Best way to preserve audio tapes?

[RodCastler]

Hi all,

 

I have these educational cassette tapes from back in the day I want to preserve.

 

They are atari basic programs that show text on screen but also control the tape, allowing for audio to come out after the program is properly loaded.

After the audio piece is played, it stops the tape allowing you to interact with the program until a point where the next program would be loaded sequentially, then more audio, and so forth. In other words, a sequence of software+user interaction, audio, software+user interaction, audio.

 

It seems to me that both data and audio are in the same channel, but I'm not 100% sure, it may be a left-right channel combination.

For this very reason, I am not sure about the correct preservation method.

 

1) Can you provide any pointers to some post or website with the right setup to record the wav files?

2) What would be the right way for an emulator to deal with such a format? I don't think .cas would work correctly on a hybrid tape. Which format should I aim for when I am finished with the wav file recording?

 

Thank you

Edited November 16, 2015 by RodCastler

[fujidude]

I'm pretty knowledgeable about audio recording, at least as it pertains to home uses. I'll lay out some info, and please ask questions if you have them. Atari style cassettes are the same as home audio cassettes, and are used at the same speed too. This means you can use cassette equipment designed for home audio use to duplicate, or digitize your Atari cassettes.

 

Your suspicions about audio and data being on distinct tracks (left/right)is correct, though I suppose there is nothing stopping one from putting audio on the channel normally reserved for data, if it is after the data part is finished. I believe the Atari will relay the sound from both channels to the user through the Atari. Perhaps it sums the channels to mono, or maybe not. Hopefully someone who is knowledgeable on the Atari cassette drives and system can chime in here and educate us all.

 

Anyway, the good news is that one doesn't necessarily have to understand those kinds of issues, because duplicating or digitizing the originals can be done without really caring about that. So what you want is a stereo cassette deck that you can hook to your computer's line in jack, and audio recording software which will create waves. I suggest "Audacity" for that purpose. It is very capable and is also free software.

 

• Set the input level so that it is peaking at 0 db. Use 44.1KHz, 16 or 32 bit, stereo wave file settings. Default is 32 bit float on Audacity. That works good, but 16 bit is a standard.
• Be sure to not engage any Dolby NR on the deck, as Atari recordings do not use it. Be sure to set bias on the deck to match the cassette if it doesn't have auto sensors. Standard Atari cassettes are normal bias.
• Trim off excess recording at the beginning and end.
• Save your wave file.

[+Stephen]

Sounds like these are the Dorsette Educational tapes. I believe these have all been preserved. Do a search here - the format has also been completely reverse engineered and new content can now be created.

[Bryan]

Your suspicions about audio and data being on distinct tracks (left/right)is correct, though I suppose there is nothing stopping one from putting audio on the channel normally reserved for data, if it is after the data part is finished. I believe the Atari will relay the sound from both channels to the user through the Atari. Perhaps it sums the channels to mono, or maybe not. Hopefully someone who is knowledgeable on the Atari cassette drives and system can chime in here and educate us all.

 

The 410/1010/etc.. is a stereo player. One channel is fed to the SIO audio pin and one channel is decoded as data. This way the Pokey loading noise can be muted so you can hear the audio clearly. There is always some residual loading noise is because the channel separation isn't perfect and the SIO cables are also a bit leaky.

 

So, the tapes must be duplicated in stereo using well adjusted decks.

 

(Teddy Ruxpin worked the same way!)

[RodCastler]

Fantastic, that's what I needed to know. Thank you.

 

And Stephen thank you for your suggestion but the ones I have are not Dorsette, but a set in Spanish made exclusively for the Chilean market in the eighties, so they are not easy to find.

 

What would be a good repository for this kind of wav files? Is it archive.org?

 

Best,

 

Rod

Edited November 16, 2015 by RodCastler

[+Stephen]

Fantastic, that's what I needed to know. Thank you.

 

And Stephen thank you for your suggestion but the ones I have are not Dorsette, but a set in Spanish made exclusively for the Chilean market in the eighties, so they are not easy to find.

 

What would be a good repository for this kind of wav files? Is it archive.org?

 

Best,

 

Rod

Oh wow - great find. Hope you manage to get them archived!

[djmat56]

Hi Rod

 

I'm part of the Preservation group on here and have contributed loads of tape dumps to this date and still going (so many to do!!)

 

If you record them as described above - stereo .wav file but make sure its 16 bit as 32bit is a waste of bandwidth and won't work with Altirra.

 

Once recorded send them to me here and I can check them for you and make the necessary edits and upload them to my folder

[charliecron]

 

I have these educational cassette tapes from back in the day I want to preserve.

 

 

Make a copy of the tape, onto another tape! I know your wanting to preserve, convert, and emulate. But don't forget the obvious A well recorded tape, properly stored, will last decades.

[fujidude]

 

Make a copy of the tape, onto another tape! I know your wanting to preserve, convert, and emulate. But don't forget the obvious A well recorded tape, properly stored, will last decades.

 

While true to an extent, it is just kicking the can down the road. And that road leads to places where there are fewer and fewer cassette decks.

[RodCastler]

 

While true to an extent, it is just kicking the can down the road.

 

I agree. Besides, one of my objectives is to have the tapes available online for whoever wants them.

[devwebcl]

how many titles do you have ?

 

http://manillismo.blogspot.cl/2011/08/telematica.html

[F#READY]

Before digitizing, please make sure the tape head is clean or clean it e.g. with a Q-tip and isopropyl alcohol.

[djmat56]

 

I agree. Besides, one of my objectives is to have the tapes available online for whoever wants them.

 

forgot to mention.....if you send them to me they will be put with all the other dumps that are currently being collected and will be available to everyone

[ACML]

My solution for audio tape preservation is the Nudmehi Cassette boot maker. It turns any disk executable into a cassette. It's pretty nice. It makes a short binary loader (about 8 beeps of the 410) and immediately starts the actual game load. No worries about analog audio signal degradation or storing huge amounts of cassettes. Need to re-write the game, just load it in Nudmehi and you have a perfect pure digital to analog copy whenever you want one.

Nudmehi cass boot maker.xex