On Sat, 18 Jun 2005, Scott Stevens wrote:
A somewhat 'crude' but simple thing you can
try is to listen to the
audiotape sound of the tape you created which you say was successful.
Then listen audibly to the tapes you're trying to recover. If the pitch
seems to match for the most part it isn't a speed problem. If you have
an oscilloscope, look at the amplitude of the signal out of the cassette
drive of the new 'working' tape and compare to the one you're trying to
recover.
As others have suggested, use the simplest tape player you can find.
Noise reduction circuits and other fancy technology will only cause
problems.
I haven't done this, but there are decent tools
nowadays for what could
be called 'high performance audio editing' that you can throw at the
problem, if you use your sound card to digitize the audio to a WAV file.
I use Cool Edit 2000 (much less expensive than full-bore Cool Edit,
probably no longer available) for audio work. There are a LOT of
powerful tools for fiddling with audio now that we have all the
horsepower for DSP that a modern pee-cee provides.
I recommened Total Recorder. It's inexpensive and the folks that develop
it are very nice. They've allowed me to upgrade to new versions without
any additional fee, and they're very responsive through e-mail. I
registered it years ago to use for recording VCF talks but never used it.
I recently started using it to digitize audio tapes and find it very nice
to use.
Somebody should develop an 'audio datacassette
emulator' for the kind of
thing you're trying to do. I have a T/S 1000 that I'd use more if I had
something like that to use with it. Ideally it would even have a
'remote on' input, i.e. the TRS-80 Model 1 could turn the drive on and
off directly.
I have a device that you plug inline between the tape player and the
computer. You then turn up the volume all the way on your tape player and
it normalizes the tones so that your computer gets a perfect read
everytime. I forget what it's called but I'll check it out later today
and report back. It's specifically for the TRS-80 so I don't know if it
would work on every computer with different encoding schemes..
--
Sellam Ismail Vintage Computer Festival
------------------------------------------------------------------------------
International Man of Intrigue and Danger
http://www.vintage.org
[ Old computing resources for business || Buy/Sell/Trade Vintage Computers ]
[ and academia at
www.VintageTech.com || at
http://marketplace.vintage.org ]