New Documentation: An authoritative reference on the YM2612

Eke · Post by **Eke** » Wed Oct 22, 2008 4:16 pm

thanks for clarifying, that seemed odd indeed

Lord Nightmare · Post by **Lord Nightmare** » Thu Oct 23, 2008 4:43 am

ouch. whoever owned that megapc snapped capacitor c113 off of the MD isa card. SOMETHING is gonna work completely wrong until that is replaced.
EDIT: nope, once again I'm wrong. C113 is NOT SUPPOSED to be populated. see a later megapc plus card here: http://aycu14.webshots.com/image/27693/ ... 198_rs.jpg
It may have only been populated on some early cards.

LN

kode54 · Post by **kode54** » Sat Oct 25, 2008 11:24 pm

Commenting this line in the MAME fm.c source:

Code: Select all

//SLOT->volume = MAX_ATT_INDEX;    /* fix Ecco 2 splash sound */

seems to fix dropped or cut notes in the following VGM tracks, at least:
Dynamite Headdy - Geisha Robot
Bubba 'n' Stix - The Spaceport

Maybe something needs further testing?

Eke · Post by **Eke** » Sun Oct 26, 2008 11:38 am

yeah, I was wrong with this one (broke some other sound effects too) and reverted it some time ago in my implementation .... unfortunately, MAME used an older version as reference and there is still some mistakes (also probably in the new one)

and Steve Snake confimed the Ecco 2's sound "bug" was not a bug so...

Arbee · Post by **Arbee** » Mon Oct 27, 2008 1:36 pm

MAME 0.128u2 will be up to date with r157 of GenPlus-GX, including removing that "fix". Any ideas on the Battletech thing?

Eke · Post by **Eke** » Mon Oct 27, 2008 2:24 pm

for me, battletech track 12 sounds like Model 1 recording, probably not exactly (kega sound a little more accurate) because it requires better filtering but close enough to me at the moment

or were you talking of something else ?

Arbee · Post by **Arbee** » Mon Oct 27, 2008 4:40 pm

That's fine. I wasn't clear if it was a problem in the MAME code or not.

AamirM · Post by **AamirM** » Mon Oct 27, 2008 5:22 pm

Hi,

Eke wrote:for me, battletech track 12 sounds like Model 1 recording, probably not exactly (kega sound a little more accurate) because it requires better filtering but close enough to me at the moment

or were you talking of something else ?

Did you tried changing fn_max to something more suitable for 48000/44100 or whatever you run at?

Although I am not an expert on MAME but it seems MAME will resample everything to 44100...even if you set sample rate to something higher (like 48000).

stay safe,

AamirM

Eke · Post by **Eke** » Mon Oct 27, 2008 7:04 pm

what do you mean by "more suitable" ? I emulate the chip at his original frequency internally so I dont think I need to change the max value

this should be the job of the resampler/filter (and indeed, the gc/wii output samplerate is 48Khz)

Arbee · Post by **Arbee** » Mon Oct 27, 2008 10:53 pm

MAME will resample everything to 44100...even if you set sample rate to something higher (like 48000).

No, it resamples to whatever rate you set it to. I run MAME at 48 kHz (since that's the native rate of my Audigy 2) and it works fine.

AamirM · Post by **AamirM** » Tue Oct 28, 2008 6:22 am

Hi,

Eke wrote: what do you mean by "more suitable" ? I emulate the chip at his original frequency internally so I dont think I need to change the max value

this should be the job of the resampler/filter (and indeed, the gc/wii output samplerate is 48Khz)

Sorry, I forgot you used a resampler now

.

Arbee wrote: No, it resamples to whatever rate you set it to. I run MAME at 48 kHz (since that's the native rate of my Audigy 2) and it works fine.

Thanks for clarifying that up.

stay safe,

AamirM

Shiru · Post by **Shiru** » Sat Nov 01, 2008 11:23 am

About decapping and FM chips emulation: http://docs.google.com/View?docid=dd8kqn9f_13cqjkf4gp (OPL2 and OPL3).

HardWareMan · Post by **HardWareMan** » Sat Nov 01, 2008 1:06 pm

Shiru wrote:About decapping and FM chips emulation: http://docs.google.com/View?docid=dd8kqn9f_13cqjkf4gp (OPL2 and OPL3).

I wonder what they used for dissolve chip shell? I've heard, there is an liquid wich dissolve only plastic shell and did not touch the chip crystal. I would like to look at chip under a microscope...

Shiru · Post by **Shiru** » Sat Nov 01, 2008 1:26 pm

HardWareMan wrote:they used for dissolve chip shell?

They used MEFAS service. You can find list of equipment of that company on their page. Part of this list:

Package Decapsulation
Nisene D cap system
B&G 250 system

I think, you can ask Matthew or Olli about hi-res photos.

HardWareMan · Post by **HardWareMan** » Sat Nov 01, 2008 5:42 pm

Shiru wrote:I think, you can ask Matthew or Olli about hi-res photos.

I mean I want to look at YM2612 crystal not YM3812.