Helder Tenor Experimentation

Part 1: Cool feature the Helder comes with! (scroll down for Part 2: Cool feature of my own)

There are lots of things I love about the Helder model, but one of them is the fact that the “roof” of the windway is interchangeable. By way of background, the channel you blow through on a recorder is called the windway, and its shape (and texture!) is a big part of what determines the sound and the response of the recorder. The top surface of the windway is usually carved into the material of the head, and is called the roof. The bottom surface is the block, or sometimes the floor. Here is a cross section of a traditional recorder head joint, with the relevant parts indicated:
halfaDenner_labeled windway

As you can see, the block is actually a cedar plug that is press-fit into the head of the recorder. It can be removed, but that’s not something you do that often. The roof is just part of the head. The Helder is different. The block isn’t a press-fit plug, it’s mobile and adjustable by a thumb screw. That means that you can adjust the height of the block at the windway’s exit just by turning that screw. And the roof isn’t carved out of the same piece as the head; it’s a separate piece that sits in a channel, and is held in place by a simple O-ring.

Rosewood roof piece, with outsides of several others: three in (stained) boxwood, one in grenadilla.
Rosewood roof piece, with outsides of several others: three in (stained) boxwood, one in grenadilla.
The Helder head joint showing where the roof piece sits, next to the roof pieces showing their playing surfaces
The Helder head joint showing where the roof piece sits, next to the roof pieces showing their playing surfaces (one of which has a lot of mold spots! 🙁  )

This system has a number of advantages. One huge and obvious one is that it lets the windway dry more effectively after playing, and you can keep playing the recorder for a longer period of time because you can switch the roof piece out when it gets soggy. I’ve found this to be incredibly useful when I spend a week playing for an English Country Dance workshop for example, where I play the same tenor recorder for many hours a day, every. That schedule would be pretty hard on most recorders, and I would want to switch around to give them a chance to dry out. The Helder lets me switch out the roof pieces and keep playing.

Another obvious advantage is that it lets me change the sound and the response of the recorder by switching out the roof. Different roofs of different woods really do sound different; and they can also have different voicing to favor different ranges or sounds. The instrument originally came with three: rosewood, grenadilla, and “synpor” (a ceramic sort of material that Mollenhauer uses because it can absorb moisture without swelling like wood does). They sent me two more in boxwood, and I made my own in boxwood as well. I used all five of these for my recording “Fantasies for a Modern Recorder”: the grenadilla one for Kuhlau, the rosewood one for Bowen, my home-made boxwood one for Telemann, one of the boxwood ones from Mollenhauer for “Coasting on Daydreams”, etc. (BTW, if you’re wondering – I stained the boxwood roofs dark, because people kept asking me if it was a clarinet, because they were the same color as clarinet reeds!)

I also like that this system gives me a lot of room to experiment with the voicing of the recorder without changing anything irrevocable! Lots of things affect the sound of the recorder: the height of the roof at the top end, the height at the bottom end, the width of the windway, the angle of the block surface, etc. With a traditional recorder the roof can be raised by sanding or cutting or carving it higher; but while you can take material away, you can’t put it back. So once raised, you can’t lower it again if you don’t like it. The Helder actually has two set screws that let you raise the lower end of the roof with a screwdriver. But what I’ve found is actually an easier and more flexible method is to put small pieces of narrow tape on the “shoulders” of the roof pieces to raise the roof at one end or the other, or both ends. By the same token, I can lower the roof either by removing tape or by filing the shoulders down further. If I file it down too much and the roof is too low, I can always adjust it back up with tape.

You can see tape on the sides of some of the roof pieces in the picture; at various times they’ve all had different configurations of tape on their surfaces.

So this system also allows for experimenting with various aspects of the voicing and being able to control variables, too.


Part 2: Cool feature of my own

The Helder instruments come with a block that is made of “synpor”, a ceramic sort of material that they use because it doesn’t swell when it gets wet. That’s important, because the Helder’s block needs to be able to move forward and back, in order for the lip control feature to work (you can squeeze the block with your lip to constrict the windway opening and make dynamic effects) and for the thumbscrew adjustment to work without everything just getting stuck. But I’ve never been completely convinced that synpor is an ideal material for a recorder’s block. Its surface texture seems to be prone to collecting water droplets on its surface, which causes clogging issues especially in the higher range. And I never did like the sound of the synpor roof piece that much. Synpor is also easily damaged, particularly when wet. In fact, I damaged my original block by accidentally scraping it with my fingernail when removing a stuck roof piece (stuck because I’d been playing it a lot… I’ve since filed them all down some more so they don’t stick as easily, and I make a point of switching them before they get to that point anyway). So I ordered a second block, and have been playing on that one.

At one point I thought it would be interesting to try making my own block out of cedar, and see how the recorder would play with it. Then I thought that since I had a spare block, it might be less work to just sand off its original surface and replace it with a cedar shim, which might have less of a swelling/sticking issue. But then I thought, wouldn’t it be cool if the surface of the block were interchangeable as easily as the roof? Why not make a removable shim instead of a permanent one?

So I ordered some very small rare earth magnets, which are surprisingly powerful even at a tiny size. I sanded down the original block, and used epoxy to embed two magnets. Then I cut down some small pieces of wood and embedded matching magnets in those. And I figured, since it will be interchangeable, why stop at cedar?

Helder head at top. At the bottom is the "normal" block, next to the modified block with a cedar shim on it, plus three alternate shims
Helder head at top. At the bottom is the “normal” block, next to the modified block with a cedar shim on it, plus three alternate shims

The last component to my new system is that I found that when held in place only by magnets, the block shim was prone to moving up and down a bit. So I added a small locating pin, which you can see sticking out in the middle between the two magnets. The block shims all have a matching hole for the pin, so they stay correctly positioned.

Modified Helder block is second from the left; the others are alternate block surface shims.
Modified Helder block is second from the left; the others are alternate block surface shims.

As you can see from the picture, I also use tape to experiment with the position of the block surface. The cedar one on the far left was the first one I made, which took quite a bit of trial and error to get working right – hence all the blue tape! The ebony one was second, and required less adjustment after the fact because I could measure the first one. The other two are cherry and yellowheart. They aren’t “finished” yet (although actually I am getting fairly happy with them), but it’s been a bit faster to get them to where they should be because I have measurements from the first two to go on.

Helder with modified block, block surface shims, and roof pieces
Helder with modified block, block surface shims, and roof pieces (Pardon the mold on that one!)

One last note about this system is that as each block shim is close to being “finished”, I have been soaking it in oil for a couple of days. Normally, we keep oil away from the block of a recorder because it will make the block swell just like moisture does, but then it won’t evaporate and go back to its original size – so the voicing will change in presumably undesirable ways. But these need to be able to go in and out and move without getting stuck, so I’ve been oiling them so they won’t swell as much with playing.

So far, I’ve been pleased with this modification, and it’s certainly fun to play around with! There are still some things I’d like to do along these lines: I’d like to make a new block “base” out of some sturdier material (since now the absorbent properties are basically not important at all anymore). I’d like to make more versions of the block surface and experiment with shapes or textures that might change how condensation behaves. I’d like to make a block shim out of boxwood. I’d like to eventually do something similar with the Helder alto.

But for now, I’m enjoying the process of discovering what things change the sound of the recorder in which different ways!

2 thoughts on “Helder Tenor Experimentation

  1. Hi Emily.

    In 1996 I went over to Buhl and met Maarten Helder, and came away with one of his tenors, with the original block design. I have played it continuously for the last 21 years. I would love a new block assembly, or even the ‘spring’ material that sits between fixed and moving parts. Do you have any ideas? The assembly is very tired.
    With thanks and kind regards

    1. Hi Mike, so sorry to take so long in replying! I often miss real comments in all the spam. :/
      Mollenhauer probably would sell you individual parts if you ask, although some things may have changed about the design since you got your instrument so it’s possible they might not fit. But I can make a couple of suggestions. First is that if the “spring” material is compressed, you can build up layers of tape or epoxy on the back side of the block to add thickness and tighten it up again. I’ve found it very interesting to experiment with things like that; if you check out the “news” button you can see what I wrote about experimenting with the instrument. You can also see a modification I made to the block, which lets me change out the surface using shims held on by rare earth magnets. It has also been quite interesting to use small pieces of tape to lift various corners of various parts to just change the angles by a small amount and see what happens.
      Sorry it took me a year and a half to answer you!

Leave a Reply

Your email address will not be published. Required fields are marked *