You can test a whistle on air to see whether it works at all and if so what note is produced . Note will be a bit different to that produced by steam but not much .

The problem is that you can't test the secondary problems of steam whistles on air . Ordinary boiler steam arriving at whistle contains both intrinsic water vapour and variable quantities of water droplets from condensation . All this wet water causes no end of problems . Most commonly the water gets spat out , trapped or recirculated near the mouth of whistle and produces a lot of hissing and bobbling sounds which won't show up on air test .

Clearing this water is an important part of whistle design – as far as possible arrange whistle so that any water just falls away . One way is by having voice slot on bottom and slight downward slope on voice tube .

Michael Williams .

I think the note will be noticeably different as the speed of sound is very different in each medium.

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The speed of sound in steam lies between "1453 feet/second and the 1520 feet/second" . the speed of sound in air is about 1100 feet/second. I'd guess the difference in pitch of the notes will be roughly in the ratio 11:15 air to steam.

Neil

The ratio of speeds of sound is closer than stated but even taking the median value which gives a frequency ratio of 14.8/11 the notes produced would only be different by about a musical fifth . Heard separately in the open air I doubt whether many people on this site could even tell the difference between the two whistles .

The difference in sound quality rather than note is due to steam being more 'energetic' and exciting the whistle to produce more overtones than air would . Worst case a steam whistle can produce an unstable range of overtones only and that gives the 'screech' sound some full size whistles have .

Just one final mention – the area of opening of the voice slot has to be smaller than the area of opening of the whistle valve for proper operation and clean notes . I mentioned some of the reasons before in connection with steam turbines .

Michael Williams .

Hi DMB ,

'Treblet' tube is ordinary brass tube that has had three finishing passes through the drawing process . This results in tube which is thin walled , true and hard . It may have had some limited application in musical instruments – such as in trombone slides – but in reality few components of brass instruments are simple tubes – many bits are curved and some are tapered or flared as well .

'Treblet' though descriptive of the manufacturing process may just have been a trade name – it is shown with a capital 'T' in some places .

I doubt whether 'Treblet' tube was actually better for any practical purpose than modern thin wall drawn tube would be .

The quality of brass used makes a difference to the tone quality of percussive instruments such as chimes and tubular bells .

What difference it makes to the tone quality of wind instruments is not so obvious . It could be subjective .

On a related topic :

Some brass band enthusiasts claim that silver instruments have a richer sound than brass ones – and this does seem to be true . It is quite possible however that the silver ones being much more costly are just made better .

Regards ,

Michael Williams .

Its OK for a brass band, but you won't see all that many silver plated instruments in other forms. One of our really good local companies has a service stripping the shiny lacquer from instuments to get the 'tone purer'. Takes on a nice patina after a while, but that could be just in context with dark bars as venues.

Military likes sivler so you can polish it – noting to do with the sound.

dave (trombone)