Eiron wrote:

Patrick Turner wrote:

I doubled the tension specified in the kit instructions but all that's
done is slightly
raise threshold for the EHT level needed before a membrane heads over
against a stator.

How does ERA suggest you tension the diaphragm?

The method they specify clearly is to cut up a lot of adhesive gaffer
tape 50mm wide,
and place them ready on the side of the bench. They supply a roll of it.
They also supply a small spring balance with a metal plate 50mm x 75mm
that hangs on the spring balance,
so that the tape pieces are pressed onto the mylar, and metal plate,
then tension is pulled up to a reading 0.8 Kg, and the tape is pressed
to the bench,
and the tension remains, and plate pulled carefully away from the tape.
10Kg could be tensioned up this way, but there is little need to tension
more than 2.5Kg/60mm
as that is the tension in the 3.5uM membrane in a Quad ESL63.
The distance betwen tapes is no more than 10mm, so there is 0.8Kg per
60mm of side length applied.
The tension is done by applying first across the middle of the maylar
sheet each way in a cross,
then at each corner, then outwards from the middle again on each side
one by one alternately
until you have worked outwards from where you start.
Because the mylar sheet is about 75mm larger than the panel size the
tension within the area of the
panel is fairly even if there are slight uneven tensions at the edges.

After 5 goes, i could tension up a membrane 1.5M x 0.55M in 20 minutes.
It becomes easy with practice, but many ppl would have bothers with
uneven tension.
The first one ripped apart into the panel area, so I just started again.

If you don't repeat some things, you'll never get any good doing them.


Is there a figure for the diaphragm's resonant frequency?

The first couple of membrane attempts gave about 32 Hz with 0.8Kg /
60mm,
but on the last one I used nearly 2Kg / 60mm, and Fo went up to 41Hz.


I would vote for charging both sides.

So would I but the construction sequence and details of the build up of
layers does not permit
coating of both sides of the membrane.



By the way, did you know that 'west' is a Jute sockpuppet?

West has had very cordial friendly private emails with me and I see
little evidence he is a sock
puppet of anyone else except his good self.

Are ye not a sock puppet for Eiron?

Just who is exactly themself while online in groups?

I try to be the same wherever I was online or offline; and no matter
whether I an dining at Her Majesty's Buckingham Palace,
or with a or with my visiting friend Nicole K at a local cafe.
Thinking, telling, and doing everything with the same game plan
where you appear consistent no matter what the circumstances is called
one-ness.

Its all I can manage, and two or three of me would be exceedingly
tiresome,
and one is bad enough :-)

West does ask a lot of simple questions, and I answer them as best i can
without being what I consider unpolite, or tactless, but nevertheless
firm, fair, bordering on terse.
Finding time to avoid stepping on peoples' toes while tip towing around
their questions
is difficult. He's never been grossly malicious, or foul mouthed, so
I can concentrate on playing the ballgame, and not have to deal with the
man.


Patrick Turner.



--
Eiron.

May contain traces of irony.