Influence of the acoustic cloth present on the panel, on the frequency response of Advent OLA

[giovanni56]

In my opinion, it would be better to listen to the speakers with the original canvases installed, which are an integral part of the design and listening tuning, in fact, as can be seen from the measurements on Advent OLAs, the canvas has the function of linearizing the frequency response and optimizing the polar output; as on the Ar3 and LS3/5a and many other speakers. 
Green response with cloth, red without

[Pete B]

You say grille cloth, but do you mean to say the grille frame including the cloth?

This is important because the tweeter protrudes from the baffle board and the 

grille frame is needed to provide a smooth baffle for it.  The notch without is most

likely diffraction from not having the grille frame.

This has been noted for a very long time that OLAs require the grille for proper

operation.

[Doug G.]

Yes, the square Masonite tweeter board butts right up against the rear of the grille frame opening and the result is a relatively flat surface behind the tweeter cone.

Doug

[giovanni56]

5 hours ago, Pete B said:

You say grille cloth, but do you mean to say the grille frame including the cloth?

This is important because the tweeter protrudes from the baffle board and the 

grille frame is needed to provide a smooth baffle for it.  The notch without is most

likely diffraction from not having the grille frame.

This has been noted for a very long time that OLAs require the grille for proper

operation.

Pete B

Posted 5 hours ago

"" You say grille cloth, but do you mean to say the grille frame including the cloth?"" "

That's right, the whole panel including the two overlapping fabrics.