Leslie louvre cut dimensions

[valotus]

In other topic there were discussion about tonal differencies between newer and older leslies (actually 122 and 122A). During years cabinets has been made of various materials, but one thing I've noticed long time ago was that louvres (or louvers...) had also felt different. "Felt", because you normally don't see the actual louvre cut, but touching it by fingertips clearly tells that some cabinets have had wider gap and some narrower.

So I finally examined and measured all leslies I had at hand:

21h from around -50. Of course this model has only one upper louvre, so it may be the reason it also has widest gap, around 17 mm.



142 from around late 60's or early 70's (?), 12 mm gap.

[valotus]

145 from maybe early 70's? It has foil sticker and text says "Hammond Organ UK", 6 mm gap.

[valotus]

Then two 251's, first one with foil sticker plate has 14 mm gap and other one just around 6 mm gap.









Louvres are machined from opposite sides with same router profile and the area where their cuts intersect will form the gap. So tooling depth, material thickness and cutting line accuracy all affects the result. But does it affect to sound? Well, if someone told me there is a construction where speaker element is inside of a wooden box and all the sound comes out throught a hole cut on the box, I would say that size of the hole will affect the sound...

[Hamman]

And yet, some of my all time favorite sounding Leslies were 21H's ...Go figure;-)

[peterb_2795]

And, just for completeness in this thread, here are some dimensions and a drawing of a cutting tool found on the web (not sure of where I collected them but apologies in advance to the author of these that I cannot correctly attribute them). The third image (I believe) is of the spindle cutter machine used to cut upper and lower vents simultaneuosly.