Question re copying cassette tapes

[Keola Donaghy]

Aloha. I'll disagree with this. I work in the recording industry outside of my academic duties, and have played around a lot with this for our own audio archives.

It is always best, IMHO, to digitize at the highest possible resolution, and you can always down-sample for online use. I've A/B live and analog conversions that were done at the 44.1k and converted down to 22k. vs. those recorded at 22k, and there is noticeably (to my ears) greater clarity and depth to those that were recorded at the higher rate and down-sampled. We tried this with our Ka Leo Hawai'i archives, and even my colleagues who lacked the recording background could hear the difference on relatively inexpensive speakers. My songwriting partner has done the same with some of his commercial recordings, and found that he can clearly hear the difference when he records at 96k and down-samples to 44.1, as opposed to recording at 44.1.

I did the same kind of experiment with scanning. Try to scan an image at 72DPI, and compare it to one scanned at a higher resolution and then down-sampled. The down-sampled ones are much clearer. Programs like Photoshop will extrapolate based on the surrounding pixels to create an image that is clearer than what the scanning software will do if it scans at 72DPI - those don't take the surrounding pixels into account. Slightly different case case with audio. but similar results.

To me a big consideration is the digital I/O device. If the tapes are valuable, get an external converter (PreSonus units are relatively inexpensive but very good). It will make a huge difference over using the built in mic or line jack on any computers.

Re: mono recordings, agreed. However, if you record mono, make sure whatever format you are going to serve it as (or burn it to) will handle it properly. It's no fun listening to a mono track through one earphone, and some software encountered will do that, i.e., assume that the mono file is simply one side of a stereo track, and leave you with one ear listening.

My 2 cents.

Keola


On 2010 Pep. 11, at 13:24, William J Poser wrote:

> I'm not so sure about the recommendation of stereo digitisation. If
> the originals are not stereo recordings, there's no point in creating a
> stereo digital recording, and indeed, even if there are two channels
> on the original tapes, if they do not reflect inputs from two different
> microphones, you don't have a true stereo recording and there isn't much
> point in preserving two channels.
> 
> Also, 44.1 K samples/second is overkill for most linguistic material. If
> it contains music, such a rate may be desirable, but for most speech,
> 22.05 K samples per second includes all of the information likely
> to be of linguistic significance. 
> 
> 16 bit resolution is highly desirable, but there's nothing sacred about
> 44.1K samples/per second sampling rate and stereo. These are merely
> residues of decisions made by the music industry and have nothing to
> do with the quality of linguistic recordings.



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Keola Donaghy                                           
Assistant Professor of Hawaiian Studies 
Ka Haka 'Ula O Ke'elikolani             keola at leoki.uhh.hawaii.edu 
University of Hawai'i at Hilo           http://www2.hawaii.edu/~donaghy/

"Tír gan teanga, tír gan anam."  (Irish Gaelic saying)
A country without its language is a country without its soul.
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