Difficult ZX81 WAV-file with cassette-tape sound

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MOB-i-L
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Difficult ZX81 WAV-file with cassette-tape sound

Post by MOB-i-L »

I have a ZX81 WAV-file that I cannot convert to a digital TZX-file using EightyOne: http://www.df.lth.se.orbin.se/~mikaelb/ ... _tatws.wav (i.e. week-end_at_cwm_tatws.wav in http://www.df.lth.se.orbin.se/~mikaelb/ ... b-i-l/tzx/). It sounds OK but in EO it looks strange. It would be good if I could get help decoding it and if you could say which program and settings you used.
Last edited by MOB-i-L on Sat Oct 26, 2013 9:55 am, edited 1 time in total.
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RetroTechie
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Re: Difficult ZX81 WAV-file with cassette-tape sound

Post by RetroTechie »

170M file size warning (32"16s, 44.1 kHz WAV) would have been in order... :o Btw you could convert to 8-bit samples - good enough for this purpose, cuts the file size in half. Cut 7 mins. of noise from the end, and perhaps rar/zip it up. :geek:

I loaded it up in audacity to have a look at the waveforms, and tried loading into a real ZX81. Also tried a few small edits here & there to help loading. But wasn't able to load anything, my ZX81 latched onto the signal but always bombed out in one place or another.

Problem is clearly with the recording itself: lots of dropouts, 'random' volume changes (loading patterns showed a 'pumping' effect in places, which to me suggests a problem with how tape runs in the recorder), a recording for some other system in the middle, etc. Not surprising load from WAV in emulators, or conversion utilities fail on this one.

So either the tape itself is very bad (which you can't fix), and/or recording to WAV equipment+process could use improvement. Probably more trouble than it's worth. Unless you know there's something really interesting / unique / valuable on it, I'd consider this tape (the recording on it, that is) a goner... :cry:
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XavSnap
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Re: Difficult ZX81 WAV-file with cassette-tape sound

Post by XavSnap »

Hi,

I will try to retrive codes...
But the sound quality is poor. (Symetry and loodness)
:D
This Mickel Bonnier's program (SEQUILL) can be rebuild !!!
Xavier ...on the Facebook groupe : "Zx81 France"(fr)
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XavSnap
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Re: Difficult ZX81 WAV-file with cassette-tape sound

Post by XavSnap »

Hi,
... ??? SEQuill ??? ...
... Wrong !
"Med tanke pa av en Handelse"... !!! TRFO COMP !!!
It's a "Glosa"... and my English is too poor to debugg this program. :D

Have a look to the 2nd Bloc : http://zx81.ordi5.free.fr/programmes/WEEK-END.zip
(The 1st blocs is a backup!)
I dont have a look to next blocs, but let me know if the bloc header is different!!!

(Can you put your waves files bloc per blocs ? I can't download the full wav!)

ToDo: > Tools: Goldwav (Lood harmonics) and ZxStectape (symerizer)
So either the tape itself is very bad
I ever seen worth !!! :twisted:
http://zx81.ordi5.free.fr/wav/
Xavier ...on the Facebook groupe : "Zx81 France"(fr)
MOB-i-L
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Re: Difficult ZX81 WAV-file with cassette-tape sound

Post by MOB-i-L »

Thanks for restoring the tape. There are a lot of spelling-errors in the data but this is probably due to the bad tape. I think this program is slightly improved over the earlier glosa.p and it contains data. It's used to exercise a word-list from a chapter from an English-textbook for Swedish speakers. It's not very important but still interesting to me. Maybe there were more programs on the cassette tape. I have another tape which is equally bad which may contain more interesting programs.

I don't have GoldWave, only Audacity, but I could get other free software.

Can't you download the full wav-file or why do you want it splitted into many smaller files?
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XavSnap
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Re: Difficult ZX81 WAV-file with cassette-tape sound

Post by XavSnap »

Hi,

"ZxSpectape" as been updated.
A new "waves tool" able to correct a wave file.
It able to count beeps, correct the symmetry, azimuth ... and decode a ZX81 file !
Have a look to the infos.html file inclued in the zip file.

http://dskcenter.free.fr/Download/ZxSpecTape.zip
Updated to 6.1
Have fun!
Xavier ...on the Facebook groupe : "Zx81 France"(fr)
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