hi-lo airhorns

[SCP01]

I'm in East Anglia which is the bit that sticks out into the North Sea to the north east of London although I'm originally from Hertfordshire just to the north of the smoke. Plenty of change ringing around here

Did you click on the picture link to load the video? I don't have it in front of me but at a guess I would say the compressor is between 8-10 inches long by 3-4 in diameter. There are no pistons it's basically a three section unit. First is the motor above which is the next section - a sealed concentric chamber into which the motor shaft passes. Mounted on the motor shaft is a metal cylinder with slots into which three sliding steel vanes are held, the motor shaft comes up somewhat off centre so that the vanes slide in and out as they rotate. There is a filtered air inlet on one side of the chamber and air is drawn through this and then blown into another chamber above by the vanes under pressure. With me so far?

The top chamber contains a sealed reduction gearbox driven by the motor shaft below. A shaft that protrudes from the top of the gearbox then turns a slotted disc that is held under spring tension against the top plate of the chamber into which the two horn hose outlets are fitted. The slots in the disc correspond with the air outlets therefore forming an air valve so that as it rotates it alternately shuts the air supply to each horn on and off.

In principle it?s a lot simpler than my description

[Robert Gift]

I'm in East Anglia which is the bit that sticks out into the North Sea to the north east of London although I'm originally from Hertfordshire just to the north of the smoke. Plenty of change ringing around here :wink:

Did you click on the picture link to load the video?

No. This, wife's computer on dial-up, takes too long.

I don't have it in front of me but at a guess I would say the compressor is between 8-10 inches long by 3-4 in diameter. There are no pistons it's basically a three section unit. First is the motor above which is the next section - a sealed concentric chamber into which the motor shaft passes. Mounted on the motor shaft is a metal cylinder with slots into which three sliding steel vanes are held, the motor shaft comes up somewhat off centre so that the vanes slide in and out as they rotate. There is a filtered air inlet on one side of the chamber and air is drawn through this and then blown into another chamber above by the vanes under pressure. With me so far? :wink:

Goodescription, but I still do not understand.

The top chamber contains a sealed reduction gearbox driven by the motor shaft below. A shaft that protrudes from the top of the gearbox then turns a slotted disc that is held under spring tension against the top plate of the chamber into which the two horn hose outlets are fitted. The slots in the disc correspond with the air outlets therefore forming an air valve so that as it rotates it alternately shuts the air supply to each horn on and off.

I understand that. Thanks.

So, this pump is really a "blower" with spinning impellers?

Glad that it has an air filter.

Thank you,

Robert the -XXI

[SCP01]

So, this pump is really a "blower" with spinning impellers?

In short yes. I should have said that in the first place and saved a heap of typing.

[Daniel]

SCP01
Thanks for the video clip. This is a 2nd interval siren, used almost exclusively in the UK and Ireland (even if made in Italy) until fairly recently, when it began showing up in places like France.

[Jim_Ferer]

The German horns are significantly different in tones. I wish I had the musical vocabulary to express it, though.

[Robert Gift]

The German horns are significantly different in tones. I wish I had the musical vocabulary to express it, though.

You do!

Think of our typical musical ascending scale: C,D,E,F,G,A,B,C
which equals "Do, Re, Mi, Fa, So, La, Ti, Do"

Call the lower horn note "Do"
If the other horn sounds "Me" up the scale (in comparison to Do), then you have identified the musical interval as a 3rd.
If you name lower note Do, and the higher horn up the scale is So, then you have identified the interval as a 5th.
"Do-Fa" = a 4th.

Pretty clever de French!

Are most Hi-Lo sirens "Me-Do"? (major 3rd)

I prefer a 2nd interval for a siren: Do-Re, Do-Re,...

A problem with 4th and 5th Hi-Lo sirens is that one not hearing
one note may also not detect the other.
A second is a better interval to stand out.

For loudest volume I suppose it would beven better to sound both notes simultaneously. Buthen you lose the Hi-Lo identifier.

[Daniel]

The sol-fa/solfege system is handy for intervals, but as in chant notation, doesn't specify pitch. Standard German sirens are (were?) a perfect 4th interval, and usually go slower than French or Italian sirens. German sirens generally sound either Bb/Eb or A/D. Horns made by Martin Signale (Martinshorns, although the word is applied to all of them) often had two horns for each note, giving a dissonant sound. Some electronic versions have a weird, Hammond-like vibrato to them. Some WWII German versions sounded the unusual sharp 4th interval Bb/E, and some electronic sirens in Sweden use this today. Occasionally one could hear an old German-made Bosch electric horn siren which sounded G/C.

In the old DDR (East Germany), there were electronic sirens which sounded a hi-lo, but slid up and down to the notes in an odd, portamento effect. They also had a slow-fast type of siren which sounded a rapid Lo-Hiiiiiiiiiiii-Lo-Hi-Lo-Hi-Lo-Hi-pause-repeat. This could be found other places in eastern Europe.

Other countries seem to allow for a mix of intervals, and the American-style wail and yelp are unfortunately taking over in more countries. Britain and Ireland had the 2nd interval horns (Ab/Bb), but at least in Ireland, they are quite rare except on older ambulances, that country preferring American siren sounds. Major 3rd horns could be found in Italy, France, and other places. The French also have an ambulance siren that gives a quick Lo-Hi-Lo every couple of seconds.

[SCP01]

Going off on a tangent, somewhere around here I have a pair of 12v hi-lo electronic horns with the controller relay that were popular on some police vehicles over here back in the 60's/70's. Basically they are very similar to ordinary car horns with the addition of an alternating device.

I also have / had a set of triple tone French horns and their controller which sound a daa dee daa tone. The horns are fairly unremarkable but the controller consists of a unit with three fixed contacts mounted in clock face style. These were swept over by a motorised contact to comple the circuit and power the respective horns.

A search on Ebay.de will often bring up some interesting bits and bobs.

http://cgi.ebay.de/Martinshorn-fuer-W50 ... dZViewItem

http://cgi.ebay.de/Martinshorn-Feuerweh ... dZViewItem

[Robert Gift]

Some electronic versions have a weird, Hammond-like vibrato to them. Some WWII German versions sounded the unusual sharp 4th interval Bb/E, and some electronic sirens in Sweden use this today. Occasionally one could hear an old German-made Bosch electric horn siren which sounded G/C.

In the old DDR (East Germany), there were electronic sirens which sounded a hi-lo, but slid up and down to the notes in an odd, portamento effect.

Portamento is closer to wail. Wail is detected better in background noise and music than any other sound.

They also had a slow-fast type of siren which sounded a rapid Lo-Hiiiiiiiiiiii-Lo-Hi-Lo-Hi-Lo-Hi-pause-repeat. This could be found other places in eastern Europe.

Other countries seem to allow for a mix of intervals, and the American-style wail and yelp are unfortunately taking over in more countries.

American influence is everywhere. Unfortunate for tradition, but wail is a superior siren.

Britain and Ireland had the 2nd interval horns (Ab/Bb), but at least in Ireland, they are quite rare except on older ambulances, that country preferring American siren sounds. Major 3rd horns could be found in Italy, France, and other places. The French also have an ambulance siren that gives a quick Lo-Hi-Lo every couple of seconds.

How fascinating, Daniel!
Especially the # (wide) 4thorns andisonant Martinshorns!
Thank you.

Is our Unitrol 480K Major 3rd?
If you press the "manual" button while in Hi-Lo mode, I recall it does a major 2nd.
(Since I can't muffle the TS100 speakers behind the grill, I can'testhis in our garage or anywhere we travel.)(Will have to wait for the next emergentransport.)

Are any hi-lo air horns as loud as an electronic siren?

[Robert Gift]

I also have / had a set of triple tone French horns and their controller which sound a daa dee daa tone.

What were the notes/intervals?

The second eBay item appears to be the dissonant set.
(Each horn appearslightly different in length to it's partner.)
(I didn'try to read the text.)
Thank you, Steve.