Jlaa

Right thanks, I did a sanity check. 0.65 lbs / sq ft (For stinger roadkill --- not dynamat --- Rod uses stinger road kill --- and at 8 sq ft for the rear deck area, that end up being 5.2 lbs..... somewhat negligible.

I'm not sure the distinction is black and white (Silence vs not silence). Dynamat (or stinger road kill) I think dampens the sheet metal thus preventing the metal from acting as a resonant drum of sorts. I think (I'm not an expert) the thinking behind putting in 5.2 pounds of this stuff is that it can attenuate the very bottom low frequency noise (say, attenuate stuff below 150 Hz by 3db). Since Dynamat is not a sound absorption pad, I think the theory is that it won't even touch the higher frequency stuff. The mellifluous parts engine sound / exhaust sound being higher frequency. And, therefore, one would be able to hear the bass that the audio system's speakers put out.

Thanks - I'd be doing something similar with Rod Birch --- focal component set in the front, kenwood 4x6 in the back for "fill", a 4 channel amplifier under the seat, a CR-220 for cassette playing and for a volume ****, and the existing CDC-3 changer in the frank. No subwoofer. I'd be utilizing a 9PDT throw "relay switch" I built to switch between the CDC-3 and a Yatour YT-M07 device that does Bluetooth music streaming / iPod integration / SD / USB stick.

pp000830

If you want better sound I would first change out the rear and door speakers, an easy driveway job or Best Buy gig,. Even basic $35 two way aftermarket speakers will be a big upgrade over stock in clarity and in volume for a given amplifier output. If you have the Porsche upgrade speaker housings attached to your doors I would remove the entire speaker system and replace it with a conventionally mounted aftermarket door speaker using stacked aftermarket speaker spacing rings (Best Buy) to extend the new speaker frames out from speaker cut-out in the door card. I would then remount the original speaker cover furniture over the new guts for a stock look.
Another option to address sound clarity is to reduce the amount of volume (power) needed from your radio to overcome engine sounds, reduced amplifier output translates into reduced distortion and increases intelligibility of the sound. In this case anything you do to cut down the volume will help. Even a small 3 db cut in engine volume reduces the power amp watt demand by half. This is where the mat comes in. By the way 3db reduction is a small change for the human ear to notice so even though it will reduces demand substantially on the audio system you may not even notice the reduction in engine sound unless you did a side by side comparison. A 6 db reduction can even be hard to hear in absolute terms even though you have reduced the demand on your radio's amp by 75%.

x50type

pp000830

You would really dump this beautifully made and carefully designed door speaker housing?


[do you have a photo of what you are suggesting?]

csmab

I followed this thread to help reduce unwanted road noise. All of the good engine noise is still there. I had enough dynamat left over to cover most of the firewall. Addressing the doors and firewall did reduce the road noise to a much more tolerable level. We have noisy concrete grooved streets in Dallas. Wide low profile tires can really make a racket.
https://rennlist.com/forums/showthre...ferrerid=72711

Jay J

Any pics where you guys put dynamat?

Jlaa

Thanks for the nuanced response. I appreciate the detail. I'll try it.

pp000830

Yes, the frequency response in the lower frequencies is very limited and the tweeters in even very basic aftermarket two way coaxial speakers seems to be a big upgrade. When these cars were made most music sources such as FM or cassetts had limited frequency response and dynamic range so the system seemed to work reasonably well. Also I bet the engineers back then were going for smooth response something of limited value in an enclosed car.
Andy