I've decided to put this how-to document together to help you to load in your plus/4 tapes. It's fairly hard to do, but once you've found a setting that works, you can load everything you have!

So, first I'll start with the overall theory, and how you should start. Firstly if you have an old MONO tape deck, thats probably the best thing to use - saying its still in good condition and gives out good sound of course. You will then have to find some sort of program to sample with; I use the excellent GoldWave. Next you need to make the actual sample..

How to Sample

Not as easy as it sounds. Recording is fairly simple under most operating systems these days, but for our tape we need to record an 8-bit sample. I use a SIGNED 8-bit sample. that is 255 is MAX and -127(0) is min, with 0($80) being no level or sound detected. I also sample at 44,100Khz. I also make sure the sample is MONO. You should then save this as a RAW file, with now WAV or VOC (etc.) header. If you are VERY (very, very, very!) lucky, this will do... however... :-) Doesn't usually work that way. SO!

Problems, and how to spot them.

a good sample should look something like this:

Notice each point goes all the way to the top and all the way down. Tapes are effectively recording zeros and ones, and the best way to show that is with values of 255 and 0 in the sample. If the tape was totally perfect you would get rectangles of up and down, with no "nobbily" bits. Looking at the sample above, you can see on the lines there are almost rounded ends to some of the peaks and dips. this is due to the tape itself (and perhaps the tape recorder). And this is what we must guard against.

The overall look of a tape should look something like this, it shows 3 clear blocks. The first is the header, the next is the turbo loader and the last is the actual program itself. The main problems are usually visible from this kind of view. dips in the volume are easily shown since the solid areas show.
(not all tapes have 3 blocks, some more, some less)

Shown here is a minor dip in volume, but this is enough to stop a load. A simple and small volume variance can be overcome with the minus4 volume threshhold command line switchs -1 thru -5. This sets the edge detection lower so you can (hopefully) ignore these volume changes.

Echos

The other thing to watch for is "echos" If you have a stereo tape deck or hi-fi, these system monify the sound before you hear it. In a normal tape, its mono, but a stereo will split the sound to both speakers giving a dull sound, without the crisp edges the computer needs to pick out 0's and 1'. The taoe deck MUST be set to MONO, and there must be no feedback from it either. Some tapedecks even if the balance is all the way over, you may still hear "part" of the other speaker. This gives false echos and again the edges are not what they should be. This is easy to spot, but you can't tell from looking at the sample this time, instead, you'll have to listen to it. Download my test tape and play a section of it, now play yours. Do your hear anything different? The samples may either have a definite echo, delay, muffling or just be not quite as crisp a sound. Rember to switch off and graphic equalizer as well, since all these kinds of equipment modify the base sound and distort it.

Volume

You should have a good volume setting, too much blasts the sounds, and the sampler starts to pick up noise. too little and you don't get the peeks right, and you'll get dips in the sample. This is the hardest one, since it varies for each tape. But the settings are usually very close. Also, even though your in a powerfull sampler, with great editing... don't be tempted to boost the volume artificially, it simply doesn't work. what ends up happening is peeks and dips are closed as a close number to the peek threshhold (say 191) where minus4 would ignore it and start looking for a 0, is turned into a peek (say 194). This means in a sequence like this...

would turn into this...

If you think of 191 and 65 as being dead zones, and the time from the last "peek" to he next "dip" as being the important fact, what you amplify has done is reduce the distance from a peek to a dip. this means the loader can't find the correct spacing of 1's and 0's. This is bad. :-) So, just stick with the tape deck volume, and balance. Also remember your sound system also has a recording level, and sometimes a "gain" control (this should be set to times 1 - or no gain assistance).

I hope this has helped, and you've now successfully managed to load in your old favorites. If you're still stuck after trying all this, drop me a line and I'll see if I can help.