Can plants act as sound diffusers ?

[OldHvyMec]

For a diffuser to work it has to have a quasi-random, irregular shape and be reflective.

Ok you're getting all fancy now. A simple 3-4 inch pleat in a purpose built frequency response curtain used in most theaters will diffuse
any sound. Diffuse being the operative word. The degree it effect other frequencies can be used to further isolate certain frequencies
and tune them even further. Depends on what your trying to do. Passive materials like simple quilted packing blankets can tame a reflective
surface enough depending on the number of layers and the space between the layers.. The same goes for the depth of the pleat in the
curtain and diffusion vs dampening. You can have both, it's not one or the other.

Run music through a hedge row. Yes plants diffuse and very well I might add.

Confusion or diffusion? Puff Puff Pass.

We can get all picky, if you want.

Time to feed the chickens.

 

[Berwhale]

Phyllotactic diffuser?

Perhaps it will function as a Holographic-vortex metasurface?

 

[sarumbear]

Ok you're getting all fancy now.

If you call a person who knows what he is talking fancy, it’s a new use of the word for me but yes, I’m pretty fancy.

However, that doesn’t change the fact that you are confusing absorption with diffusion, I’m afraid.

 

[fpitas]

Phyllotactic diffuser?

Perhaps it will function as a Holographic-vortex metasurface?

We might even get our deep-dyed subjectivists on board with holographic vortices!

 

[DonH56]

I have a vague memory of acoustic curtains that included a membrane (plastic sheet) so they would reflect/diffuse some frequencies and absorb lower ones. How much depended upon how you hung them; membrane out or in, and how many/tight folds were. We installed them in a multipurpose room at church so you could open and close them like regular curtains to help control how much area they covered. Similar to absorption panels with a membrane to reflect (some) high frequencies whilst absorbing lower frequencies. The panels didn't really diffuse per se, just reflected. The curtains could diffuse, sort of, depending upon how the folds were aligned. They were useful but IIRC were not all that great at absorption or diffusion, just cut the reverb/flutter down some. The "real" acoustic curtains I have seen, a while ago, were much heavier and thicker, with outer decorative cloth for looks, then a thick (1"~2") layer of "padding" (in pockets to keep it in place), and a final rear cloth. Still not diffusive in any way, and not helpful for bass, but did cut some of the high-frequency ringing to make the sound guy's (my) job easier.

I had similar curtains at home, designed to black out light, with a heavy'ish membrane on one side and cloth on the other. Acoustically they do almost nothing however; material is too thin, and there is a window behind them that is reflective.

 

[Bjorn]

They can scatter the sound but will not diffuse the sound. Two different things where the latter distributes the sound evenly. Obviously that's what we ideally want just as we want a speaker with even dispersion.

 

[DMill]

Best to use speaker grills if you keep an owl as a house pet.

 

[Flaesh]

placing well trained animals at strategic points around the room?

The most commonly used are lazy, hairy mammals at the first reflections on the floor, and a variety of random-sized bats on the ceiling.

 

[Emlin]

Best to use speaker grills if you keep an owl as a house pet.

Grilled owl, anyone?

 

[dogmamann]

Yes, marijuana can.

 

[Emlin]

Yes, marijuana can.

Pot plants, you mean?

 

[Axo1989]

Phyllotactic diffuser?

Perhaps it will function as a Holographic-vortex metasurface?

You jest, but I assume you intentionally refer us to some serious inquiry in the latter reference:

Nice.

In this work, we have shown that scattered acoustic vortices present remarkable radiation properties in the far field. We have designed broadband spiral metasurfaces to generate holographic vortices. The destructive interference of the scattered waves along the axis of the spiral metasurface generates a phase dislocation with tuned topological charge in the near field. In the far field, all scattered waves at the specular direction also interfere destructively. Therefore, metasurfaces based on holographic vortices inhibit specular reflections because the field presents a phase dislocation in this direction. In addition, the scattering function in the far field is particularly uniform because the waves diverge spherically from the focal point. Moreover, under oblique incidence the present metasurface preserves the ability to scatter vortices, but at frequencies higher than the design. Therefore, the scattering patterns of spiral metasurfaces are very uniform and non-specular.

 

[dogmamann]

Pot plants, you mean?

Yes plot plans.

 

[OldHvyMec]

confusing absorption with diffusion, I’m afraid.

Again a hedge row is a perfect example of diffusion. Dampening = absorption? I'm not sure I haven't had a need to think about it.

Dampen: to check or lessen in activity or vigor.

Absorption: interception of radiant energy or sound waves.

Diffusion: to deflect or scatter.

Diffusion is used to SCATTER sound and the secondary effect is a dampened sound or not as lively. It works very well with higher frequencies.

DB reduction is a result of absorption, dampening and cancellation (helmholtz). The next question for me was what happened to the vibration
left behind by absorption vs cancelation.

I know people think along a pretty thin line and want to stick to words. Plants/diffusion. The fact is there is a whole lot more happening.

Is a Porcupine diffuser the only type used in home/stereo application? Usually a hefty cannabis tree (common in California.) works very well.
Several lazy kids will work too. "Just stand there kid and eat your 3 pizzas" "no everyone get's three." Now, get out from in front of the speaker
and move to the right, KID number 13.

Maybe that's deflection? LOL I'm getting ballistics mixed up with sound terminology or am I?
If a leaf can deflect a hard projectile traveling at 2700fps what do you think it will do to sound. I'm just thinking out loud. 60-100 gram missile
traveling at 2700 fps. A POINTED boat-tail projectile is deflected by a .06" leaf that bugs eat.

Time to feed the GOAT I think.. He's been trimming my diffusers and the neighbors too. LOL

Regards.

 

[sarumbear]

I know people think along a pretty thin line and want to stick to words.

 

[phoenixdogfan]

So time to put your speakers Between Two Ferns?

 

[Flaesh]

The Japanese manufacturer of wooden stick diffusers and the Swedish CMT AB describe the forest as an acoustically diffuse space\listening room prototype. Why not use natural living trees?)) Which will go well with mentioned trained ceiling acoustic bats (BTW Google showed 22 million results for the query acoustic bats)). The obvious problem is to find trees with a sufficient trunk thickness if the height is limited by the ceiling..
For a more scientific view, see Richard J. Hughes PhD thesis "Volume diffusers for architectural acoustics" http://usir.salford.ac.uk/17672/

 

[Axo1989]

The Japanese manufacturer of wooden stick diffusers and the Swedish CMT AB describe the forest as an acoustically diffuse space\listening room prototype. Why not use natural living trees?)) Which will go well with mentioned trained ceiling acoustic bats (BTW Google showed 22 million results for the query acoustic bats)). The obvious problem is to find trees with a sufficient trunk thickness if the height is limited by the ceiling..
For a more scientific view, see Richard J. Hughes PhD thesis "Volume diffusers for architectural acoustics" http://usir.salford.ac.uk/17672/

An installation with living trees would be nice. Acoustic bats would presumably use the trees in the normal way.

The latter present some sonic issues: I've found bats quite noisey when disturbed, so dancing to the music would be out. I'm not even sure which music they find acceptable in repose. You may have to consider ultrasonics as a potential issue at least. Also, they'll be foraging at night and the mammalian absorption* quotient will decline significantly, so they're contra-indicated for home theatre installations I think. But achieving sufficient unit or overall density with diurnal species is more difficult.

*as we are reminded that this thread is about diffusion it occurs to me that more optimal diffusion may indeed occur when the colony is mobile with extended wings, but as noted, that mode is usually accompanied by an increase in the noise floor ... or noise ceiling, as they'll aviate, not perambulate.

Edit: the volume diffusor reference is fun reading: I'm imagining a collapsible arrangement of surfaces that can be extended from the back wall for a multi-purpose room. Using cylinders or spheres looks like even more fun.

 

[Byrdsmaniac]

Can plants in my living room act as diffusers ?

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Bo Thunér / Linköping / Sweden

Of course. Just walk a meter into some woods or go behind some shrubs and you can hear it for yourself.

 

[sarumbear]

Of course. Just walk a meter into some woods or go behind some shrubs and you can hear it for yourself.

Diffusion (acoustics) - Wikipedia

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