I have been watching Peterborough Cathedral's 'PipeWatch' series of youtube films concerning the current work to lower the pitch of the Hill Organ. See https://www.youtube....Kknv7UNQ/videos
In the most recent of the series, 'Meet the organ builders' (https://www.youtube....h?v=wdSFNc_e57g) I was interested to note that some of the smaller pipes (1ft in length or less) will not need to be lengthened, but may be retuned to the new pitch simply by using the tuning collar.
It seems to me that there are clear pragmatic, tuning reasons for not employing this approach throughout the organ. I do wonder, however, what the effect tuning collars have on the tone of an organ pipe. I understand that the scale of pipe construction has some effect on the tone of the pipe, clearly demonstrated between distinctly narrower and wider pipes. But what of the different material that tuning collars seem to be made from?
Taking the discussion further, does cone tuning also have an effect on pipe tone as this does change the shape of the column of air?
I suspect that the answers may involve subtleties, but aren't we often interested in such subtleties and their musical ends? I look forward to reading your reflections on all of the above, and any else that seems relevant to this discussion of pipe construction, tuning, and tone.