I've been thinking for a while now about trying to make some really long recordings.
I got involved in a film project about honeybees some time ago, and as part of it I would really like to record the sounds and vibrations inside a bee hive. I'm also interested in the changes in these sounds over long periods of time - the colonies develop over the seasons from nearly dormant in the winter to tens of thousands of bees in the summer. This got me thinking about how amazing it would be to make a continuous recording of a whole year cycle of a bee colony. Imagine the spectrogram.
Now the beekeepers in question are not necessarily interested in opening up the hives to extract honey, so there's potential for the recording to have no human intervention. But the question of how to do it is a difficult one. I'd really like to have at least two mics in the hive, and I'd like to record uncompressed. A quick calculation of Stereo 48k 24bit for one year is 8.2 terabytes. In a way, I'd rather not rely on a computer for this but can't think of any other way. It's possible to build a RAID array of that size (with redundancy) and you could have a UPS system in case of power cuts, but I still don't like the idea of trusting a regular computer to this. The other question is some kind of recording software to write the files, it would need to automatically write and name files to fit them into the maximum file size for the OS.
Other questions are where and how to mount microphones? I'm thinking miniature omni lav mics, but the hive might need to be designed specially for these as the bees fill the entire hive with comb and encase foreign objects in wax! Another option is contact mics on the hive itself - that's actually quite an interesting route as the bees communicate in vibration across the comb itself.
I could visit the site every month to check it's still running, but it would need to be self sufficient between these.
So this is project is really still in the ideas phase, but I'd welcome any thoughts or suggestions.
Do you know of any tested techniques for making recordings of this length, or have any other ideas on how it might be done?
Is there any equipment designed specifically for this?
Has this been done before?
or anything else you think is interesting.
ps. I think they record the Longplayer installation continuously, so that's on my list to investigate already.
Thanks for the responses and interest. I think it's clear that I need to do some more research around this, and as it's such a commitment in terms of time it's worth getting right. I'm also wondering whether if done correctly this could also have scientific value, so I'm going to try and investigate that further. Similarly, options for mics etc need to be talked through with the beekeepers to find out what's acceptable for the bees.
The recording device is a separate and interesting issue though, as there seems to be no dedicated low cost option. Matt Glenn's suggestion of using a Sound Devices recorder is probably the most solid idea, but I don't think this project will have the funds for that solution. But forgetting my particular problem with the bees for a moment, I've been wondering what the reason is for? Are people not making long recordings because there's no call for them, or are they not doing it because the tool required is not easily to hand? Would the device inspire the use?
I like the idea of a device being designed to do this which you can build yourself from off the shelf parts that is relatively cheap and adaptable. I think it could potentially make a good open source project. I've also been looking for a reason to get involved with the Raspberry Pi for a while now and this could be it.
So breaking this down into components of a system, at the core would be a flexible recording system controlled by editable/configurable open source software. The spec could be something like this:
- Raspberry Pi running a minimal Linux distro on SD
- Custom PD patch for control and recording
- USB hub
- 2tb HDD (Raid1 over USB?)
- Basic USB audio interface
- Set of preamps for microphones
- LAN or USB 3g modem for streaming and/or remote desktop/control
- Power supply
- 4-5" touchscreen for display/input
Now, I'm not 100% sure about this, but with careful choices I think you could power that from a battery and you could charge the battery with a solar panel. Build this into a case and you have a system which can be installed and left to run independently. Build a weatherproof case and you can leave it anywhere (although I'm not sure about protecting the mics from rain.. any ideas?). By adapting the casing and mic setup you could then create different designs for different purposes, for example you could add a parabolic dish for focused recording of one point or add two hydrophones and record a whole season in a pond or even build it all inside a binaural head...
If you're using PD for this there's also potential for expanding the system to take input and respond to external factors. Add an arduino talking to PD and you can use sensors to detect rain, temperature and sunlight, move parts of the system (like mic positioning) with servos or other motors for example. Even record other data as text. Think recording robot.
I can't say that I think I can do this myself – I've had some experience with Linux, PD and some basic Arduino interfacing, but my knowledge of electronics is pretty basic for one. But it could be a community project run from a Wiki which anyone could contribute to. Perhaps of interest to design students as well as sound recordists. The Wiki could suggest tested parts and configurations, provide install guides and software etc.
Well I'd love to hear your thoughts on this. Is it possible? useful? Do you see any serious problems? solutions? Would you contribute?