c2t-96h fails, 8000 c2t works

[majick]

I've yet to produce a file from -96h (or any other 9600 file) that loads. Consistently all fail checksum and dump to monitor. I've tried this from multiple output devices, at various output levels, with the same result. I've tested this with my 65C02 and 6502, and with the full enhancement kit installed or not. Nothing seems to get 9600 to succeed.

I know the intent was for -96h to be quite a bit more compatible hardware-wise but I think I've got an outlier here. Anything that'd be useful for me to test or experiment with to narrow things down?

[majick]

I guess a little more detail might be slightly helpful:

master branch, as of c7f3d16

//e, both unenhanced and enhanced, barebones with nothing but OEM 80 column card and OEM disk II card. I'd have to crack it to get revisions, but considering it came unenhanced that means it's a little early.

No 9600 file from any source, mine or anyone else's, has succeeded, regardless of method of creation.

[datajerk]

9600 and 8000 should work on all apple 2s where one of them works. What breaks 9600 is the player. Some players do not like the 1/2 cycles used to get 9600. What are you using to play the audio?

[majick]

Two devices have been used as sources, with identical results: an iPhone 11 via lightning-to-1/8" adapter, and an iPad Air 4 via USB-C-to-1/8" adapter. Various pieces of software have been tried for playback on the off chance something clever was happening on the software side: VLC, FileBrowser PRO, Apple Files, and I think at one point we even took a crack at transcoding to FLAC, texting the file, and playing it out of the Messages client.

The DAC in the lightning-to-1/8" in particular is generally fairly well regarded although I don't know if it's well regarded for this particular purpose.

[datajerk]

Avoid transcoding, that will surly fail. Apple Files with iPhone X and lighting-to-1/8" I can confirm works; it's how I do testing. I will test again this weekend, perhaps something changed in the latest iOS.

[majick]

Just as a side note, and obviously orthogonal to this particular issue I'm running into: FLAC at 8000 works totally fine, amazingly enough.

The only reason we tried it at 9600 that time was to avoid Messages "helpfully" transcoding to AAC, which I had no idea it would do to a WAV when texted. On the off chance that Messages had a different playback code path it was one more thing to try.