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x-station / xstation-issues

Issues and support for the xstation optical drive emulator
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CDDA - Change in audio fidelity #168

Open KidDynamite85 opened 3 years ago

KidDynamite85 commented 3 years ago

The redbook music tracks sound excellent for a while and at some random point a subtle change in audio fidelity occurs instantly. When it happens the bass flattens a bit and the higher frequencies aren’t as crisp, it just sounds less lively overall. Someone who’s not observant or playing with a poor audio setup might not notice, but the music is not as robust as it is before the change. It sometimes occurs as soon as a few minutes after starting and other times it has taken over a half hour to come into effect. The change can happen between tracks or mid-track, probably about 50/50 in my experience, and is easier to notice when it occurs mid-track. It seems to be indiscriminate with regard to which track it occurs during, before, or after. Once the change happens all redbook music tracks are affected for the rest of the time the game is played until it is reset or powered off. I’ve booted the game about a dozen times using fast load and full load and it occurs every time. The only other redbook audio game I’ve played is Rayman and I did not notice the same change, but I only tried that game once.

This has been reproducible on two different SCPH-1001 consoles with 2 different x-station units, one purchased about 4 months ago, another about a year ago. Both units were installed by different people. Also tested with both Sandisk Ultra and Samsung EVO Micro SD cards, both formatted with SD association tool. My x-station is running current firmware from October 2021 and the failure also occurred on the previous firmware of both tested consoles. My Playstation did not present this oddity when it ran the original disc before modding. This happened to be the very first game I tested the x-station with as it is my most nostalgic on the console. Very hopeful this can be corrected.

ramapcsx2 commented 3 years ago

Yea, I can confirm that this happens. I've noticed it but it took me a while to realize something changed. I'm investigating and it seems to have to do with a separate audio sampling clock for CDDA. I'm working on this :)

ramapcsx2 commented 3 years ago

What I have so far: I made a test CDDA that plays a noise tone that can be viewed in the Caetla CDDA player. If this bug strikes, the FFT display goes lower by 10% overal. Sometimes a specific frequency band alone drops by 5%. This bug occurs randomly, at random times, sometimes not at all for several hours.

I assume there is a problem with the various I2S clocks in the system: Around the 1815Q chip and around the SPU chip. I'm trying to do something about it, with the current 1.4.4 version having some attempts to align more signals. So far it didn't fix it, but I've only noticed a while ago. There's still more that can be tried..

KidDynamite85 commented 3 years ago

Wow, this is awesome feedback so soon!! I’m glad to know this has been identified. Street Fighter Alpha is the only game that I’ve given a solid amount of time to. After posting the bug here I played the game again and probably had my longest run yet before it occurred, roughly 45 minutes.

KidDynamite85 commented 3 years ago

And thank you so much for your investigation into this, I wish you the best of luck.

ramapcsx2 commented 3 years ago

Thanks! Yea, the bug is insidious. It can take a long time to happen, and I have to have that test disk running with the FFT display to be sure. Otherwise, it can be hard to make out whether any given music is affected at a time ><

KidDynamite85 commented 3 months ago

Hi there. Was just checking back in to see if this bug is present in other models of PlayStation or just the SCPH-1001. I’m considering switching console revisions if the bug isn’t present in another model and if a fix for the SCPH-1001 is unlikely. Thanks again for your investigation into this, even without a fix your efforts are appreciated.

ramapcsx2 commented 3 months ago

Latest on this: Recently a few more sources of the bug have been ruled out, but the problem still persists. It will randomly degrade audio (or randomly not) on all supported consoles.

The new findings show that the DSP cannot be responsible for this, which reduces the possible sources to something that happens on xStation, and/or rather specifically, the APLL system.

I'm going to release the next update first, then do another deep dive on just this topic.

KidDynamite85 commented 3 months ago

Thanks for the update! It’s helpful to know that getting another console revision won’t benefit in any way, I’ll be sure to keep what I’ve got. Best of luck on the continued investigation. Thanks again.