Does anyone here have a cassette recorder? I want to ask a favor of you.
I've written a program that converts data to an audio signal, and converts the audio signal back to data.
I currently have it working reliably with two different cassette recorders that I own, but I want to know if it works with other cassette recorders as well (since every recorder differentiates the signal in a different way).
I'll post a flac recording of the signal, and if you have a tape recorder, please record the signal on a tape, and link to a flac recording of the output from your cassette recorder.
Here:
https://my.mixtape.moe/shplje.flac
Anyone?
>>54752363
I have a recorder but I'll be near in an hour.
How about you tell about your technical sides of the program?
>>54752363
Nice ear rape. So is this just sstv but with anything instead of just images?
>>54752712
I wrote it in BBC Basic. It stores a binary '0' as a high amplitude wave and a binary '1' as a low amplitude wave.
>>54752729
I dunno anything about sstv, but yeah, it can take any kind of data.
>>54752363
I have troubles understanding what's so special about a 2 bit PWM triangle shaped signal with 3.14 kHz of base frequency and what's a tape recorder got to do with but the DAC of my soundcard
>>54752363
I have over 50 recorders and 20 tape decks (collection). Want me to test it on a few for you.
>>54754993
Yeah, if you don't mind trying it out. Record it on a tape, then record it into your comptuer from the tape using the same tape machine you recorded it with.
>>54755032
okay.
>>54754975
I think OP assumes (some) tape recorders distort the audio.
And he's probably right.
Anyways, storing data on cassette tapes used to be very common.
I'm sure there's still plenty of documentation about it available.
this seems really interesting even if I don't understand what's going on
>>54755064
>probably
there's no doubt both the recording operation and the nature of the tape media will distort the sound. it'll just add some arbitrary phase shift, cut the frequency components higher than 8 kHz at some filtering order and add a little bit of brown noise. nothing you can keep track of with a 2 bit input signal imo.
>>54755064
Yeah, in my tests with the two different tape recorders I own, the signal looks different depending in which tape player I used.
Okay, so I did with my crappiest recorder.
https://cocaine.ninja/upload.php?output=html
>>54755994
whoops
https://a.cocaine.ninja/lmcypw.flac
>>54756014
holy shit... the signal is totally distorted beyond all recognition. Maybe you had the input volume into the tape recorder set too high. Thanks anyway.
>>54756257
Nope, thats just how shitty the recorder is.
Can you post the code?
>>54756257
Let me just say the default tape loading system used by the ORIC-1 sucked donkey balls and closely resembles what you're using...
The BBC Micro used a better trick. (I mean, if you're writing it in BBC Basic you may as well just *SAVE to use it yourself! You'd want to use 6502 assembly language to process the raw signal fast enough.)
>>54755064
Yes, tape distorts the audio more than you might even want to believe. Think of it as bandpass 500Hz-2500Hz on a good day, with wow, flutter, phase all over the place, random volume fluctuations, god, everything. You're going to want to get the screwdriver and adjust the phase to get some 3000Hz+ frequencies back at least.
A lot of docs got thrown away. I know mine did from when my brother wrote his own tape loading system (with built-in XOR scrambling!). Common copy-protection thing, but block markers and checksums were luxuries that it was worthwhile to add too, so you could rewind and try again on errors... I even saw one with parity once.
>>54752363
uhmmm, whats so special about this? are you trying to recreate a c64 datasette or something?
or are you trying to improve the amount of data you can store on a normal tape?
>>54755994
Holy crap, someone else has that cassette recorder!
Mine's broken right now, but still. (Turns out putting it in your pocket with headphones inserted is an awful idea. Gotta get out the soldering iron. Blegh.)
Also, yeah, it's kinda crap. Speed is a bit all over the place. But it's nice for listening to music, anyways. Never tried recording.
>>54756826
Do you have any ORIC-1 recordings or know where I could find some? I'd really like to see what the signals look like.
>>54757030
just for fun project
>>54757172
Hey, that's pretty cool.
Mine had speed issues so I had to buy and replace the rubber belt on the inside. Works fine now except it records and plays terribly.
