Volume issue in MiSTer cores

[mills32]

Hi, Thanks a lot for this great opl implementation :).

I noticed some opl/opl2 tunes from a lot of games do not sound as the original ones.

For example the music from terra cresta: 1 - Recorded from MiSTer core): Terra cresta_JTOPL.zip 2 - Original (vgmrips.net) click on "02 theme of terracresta": https://vgmrips.net/packs/pack/terra-cresta

I noticed the drums have very low volume on jtopl.

This opl implementation has been included in the pcxt core, so I made a vgm player for 8088 cpu, and the result is the same. I found a lot of themes with low volume drums, all of them seem to use the "percussion mode" of ym3526 (terra cresta) and also ym3812.

In percussion mode, the chip can output 6 melodic instruments and 5 percussion ones (which seem to output wrong, or at very low volume in the cores).

Another example is the Wacky Wheels intro theme (ym3812): 1 - Recorded from PCXT core, sorry this also has some clicks and noises, I don't know if this is a problem of the core, or the opl: WWHeels_JTOPL.zip 2 - Original (vgmrips.net) click on "02 Dream": https://vgmrips.net/packs/pack/wacky-wheels-ibm-pc-at

Thanks!.

[thehughhefner]

There are other cores that have reported issues with audio that uses jtopl:

Toaplan V1: Issue here

ArmedF Nitchibutsu: Issue here

Prehistoric Isle In 1930: Issue here

[thehughhefner]

Another core that highlights this issue: SNK68

[jotego]

Thanks for the detailed report. The volume for percussion operators should have been 2x. That is fixed in commit a217a0c.

[sherhacky]

@jotego At least for the Toaplan core, https://github.com/jotego/jtopl/commit/a217a0c45c772967f8330247d52fe4dbba5fbb58 appears to have only partially addressed the issue; here is a report with examples on that issue in Truxton, where it sounds like some of the restored instruments are too loud.

For reference here is the Stg 1 BGM from Outzone in the build with the fix in place; some percussion is still missing, and other instruments sound blown out/distorted compared to PCB.

[Toryalai1]

@jotego At least for the Toaplan core, a217a0c appears to have only partially addressed the issue; here is a report with examples on that issue in Truxton, where it sounds like some of the restored instruments are too loud.

For reference here is the Stg 1 BGM from Outzone in the build with the fix in place; some percussion is still missing, and other instruments sound blown out/distorted compared to PCB.

@sherhacky it is better if you open a new ticket here and reference this ticket

[atrac17]

@Toryalai1 but it's still the same issue. Why can't it can be reopened.

[Toryalai1]

You are correct. I’ll edit my comment. Thanks