The National Physical Laboratory in Teddington has always fascinated me. I’ve lived in the general area for years and some of my family’s history is centered around this town so it’s been a constant source of intrigue. I’d always imagined that behind those security guarded gates, inter-dimensional portals were being opened, nano technology was being tested and alien saucers were being reverse engineered but the reality is far less sci-fi than that.
Lainy Lewis Photography and Image Processing
For those that don’t know, the NPL is a government laboratory where behind closed doors all manner of scientific testing and measurement takes place. Once every two years they open the doors to the public and being local and interested I took the day off to go and take a look. For someone obsessed with sound like I am this was a rare chance to to see two very important rooms; an acoustically ‘dead’ room (scientifically known as an Hemi Anechoic Chamber) and at the opposite end of the sonic scale, a hyper-reflective room (referred to by staff as the Anechoic Chamber or Reverb Room).
These chambers have many scientific purposes, from testing experimental microphones to calibrating speakers and are guarded by friendly staff politely enforcing the ‘no pictures’ rule. Apparently the experimental microphones being used were top secret so despite the temptation to distract them and take some sneaky pictures I complied with their wishes (the interior pics you see here were kindly sent to me by a member of staff)
Courtesy of NPL
The Anechoic Chamber
This extremely reverberant room is designed to create an exaggerated sense of space and does so through the usage of reflective floor, walls and suspended sheets of plastic at different angles hanging from the ceiling. On the wall for the open day was a projection featuring a spectral plot of the frequency energy in the room and it made an interesting interactive backdrop.
There were several staff in the room, wearing the standard issue blue polo shirt and the interesting thing was some NPL worker themselves were visiting this room. You see, each member of the staff has their own ‘clearance’ and these guys, despite working there for a while had not been allowed in previously.
They were genuinely excited to be inside also, it was mad to consider that under usual circumstances they just wouldn’t have had the chance but they made the most of their time in there and quizzed their colleagues. I did the obligatory wander around the room, clicking my fingers, saying short percussive syllables and clapping my hands to see how the reverb tail sounded and it was amazing, all 25 seconds of it.
To communicate you seriously had to whisper, otherwise the reverb would take over, blurring the definition between words. I suggested the room would make a great convolution impulse and the lady nodded excitedly telling me that on a recent “music hack day” they fired off some test tones and created an impulse for students to use in their productions.
Courtesy of NPL
The Hemi Anechoic Chamber
Visually this looked the most interesting and boy did it sound weird. It was how I’d imagine things would sound if you were trying to communicate from within a vacuum. I’ve been in plenty of vocal booths and recording rooms so I’m used to hearing dead spaces but this was the deadest I’ve ever come across.
I asked about the ‘blue’ room I’d seen and was told that was off limits for health and safety reasons (a lack of a proper load bearing floor being one!) This room is even deader and actually looks amazing in pictures (see below).
Courtesy of NPL
Although there were tons of other things to see and do there my curiosity was satisfied so I left and as I did so a full coach load of NPL open day attendees poured out onto the pavement, people had seriously come from far and wide for this opportunity. I really enjoyed the chance to visit the NPL so big thanks to all the staff, especially Kinnie Kelly for sending me the fantastic photography taken inside those wicked testing rooms.
