I recently travelled to Isturitz Cave in Southern France to make a number of recordings: of a singer; a reconstruction of a 30,000 year old Vulture bone pipe (played as a flute); and to carry out acoustic experiments. I used the opportunity to test a Resident Audio T4 Thunderbolt soundcard. I needed to record with 3 condenser microphones and would have no mains electricity, so needed a soundcard that could be bus powered from the computer’s battery. The project needed a soundcard that featured high quality audio from great analogue to digital convertors, and long battery life, as there would be no chance to recharge during the recording session. The Resident Audio seemed the ideal choice, but there was little information about battery life available from this relatively new product.
The recordings used a Mac Laptop Pro (Early 2013, 15″ retina display model) with OSX 10.9.5, Logic Pro and three high quality mics, two DPA 4006 omni mics and a Neumann UM87. The Neumann was placed close to the sources to record direct sound, with the DPA spaced pair 10m or more away, catching the reverberation of the cave; all needed 48v phantom power. A test before leaving home showed that the system used only 1% of battery life when recording silence, but that as more level and current passed through the system, the computer’s battery started to drain more quickly. The soundcard has lights on the mic volume knobs that indicate levels (green, orange, red), which no doubt draw current. I longed for the option to switch these off, worried my battery would not last.
In the end I need not have worried, the recording session lasted 6 hours or more, and the computer’s battery had more than half left at the end. I was careful to turn off the phantom power to the mics when not in use, and even shut down the computer when there was a gap in recording. But battery life was plenty for what I needed to do. The recordings sound fantastic (and will be available on this website in due course), and for a portable system the convertors seem to be of really good quality. There were some clicks in the recordings on multiple channels simultaneously, and I still need to work out where they came from, so the soundcard is yet to get a completely positive review until I work out where they came from and how well they can be removed. But at a really good price point, this sound card seems to be ideal for those wanting to record in unusual places with a few condenser mics when no electricity supply is available. It makes for a recording set up I can carry in a laptop rucksack to the most inhospitable of places.
Using a B&O Beolit loudspeaker, I also made a number of impulse response recordings, which will allow me to both study and reproduce the acoustic of the cave. The 7 second reverberation time was really quite remarkable, and impulse responses will be posted on this site when they are ready.