jreiter

iTrader: (6)

Anyone else interested dB level measurements inside the Z? I like to keep track of that, so it gives me an idea of how loud I have to turn up my music on the freeway. I'm a music fanatic, and I listen to it constantly, so a relatively quiet car on the freeway is important. In a loud freeway car, I have to turn up the music too high which will result in me going deaf sooner.

I used a standard Radio Shack Sound Level Meter set to A-weighting, slow response. Measurements were done with the windows up, fans turned off, and the radio off. I was driving on the freeway with the cruise control enabled on flat terrain at 75 mph in 6th gear. I held the meter at roughly chest level in the middle of the cabin.

Quietest roads: 71 dB
Loudest roads: 74 dB

If I drove at 70 mph, it would drop about 0-1 dB off of the 75 mph results.

The interesting thing is that I had a huge amount of Dynamat installed when I did my stereo. Stripped the interior from the doors all the way back and covered every last bit of metal with the stuff. It made almost no difference in the interior noise level. (Perhaps suggesting there is a substantial amount of road noise coming from somewhere else. Roof, maybe?)

Anyone else do these measurements? I have a stock exhaust and intake, other than Kinetix cats which made no difference in loudness, either.

KShep

iTrader: (4)

Interesting experiment...I've read that others experienced similar Dynamat results, a disappointing suprise. If I can ever track down this last rattle, I'll happily accept 74db ambient interior noise. I still have the OEM HU and speakers, so the road noise may actually be preferable.

boyze

I haven't done the noise measurements but I just had the front tire replacement TSB for tire feathering done and the noise improvement is unbelievable. At least a 3-5 dBA drop.

Dream

IIRC, dynamat is meant to prevent rattles, not filter out road noise. There are probably some other types of material out there that filter road noise.

jreiter

iTrader: (6)

Yeah, I was going to mention that in my first post, but I figured I'd wait and see if anyone brought it up. But you are correct. Dynamating the car *significantly* deadened it. There is virtually no resonance anywhere now, making the bass response so much more enjoyable.

However, I would've thought something as dense as Dynamat (or Bround Bread, in my case) would do some noise reduction. The Brown Bread I used basically looks like tar covered with foil. It's very heavy and very dense. I figured that would at least get me something.

fueledbymetal

Out of curiousity, what sound levels do you see in your A4? I wonder how much quieter it is using the same meter...

328skidpad

I used http://www.b-quiet.com/extreme.html

Spent about $75 and it did wonders. It dosent have to be heated and it was very easy to apply. I noticed a majority of noise comes from the rear wheel wells and the rear compartment which is right in front of the license plate.

I must say that my car is a quiet as my last car bmw 2000 328.

good luck

jreiter

iTrader: (6)

You know, I'm a goober and never measured my Audi's road noise before I finally sold it. It was *definitely* much quieter than the Z as far as road noise simply based on subjective listening. I even had a Neuspeed exhaust on the A4 which was quite loud... and I still feel the overall cabin loudness of the A4 was significantly quieter than my Z just due to the excessive road noise in the Z.

My main point of comparison here is my cellphone. In my Audi (with a relatively loud exhaust), I had no trouble talking on my cellphone on the freeway. However, in my Z it's difficult to hear even on quiet roads and on loud roads it's virtually impossible to understand the other person at all. I never had that problem in the Audi. I do wish I had taken some official measurements, though.