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Alpha: Differently shaped breath pipes

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written by: john

Yes, all the Eigenharps share the same mouthpiece.

written by: dhjdhj

Sat, 7 Jul 2012 21:18:00 +0100 BST

Don't laugh, but now that I've started experimenting with the breath control, I'm finding that I can't hold the Alpha they way I want to and still reach the mouthpiece.

I hold the Alpha against my right shoulder, sloped enough that I can see the keyboard.

How can I get a breath pipe that will work for me?

written by: keyman

Sun, 8 Jul 2012 05:01:10 +0100 BST

You are not alone on this, as I also have a standing up position (with the shoulder strap) that most of the time does not allow it's use (breath pipe) ; not to mentioning the fact that I would like it flexible enough to be able to bend while playing

written by: carvingCode

Sun, 8 Jul 2012 13:12:51 +0100 BST

Same here with the Tau. The breath pipe does not lay right for me.

Antonio's suggestions for a flexible breath pipe would be a solution. Also, what about a flexible extension to the existing breath pipe?

written by: 0beron

Mon, 9 Jul 2012 12:12:11 +0100 BST

I'm sure I saw Dino Soldo playing his alpha with a length of plastic tubing stuck onto the existing breath pipe - is that something that would work, or is the plastic mouthpiece crucial in getting the double walled pipe to work correctly?

written by: john

Mon, 9 Jul 2012 12:44:45 +0100 BST

Dino has an early pre-production Eigenharp that predates the current breath pipe system. It works in a completely different way and unfortunately that technique cannot easily be used with 2.3 version instruments. That system has a number of advantages over the current one and some serious disadvantages too, which is why it was changed. It does allow for a much easier customisation of the BP shape though.

As anyone who has ever spoken to me on the subject will know, breath systems are much more difficult to design and make work than anyone might believe. We spent a very disproportionate amount of design time on them in the Eigenharps and they went through a huge number of modifications in early user testing. Even with all that effort they caused a large number of problems in our earliest instruments and it was a good six months after launch that we finally stopped seeing things like corrosion problems.

I'm still not happy with the system to be honest, I too would very much like a flexible arrangement but we spent a lot of time looking at how to do that well and never did find a good solution. I have thought of a few ways to make that possible but the cost of tooling for them and the volume of customers who might buy them do not add up to a sensible proposition. If anyone wants to experiment with a view to making something for production I'm happy to help them as far as we can.

If enough people want a different shaped breath pipe for the Alpha (or Tau) then it is possible. It's just quite expensive. Tooling for the pipe bending is probably around 2-3K (just guessing here, would need to come back to you with an actual number) providing that the curves aren't anything too compound. After that the minimum quantities to make a batch are about 30 off. You could probably figure the eventual cost, across 30 people, as around £200-300 each (assuming we don't put any kind of profit margin in there) per pipe. I'd happy to do such a thing if enough people want to sign up for it and everyone can agree on a shape they want.


written by: carvingCode

Mon, 9 Jul 2012 17:50:00 +0100 BST

Could you somehow decouple the end pieces, sell those separately, along with some length of an acceptable, flexible tubing?

written by: john

Mon, 9 Jul 2012 19:30:04 +0100 BST

Possibly, though that's harder than it seems as the tubing runs co-axially and endpoints are designed with that in mind - you need two pipes remember, one for bypass air and one for the static sampled pressure from the mouthpiece. If it were a single pipe it would be trivial, it's the fact that there are two of them that makes it all complicated and difficult. It's not inconceivable though. It would still require tooling though, and probably comparable costs to making a new shape breath pipe, so it's still down to whether or not enough people are interested.

I'm not exactly sure what you mean by 'acceptable flexible tubing', do you mean 'deformable tubing' that you could bend? Or do you mean floppy tubing like Tygon (which is the stuff used internally in the instruments)?


written by: keyman

Mon, 9 Jul 2012 20:13:12 +0100 BST


It's funny to realize only today this two misconception:
flexible tubing as deformable tubbing (yes please!) and
one pipe that in reality is a two pipe; Pipe - one inside the other.

Leave my yes "vote" for some kind of cleaver solution.


written by: dhjdhj

Tue, 10 Jul 2012 04:38:12 +0100 BST

That was my immediate reaction as well.

carvingCode said:
Could you somehow decouple the end pieces, sell those separately, along with some length of an acceptable, flexible tubing?

written by: 0beron

Tue, 10 Jul 2012 14:16:22 +0100 BST

Does the pipe need to be coaxial, or is this just for ease of construction and aesthetics? Could you rig up something that plugged in to the Alpha and split the outer and inner tubes out to two individual spigots onto which you could attach two lengths of tubing, then have another Y junction just before an eigenlabs mouthpiece?

Making even a single walled tube deformable (but such that it holds its shape after bending) strikes me as being very hard without running the risk of crushing the tube's circular cross section all the time?

I'd be interested in having one if a solution is found.

On that note, are the Alpha breathpipes nowadays of the anodised variety? I have an early one that shows signs of corrosion (some of the silver coating on the mouthpiece spigot is flaking off). It doesn't seem to affect the playability of the instrument though.

written by: mikemilton

Tue, 10 Jul 2012 14:59:17 +0100 BST

This is clearly quite a challenge. The pipe has a few requirements including (but probably not limited to):

-Sufficient rigidity to hold a shape.
-Constant back-pressure in any position.
-Managing humidity
-Reasonable service life / cost balance.

The current one seems to meet these but when you add adjustability other than provided by the swivel in the present plug the other requirements become problematic.

There are such things as silicon tubes extruded with a spiral of material in the wall to maintain their cross section (within reason) and one might consider placing two on an exoskeleton. This might actually look quite good in the hands of a good designer. The exoskeleton could also limit the radius of any bends (sharper bends->thinner silicon->lower life).

The cost would be something tho.


written by: john

Tue, 10 Jul 2012 18:39:44 +0100 BST

The history of our experiments with breath pipe designs, prior to the current one, is long. We spent five years trying different things out and have tried most ideas at least once - they all suffer from one downside or another in use and whatever approach is used is inevitably a compromise. The current design sacrificed user configurability (ie, the ability to reshape the tube) for reliability, corrosion resistance, low noise (the noise introduced by turbulent flow in the breath stream, a thing that turns out to be a significant issue) and appearance.

If you're interested in the biggest design change between the 2.1 and 2.3 Alpha's, it was the improvements to reduce the turbulent flow noise in the sensor signal. To do this we sample the air pressure in your mouth cavity rather than the air that you're blowing through the system. This is quite complicated to achieve, and results in needing the two air pathways through the breath pipe as well as a really difficult piece of manufacturing in the mouthpiece.

I thought you might all be interested in a little summary (not complete, but the highlights) of the major design choices we experimented with prior to the current one:

Deformable single channel pipe with breath bypass restriction inside instrument

- Only useful user deformable, self supporting material that we could find is specially drawn copper tube. Can't be plated (plating flakes off on deformation) and poor corrosion resistance with saliva (possibly could be mitigated by internal epoxy coating but no research exists as to compatibility of these coatings with copper rather than the usual aluminum so this work would need to be undertaken to demonstrate longevity and user safety).

- Breath pressure restriction inside instrument is very hard to make adjustable, impossible to clean and prone to blockages with saliva.

- Physically practical breath restrictions inside the instrument result in too high a Reynolds Number and create turbulent air flow as a result, creating significant white noise in the sensor signal

- use of copper rather than aluminium that far up the instrument adds considerably to balance issues, raising the overall mass of the whole instrument considerably (by over three times the actual tube weight in fact)

Deformable single channel pipe with adjustable breath bypass restriction in mouthpiece

- The design used in the 2.1 (last pre-production version) instruments

- Breath bypass causes steady dribble of saliva down ones front

- Impossible (basic physics sadly) to make the system turbulence free, so white noise in the sensor signal. This could probably be dealt with using a different mouthpiece design, but the dribble of saliva above sent us in another direction

- Still suffers from the plating/deformation cosmetic issue - you can bend the pipe but you wreck your plating

- Still has some corrosion issues, though less significant

- Still has weight/balance impacts

Deformable co-axial pipe

- Two approaches - the coiled 'shower pipe' and deformable drawn copper
Coiled stiff shower pipe spectacularly ugly in the needed bore size and not that rigid. Serious doubts as to it's longevity after some testing - we found acceptable stiffness declined precipitously after a relatively small number of flex cycles. Deformable drawn copper - see above downsides. Also would need to be 9mm tube at least, non standard and requiring both a specialist die and a large, very wasteful production run to have made.

All the solutions involving copper pipe have finish issues - it can't be anodised and paint or plating mostly just flake off when the pipe is deformed after finishing. And very hard to make it look right with a Tau, or a Silver or Gold Alpha. Having said that we'd probably have lived with that, or found a way, if the other issues hadn't also been there.

Scaffolding framework with two flexible Tygon pipes

- This is essentially Mike's suggestion above. We spent some time looking at this. As an option it's possible. There are only three downsides, one engineering, one cost and one visual. One, it's hard to make 3 (at least, for the requisite adjustability) nice adjustable yet rigid locking joints that work well. Just hard though, not impossible, which gets to the next point, it's going to be expensive because of that, in design time, probably a number of prototype cycles with lots of testing and in the end quite a number of non standard parts to have made (I'd be surprised if the design cycle ended up costing less that £25-30K with the final item costing £200+, and that's being optimistic). The third point is much more subjective - it's going to look pretty 'steampunk' whatever one does. If you like that look (I don't mind it) that's cool, if you don't then it's not so good. For those three reasons we never got as far as pushing the button on making one.

Please don't think me negative about the idea of an adjustable breath pipe - I think it would be a great idea and have wanted exactly that all the way through the creation of the 'harps. I thought you might all be interested in the things we tried before we arrived where we are today, and if anyone at all has a bright idea how we might find a better way, or wants to have a go themselves then I'm in full support of that.

As far as I can see there are really two viable alternatives, one is the two pipe adjustable scaffolding, as Mike just suggested, the other is to do a single pipe thing and put the bypass up at the mouthpiece, possible using the existing mouthpiece but with some kind of spigot and then living with dribbling down ones front from time to time. Both of these could be made to work.

What we really need of course is some tube made from that great engineering material, Unobtainum. 0.4mm wall thickness, 7mm o/d, deformable but drawn with sufficient inbuilt stress to resist wall collapse at bend radii of down to 20mm. Oh, and totally inert, can be polished or anodised and doesn't cost the earth.

Wouldn't that be nice?


PS; apologies for the long post, lots of history to try and get across

written by: carvingCode

Tue, 10 Jul 2012 19:17:45 +0100 BST

First: I had no idea until this thread started that the breath pipe was a pipe-within-a-pipe.

Second: I'll be satisfied and adjust myself to the existing pipes. Enough work has been done to get a system that works well.

Great work! (Should have known.)


written by: mikemilton

Tue, 10 Jul 2012 21:00:08 +0100 BST

John... I am always left agog at the level of reflection and experimentation that gets exposed in these conversations. Thanks for sharing them. They are neither overly long (except for you to type) not negative.


written by: dhjdhj

Wed, 11 Jul 2012 04:49:13 +0100 BST

For those of us who are not ambidextrous, it is not possible to adjust oneself, at least not easily.
I am also quite fascinated and impressed with the work and inventiveness that went into it, but I still would like to be able to really use it.
Now, understanding that it is a pipe within a pipe, it must surely still be the case that there's only one actual hole into which I blow, given that my mouth has only one hole!
So I'm wondering how hard it would be to make something that just securely wraps around the end of the mouthpiece (with rubber or maybe even just tape) to keep it airtight such that it could just be extended with a bit of rubber tubing? It doesn't have to look pretty.

carvingCode said:
Second: I'll be satisfied and adjust myself to the existing pipes. Enough work has been done to get a system that works well.

Great work! (Should have known.)


written by: john

Wed, 11 Jul 2012 08:45:04 +0100 BST


The problem with extending the mouthpiece that way is the Reynolds Number - you don't want to end up with turbulent flow in the tube or that creates noise in the sensor. There's not actually one hole that you blow into, there are two, one for the air flow and one to sample the air pressure in your mouth cavity, where it is still 'clean' and free from turbulence noise. The reason that your throat doesn't produce such turbulence as you breathe in and out is because it has a larger diameter and hence a lower Reynolds Number (although you can still hear the onset of such turbulence if you open your mouth and breathe in or out very quickly), as soon as we have to put the breath into a small tube that's all out of the window.

You might get some mileage out of some suitable tube though, it's probably worth seeking some out and having a go. If you do experiment please let us know the results here. I'd probably play about with some thin walled rubber tube with a coil of deformable wire (say 0.75mm nickel-chrome or soft iron) wrapped around it for stiffness (you could make the coil by wrapping the wire around a piece of suitably sized wooden dowel as a former). It would look pretty ugly, but might let you try new shapes out.

Probably the best option is still to make another tube suitable for that playing position - it's quite possible to make other tubes, just a bit expensive. Once again, if enough people can get together to make it worth doing (and can agree on the shape that's wanted), we'll do it.


written by: dhjdhj

Wed, 11 Jul 2012 13:28:37 +0100 BST

Thanks, John. I'm not much of a handyman (we are a family where, after I repair something, my wife hires a handyman to repair my repair) but I'd like to try this if I can make it work easily.

Where would I get the kind of tubing your talking about (and that wire) --- is it something that would be available at a regular hardware store?

written by: john

Wed, 18 Jul 2012 11:53:58 +0100 BST

Hi David

I'm afraid I have no idea where you'd get those materials in the US. Here in the UK soft iron wire can be obtained from agricultural suppliers (it's used in fencing) and tubing can be bought from either lab supply companies (for high grade stuff) or plumbers. We have a really good company here in the UK called RS Components that sells all this sort of thing (they have an absolutely vast catalogue of electronic and engineering supplies) but unfortunately I know that you don't have any kind of equivalent in the US. Google, as ever in this kind of thing, is your friend.

If you're a bit 'handyman challenged' then it might be a good idea for you to seek out a friendly local engineer. It might also make a great high school project for a local kid who's interested in that sort of thing, it's full of interesting problems, involves music and has some good physics (turbulent flow) as well. If you can find one and they write to me, I'll loan them a Pico to experiment with.


written by: stuwyatt

Wed, 18 Jul 2012 17:01:34 +0100 BST

Thanks for all the advice in this thread. I was looking for a way to extend the tau's breath pipe so that I can play with the tau in a horizontal position - i.e. on top of a keyboard, and was going to go down the route of extending it with silicon tubing. John thankfully saved me from such a wasteful venture.

I didn't realise that the breath control of the eigenharp was so complicated. I've never been a huge wind player, so I have a lot of potential control to discover and master with the Tau + VSTi's.

It looks like I'm going to have to rethink my preferred playing position for now, and might go down the route of a fixed stand that supports the eigenharp in a firm position that's compatible with my body screwups.

Needless to say, I'm going to be keeping a very close eye on this thread. :)

written by: dhjdhj

Wed, 18 Jul 2012 17:36:32 +0100 BST

John, is the Pico mouthpiece identical to the alpha mouthpiece?

That's an excellent idea about schools, I have some connections into a science focused high school in NYC.

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