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ArticlesAn introduction to a unique design of pad for use in Woodwind instrumentsArticle by Eddie Ashton Since its inception about 200 years ago, the humble key/pad system of remotely opening and closing the tone holes on woodwind instruments has hardly changed at all. True, keywork is somewhat more accurate now but it's still hardly cutting edge engineering and the pad, which is the main subject of this essay, is all but identical to its predecessor. Originally of course, keys were cut from flat sheet metal and a piece of leather glued onto the blade which opened and closed a tone hole whose surround had been milled flat. It's common on many boxwood instruments of the 18th/19th century. This gave way to the familiar raised-lip tone hole we see today and a cast or forged key housing a resilient pad made from a small leather sack filled with horsehair. And what's today's modern pad made from? A small leather sack filled with felt. Well okay, the felt is more consistent than the horsehair and we use a finer quality leather (it's sheep's back actually) or more commonly what we euphemistically refer to as skin pads, but which is in fact anything but skin - it's cow's intestine for heavens sake! Still, I suppose it sounds marginally more acceptable to refer to skin pads as opposed to intestinal pads! Anyway, enough of the biology lesson. My point is that the use of these materials in this application is, on the face of it, well chosen as they combine the desirable properties of resilience, the ability to create a reasonably airtight seal and quietness of operation. As with most things however, there is a down side - or to be more accurate, there are quite a number of down sides. Firstly there's the question of the basic difference between the two pads described. Essentially one is softish and the other harder. A soft pad is mechanically quiet, which is good. It will squash down onto the tone hole and not be too fussy as to positioning, thereby accommodating inaccuracies in keywork bearings and tone hole surface and therefore achieving quite good reliability, which is also good. But a soft pad requires pressure in order to use the resilience which allows it to reform itself each time it hits the tone hole. So the player must work harder to overcome the inaccuracy of the pad and the keywork becomes less of an extension of the fingers and more a mechanical hindrance, which is bad. Furthermore the materials in this soft pad are not very stable when subjected to temperature and moisture changes, so it's going to move unpredictably and thus ruin its potentially good reliability record. So, a harder pad is more accurate, more precise, requiring less effort to operate and thus being nearer the ideal extension of the fingers. But in being so it becomes noisier and less resilient and therefore less able to accommodate any slight misalignment of associated parts. It becomes more like a switch. It's either on or off. It either works or it doesn't. Reliablility is in the balance here, and the fact that it is still subject to the movement caused by temperature and moisture changes means that that balance is tipped to the negative side of good. And there's more. A conventional pad is made by stretching a piece of skin over and around a disc of felt, and securing it on the underside. In use, the felt acts as a resilient cushion on top of which the skin is brought to bear on the tone hole in order to seal it. So far so good - but the felt is also being required to hold the stretched skin in position and stop the pad collapsing. As a result of this the pad is not evenly consistent across its face. In the centre it is relatively flat and soft but it gets progressively harder and more misshapen towards the edge. It follows therefore that unless the key sits on its tone hole perfectly centrally, and all too many don't, the tone hole "sees" a different type of pad in different places around its own circumference. This is bad news because now, the pad is expanding and contracting at different rates across its own surface in addition to which, because of the nature of a piece of skin, any reaction on one part of its surface has an effect on adjacent parts. In order to minimise the effects of this and eliminate the microscopic blemishes in the wood of the tone hole and the skin, which would cause air leakage, it is common practice to "bed" the pad in much the same way as one might iron a crease in a garment. This unfortunately is no more than forcing the material into a position it didn't really want to be in in the first place and nothing is more certain than the fact that, over a period of time, all materials try to revert to an initial state of rest. Car bodies take quite a long time : pads take a very short time. Its useful to realise that all materials are on the move in varying degrees and from different influences. As far as we are concerned with instruments, the relatively soft materials from which the pad is made are highly volatile in terms of dimensional change, from the combined influences of temperature, moisture and stress. The metal of the keywork, (and bodies in the case of flutes and saxophones) is very much influenced by stress movement due to the shaping processes used during manufacture, although this occurs over quite a long time (years). The effects of temperature change within normal use are probably insignificant in this context and moisture has no effect at all. Wood on the other hand, is highly influenced by moisture and temperature although movement due to machining is probably better described as stress relief. So back to the humble pad. It's a wonder it works at all isn't it? The poor thing is alternately soaked and dried out. It's changing its shape all the time. The chunk of metal to which it's attached has probably got lousy loose bearings which means it doesn't come down in the same place twice, and when it does, it nearly misses the hole it's trying to cover 'cos the key's been made either too long or too short, or the tone hole is nearly bigger than the pad itself! I've spent many of my 35 years in this business trying to overcome these problems. When trying new and processing different traditional materials in an attempt to eliminate their shortcomings, a solution to one problem always brings with it a drawback in another area. Use cork pads - they're stable and waterproof - problem solved - nope! They're unacceptably noisy, and when the short fibres at the top and bottom of each tone hole start to pull out, as they do, cork is too hard to take this into account. And they are the ultimate switches. Okay maybe for the smaller key movement of oboes and piccolos, but not for clarinets. Who wants to listen to the Mozart Clarinet Concerto with clog dance continuo? Make the pads completely waterproof - Yippee! No more swelling up and letting you down just when things are getting really hot and sweaty. No more deterioration - they last for ever. - but nope. Now, instead of some of the water being soaked up by the pads, it's clogging up every tone hole, then it starts to drip off your right elbow! And they're too noisy. Slap! Slap! Slap! And as if that wasn't enough, there's the debate as to which type of pad sounds best, for crying out loud, and guess what - it's almost certain that according to a law attributed to a certain Irish gentleman, the best sounding pad is guaranteed to be the most impractical thing (from every other point of view) that you've ever seen in your life! It's just not fair! Well hold on to your hats folks - I think I've found a solution. It came about by pure chance, which is where all the best solutions come from. It's very simple, which is what all the best solutions are, and it completely kills - stone dead - all the problems mentioned here, plus all the ones not even mentioned here ( 'cos it can get a bit technical and/or boring). Best of all - it has no drawbacks. What none? No None. What none? Well hardly any (Thanks G&S). There are two drawbacks that I can think of, so let's get rid of them first. No.1 is that they're not white - or brown - they're black. No. 2 is that they're so good you won't be able to believe it! And that's that. What are they then? Well they're called "Super pads" - obviously! They are a combination of traditional and modern materials utilising a very thin synthetic facing bonded to a cork base. That's the simple part. The clever bit is the unique way by which they are set in the key to ensure that each one is perfectly positioned, without any application of force and regardless of key orientation with its tone hole. And what is it that makes them so good then? Well, they're compliant enough to be forgiving yet firm
enough to be accurate. Having used these pads exclusively for over 5 years now, their reliability and longevity has proved to be faultless, testimony to this being their adoption by most of the north's leading players and their pupils. For more information and advice, talk to Eddie Ashton at |
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