Loading speed of cassettes seems to between 1200 and 2400bps

Rookie (20)

14-12-2015, 21:09

I'm loading some actual cassettes with a Philips NMS 1510. Most cassettes work and I just loaded the game "Flight Deck from Aackosoft". While I was monitoring the loading I notices that the pitch was higher than other tapes. After recording the tape on my PC I converted it with wav2cas and then back to wav with cas2wav. Interesting thing is that it resulted in a much lower pitched wave form. I then converted it with -2 argument to convert it as 2400bps but that is much faster.

So it seems that the Aackosoft game was stored as 1600-1800bps? Did this happen often on cassettes?

Does this mean that I can save a wave to any speed between 1200-2400bps? Could I even try to stretch it and try to load 2600/2700 bps?

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Par Philip

Champion (380)

14-12-2015, 21:44

As I was playing with baud speeds lately I found how the turbo 5000 cardridge sets the baud speed to 3200:

10 AD=&HF3FC:RESTORE 50:GOSUB 40
20 AD=&HF406:RESTORE 50:GOSUB 40
30 END
40 READ A$:IF A$<>"*"THEN POKE AD,VAL("&H"+A$):AD=AD+1:GOTO 40 ELSE RETURN
50 DATA 19,21,09,10,29,*

So try it But perhaps it's too fast for actual tape.

Par Manuel

Ascended (19691)

14-12-2015, 21:48

ramonsmits: yes, any speed will work, the BIOS circuit will auto-detect it. But there is some high limit of course

Experimentally I didn't get the baudrate higher than 3744 baud. Anything above that failed on several machines.

What is the maximum speed supported by Turbo 5000 and Speedsave 4000? Did someone try?

Par ramonsmits

Rookie (20)

14-12-2015, 22:01

If I have e wav file at 1200bps and I change to the speed 3x to 3600bps (nice integral multiplication) will it then just be detected?

The above baud speed config is only for writing or is it also needed for reading?

Par Wild_Penguin

Hero (644)

14-12-2015, 22:10

Years ago when I was playing around with a Goldstar FC-200, I could go slightly over 2400bps but not much (I needed to stay under 3000bps). So it might be model specific (maybe by some circuit difference), or I could have had bad cables or something else non-optimal with the playback setup.

Par Philip

Champion (380)

14-12-2015, 22:15

The above config is for writing, reading the msx should detect itself.

I was able to convert a 2400 baud wav file into 3200 baud by just speeding it up with sox (x 1.3333).
Faster wouldn't work but that may have been caused by the iPod nano I was playing it with.

Par Hrothgar

Champion (479)

14-12-2015, 22:35

Manuel wrote:

What is the maximum speed supported by Turbo 5000 and Speedsave 4000? Did someone try?

I didn't try, but my photographic memory served me well in telling me Turbo 5000 was mentioned in MSX Gids 17, and it says 4600 is the upper limit.

Par ramonsmits

Rookie (20)

15-12-2015, 08:57

I can faintly remember that I could set the baud rate to 1800 when writing to tape. I think a piece of code was listed in a MSX magazine.

That listing for the Turbo 5000, does that work on an MSX?

Par NYYRIKKI

Enlighted (6096)

15-12-2015, 09:41

I remember that friend of my had lost the original PSU of cassette player, so he used a variable voltage converter. By turning it to high enough voltage the cassette rotated much faster than normally, so the loading times were reduced quite a much.... Naturally I don't recommend this to anyone.

Par Philip

Champion (380)

15-12-2015, 10:13

ramonsmits wrote:

That listing for the Turbo 5000, does that work on an MSX?

Yes it does, Turbo 4000 is just software for the msx:
http://www.generation-msx.nl/software/arcksoft/turbo-5000/release/3459/