Simple Bass sound improvement using sound deadening material

[T3s1a]

I’ve always loved the Cybertruck’s sound system—the bass hits hard and feels powerful, especially from the front seats. It consistently impressed me up there. But one time, while riding in the back, I noticed this terrible thumping that lagged just a millisecond behind each bass note. It sounded like an extra, delayed thump that completely ruined the clean, crisp low-end I enjoyed upfront.

I hopped on the forums and saw others describing the exact same issue. The general consensus pointed to the carpeted panel covering the subwoofers (under thr rear seats) as the culprit—it vibrates and adds that unwanted rattle. Tapping on the panel by hand produces a hollow, drum-like sound, and I could easily recreate the same rattling thump when playing music through the system.

Some owners fixed it temporarily by stuffing a microfiber towel or similar material in there to apply pressure and stop the panel from flexing. I managed with a simple foam block wedged between the panel’s sloped section and the base of the rear seats.

Tonight, my son dropped something small near the seatbelt buckles, and retrieving it required popping off that panel. It came loose with just a few clips and snaps.

While I had it out, I applied sheets of butyl/foil sound deadening material (the Amazon Basics version, which feels a lot like the Dynamat Xtreme I’ve used before) across most of the panel’s surface.

After snapping everything back together, I’m thrilled to report the annoying bass rattle is gone. It might be a bit of placebo effect, but the low end now feels noticeably stronger, tighter, and crisper—all the sloppy or muddy sound is gone.

What a satisfying upgrade from a random mishap! The audio experience is balanced and impressive from every seat now.

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[drjohnf]

Brilliant.

 

[Cyberham]

Great! Will try this when I have time

 

[d_hyde]

I'm definitely looking for any type of bass improvements. For a stock.system it's cool..I'm used to having my bass sound like Gorilla's fighting. Aside from the light harmonic has there been anyone that has successfully upgraded their subwoofers?

 

[Dahongfei]

Sounds like a fun project to try. And cheap!

 

[The Tesla Guy]

I’ve always loved the Cybertruck’s sound system—the bass hits hard and feels powerful, especially from the front seats. It consistently impressed me up there. But one time, while riding in the back, I noticed this terrible thumping that lagged just a millisecond behind each bass note. It sounded like an extra, delayed thump that completely ruined the clean, crisp low-end I enjoyed upfront.

I hopped on the forums and saw others describing the exact same issue. The general consensus pointed to the carpeted panel covering the subwoofers (under thr rear seats) as the culprit—it vibrates and adds that unwanted rattle. Tapping on the panel by hand produces a hollow, drum-like sound, and I could easily recreate the same rattling thump when playing music through the system.
Some owners fixed it temporarily by stuffing a microfiber towel or similar material in there to apply pressure and stop the panel from flexing. I managed with a simple foam block wedged between the panel’s sloped section and the base of the rear seats.

Tonight, my son dropped something small near the seatbelt buckles, and retrieving it required popping off that panel. It came loose with just a few clips and snaps.

While I had it out, I applied sheets of butyl/foil sound deadening material (the Amazon Basics version, which feels a lot like the Dynamat Xtreme I’ve used before) across most of the panel’s surface.

After snapping everything back together, I’m thrilled to report the annoying bass rattle is gone. It might be a bit of placebo effect, but the low end now feels noticeably stronger, tighter, and crisper—all the sloppy or muddy sound is gone.

What a satisfying upgrade from a random mishap! The audio experience is balanced and impressive from every seat now.

View attachment 117213

Amazon link to Dynamat Xtreme butyl/foil?

 

[yamadirt]

I’ve always loved the Cybertruck’s sound system—the bass hits hard and feels powerful, especially from the front seats. It consistently impressed me up there. But one time, while riding in the back, I noticed this terrible thumping that lagged just a millisecond behind each bass note. It sounded like an extra, delayed thump that completely ruined the clean, crisp low-end I enjoyed upfront.

I hopped on the forums and saw others describing the exact same issue. The general consensus pointed to the carpeted panel covering the subwoofers (under thr rear seats) as the culprit—it vibrates and adds that unwanted rattle. Tapping on the panel by hand produces a hollow, drum-like sound, and I could easily recreate the same rattling thump when playing music through the system.

Some owners fixed it temporarily by stuffing a microfiber towel or similar material in there to apply pressure and stop the panel from flexing. I managed with a simple foam block wedged between the panel’s sloped section and the base of the rear seats.

Tonight, my son dropped something small near the seatbelt buckles, and retrieving it required popping off that panel. It came loose with just a few clips and snaps.

While I had it out, I applied sheets of butyl/foil sound deadening material (the Amazon Basics version, which feels a lot like the Dynamat Xtreme I’ve used before) across most of the panel’s surface.

After snapping everything back together, I’m thrilled to report the annoying bass rattle is gone. It might be a bit of placebo effect, but the low end now feels noticeably stronger, tighter, and crisper—all the sloppy or muddy sound is gone.

What a satisfying upgrade from a random mishap! The audio experience is balanced and impressive from every seat now.

Hi. Where do you get this material from? Can you add an Amazon link or something like that?

 

[TexasDev]

Just search dynamat on Amazon.

 

[T3s1a]

Link to the material used:

https://a.co/d/0eJulWi5

I think I used 5 sheets so one pack is plenty

I also highly suggest using a hard roller to apply the material so it really presses into all the creases

https://a.co/d/0hVhjcgl

 

[Tallgeese179]

Great idea! Adding mass to any panel will drop it's natural frequency way down and the butyl probably adds some damping to dissipate any vibrations.

One thing I wanted to ask about, since I don't have first hand experience with this trim piece: I think you may have also covered over the subwoofer openings in the trim piece. Looking closely at the ends, it seems like there is a section with hexagon shaped grille structure instead of the square shaped solid plastic. Wouldn't this muffle/block some of the sound?

 

[GaryS]

Great idea! Adding mass to any panel will drop it's natural frequency way down and the butyl probably adds some damping to dissipate any vibrations.

One thing I wanted to ask about, since I don't have first hand experience with this trim piece: I think you may have also covered over the subwoofer openings in the trim piece. Looking closely at the ends, it seems like there is a section with hexagon shaped grille structure instead of the square shaped solid plastic. Wouldn't this muffle/block some of the sound?

I am not familiar with this cover part also, and was questioning the same thing. Don't cover up the grill holes identified by the hexagon shape. Otherwise this should be a good improvement.

 

[hemiarch]

Link to the material used:

https://a.co/d/0eJulWi5

I think I used 5 sheets so one pack is plenty

I also highly suggest using a hard roller to apply the material so it really presses into all the creases

https://a.co/d/0hVhjcgl

What size piece/pack do you recommend getting?

 

[T3s1a]

The 14.5” x 10” 10-pack (currently $14 on Amazon) is more than enough to do this. I think I used 5 of the 10 sheets in total.

I contemplated not covering over the speaker but that’s right where it sounds the most hollow like a drum/rattles. Bass waves are omnidirectional and everything I’ve read states that the direction of where the front of the woofer points really doesn’t matter. There is carpet covering the “grill” anyway and it is definitely not any type of acoustic fabric.

I’ve had a couple more days listening to music and I still think the bass sounds better after the mod. Would be interested to hear if anyone else does it and has a similar experience.

 

[TARS69]

Awesome, thank you for the share. Going to probably do the same!

 

[HaulingAss]

One other tip:

I recently noticed the audio didn't sound as dimensional as I'm accustomed to. I noted I had filled the rear seat/floor area with duffels and other soft luggage, blocking the air channels under the front seats. Removing the luggage restored the balanced dimensional sound I was accustomed to.

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