This is really where the internet stands out. A personal site by a personal enthusiast. It's sad seeing similar stuff get stuck behind the facebook wall and disappear after a year or two. Great site and great job.
On the flip side, the people most likely to do things like this are also most likely to set up their own site somewhere and keep it running. For instance, http://www.windytan.com/ (Oona Räisänen) and http://tronixstuff.com/ (John Boxall).
Agreed - the other day I was getting nostalgic for this kind of thing, when ISP's gave you 2MB of space and an ftp account to do whatever you wanted with. I kind of wish that model had continued; maybe $45 a month for broadband and a microvps included for hosting your own stuff.
I had the opportunity to hear Marvin Camras, the inventor of magnetic recording, speak at a local Ham Club. The key idea behind recording was the idea of "bias", which was his invention. He brought a sample recording made very long ago, ant it was amazing how clear the sound was.
He had over 500 inventions during his life, most of them relating to recording.
Even for more recent formats there is a need I think. For instance I struggled a lot for recovering Video8 and Hi8 tapes [1], in the end I had to buy an old camera. I think it's the kind of thing it would make a great Kickstarter project.
Compared to magnetic tape wire recording is quite robust, which is why it's not surprising they've survived over half a century. The heat resistance is one of the reasons why wire-based recorders were used for aircraft CVR/FDR - the Curie temperature of steel is far above the point where plastic/organic-based tapes would be incinerated.
I can almost imagine a page titled "Recovering old family recordings made on aluminium platters" many decades from now... and wonder if the chances of success would be nearly as good. :-)
I absolutely love this kind of thing. I spent some time restoring an old 8mm projector so I could watch a few films I had found at an antique store. It felt wonderful to finally flip the switch and see the images flicker to life on my wall.
It's a shame the clips are so short, though. I'd really like to hear the rest of his great-grandfather's story.
It's basically the fore-runner of the tape recorder. The fields used are much higher strength (as is the wire speed), the steel wire used was processed to make it easy to magnetize.
There is nothing 'special' about it, it's just the same principle as magnetizing a needle with an electromagnet only you move the needle as you go and you alternate the current in the electromagnet with the sound you wish to record.
Then later when you move the wire past the head it will induce an electric current which you can amplify.
Why on earth would you transcode the recordings to mp3 -_- Flac is perfectly capable of decent compression and won't permanently damage these historical recordings.
2:1 is hardly what I'd call "good compression" for audio. At reasonable bit rates, MP3 is sonically transparent, except for the region above 15 kHz which is almost certainly not of interest in these recordings. This is the conclusion you get from doing actual scientific studies that compare the audio fidelity of different encodings, although if you have some data that uses human subjects which shows otherwise, I'd be glad to look at it. 8:1 or better is probably fine for recordings like this.
I thought that mp3 was not transparent at any bitrate for certain percussive sounds? There certainly are several other lossy formats which are though (e.g. AAC, vorbis, opus, musepak).
mp3 is far better than the source material here even at relatively low bit rates. So even though in principle you are right and flac would have been better it would also have been overkill.
Note that the files are not just stored but in this case also transmitted. And I know that the 'storage is cheap' and 'bandwidth is cheap' mantras are thrown about all the time and yet, I feel that it is perfectly ok to select your algorithms with care.
