PIEZO NXT type panel

Status
Not open for further replies.
Jump to Latest
#402
Hi There,

I'ts my first post in this thread but I've been following it with great interest.
Have you come across Aerogels or as it is sometimes called Frozen Smoke?
Seems like ideal material for NXT panels with its strength to mass ratio.

Peter.
 
#403
Hello Peter,

i heard about it but did not have it in the materials list
up to now.

I think some loudspeaker manufacturers use Aerogel (Focal e.g.)
to build sandwich laminates for conventional
drivers.

Would an aerogel of thickness from 0.5 to 5 mm be airtight ?

If not, we would possibly need a coating for low frequencies, where
tightness of the panel is an issue.

Then the low mass advantage compared to other materials would
decrease. Also damping is an issue.

Styrofoam e.g. has also low mass and high stiffness and is still
airtight when cut to thin panels. But styrofoam rings like a bell
and needs a damping coat IMO.

Are you experienced with aerogels ?

en:
Aerogel - Wikipedia, the free encyclopedia

ge:
Aerogel – Wikipedia


Kind regards
 
Last edited:
#406
LineArray said:
Hello Peter,

i heard about it but did not have it in the materials list
up to now.

I think some loudspeaker manufacturers use Aerogel (Focal e.g.)
to build sandwich laminates for conventional
drivers.

Would an aerogel of thickness from 0.5 to 5 mm be airtight ?

If not, we would possibly need a coating for low frequencies, where
tightness of the panel is an issue.

Then the low mass advantage compared to other materials would
decrease. Also damping is an issue.

Styrofoam e.g. has also low mass and high stiffness and is still
airtight when cut to thin panels. But styrofoam rings like a bell
and needs a damping coat IMO.

Are you experienced with aerogels ?

en:
Aerogel - Wikipedia, the free encyclopedia

ge:
Aerogel – Wikipedia


Kind regards
Click to expand...

Aerogels are insanely expensive.
 
#408
Yeah...the capillary size in the inter-connected pore structure is so small that the water's surface tension in the small capillary crushes the glass web. Go ahead, put a piece on your tongue. If you pull it off, the surface of your tongue will come with it. (No...I did not experience that myself.) But, that is the stuff I have made/worked with before.

When people say "aerogels" I wonder what they really mean...just like "nanotechnology" that actually works on a "micro" scale.
 
#410
croat47 said:
When people say "aerogels" I wonder what they really mean...just like "nanotechnology" that actually works on a "micro" scale.
Click to expand...

yes i know the feeling...to my knowledge neither styrofoam, polyfoam or any other readily available foam is ACTUALLY an aerogel...i believe they are by themselves extremely delicate , usually best utilised within a composite consisting of fibres(maybe Carbon fibre? Aramid? Both?) or perhaps a honeycombed Al structure, filled with it? i duno this is all way to conceptual. maybe we should all try and fashion a diamond monocoque tweeter diaphram too........or maybe if the sky wasnt the limit we could just limit it to silicon carbide....LOL

I believe they were originally developed for their heat insulating properties, and are still very hard to obtain, hence mucho expensivo

:headshot:
 
Last edited:
#413
Aerogel Ringing...

The "real" silica-based gels made from TEOS pre-cursors do actually ring audibly in bulk. Granted, it takes a piece larger than any cone thickness to hear. And, to make such a piece it takes a positive pressure drying oven to raise the pressure above the vapor pressure of the MeOH byproduct. It is dependent on teh final structure as well. Along the "sky's the limit" path, there are materials such as AlSiC (AlSiC Materials, Electronic Thermal Management System, Packaging Solutions) and Osprey Sandvik's SiAl alloys. Low weight, stiff, and machinable. But, I could not imagine the price of a piece to make, say a 15" cone. We use a 0.040x2.5x3.0" piece of AlSiC and it runs about $100/pc. But, that is made only 0.070" thick. To make a blank 4" deep and 16" square...or even round...
 
#416
I have BMR drivers. They are very good, well balanced loudspeakers. No complaints. Much better then more expensive Tangbands. For about 10-20$ a true star.
 

Attachments

  • BMR power response.gif
    BMR power response.gif
    14.5 KB · Views: 688
#417
hardwax oil

Some time ago I treated a paper tweeter with two layers of hardwax oil, which is a blend of shellac, natural waxes and oils. It showed a perfect CSD after the treatment.
As I have already mentioned earlier in the thread I liked the neutrality and transparency of balsa wood, but it didn´t work due to nasty resonances.
So I wondered what the hardwax oil would do with the balsa. I had only a little bit of the (expensive) hardwax oil left, so I took two 100x500x1 mm balsa stripes, one coated on one side, one uncoated for a reference. The finger snip test showed that the first layer already gives a massive improvement and after the second coating the balsa is dead like a dodo. I didn´t remove the overshoot after each application as suggested, this gives a rough surface, but saves time and money (two layers probably wouldn´t be sufficient otherwise). I am quite sure a double coating on both sides of a 3 or 4 mm balsa plywood would tame it sufficiently.
I am currently not in the mood of organizing two monstrous boards, apart from the fact that the little rooms in my old house aren´t very well-suited for planar speakers. So I pass this finding over to the public.


Oliver
 
#419
 
Status
Not open for further replies.
Top Bottom