[Rob Babcock]

If it isn't giving away anything proprietary, I was hoping that Nathan/8th Nerve might explain laminar flow in laymans terms.  The 8th Nerve stuff takes a very different approach than most- the majority of popular  treatments seem to focus on a huge amount of material to physically absorb sound or a large area of material shaped to scatter/diffuse it.  Can you give us a little insight to your methodology?

[_scotty_]

Here are some links to definitions of laminar flow.  http://www.exploratorium.edu/xref/phenomena/laminar_flow.html
http://hyperphysics.phy-astr.gsu.edu/hbase/pfric.html

[Rob Babcock]

Thanks, Scotty.  I was really trying to get a little input from the 8th Nerve guys as to how their products address this.  Everyone raves about their Response treatments, just curious how they work.

[John Casler]

On Old Olympus Towering Tops, A Fin And German Viewed Some Hops

Anyone?  

In any event, in looking over the definitions of Laminar Flow, I too would be interested in what or how an uninterupted "flowing fluid" relates to sound pressure waves.

[WilliamL]

Hi,

We don't really talk specifically of "laminar flow" because it sounds a little pretentious. Some people who talk of this phenomena in audio have no idea or training on what laminar flow really is. The links posted by Scotty pretty much describe what it is. Just transpose that idea to sound waves and you have it. Thanks Scotty!

Nathan's post in this circle on a different thread (overdamping rooms) touched a lot on the crux of our methodology. There is no black magic to our products so I am not going to go overboard on trying to explain things from a laminar flow perspective. , which is somewhat of a reach in analogies anyway.  Sound hits a flat surface: the sound waves scatter and continue along that flat surface AND reflect back to the room.

Best,
Bill

[Rob Babcock]

Hmmm....I was hoping for something a bit more *technical*, but I guess I probably wouldn't understand it anyway.   My reason for asking wasn't to "call you out" or get you to reveal any trade secrets- I was more contemplating how that methodology might be made to dovetail with other theories.

What I've been contemplating is a mix of LEDE with some 8th Nerve corners and seams.  Do you think the two types of treatment can coexist effectively in one room?

[WilliamL]

Rob. I hate to tell you, but we don't have any trade secrets!      

I will ask Nathan from Eighth Nerve to add his spin to the laminar flow question to satisfy your craving. But yes, our products will certainly compliment other sollutions and we are glad to specifically guide you through the process when you are ready to contact us.

Best,
Bill

[Rob Babcock]

Thanks.  I sorta wanna staple up a bunch of foam because your treatments are a little too aethestically pleasant- it just isn't industrial enough for me!   Naw, just joking.  My house has lathe & plaster walls and I really want a bit of dampening to go with the diffusion.  Especially since I listen to so much MC stuff (the extra speakers really seem to accentuate the liveliness of the room).

[brj]

On Old Olympus Towering Tops, A Fin And German Viewed Some Hops

Anyone?  

The credit goes to google, but why the mnemonic for the cranial nerves?

In any event, in looking over the definitions of Laminar Flow, I too would be interested in what or how an uninterupted "flowing fluid" relates to sound pressure waves.

Pressure waves are longitudinal waves that propagate when one molecule slams up against its neighbor, which slams up against its neighbor, etc..  This is why sound travels faster in denser materials - the molecules are closer together.  No one molecule actually moves that far due to the pressure wave itself.  Energy is transported in the direction of travel without the accompanying transport of matter.

An actual "flow", whether laminar or turbulent, implies a moving mass of air, i.e. the molecules are being physically transported over some distance.  Whether a flow is laminar or turbulent depends upon the Reynolds number, Re, for that flow.  Reynolds number is a dimensionless parameter that expresses the ratio of inertial to viscous forces in a fluid.  If the viscous forces of a fluid are large enough (small Re), they will overwhelm the effects of the the many small disturbances that naturally occur in any flow, and that flow will remain laminar.  If the viscous forces are small (large Re), then these disturbances will be "under-damped" and will quickly dominate the flow, transitioning it to turbulent.

I have no idea what specific audio application prompted the question, but in real life - whether airplane wings, room walls or speaker ports -  it is very difficult to maintain laminar flow over a significant distance, although frequently desirable.  You certainly won't find laminar flow out in the middle of a typcial room where one might listen to music.  Natural room currents due to pressure differences between rooms, convection due to heating, etc. will quickly result in turbulent flow, even if you don't notice it.  I have heard people claim that speaker ports ("golf ball" dimples, etc.) are designed for laminar flow to prevent "chuffing."  This is false.  What they are actually doing is preventing the boundary layer of air along the port surface from separating from that surface.  (The separated flow produces the "chuffing").  It is much easier to keep turbulent boundary layers attached than laminar boundary layers.  The dimples increase the turbulance to accomplish this exact behavior.  (Note that sound waves will propogate more evenly in a laminar flow than a turbulent one, but I have to imagine that the air turbulence level would bother you long before the resultant sound differences would!)

I might be new to this audiophile thing, but I do know aerodynamics!

[John Casler]

 John Casler wrote:
On Old Olympus Towering Tops, A Fin And German Viewed Some Hops

Anyone?  


The credit goes to google, but why the mnemonic for the cranial nerves?

Since this post was directed to "Eighth Nerve" it brought back old memories of the pre-med study methods we used to remember the cranial nerves, of which "Auditory" is the 8th.

I think it is an excellent name selection.  Very creative

[8thnerve]

As Bill said, when we talk about laminar flow, it is somewhat analagous.  We use that term because the behaviours of sound pressure share more similarities with laminar flow than with any other establsihed methodologies for how different materials react with solid sufaces.  Although for the most part the rules are based on flowing matter reacting with static matter, many of the interactions are applicable.

Sorry I don't have a more in-depth discussion on this topic specifically, but check out another post I just wrote here in the Acoustics Circle under "Overdamping a room" for explanation on our methodologies.

[brj]

On Old Olympus Towering Tops, A Fin And German Viewed Some Hops

Anyone?

The credit goes to google, but why the mnemonic for the cranial nerves?

Since this post was directed to "Eighth Nerve" it brought back old memories of the pre-med study methods we used to remember the cranial nerves, of which "Auditory" is the 8th.

I think it is an excellent name selection.  Very creative

Oops! I looked up the mnemonic, but didn't follow through enough to realize that the 8th cranial nerve was the auditory nerve.  I should probably stop posting at 1 AM...

You're right - that is a clever name!