"How To" Duelund thread suspension on Scan Speak 21W

[FrederikCaroe]

Hi,

Due to kind requests in this thread: Speaker-Camp, R&D for Modula NeoD CC speaker variants

We've done an article describing how to do a "Duelund" thread suspension instead of the regular spider on a Scan Speak 21W.

As stated in the article this modification might ruin the driver if not done correctly, you have been warned...

The article can be found here: http://www.steenduelund.dk/scanspeak8554.pdf

Hope you enjoy it. :T

[TacoD]

Thanks!
Some questions:
1) Can you buy the phase plug and extra magnet from Scanspeak?
2) The bitumen treatment increases the weight of the cone, how thick is the layer you must apply?
3) How much must the strings be tightened? I do not want to limit the x-max to much.

[FrederikCaroe]

1) I believe you can.
2) About 3 mililitres was used for this driver by Steen Duelund. I wouldn't call it an exact science.
3) This is determined by the desired data, X-max can be improved by using pieces of wood or similar which allows for longer strings.

[TacoD]

1) Which scan woofer has these plug?
2) 3 mm seems rather thick
3) Somewhere at the Steen Duelund website I saw a picture of a woofer with some triangle blocks glued to the basket and with the strings connected to the woofer flange. If I understand it correctly this is done to get extra excursion?

[FrederikCaroe]

1) Not sure if they are used as standard.
2) you misread, not mm but mililitres for the entire surface.
3) Exactly, and in turn it lowers the Qts and Fs.

[TacoD]

thx

[FrederikCaroe]

thx

A pleasure.

:T