Whistles/flutes/recorders--Why is the bore round instead of square?

[Steve Senseney]

I don't want to mess up the current discussion on recorders and whistles and flutes, so I am asking this question here.

It is relatively easy to make a square tube out of wood, and this can easily be tapered and shaped in multiple ways.

Is there a reason recorders and flutes are not made with a square bore?

[Yuri Terenyi]

Two reasons.
One is that up till the mid-20th century there simply haven't existed any adhesive that is truly waterproof.
The other, much less important is that it's simply very awkward to play. Paetzold (of Germany) make huge (that's HUGE) contrabass and subcontrabass recorders from plywood. These have keys for each note, however.
Otherwise there isn't any acustical reason. Wooden organ pipes (nearly always square) are a good proof of that. (There have been a perishingly small amount of turned wooden pipes made, and one type of pipe is triangular.)
In fact, I just remembered, Alec Loretto has made and published plans for a square, very simple recorder that is (acustically at least) a reproduction of the Dordrecht one (the first medieval one found (in about 1940 or so)). If you go on the Yahoo flutemaker forum, it has been discussed some years (maybe 5 or 6) ago, and the measuremnts are there. You can search under Alec's name on the forum.

[Jim McConkey]

Someone here made a serpent a few years back from laminated plywood, essentially given a square bore. The air flow is not as consistent in a square bore as a round one - there is more "dead" air in the corners - so the timbre will change subtly. Almost any shape bore will work, and on flutes, didgeridoos, etc. make of natural materials, the bore is almost never consistently shaped.

[Andy Barnhart]

If you look in Bart Hopkin's book "Making Simple Musical Instruments", the tapered bores are all square (basically very sharp pyramids). I have been messing with ocarinas that are basically hollowed carving blanks (so it becomes a carving with finger holes on the back or bottom) and other than some general rules about where the cavity starts relative to the windway and edge, it's just volume of the cavity that matters to get a particular pitch. It can be tubular, cubic, amoebic or whatever. I have seen some NAF plans that use a router that are square or rectangular. The rectangular one was a double/drone plan where the finished instrument was square.

[Steve Senseney]

Thanks!

[Stephen Bacon]

Dr. Blood of Dolmetch as well makes square recorders. Square recorders have great volume for the big sized recorders. But that is because of the key system. Von Huene's (round) keyed big recorders as well have great volume but at the greater cost. Most traditional big recorders(4-8 feet)have a softer sound, or as Bob Marvin states a soft roar. I think the earlier makers if they had conceived of the key system would have experimented. DaVinci did but we didn't find out till later. There was no problem making hide glue water proof.

[Jason Rodgers]

Heck, while we are talking out-of-round, one could make an octagonal staved instrument.

[Yuri Terenyi]

Heck, while we are talking out-of-round, one could make an octagonal staved instrument.

Some Balkan double pipes are octagonal, though not because they are staved. They are made from solid pieces of wood, as normal, except the playing part of the pipes is shaped into an octagonal shape, since it's rather difficult to make them round.
Just a side remark.

[Owen Woods]

The shape of the bore I don't believe affects the sound. What it can do however is change the rigidity of the walls. The vibration of the walls does make a difference to the sound, so a square bore instrument would have to have thicker walls in order to retain the same characteristics. I think I'm correct in saying that, I read it somewhere or other, so it must be true

[Stephen Bacon]

Logical and factual if it weren't for the fact in this instance that the squire bore instruments were made of plywood , allowing them to be thinner.

[Owen Woods]

Ah, fair enough! I'll rephrase then. Square bore instruments need walls with a higher rigidity than round bore instruments. This may not mean thicker walls, since laminated board can be used, as you say.

[Tim Richardson]

Ah, fair enough! I'll rephrase then. Square bore instruments need walls with a higher rigidity than round bore instruments. This may not mean thicker walls, since laminated board can be used, as you say.

I think that you are correct.

But. I also suspect that it is all but impossible to make a wood wall thin enough not to have the required rigidity.

Metal or plastic would be a different story.