Pascalite

[Bill F777]

What is Pascalite? I was working on a 908-8a driver, and the spec sheet said it used a Pascalite diaphragm.

Thanks!

[Old Guy]

It's aluminum, just a tougher alloy.

The Pascalite frams also use a carbon fiber voice coil form...

[gamalot]

I have a few of those Pascalite frams and don't really like the way they sound.

I think they were for PA or Band use applications with the loading caps.

Usually, when you see an aluminum dust cap on the woofer, you can expect to find a Pascalite fram in the HF driver and a loading cap.

Here is a part of the equasion I am not at all sure of. Aluminum dust caps and Pascalite frams always seem to be with 500 or 800 Hz XOs. I have never seen either coupled to a 1200 Hz XO.

Gary

[Old Guy]

I've heard it both ways- that there isn't much difference, and that the aluminum sounds better.

I'm in the group that thinks the aluminum is slightly better- not the difference you seem to feel though.

Obviously we didn't listen under the same test conditions, so room for a lot of subjectivity.

[Todd W. White]

They measure the same on the same driver.

[Ronald Lee]

So what's the diff between a Pascalite and a Symbiotek diaphram?

[RonSSS]

Symbiotic used a mylar surround.....you can see through it. Alum center though. They handled more power....ie....didn't tend to break.
Pascalite frams can usually be identified by the Altec Guy printing on the back side.
I've never heard a diff between alum and Pascalite. Nor measured one either.
In home use, like many of us are after, power handling just isn't an issue. 15watts of mid and hf is ear shattering......
Great Plains can build you either one.
Remove the loading caps, get new SS screws or cut the stock ones, add the felt to the rear cover, and you will be happy. Great Plains has the felt kits.
I like to remove the bug screens as well, it does make an improvement, although others here may disagree.

Ron

[gamalot]

It all sounds like an adventure in to the meterological properties of various metals used for sound reproduction.

Altec used a few and others went way further with such fancy metals as Titanium and Berrylium and I honestly can't say if one metal is any better then another.

Here we are, right back where we started and it all comes down to what your ears tend to appreciate the most.

Todd stated "They both measure the same on the same drivers"!
That might be a clue because if they both measure the same, I sincerely doubt any of our ears will be able to hear what the measurements PROVE!

If you like the sound of cheaper aluminum or a bit more expensive Pascalite, Titanium or Berrylium then thats what you should run right out and get.

I'm OK with standard grade 12 gauge fine stranded copper wires and if you think the high priced designer cables work for you then go for it.

I think I can hear a difference between symbiotics, pascalites and pure aluminum diaphragms but I wouldn't want to embarrass myself in a blind test!

An original 23744 (Light) fram in an 802-8G is sweet. A new GPA 34647 in the same driver is undetectable to me. Add a loading cap behind either and I think it harshens the highs.
Remove the loading cap and add some felt and I can't honestly say I would hear any difference.

Same goes for 802s or 808s with tangerine phase plugs Vs metal.

Buy what ever it is that you think sounds best!

Gary

[Old Guy]

Originally posted by RKLee:
So what's the diff between a Pascalite and a Symbiotek diaphram?

<font size="2" face="Verdana, Helvetica, sans-serif">AFAIK the Symbiotik is the same aluminum as the Alum fram, but most have a brownish Mylar surround- this tends to break less at high power than the aluminum surround- downside is less HF response, the traditional trade for power handling.

Radian diaphragms are very similar to Symbiotiks, but better.

Most people use the aluminum for home use, Pascalites or Radians for pro live use.

[whitebroncoii]

In the late eighties Altec engineers wanted to standardize the 902/908 driver. The primary interest was to simplify inventory. They found a material developed by NASA that was stronger than the aluminum alloy used on the 902 and could be pressed using the same tooling. The new diaphragm was able to handle the power of the 908 and sound identical to the 902. This one change improved all products using either driver. Marketing needed a name for this new wonder material that would be unique to Altec and not give away the material to competitors . . . Pascalite