STIEBEL NAUTILUS
I HAVE ONE , UNUSED
I HAVE ONE , UNUSED
Best HORN
- Thread starter ROLL DOG
- Start date
Denali Soundbomb just fitted and its feckin loud
Had a thought about comparing horns that I seem to have acquired over the months in a search for a suitable replacement. I have some calibrated test kit (I design/manufacture loudspeakers for a living) and I thought it would be a bit of fun to test the output of each measured at 1m on axis. Quietest was my stock horn which struggled to better 88dB. They can vary a lot depending on how taught the diaphragm is set. Next was an Ebay el-cheapo special (one of the £15 510Hz ones which looks suspiciously like the Denali mini soundbomb). That didn't live up to the claimed 115dB but it was close enough at just under 110dB. The winner was the E39 Horn which topped out at 112dB which sounded a heck of a lot louder than the next one (no surprise as 3dB is effectively a doubling of spl). It would be interesting to test a denali full beans sound bomb. If anyone lives close (Glos) and fancies getting there's tested, give me a shout and I can rig up the test. It's academic I know as loud is loud is loud...but it's all a bit of fun.
The other thing worth noting is that HF can be more easily attenuated so lower frequencies tend to carry for longer. Mind you, if you want really loud...look no further than intercity trains. Out of interest I researched comparisons across the motoring spectrum. Trains can by way over the 140dB (instantaneous hearing damage) at 1m. In the USA, they have to be between 96 and 110dB at 100ft from the train. Must check ebay...
The other thing worth noting is that HF can be more easily attenuated so lower frequencies tend to carry for longer. Mind you, if you want really loud...look no further than intercity trains. Out of interest I researched comparisons across the motoring spectrum. Trains can by way over the 140dB (instantaneous hearing damage) at 1m. In the USA, they have to be between 96 and 110dB at 100ft from the train. Must check ebay...
I thought there was a db limit for horns designed for vehicles?
Under the Motor Vehicle (Construction and Use) 1986 Regulations, there is mention, and definition of what a horn is:
A horn means an instrument, not being a bell, gong or siren, capable of giving audible and sufficient warning of the approach or the position of a vehicle to which it is fitted .
From 1973 onwards, a horn has to have a single continuous and uniform tone (so two tone horns will not pass MOT), it must not be "harsh or grating" and "must be loud enough to be heard by another road user".
It does not stipulate any dB range afaik.
The MOT itself only require that a horn be fitted and must be constructed and used in accordance with the regulations above, so no, there does not appear to be any restrictions on how loud it is.
As a matter of courtesy come MOT time, I will be warning the tester that the horn is pretty loud so that he doesn't deafen himself. If you know that your horn emits noise above the threshold for hearing damage and you don't warn the tester, it is a moot point whether you could conceivably leave yourself open to civil proceedings should they suffer any hearing damage as a result of the test.
I think that common sense dictates that you fit and use a horn that is loud enough to be heard close by but not so loud that it could potentially damage the hearing of those nearby (particularly pedestrians). To be that loud beyond a few metres would be a bit reckless.
A horn means an instrument, not being a bell, gong or siren, capable of giving audible and sufficient warning of the approach or the position of a vehicle to which it is fitted .
From 1973 onwards, a horn has to have a single continuous and uniform tone (so two tone horns will not pass MOT), it must not be "harsh or grating" and "must be loud enough to be heard by another road user".
It does not stipulate any dB range afaik.
The MOT itself only require that a horn be fitted and must be constructed and used in accordance with the regulations above, so no, there does not appear to be any restrictions on how loud it is.
As a matter of courtesy come MOT time, I will be warning the tester that the horn is pretty loud so that he doesn't deafen himself. If you know that your horn emits noise above the threshold for hearing damage and you don't warn the tester, it is a moot point whether you could conceivably leave yourself open to civil proceedings should they suffer any hearing damage as a result of the test.
I think that common sense dictates that you fit and use a horn that is loud enough to be heard close by but not so loud that it could potentially damage the hearing of those nearby (particularly pedestrians). To be that loud beyond a few metres would be a bit reckless.
Strange how there are motor vehicle regulations regarding alarms levels but not horns.
EDIT I remember those Dukes of Hazards air horns many people had years ago
'(1) The Road Vehicles (Construction and Use) Regulations 1986 (S.I. 1986/1078) are amended as follows.
(2) In regulation 3(2) (interpretation), in the Table, at the appropriate place in alphabetical order, insert—
99A Restrictions on audible motor vehicle alarms on certain motor vehicles first used on or after 1st January 2007
(3) The audible motor vehicle alarm of a motor vehicle to which this regulation applies—
(a) may not at any time emit a noise exceeding 55 decibels,
(b) may not emit a noise for a continuous period of more than ninety seconds,
(c) may not emit a noise for more than ninety seconds in response to a single event initiating the emitting of a noise, and
(d) shall be maintained in good working order so as to comply with the requirements of sub-paragraphs (a) to (c).
https://www.theyworkforyou.com/debates/?id=2005-02-21a.82.0
https://hornblasters.com/
EDIT I remember those Dukes of Hazards air horns many people had years ago
'(1) The Road Vehicles (Construction and Use) Regulations 1986 (S.I. 1986/1078) are amended as follows.
(2) In regulation 3(2) (interpretation), in the Table, at the appropriate place in alphabetical order, insert—
99A Restrictions on audible motor vehicle alarms on certain motor vehicles first used on or after 1st January 2007
(3) The audible motor vehicle alarm of a motor vehicle to which this regulation applies—
(a) may not at any time emit a noise exceeding 55 decibels,
(b) may not emit a noise for a continuous period of more than ninety seconds,
(c) may not emit a noise for more than ninety seconds in response to a single event initiating the emitting of a noise, and
(d) shall be maintained in good working order so as to comply with the requirements of sub-paragraphs (a) to (c).
https://www.theyworkforyou.com/debates/?id=2005-02-21a.82.0
https://hornblasters.com/
The purpose of an alarm is not the same as a horn though, and to have alarms made that emitted over 100dBA would be an antisocial nightmare, especially with so many triggered by wind or being over sensitive etc. An alarm to my mind is only any good for telling the owner that their car is potentially being broken into, so providing that it can be heard from relatively closely, that's what matters.
A horn needs to be heard from the inside of a vehicle, travelling with it's own road noise (lets say for argument's sake 70dB road noise from inside a car on the motorway) from a reasonable distance to warn others of your presence. 80 -r 90dBA doesn't really cut it in some circumstances and 55dBA (as per the alarm limit) would be next to useless.
A horn needs to be heard from the inside of a vehicle, travelling with it's own road noise (lets say for argument's sake 70dB road noise from inside a car on the motorway) from a reasonable distance to warn others of your presence. 80 -r 90dBA doesn't really cut it in some circumstances and 55dBA (as per the alarm limit) would be next to useless.
I don't wish to be picky when you've provided such useful info, but I think you're worrying unnecessarily here. I've had 2 BMW e39 5 series, both fitted with twin horns rather than a single half of the standard pairing, and have not been pursued through the courts by any irate MOT testers.
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