Pat Heigham
For those insomniacs who may stay awake for the midnight news on Radio 4 – has anyone noticed the quality of the bongs?
Sounds like a condenser mic well into overload!
Alan Taylor
For decades, the BBC had a specially modified STC 4035 installed in the tower. I’ve never discovered the nature of those modifications.
I was told, and have no reason to disbelieve it, that the microphone used to be connected directly to a PO line and onwards to BH without any amplification before being distributed to the various control rooms.
Ensuring that all the active parts of the chain are within BBC premises certainly enhances reliability. When the chimes are sounding, I would expect an unamplified 4035 to produce quite a significant level. Listening to the Big Ben feed on a jackfield and cranking up the gain, you could easily hear the passing traffic.
You might think that a dynamic microphone like that should work indefinitely, but the fact that the spare version is now an exhibit in the Science Museum implies that they use something different these days. I’ve seen various discussions and a lot of speculation about what might be used instead of the 4035, but haven’t seen a definitive explanation.
Hugh Snape
There’s a fine view of the new setup in this YouTube video https://www.youtube.com/shorts/UiFPo34C9DU but unfortunately the mic. itself is hidden inside a Rycote basket windshield. Funnily enough I thought I’d read an account of the new Elizabeth Tower mic. arrangement somewhere but if I did I can’t find it now.
Graeme Wall
In answer to the question of what the modification of the original 4035 consisted off, according to the Science Museum website it was a special mounting spigot fitted on the back for use directly below the bell.
The Parliamentary archive website has a photo of 4 mikes on a frame with the top two with very tatty windshields. <https://archives.blog.parliament.uk/content/uploads/sites/4/2020/11/DSC_8885- scaled.jpg>
Mike Jordan
Regarding the Big Ben audio installation, a long long while ago when I was working in BH Lines Department, I had to go to what was then the St Stephens Tower to check out the GPO lines. There was a tiny control room a few floors up which contained the line send amps to feed the signal to BH and the Bush (standby line) I certainly saw the send amps but I suspect there were mic amps as well. I did of course have my PTS 10 battery tone source to test with.
Whilst there, I walked up all the inside stairs to the bells and inspected Ben.
In those days, just a BBC ID got you into and up the building. Not like now when one has to go through an airport style entry/inspection by the door in Black Rods Garden (I went to a meeting there some time ago) My State Opening coverage passes from 1983/4 (in box upstairs of course) were just hand written on a card. That got me from the scanner at Black Rods Garden, underneath all the buildings and into the Westminster Hall to plug up the LOCO network. I always tell of how spooky it is in there, totally silent (good very old solid walls) and walking around memorials like where Cromwell was condemned to death and scene of many lying in state.
I think the pass to the Victoria Tower (Radio link point for many OBs) was just “show me your BBC pass” All so easy back in the day.
Hugh Snape
NB, if anyone’s had a look at the YouTube video I posted what do you suppose the device below the Rycote is, a movement sensor of some kind perhaps?
Alan Taylor
My guess is that the strangely curved triangular object beneath the microphone is an LED lighting fixture. The top part has an array of what could be LED chips and behind it appears to be connected to metal conduit of the sort typically used for mains wiring.
The microphone windshield is a bit of an oddity. I’ve never seen a Rycote with those radial seams on the front.
Hugh Snape
The basket windshield is a Rycote Cyclone, https://rycote.com/microphone-windshield-shock-mount/ cyclone/ never seen one in the flesh and it does strike me there aren’t many cyclones in that location but I suppose “only the best” for the Elizabeth tower . . .
Would still like to know what mic. they’ve put inside, would be funny if it was a 635a !
Chris Woolf
Well I would know it was that, since I designed it!
The Cylones have a much larger diameter around the capsule end of the microphone. Noise reduction is based on the distance between the first surface where the wind hits (causing the turbulence that you hear as wind noise), and the microphone. Since the noise reduction is a cube law one, small increases in distance make a big difference. The downside is trying to keep larger shields rigid enough to avoid them shaking, and thus creating more noise. With the Cyclone the co-designer, Tim, produced a very clever and strong mesh structure that was mouldable, as opposed to the somewhat soggy fabricated garden netting/fabric laminate.
Without any fur cover, which is prone to picking up dirt and moisture, the Cyclones can give somewhere between 40 and 50dB suppression of wind noise.
