The Battle between Stiffness And Damping Of The Speaker Enclosures!


This is a good article I found on 6moons! 
 
Not connected with this company in any way
  

  
https://www.6moons.com/audioreview_articles/aequo3/
highend666
atmasphere
  
In the 6moons review on page 4, they said they used a 300B amp with only 8 watts and it worked just fine and their room is not small.
I think it depends on the listening level highend666. 

If the gentleman at 6moons prefers listening to a peak level of 85DB, then of course the 8 watt should be sufficient. 

105DB at the listening position with those speakers is probably a pipe dream. 
In the 6moons review on page 4, they said they used a 300B amp with only 8 watts and it worked just fine and their room is not small.
If the specs are correct, then this was entirely inappropriate use of an SET, since it would have been making a lot of distortion to make significant (above conversational level) output. Because much of this distortion would have been higher ordered harmonics on the transients, I bet they were saying it sounded really dynamic. But because the ear uses the higher ordered harmonics to sense how loud a sound is, what was really going on was the distortion masquerading as dynamics.
I saw this posts and couldn’t resist to sign on and clear things up. I know it’s a complex topic but let’s try:

“And what will we do when we get this super stiff highly damped speaker? Put it on springs.”

Good question. 👍🏻The answer:If the cabinet is stiff enough to not vibrate within its walls and well damped enough to not resonate, it depends in the moving mass and positioning of the drivers if it lives and how much “spring” it needs. Hence some speaker to well with some rubber/damping in the feet while others need something solid.  Less spring (softness) means better imaging precision and efficiency. Just as important is the mass of the cabinet: lighter cabinets such as the Stilla (26kg) but with very powerful and deep lf needs all kinds of measures to keep it from starting a dance on the floor, such as can be read in this paper: https://static1.squarespace.com/static/5690c974a976af0bfc4aeaaa/t/5b14f34370a6ad083bf0a3cf/1528099675199/Stilla_development_story.pdf


“Diamond is stiffer, so better”

Diamond is very poor in damping. It will more easily ring/resonate relative to various other components. It also depends on the cvd process, dimensions, and the type of coating (enhancing damping). Not to understate the extreme costs… To understand more about new and better materials, please visit our sister company for b2b projects : www.diluvite.com “Cabinet materials and driver membranes are not the same” 

Indeed, they are certainly not. Membranes have to move and therefore need to be sufficiently lightweight for better efficiency. This also lowers structural basket/enclosure demands.  And they often handle not the full audio frequency spectrum. LF drivers need stiffness especially, to prohibit flexing under high force, whilst midrange membranes need a high level of combined stiffness and damping. Depending on frequency band/ filter type they need more stiffness (upper bass) or more damping (to lower thd in the upper pass band). For HF drivers it is more complex as in small pistonic tweeters, very high stiffness might help to push resonance far enough up to best benefit from this property. But without damping, still some unnatural crisp or sound signature might be observed. 

“Oversimplifying material physics in view of the real world practise”

This is THE abundantly occurring problem. In practice we need to consider the specifics and goals of the application including static and dynamical design. For  both cabinets and pistonic membranes we need to look not only at stiffness, damping and weight but also on damping loss vs frequency and dimensional inflicted resonance at the eigenfrequency and avoid circular and rectangular solids as well as avoiding flat walls and non-variable wall thickness. Combining (sandwich) of materials with different properties is also helpful and last but not least: tension loading (such as with bolts) have huge benefits for damping. In my attempt to explain things more easy and thoroughly, I wrote this paper to present the first Diluvite-made speaker cabinet: https://static1.squarespace.com/static/5690c974a976af0bfc4aeaaa/t/5e9d108139f0f40fc886249b/1587351700710/ADAMANTIS+Creation+of+a+Nano+Infused+Zero+Resonance+Loudspeaker.pdf

Hope this helps or some find it interesting.