GadgetUK
Ace Ghost Pilot
- Joined
- Sep 27, 2013
- Posts
- 1,323
I wanted to ask this of the wider community since I've got limited access to different MVS hardware. I've been wondering about some sound issues on MVS multicarts for a while now and in the first instance I put it down to dodgy NVPROM chips or the odd incorrect byte in the ROM images etc. I've started to question that thought due to the fact that it always seems to be related to PCM sound and nothing else. ie. I have a 161 in 1 which has very good sound, with only noticable glitches in Pulstar. I recently got a couple of 138 in 1s and for one or two games the sound can occasionally glitch, but not always. You can play say the title music of Ninja Masters and it can play perfectly. You can then power the system off and on and listen to it again and it can glitch on one note and be OK all the rest of the way through.
I've been told that some of the older slots are less reliable in terms of connection, and ultimately the board design - buffering etc. I am now wondering if some of the 1 slots have more of an issue related to sound vs some of the larger 2, 4 and 6 slot boards.
Has anyone experimented with these kinds of PCM issues on multicarts vs different MVS boards to see (or hear) if there's any improvement?
Part of me thinks its a glitch in the implementation - track layout, lack of bypass caps, FPGA / CPLD implementation perhaps inaccurate or some minor timing glitch etc.
But just to be clear, it is always sound, never P ROMs, S, C, or M. Seemingly just V ROMs only.
I've tested in both of my MV-1FZ boards and they behave identically.
All of that said, I can't discount that maybe there is the odd bit flakey in the ROM images, or maybe the odd lost bit in dodgy NVPROM chips, and possibly in C ROM it might not be visable, yet with PCM audio that 1 bit is enough to raise the volume.
It's also worth pointing out that the problem I hear is the volume goes loud on its own for that one note. It doesn't sound garbled etc, it increases in volume - almost double.
Starting to wonder if my board needs a recap or something as well - but then why does it only do this in specific games, and only from multicarts?
I've been told that some of the older slots are less reliable in terms of connection, and ultimately the board design - buffering etc. I am now wondering if some of the 1 slots have more of an issue related to sound vs some of the larger 2, 4 and 6 slot boards.
Has anyone experimented with these kinds of PCM issues on multicarts vs different MVS boards to see (or hear) if there's any improvement?
Part of me thinks its a glitch in the implementation - track layout, lack of bypass caps, FPGA / CPLD implementation perhaps inaccurate or some minor timing glitch etc.
But just to be clear, it is always sound, never P ROMs, S, C, or M. Seemingly just V ROMs only.
I've tested in both of my MV-1FZ boards and they behave identically.
All of that said, I can't discount that maybe there is the odd bit flakey in the ROM images, or maybe the odd lost bit in dodgy NVPROM chips, and possibly in C ROM it might not be visable, yet with PCM audio that 1 bit is enough to raise the volume.
It's also worth pointing out that the problem I hear is the volume goes loud on its own for that one note. It doesn't sound garbled etc, it increases in volume - almost double.
Starting to wonder if my board needs a recap or something as well - but then why does it only do this in specific games, and only from multicarts?