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<blockquote data-quote="Rudy" data-source="post: 2807211" data-attributes="member: 568035">I&#039;m updating that site right now to cover liquids and a few more mats. It&#039;s impossible to say exactly how the different mats and liquids compare to each other in effectiveness. The Acoustic Loss Factor tests that the manufacturers publish are not accurate and since it costs $600 per sample to have them run, I&#039;m not going to do it. That said, there are some general principles that apply and I&#039;ve used a lot of both types myself.The two types of vibration dampers we are using are the aluminum faced mats, which are classified as constrained layer viscoelastic vibration dampers (CLVED) and Mylar or PE faced mats, unfaced mats and liquids or extendional viscoelastic dampers (VED). We&#039;re not including asphalt products since they aren&#039;t viscoelastic at all. All of these things add mass to panels. Those with viscoelastic properties bring much more effectiveness to the table.CLVEDs are much more effective per unit of thickness that plain VEDs. In an optimal configuration, a plain VED would need to be at least 3 times thicker to work as well as a CLVED. Unfortunately, none of the products available to us are optimally configured. I think it is safe to assume that the aluminum clad sound deadening mats are at least somewhat more effective than the others, everything else being equal. The foil layer also makes them a better barrier.The testing I&#039;ve seen shows that mats and liquids are most effective over slightly different frequency ranges. This makes sense when you consider that the liquids are quite a bit less flexible when cured. This suggests, and my own experience supports the idea that, applying liquid on top of mat is more effective than either mat or liquid alone. For example, 1mm of mat covered by 1mm of liquid seems to work better than 2mm of either.</blockquote>

[QUOTE="Rudy, post: 2807211, member: 568035"] I'm updating that site right now to cover liquids and a few more mats. It's impossible to say exactly how the different mats and liquids compare to each other in effectiveness. The Acoustic Loss Factor tests that the manufacturers publish are not accurate and since it costs $600 per sample to have them run, I'm not going to do it. That said, there are some general principles that apply and I've used a lot of both types myself. The two types of vibration dampers we are using are the aluminum faced mats, which are classified as constrained layer viscoelastic vibration dampers (CLVED) and Mylar or PE faced mats, unfaced mats and liquids or extendional viscoelastic dampers (VED). We're not including asphalt products since they aren't viscoelastic at all. All of these things add mass to panels. Those with viscoelastic properties bring much more effectiveness to the table. CLVEDs are much more effective per unit of thickness that plain VEDs. In an optimal configuration, a plain VED would need to be at least 3 times thicker to work as well as a CLVED. Unfortunately, none of the products available to us are optimally configured. I think it is safe to assume that the aluminum clad sound deadening mats are at least somewhat more effective than the others, everything else being equal. The foil layer also makes them a better barrier. The testing I've seen shows that mats and liquids are most effective over slightly different frequency ranges. This makes sense when you consider that the liquids are quite a bit less flexible when cured. This suggests, and my own experience supports the idea that, applying liquid on top of mat is more effective than either mat or liquid alone. For example, 1mm of mat covered by 1mm of liquid seems to work better than 2mm of either. [/QUOTE]

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