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BBC Location Recording

All about the tools and techniques involved in capturing sound, in the studio or on location.

Re: BBC Location Recording

Postby forumuser840717 » Fri Jul 12, 2019 11:03 pm

Symphony Hall is structurally decoupled by 2000 specially engineered laminated rubber bearings (pads) (laminated in that they're made of sandwiched layers of rubber and steel). They're 300mm x 300mm x 125mm thick. Each bearing takes a load of up to 40,000kg with a primary resonance at 40Hz. They're mostly mounted in groups of eight on the tops of concrete column piles. On top of these is a concrete raft which supports and distributes the load of the building.

The hall was designed as part of the ICC by the Percy Thomas Partnership and Renton Howard Wood Levin with Artec founder Russell Johnson as the principle acoustic consultant. And a very nice job they made of it. IMO. But then Artec are probably my favourite halls generally. Those and halls by Nagata Acoustics.
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Re: BBC Location Recording

Postby Hugh Robjohns » Fri Jul 12, 2019 11:51 pm

Thanks for that detail. I'm still awaiting a response from the hall office. I'm wondering if my 50 feet comment referred to the supporting pile depth?

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Re: BBC Location Recording

Postby Bob Bickerton » Sat Jul 13, 2019 4:13 am

forumuser840717 wrote:Symphony Hall is structurally decoupled by 2000 specially engineered laminated rubber bearings (pads) (laminated in that they're made of sandwiched layers of rubber and steel). They're 300mm x 300mm x 125mm thick. Each bearing takes a load of up to 40,000kg with a primary resonance at 40Hz. They're mostly mounted in groups of eight on the tops of concrete column piles. On top of these is a concrete raft which supports and distributes the load of the building.

The hall was designed as part of the ICC by the Percy Thomas Partnership and Renton Howard Wood Levin with Artec founder Russell Johnson as the principle acoustic consultant. And a very nice job they made of it. IMO. But then Artec are probably my favourite halls generally. Those and halls by Nagata Acoustics.

Isn’t wonderful what you can learn on thee forums!!

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Re: BBC Location Recording

Postby awjoe » Sat Jul 13, 2019 7:03 am

Kwackman wrote:
Ariosto wrote:So would the experts at SOS recommend 96KHz rather than 44.1KHz (or 48K)? At present I record at 44.1KHz and 24 bit.

I am NOT an expert (and this isn't false humility!) I record 24bit and 44.1 KHz.

We're equally inexpert, then, because I do the same, for similar reasons. I'm grateful in fact that I don't do any video work because that would require me to remember which of two sample rates I was operating in. :mrgreen: Life's difficult enough already. Most of my time's taken up with mic placement and performance. Attention to the weakest link, me.
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Re: BBC Location Recording

Postby blinddrew » Sat Jul 13, 2019 9:36 am

awjoe wrote:Most of my time's taken up with mic placement and performance. Attention to the weakest link, me.
So much this ^^^
I record in 24/44.1 because there are about a billion other things that i can screw up long before i get to worrying about sample rates.
By chance i struck it lucky on the video side as well as it turns out that Canon DSLRs and my phone all record their audio-for-video at 44.1 as well. :)
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Re: BBC Location Recording

Postby Hugh Robjohns » Sat Jul 13, 2019 10:53 am

The critical thing with digital video is that there are a whole number of audio samples within each video frame. That's the reason the digital audio wordclock has to be synchronised (in one way or another) with the video frame rate. It's also the reason we have the sample rates that we do.

Sony originally chose 44.1kHz because it was more than double 20kHz (to comply with Mr Nyquists requirements), and it worked very neatly with 30fps B&W NTSC video which was convenient for the video recorders MR Sony wanted to use. It provides 1470 audio samples per frame.

As it happens, it also works perfectly with European TV at 25fps (1764 samples), but not with film at 24fps (1837.5).

Consequently , when the standards were being drawn up for digital video recording, it was decided to use 48kHz as the standard audio sample rate, as that gave 1600 samples at 30fps, 1920 at 25fps, and 2000 at 24fps.

Inevitably, it didn't give an integer number for American colour NTSC with its slightly wacjy 29.97fps rate... but then nothing practical ever would. The solution was to allocate the audio over five video frames rather single frames, with 8008 samples across 5 frames.

So... digital cameras working at 25fps (or 50 field progressive) can work quite happily with either 44.1 or 48k audio -- as can most non-linear video editing software.

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Re: BBC Location Recording

Postby awjoe » Sat Jul 13, 2019 5:25 pm

blinddrew wrote:I record in 24/44.1 because there are about a billion other things that i can screw up long before i get to worrying about sample rates.

I just don't think sample rate's that important. I've tried to hear the difference between 44.1 and higher rates, and I can't. And so if I'm *trying* to hear a difference and can't then the sort of casual listeners who hear my stuff probably aren't going to hear it either, or if they do, it's going to be miniscule.

Digression: Actually, the fact that my ears are shot is a sort of advantage - if I *can* hear something, then by God it's significant. Again, priorities.
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Re: BBC Location Recording

Postby awjoe » Sun Jul 14, 2019 4:02 am

Mike Stranks wrote:2) Here we sometimes agonise about whether a particular piece of kit is 'good enough'. Used sensibly, leaving sufficient headroom, these days even quite modest equipment is capable of 'broadcast quality' results.

Discuss...

The only way you can put that one to the test is to see if you can get something broadcast, right?
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Re: BBC Location Recording

Postby Mike Stranks » Sun Jul 14, 2019 9:40 am

awjoe wrote:
Mike Stranks wrote:2) Here we sometimes agonise about whether a particular piece of kit is 'good enough'. Used sensibly, leaving sufficient headroom, these days even quite modest equipment is capable of 'broadcast quality' results.

Discuss...

The only way you can put that one to the test is to see if you can get something broadcast, right?

Not these days. Unless its quality is so abysmal that even my 8-month-old grandson would raise an eyebrow they'll use it - especially if they don't have to pay for it!

Technical quality is now very low down the list in what will and won't be accepted.
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Re: BBC Location Recording

Postby James Perrett » Sun Jul 14, 2019 1:57 pm

awjoe wrote:The only way you can put that one to the test is to see if you can get something broadcast, right?

The first thing that I had broadcast back in the early 70's was recorded on a basic Philips cassette recorder with the mic that came with it. I would have to say that its recording quality was much better than most of the competition though the AM radio system managed to lose any hint of high frequencies.
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Re: BBC Location Recording

Postby FrankF » Sun Jul 14, 2019 2:47 pm

"My understanding of this type of construction is heavy duty coiled springs with neoprene rubber on top (and bottom?) are used between the real floor and the floating floor.
Maybe Hugh put a ‘ instead of a “ (plus springs) or maybe it was 50 cm or maybe it was just 5’."

Are you suggesting that Hugh might have had his very own Spinal Tap moment? :-)
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Re: BBC Location Recording

Postby MOF » Sun Jul 14, 2019 2:53 pm

By chance i struck it lucky on the video side as well as it turns out that Canon DSLRs and my phone all record their audio-for-video at 44.1 as well.
The industry standard for video cameras is 48k because it’s easier to mathematically marry the frame and sample rates. I’ll be very surprised if your Canon DSLR is different.
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Re: BBC Location Recording

Postby FrankF » Sun Jul 14, 2019 3:00 pm

This thread reminds me of the ongoing mystery-cum-debate of why, or indeed whether Stradivarius' instruments sound better than modern equivalents or not.
Academics have done several blind tests over the years, and each time the "experts", that is to say the world's top fiddlers (no pun intended), get it wrong. Here's a great article that's full of contradictions, but fascinating pabulum for thought nonetheless:
https://www.sciencemag.org/news/2014/04 ... rn-fiddles
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Re: BBC Location Recording

Postby MOF » Sun Jul 14, 2019 3:12 pm

whether Stradivarius' instruments sound better than modern equivalents or not.
There was an item on The One Show about this very subject, I liked the good quality modern violin in preference to the Strad’.
I seem to remember the experts got it right in blind tests.
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Re: BBC Location Recording

Postby MOF » Sun Jul 14, 2019 5:12 pm

Are you suggesting that Hugh might have had his very own Spinal Tap moment? :-)
Very good, I hadn’t thought of that, maybe he wrote out his notes on a paper serviette and the “ got a bit smudged into a thick ‘. :clap:
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Re: BBC Location Recording

Postby Hugh Robjohns » Sun Jul 14, 2019 6:39 pm

Hang on, I'll be with you in a minute... just as soon as I get these pod doors open... :lol:
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Re: BBC Location Recording

Postby blinddrew » Sun Jul 14, 2019 7:37 pm

MOF wrote:
By chance i struck it lucky on the video side as well as it turns out that Canon DSLRs and my phone all record their audio-for-video at 44.1 as well.
The industry standard for video cameras is 48k because it’s easier to mathematically marry the frame and sample rates. I’ll be very surprised if your Canon DSLR is different.
I was surprised too, to the point when I first used one of the work ones in combo with an audio recorder, I had it set at 48kHz. Took me a few moments to figure out why things weren't matching up. It took even longer to actually find the audio specifications for video recorded by the DSLRs, but both work and both my personal ones all record at 44.1kHz.
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Re: BBC Location Recording

Postby Wonks » Mon Jul 15, 2019 7:13 am

Failed on the info front from the office. People I'm still in touch with all seem to have left. :(
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Re: BBC Location Recording

Postby Folderol » Mon Jul 15, 2019 7:40 am

Wonks wrote:Failed on the info front from the office. People I'm still in touch with all seem to have left. :(
Ummm. Don't follow you ol' bean - have I missed something?
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Re: BBC Location Recording

Postby Wonks » Mon Jul 15, 2019 7:48 am

Folderol wrote:
Wonks wrote:Failed on the info front from the office. People I'm still in touch with all seem to have left. :(
Ummm. Don't follow you ol' bean - have I missed something?
I did mention that my company (Arup) were the consulting engineers on the Birmingham Symphony Hall project and I had read articles published in internal mags on the spring system. As I haven't been actively working there for 5 years now, I was hoping someone could see if there was any archived data available.
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