Out-of-Round Pipes: Fix or Not Fix

[myorgan]

I just saw an advertisement for some pipe organ pipes that have been in trays for a number of years. The ad mentioned the pipes may be out-of-round and should be fixed before use.

My questions: Is it really necessary to round pipes that are slightly oval in shape? Does it affect the sound of the pipe that much?

I suspect I know the answer already from my understanding of physics, but I'm looking for someone who can explain it better than I.

Michael

[Coenraads]

Slightly out of round? Physics says the air molecules don't care. But why not round them out again?
I once received a shipment of pipes and a few of the pipes, made out of pipe metal, were squashed quite flat. I thought they were destroyed and would have to be replaced, but I put a long dowel in a vise, slipped the pipes onto the dowel and gently "massaged" the pipes back into shape.
The key thing is not to stretch the metal, so work carefully and just use finger pressure and not a hammer. The pipes ended up working just fine and didn't even look too bad.
John

[jbird604]

My question is: What are you doing buying yet another organ, Michael!!!! I know -- OAS strikes again!

[AllenAnalog]

I've heard of "pear shaped tones" so maybe those pipes will produce "ovaltones" - perhaps rich in harmonics but certainly not to be confused with that powdered Swiss milk flavoring product.

[tucsondave]

Decoded message: "Be sure to drink your ovaltones."

[Larason2]

It depends how they are squished, but yes, it will affect the tone. If they are squished off centre, the wind flue coming from the toe will not hit the pipe lip square, leading to all sorts of voicing issues, depending on what kind of pipe it is, and how it is deformed. If off enough, the pipe won't sound at all, or it may be much breathier, or have an abnormal transient, or incline more towards flute or string tone, or be too loud or too soft. An oval pipe also affects the vibration of air through the column because of laminar flow, and affects what overtones can be produced by the pipe body. At the squished edges, air can not flow as fast because of edge effects, and this makes the pipe overall sounding as though it's diameter is smaller, which will affect the scaling. Overtones are also affected by how the vibrations are allowed to pass through the pipe in three dimensional space. An oval tube cuts down on angled vibrations of the air column, affecting what overtones can be produced, particularly some of the higher overtones that give certain stops their character. I think pear shaped tones refers to a tone that is rich and sonorous (which is a definition if you do a google search for the term!), and I would think that oval tones refers to oval shaped notes on a score, unless I am missing something! I don't think a squished pipe will produce a pear shaped tone!

[AllenAnalog]

I forgot to end my comment with a 😈

[myorgan]

Thank you all. I saw the advertisement, and knowing some of the pipes in my pipe organ are probably oval in shape by now (I packed them on their backs-mouth up) from gravity. It was just a curiosity question more than an immediate need.

I really appreciate the thoughtful responses-especially the ovaltones!👿

Michael