The Hulme Hum - Did I Hear It?

[Mosaic]

Stuck in traffic yesterday evening on the Mancunian Way in the Cambridge Street vicinity, a loud hum could be heard. So loud it was above the general traffic noise and even audible when my radio was playing. I think this was the 'Hulme hum' which I have read about, generated by the 'fins' on top of the Beetham Tower (that really tall building in Manchester).
Has anyone else experienced this? Or was I hearing something else?

[boxtops]

I've never heard of it, mosaic.....

[jomifl]

what frequency was it?

[wolf63]

Tinnitus Hum?

[Mosaic]

Frequency? Hell's Bells! It sort of went 'ooooooooooooommmmmmmmmm' like a sonorous bell but not stopping.

I had read about it before in a number of articles like this one: http://en.wikipedia.org/wiki/Beetham_Tower,_Manchester

Always imagined it would be a distant sound that you could pick up when all was quiet but this was louder than the traffic roar.

[Mosaic]

No wolfie it wasn't tinnitus (mine buzzes anyway). This was external to the car and louder when I opened the window. Traffic moved very slowly - I first noticed it near the MMU new glass building adjacent to Mancunian Way, and lost it at the underpass at All Saints.

[factor-fiction]

Yes, it's Beetham Tower. I remember reading that when it was first built when the humming/whistle from the fins was sometimes affecting filming on Coronation Street

[jomifl]

according to your link it is the B (247 hertz) below middle C. Could it have been grooves across the road?

[Teddio]

Could it be a resonance effect caused by the strong wind flowing over the "fins" ? Low frequency sounds can travel a large distance and are able to penetrate buildings and cars with relatively little attenuation.

[jomifl]

Teddio, it isn't that low a frequency^

[Teddio]

The attenuation of sound is proportional to the square of the frequency. Without being pedantic I am saying that a "low" frequency of around 247 Hertz would be attenuated significantly less than a "high" frequency of say 20kHz.

[Mosaic]

Jomifl the thing about grooves in the road making the sound is that most of the traffic was crawling. The sound was very like a giant bottle being blown on, or a wineglass rim being rubbed.

[factor-fiction]

I recall this road is a 'flyover'. It could just have been the sound of the structure you were on as it was probably being affected by the strong winds

[dunnitall]

I knew nothing about this until you posted but I would say it must have been what you heard from reading up on the link posted. Fascinating to me as I'd not come across this before. What I would like to know is, if it's that loud outside, do the residents and people in the building hear it as well? If so I would hate to be living there having to endure that!

[Mosaic]

Apparently the nature of sound waves is that you hear them 'downwind'. So the people in the Beetham Tower don't get hummed, but the downwind residents of nearby Hulme do, and many are not best pleased apparently.
Sounds like this one are also carried as the wind changes direction. It was an incredibly windy evening when I heard it. I travel the route every week and haven't heard anything like it before.
The super-fast trains in France created similar noise-related distress, and I wonder if anyone in the UK has thought about this one with the HS2 proposals.

[Mosaic]

Factor: parts of the Mancunian Way are flyover. I picked up the noise on both elevated and ground-level sections.

[factor-fiction]

Was it the sound of boos coming from Old Trafford?

[Mosaic]

Factor - you may have hit on something - it did sound weirdly like a prolonged moan......

[mibn2cweus]

blinkyblinky . . . was that you?

http://www.theanswerbank.co.uk/Science/Question161754.html