[sebhc] H8 tapes for Dave - archiving tapes?

[Dave Dunfield]

At 08:06 13/04/2004 -0500, you wrote:
>> >
>> >Input from anyone else on best practices for audio tape 
>> archiving would 
>> >be appreciated.
>> 
>> 
>> You can probably turn your .WAV files into a CD with any of 
>> the home audio recording packages, and then play them out of 
>> a CD deck. You can probably also play them straight out of a 
>> computer, although you might need an older sound card with 
>> built in amplifier (SB-16?) or use a small external amplifier 
>> to get the levels required for the input to the tape interface.
>
>Dave,
>
>Sorry - I should have been more specific - I'm recording using PCM at
>48KHz in 16 bit mono (I use Total Recorder). Is this the best choice for
>preservation in terms of lossless compression and common format? 
>
>Your point about playback amplification is interesting - how do I know
>or measure the "level" of the audio output? Can I scope the signal and
>measure amplitude? I guess I don't need to mention that I'm a pretty
>naïve audio guy.

Hi Jack,

CD quality (44khz 16 bit) has worked well for me, although I don't know if
it is ideal. I highly recommend that you also extract the data and store it
as a binary image ... The audio tracks are good for systems which do not
provide another loading means and I like to have the audio files so that I
can show a system working "the way it originally did", but keeping ONLY the
audio files it placing to much trust in an antique analog interface... If
you extract the binary code, you can always figure out some way to load it
if the tape board dies...

Regarding playback level - most modern sound cards provide only a line level
output, and are intended to drive amplified speakers. Most cassette interface
designs are driven by an audio amplifier intended to run unamplified speakers,
and the line-level is simply not strong enough. A small audio amplifier (or
amplified sound card) will essentially duplicate what was in the original
cassette recorder. You get the level right exactly the same way you did with
the cassette machine - start with a signal which plays at a good volume through
a small 8-ohm speaker without distortion, then "tweek" it up/down to find the
level most suitable to your audio board. This is one case where having a physical
volume control (not a drop-down menu) is a bit easier to work with.

Regards,

-- 
dave04a (at)    Dave Dunfield
dunfield (dot)  Firmware development services & tools: www.dunfield.com
com             Vintage computing equipment collector.


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