Acoustic Spectrum Factory 21” T2 PS4S With Foam vs. 20” Track Package PS4S Without Foam

[PR0FESSOR]

All,

As promised, I measured the acoustic spectrum of my factory T2 PS4S with the acoustic foam liner vs. the 20” track package sized PS4S without the foam liner. The results surprised me. Let’s just say I am no longer concerned about having acoustic foam in my tires.

I measured the acoustic spectrum at the same speed and on the exact same 1 mile stretch of highway. Note that the rim sizes are different, as are the actual tire sizes since I purchased the PS4S tires for the track package on my Model S Plaid.

First up, the 21” T2 PS4S with the acoustic foam in them:

Next up are the Track Package sized PS4S without acoustic foam:

If you compare the average values (not the instantaneous or max), the acoustic foam accounts for .3 dB of difference. By the way, it is important to note that the spectrums are slightly different, and some folks might be sensitive to the differences. I am definitely not one of those people. The tires sound identical to my ears.

Hope this helps if someone is concerned about whether or not acoustic foam makes a difference, and if so, how much of a difference.

Joe

 

[xEvoLveDx]

I experienced very little difference comparing the same sets of tires. It's a non issue for me and if I did hear any additional noise, it seemed very dependent on road surfaces.

 

[Muzzman1]

Im interested to know if you had the Road noise reduction on with the sound system?
I too have 20" non acoustic foam PS4S on my plaid now for 30k miles, and from the 19"'s I remember they were much louder, but that was back in Aug 2021.
I recently installed a new set of PS4's, and they are MUCH quieter than the worn set.

 

[Unclepaul]

Tire acoustic foam is only designed to dampen sound for certain low rumbling frequencies. Active noise reduction also is focused on certain frequencies. Testing at these frequencies (if known) would show their effectiveness.

 

[PR0FESSOR]

Indeed. If you examine the spectrum analyzer output, you can see that the low frequencies are indeed attenuated on the foam tires.

Joe

Tire acoustic foam is only designed to dampen sound for certain low rumbling frequencies. Active noise reduction also is focused on certain frequencies. Testing at these frequencies (if known) would show their effectiveness.