an engine on its own. We rely on the engine for all of the audio content, but given the passby requirements and the multiple cavities between the exhaust tips and the driver, some frequencies are lost and need to be supplemented."

This is a hard battle for an automaker to win. Car design, global regulations, cost, and production concerns tamp the natural cabin frenzy an OEM could get from a set of quad-pipes. But auto writers, myself included, will be the first to take shots at a soggy exhaust note. Enter technology. And as Farah says in a follow-up tweet, he didn't try to disconnect the C8 system, but "In the two cases where I have disabled [exhaust augmentation], I re-enabled almost immediately. The experience was just better with it on even if it was artificial."

Note: I haven't driven the new Corvette, and couldn't talk about it even if I had. But until the embargo lifts on driving impressions and Autoblog can talk about the C8, we have the fact that we've heard no tide of complaints about the exhaust. And we have the video above, which you should check out.

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