Reply to thread

Message

<blockquote data-quote="FoxPro5" data-source="post: 4596257" data-attributes="member: 562649">Ok, sweet. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif Not saying what you did didn&#039;t work. But, 1/8&quot; close cell foam cannot absorb anything at all really. Depending on it&#039;s porosity and the angle at which the sound waves hit it, it MIGHT be able to diffuse higher octave frequencies (like 10k + due to their wave lengths) and therefore eliminate them.If you&#039;re talking absorption, you&#039;re talking about changing sound energy to heat. If there&#039;s no matrix for the sound to try to &quot;fight&quot; through, then this is not what&#039;s happening. Absorption is particle-velocity dependent. That means, the higher the particle velocity, the greater the phenomenon. Since the foam is basically right next to the driver (where particle velocity is low) absorption is very limited.If you&#039;re talking diffusion, then that&#039;s what Deflex Pads do. Close cell foam is also a diffuser in some cases, but it&#039;s main benefit in a car is for thermal applications (blocking cold/heat) and/or acting as a mechanical isolator/decoupler. This is why closed cell foam is the material of choice for something like Luxery Liner Pro.If you&#039;re talking blocking, you main concern is mass. Search: Mass LawIf you&#039;re taking damping, you&#039;re taking change in elastic modulus: Search: hysteresis or hysteretic damping</blockquote>

[QUOTE="FoxPro5, post: 4596257, member: 562649"] Ok, sweet. [IMG]//content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif[/IMG] Not saying what you did didn't work. But, 1/8" close cell foam cannot absorb anything at all really. Depending on it's porosity and the angle at which the sound waves hit it, it MIGHT be able to diffuse higher octave frequencies (like 10k + due to their wave lengths) and therefore eliminate them. If you're talking absorption, you're talking about changing sound energy to heat. If there's no matrix for the sound to try to "fight" through, then this is not what's happening. Absorption is particle-velocity dependent. That means, the higher the particle velocity, the greater the phenomenon. Since the foam is basically right next to the driver (where particle velocity is low) absorption is very limited. If you're talking diffusion, then that's what Deflex Pads do. Close cell foam is also a diffuser in some cases, but it's main benefit in a car is for thermal applications (blocking cold/heat) and/or acting as a mechanical isolator/decoupler. This is why closed cell foam is the material of choice for something like Luxery Liner Pro. If you're talking blocking, you main concern is mass. Search: Mass Law If you're taking damping, you're taking change in elastic modulus: Search: hysteresis or hysteretic damping [/QUOTE]

Verification