I'm experimenting with a pair of cheap Chinese ribbons I have. One of the things I'd like to try is extending a baffle around the ribbon motor to increase LF extension, ala the Coles 4038.
The BBC Monograph from which the Coles is derived refers to "closely woven gauze," later specifying further a "a single layer of bolting cloth supported by a coarse wire mesh": https://downloads.bbc.co.uk/rd/pubs/archive/pdffiles/monographs/bbc_monograph_04.pdf
The original Harry Olson patent suggests a "fine silk mesh": https://patentimages.storage.googleapis.com/b5/60/f1/d0147ef61c707c/US2348356.pdf
I'm not sure how to find fabric with the right impedance. There are a number of different types of fabric available.. silk and nylon meshes with various hole sizes, in addition to metal "bolting cloth." (I think the "bolting cloth" in the BBC pdf refers to a fabric bolting cloth though.)
I suppose trial and error is a simple way to figure it out, though I'm not sure how to accurately measure LF with the equipment I have. I'm considering building a "motional impedance bridge" as per the BBC monograph.
Has anyone trodden this ground already?
The BBC Monograph from which the Coles is derived refers to "closely woven gauze," later specifying further a "a single layer of bolting cloth supported by a coarse wire mesh": https://downloads.bbc.co.uk/rd/pubs/archive/pdffiles/monographs/bbc_monograph_04.pdf
The original Harry Olson patent suggests a "fine silk mesh": https://patentimages.storage.googleapis.com/b5/60/f1/d0147ef61c707c/US2348356.pdf
I'm not sure how to find fabric with the right impedance. There are a number of different types of fabric available.. silk and nylon meshes with various hole sizes, in addition to metal "bolting cloth." (I think the "bolting cloth" in the BBC pdf refers to a fabric bolting cloth though.)
I suppose trial and error is a simple way to figure it out, though I'm not sure how to accurately measure LF with the equipment I have. I'm considering building a "motional impedance bridge" as per the BBC monograph.
Has anyone trodden this ground already?
