As a senior medic, I was invited to participate into a siren-study funded by European Council and it was conducted here in Helsinki, Finland. We went through 22 different siren types by different manufacturers - both European and American. These were analysed in audio lab and then based to this info a new siren was produced. The study proved the following facts that are simply as follows:
- Wail sound was the most audible from longer distance - it changes pitch continuously and breaks through the traffic noise
- Yelp should only be used closer to intersections/from short distance warning
- Air Horn is effective at close range - like when approaching intersections.
- Phaser/ are almost useless. They can be only heard from short distance.
- Dual tone - if used wail+yelp simultaneously did not improve audibility. Dual tone "stereo" in two simultaneous pitch improved slightly audibility.
- Low-frequency sirens, as Howler/Rumbler did not break through traffic noise as well as higher pitched sirens.
- Hi-lo changed pitch too slowly compared to wail. The German type "Martin Horn" was audible but had too much tonal pressure eq. desibels and was dangerously to human and canine ears.
- Mechanical siren types - Federal Q, Timberwolf, etc were very audible but had a problem with weight and were quite noisy to be used in ambulances/police cars. Excellent for fire engines though.
- The siren amplifiers should have min. 200W power and always should use two speakers mounted on grill - never behind it.
So friends - I suggest everyone to use WAIL as the main sound and wail/phaser/airhorn on intersections. That's all we need. Forget hi-lo.
The new demo-siren based on the study can be heard/seen on my tiktok-feed under user @drumgretsch
- Wail sound was the most audible from longer distance - it changes pitch continuously and breaks through the traffic noise
- Yelp should only be used closer to intersections/from short distance warning
- Air Horn is effective at close range - like when approaching intersections.
- Phaser/ are almost useless. They can be only heard from short distance.
- Dual tone - if used wail+yelp simultaneously did not improve audibility. Dual tone "stereo" in two simultaneous pitch improved slightly audibility.
- Low-frequency sirens, as Howler/Rumbler did not break through traffic noise as well as higher pitched sirens.
- Hi-lo changed pitch too slowly compared to wail. The German type "Martin Horn" was audible but had too much tonal pressure eq. desibels and was dangerously to human and canine ears.
- Mechanical siren types - Federal Q, Timberwolf, etc were very audible but had a problem with weight and were quite noisy to be used in ambulances/police cars. Excellent for fire engines though.
- The siren amplifiers should have min. 200W power and always should use two speakers mounted on grill - never behind it.
So friends - I suggest everyone to use WAIL as the main sound and wail/phaser/airhorn on intersections. That's all we need. Forget hi-lo.
The new demo-siren based on the study can be heard/seen on my tiktok-feed under user @drumgretsch
