decay by 60dB

It’s been a bad week, architecturally speaking; making spaces and places hasn’t been as much fun as usual. Problems on site, a roof that wouldn’t fit, wasting time explaining why it wasn’t my fault and grappling with more design codes is a small sample of the last seven days. This week’s bid and this week’s design brief has some great examples of the dangers of the belief that codes are always necessary and that all aspects of a project can be deftly summarised using recognisably urban designer type words. For example,

…the site layout should be sensitive to the nearby linear canal and edges of the space should be softened with the use of bollards…

If anyone can point me to either a non-linear canal or a soft bollard, I shall be forever grateful. I’m paraphrasing the document in question, but you get the picture. The problem with employing an army of consultants to produce a document like this is that the need to keep saying something outweighs the ability to recognise, and therefore keep quiet about, the blindingly obvious.

Musically speaking, it’s been a great week. Hence the chosen category for today’s entry.

t  =    0.16 V


A

where
t = reverberation time in seconds (s)
V = volume of hall in cubic metres (m3)
A = area of absorption in square metres (m2)

Much like the academic culture that has really important things to say about linear canals, reverberation is, according to my Longman text book, the persistence of sound in an enclosure due to repeated reflections at the boundaries. t, in the equation above, is the time taken for a sound to decay by 60dB.

One night last week I became a small fraction of A whilst I was sat in the V of the Symphony Hall in Birmingham. When you’re sat in the cheap seats1 at the back of hall, as I was during a recital of Mussorgsky, Tchaikovsky and Rachmaninov, the value of t becomes very important to you. The wonderful thing about listening to the CBSO in their own hall, is that the designers who were charged with the responsibility of keeping a close eye on the way V and A monkeys around with t, did a great job. In truth, I don’t think there’s any such thing as the cheap seats, acoustically speaking, and personally I like the view from top2.

cbso

Regardless of your opinion of classical music, if you live in or near Birmingham you should go and listen to the CBSO at least once in your life. If you do, here’s a few things to look for whilst you’re waiting for the house band to finish tuning up and for the conductor to swagger on stage with all the usual pomp and circumstance.

Since different performances require different optimum values for t, being able to adjust A or V is necessary to get the most out of a space. At the Symphony Hall it’s possible to change both.

acoustic adjustments

On either side of the organ are two large sets of doors. When these are open the hall increases in size by a third of its usual volume. Around the edges are retractable curtains that increase the area of absorption and above the stage is a lighting gantry whose height can be adjusted to reflect sound at the stalls more effectively. Some time ago I attended a lecture3 by the acoustic engineer who designed the hall, he was more than a little smug about what a good job he’d done (both here and in other halls across the world) but there’s no denying that fact that he got it right.

Here’s a quick summary of the music for those more interested in the art than the science, as opposed to the art of the science which I’ve been talking about so far. The wonderfully named Modest Mussorgsky’s Night on a Bare Mountain was a good, bouncy start to the proceedings to liven us all up; Rachmaninov’s Piano Concerto no.4 was complex, restless, unstructured and perplexing; Tchaikovsky was, as usual, flawless. Towards the end of the Rachmaninov piece I started to find a way in by imagining it as the proceeds of an argument between two lovers. Neither of whom were in the right. In the car on the way home the DJ on Classic FM spoke about how Mozart was responsible for introducing the argumentative interplay of opera arias into piano concertos. It seems I wasn’t far from the mark and the two lovers should blame Mozart rather than each other.

Other musical journeys over the last week:

At work, getting our daily fix of ‘Legends’4 on the local radio station I’ve mentioned previously, we found ourselves listening to ‘Crazy, Crazy Nights’ by Kiss. My knowledge of Kiss is minimal, so I decided to download some more of their work and chose their MTV unplugged album from allofmp3.com. Half way through the set they play a track called ‘2000 Man’. One of the partners points out that it’s a cover of a Rolling Stones track but he can’t remember which album. Google tells us that it’s from their 1967 album ‘Their Satanic Majesties Request’ (which, strangely, sounds like it should be a Kiss album). Ultimately we end up listening to and unanimously enjoying a track on that album called ‘She’s a Rainbow’. I’m willing to bet that most of you haven’t heard either that album or that track; it’s good, you should try it out. I’m sure if you look hard enough you’ll be able to get hold of a copy.

Over at kryogenix.org, some kind soul has posted a link in the comments to a download of the first Half Man Half Biscuit track I ever heard (thanks to John Peel) called ‘Paintball’s Coming Home’. Inspired by Stuart’s entry about a particularly dodgy quiz to determine how middle class you are, the track is the perfect accompaniment. There’s a second version of this track with different lyrics which you can also download from the site I added to the linklog a few weeks ago.

Last week’s Mixing It on Radio 3 had a collection of tracks from bands based in Montreal. It was a fantastic show and you’ve got until tomorrow night to exploit the ‘listen again’ option on the BBC web site. Tracks to listen out for are the curious Le tresor de la langue by Rene Lussier, which ‘…was written as a celebration of the Québécois French language, and features some of his improvising colleagues following the speech patterns.’; also the breathtaking Le Projet Ulysse by Christian Calon.

Christian has this to say about his work:

The architectural dimension of sound and a reflection on the narrative processes are the main focus of my present work centered around the ideas of Time, presence and transformation. Through various forms including spatial sound installations, acousmatic or radio pieces, my recent pieces explore the modality of the audible and of the listening experience. Space, at the heart of my reflection, has become today an essential way through to the central question of Time.

It seems the values V, A and t are important to him too. It also seems plausible that he had a hand in writing the design code I’m working with at the moment, perhaps whilst he was travelling along a non-linear canal. Pensively.

notes:

  1. £7
  2. I’ve captured this view before in the sketches category
  3. My family often jokes that my grandfather’s grave stone should start with the words ‘When I was in the desert…’ due to the way his stories about the war would always start. I’m beginning to wonder if mine should say ‘I once attended a lecture on…’
  4. I learnt this week that this is a word ill suited to describing a radio show, it comes from the latin legendum, which means ‘to read about’.

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