Beam Blocker Design

[tubeswell]

Hi there folks

After having a few jams with the 5F2A I recently built, and getting some criticism about the piercing treble response it gives when you are standing directly in front of it about 10-20 feet away. Titling the cab back to point it at the ceiling is a temporary fix and can be somewhat unstable, so I was thinking I might try a beam blocker.

Can anyone enlighten me about the theory behind beam blocker design, and for a 12" diam speaker in a tweed princeton, what size beam blocker might be good. (1"?, 2"? etc?)

Cheers

[stokes]

The idea of the "beam blocker" is to difuse the high frequencies that come out of the center of the speaker.www.tedweber.com has them for sale,if you check his site,it may give you an idea of what size it should be.I would imagine it should cover the center "dust cap" of the speaker,so I think that would be more important than the speaker size itself.I have heard of some people just putting a piece of duct tape on the grill in front of the center of the speaker to accomplish the same effect.

[Alf]

This another approach :

http://i113.photobucket.com/albums/n233/alfafalfa/alnicofrontsm.jpg

for these speakers:

http://i113.photobucket.com/albums/n233/alfafalfa/alnicobacksm.jpg

Alf

[tubeswell]

Wow! those are nice Alf

Seeing your design I am curious about whether there are any differences between a vertical (as opposed to horizontal or diagonal) support strut?

Cheers

[Alf]

Tubeswell,

It doesn't make any difference , I made them vertically because Vox used the struts, without the circles, in their earlier days.

The cabinet is a sort of oversized cabinet to be used with an open back.

It sounds already very nice as it is.
Of course this way it's easy to experiment with lager circles because there's something to attach them to.

Alf

[flyingtele]

what i did was take an aluminium dustcap (the guy who i got it from removed it from a JBL K120 to cut out the top end and replaced it with a cardboard dustcap. So, i simply took the aluminium dustcap and glued it onto the inside of the grille cloth on my fender performer 1000 combo amp, right in the centre of the grille. Made a great positive difference

[Tiago]

Hi all,
What I use as a beam blocker is a CD in the front grill.
If the cab has a grill, I would simply attach with velco a regular CD or maybe a small (80mm) CD like in the picture:
http://www.digit-life.com/articles/80mmcd/compare.jpg


Regards,
TMP