Spectrum Computing

Ah, I think I've found the solution.

I converted your turbo .TZX file with Tape2Wav 1.8 (I use this prgram for all .TAP to .WAV conversions and play the .WAV file in media player to the Spectrum) and found that it creates a .WAV file that is louder than Tapir.
I didn't need to add any extras to the header or gaps between the code blocks.

As per the screenshot


I also boosted your original Tapir .WAV file in Soundforge to match the Tape2Wav volume and that worked too.
It looks as if Tapir is outputting a .WAV file a lot quieter than it should be.

Hopefully solved.

Logic-wise, my loader doesn’t need as much time to sync up to the pilot tone. I just tested it with even shorter pilots and everything was hunky-dory.

Looks like the problem is in the analog circuitry. I’m not sure if the problem is inherent in the design on the +2’s tape head amplifier, the cassette adaptor you’re using, or your WinAMP/laptop. It seems there’s something akin to an auto-level adjustment circuitry that kicks in with a rather long relaxation period. It doesn’t like certain amplitude changes and tries to compensate. While it’s doing that, the ULA doesn’t get much in terms of an audio signal.

Could you test the TZX files themselves? How do you normally convert them to audio? Did you have problems with, say, Bleepload-protected games?

Addendum: I just cobbled together my own cassette adaptor (found and old tape head and soldered a lead with a 3.5 mm jack to it). I then held my adaptor head against the tape head in the Datacorder of my +2A and gave my loader a few tries, playing back the audio from my phone. I even played around with the volume setting just to see if that mattered. Everything loaded on the first try; no errors.

MatGubbins wrote: ↑Fri Nov 23, 2018 12:50 pm Ah, I think I've found the solution.

Cool! Disregard my previous post then. (I had it sitting a few hours before I edited and posted it, so I didn’t see yours.)

Tapir’s output is surprisingly close to what a real Spectrum would produce, but since it’s operating entirely in a digital domain, the amplitude is limited by your device’s output voltage/impedance, which, in modern equipment, is quite skimpy, compared to that of the ’80s.

Thanks again for your time and patience!

Nice loader! Did you compress data or just increase loading speed?

DenisGrachev wrote: ↑Mon Nov 26, 2018 9:40 am Nice loader! Did you compress data or just increase loading speed?

Thanks!

I only compressed the loading screen. The rest is uncompressed but the data rate is about 3x the standard ROM loader. It’s also more compact than the ROM loader, and can load only specific data blocks. Aside from ignoring the “wrong” high-speed data blocks, I also fine tuned it to ignore the standard pilot tone or long sequences of ones and zeros, so the they wouldn’t trigger it, either. A fairly robust beast all around.

I could make it even faster, but that would require testing it with real tapes (ideally of the poorer quality) and low-end tape players, to simulate a typical loading setup of the 1980s. The Spectrum’s ULA and analog filtering circuitry can handle fairly high data rates. The real bottleneck is the tape medium itself: the amplitude will drop dramatically (depending on the tape’s type and quality) as the frequency goes up. Besides, many cheap-o tape players had a cutoff frequency of about 6 kHz or even lower, so at least theoretically, my loader operates at the upper limit of what would have been possible back in the day.

A typical Type I ferric oxide tape can go up to, oh, say, 8–12 kHz. My loader peaks at about 6.3 kHz—well within the tape’s frequency range. These latest tests by Matt on his +2 and by me on my +2A demonstrate that the built-in datacorders in these machines are easily capable of loading data at the rate offered by my turbo loader. Whether the rate can be safely increased is subject to long and rigorous tests, which I’m not inclined to perform at the moment.

Still, three minutes for a fairly fat 128K game isn’t that bad, if I do say so myself.

Finished this ,frankly brilliant game, earlier today without any bugs or crashes.

stupidget wrote: ↑Sat Dec 01, 2018 7:17 pm Finished this ,frankly brilliant game, earlier today without any bugs or crashes.

Top stuff. Only one life lost? Did you play on bread and water, or POKE it? If the latter, did you BREAK the loader to do so?

R-Tape wrote: ↑Sat Dec 01, 2018 8:47 pm

stupidget wrote: ↑Sat Dec 01, 2018 7:17 pm Finished this ,frankly brilliant game, earlier today without any bugs or crashes.

Top stuff. Only one life lost? Did you play on bread and water, or POKE it? If the latter, did you BREAK the loader to do so?

I played it on my +2 using a DiVMMC so i took lots of snapshots

At last I had some time to sit down and play this properly. What can I say, it's simply great, not only the silky smooth multicolour scrolling tech and nice pixelart but the gameplay as well. The game design is also superb. For instance; I love how it introduces the 'switch-character' mechanic, the two are placed in separate rooms so when you've collected everything with the first character and got nowhere else to go, you look at the other room, notice the other character and try the fire-button, no instructions needed, just great! Had a lot of fun completing this. Great job!

Edit: Oh and also the pacing was excellent, having some more action-oriented levels after a particularly taxing puzzle level. Helps with the motivation.

ok, here is another one quick and dirty way to edit a levels in old tower
http://www.retrosouls.net/zx/!otCustom.zip

edit with charpad run a build.bat, enjoy a show!
there is a limitation with number of coins,enemies,guns and heroes on level, do not remember it right now.

kudos!

That's bloody brilliant Denis! Thanks for all your hard work!

Upload an Old Tower sources, as is:

http://www.retrosouls.net/zx/!otSrc.zip

have fun!

DenisGrachev wrote: ↑Wed Jan 16, 2019 5:36 am Upload an Old Tower sources, as is:

http://www.retrosouls.net/zx/!otSrc.zip

have fun!

That's awesome, thank you!!!

Hopefully your example will motivate more developers to release their source codes too!!!

This gane is mint.

Not much else to say

In case you missed we made a port to Sega Genesis\Megadrive with new levels and gfx.

https://retrosouls.itch.io/old-towers

https://youtu.be/otnIIrQYpbU

Cheers!