Some Genesis and Nintendo MP3s

You picked up my curiosity: what resampling library are you using ? From your posts, it seems to be something very similar to libsamplerate (http://www.mega-nerd.com/SRC/api_misc.html) which also has different quality levels (Fast, Middle & High aka "Insane") with detailled signal to noise ratio comparison charts.

I personnaly never found any really notificable improvment when using the High Quality filtering compared to the other ones, probably because the output (soundcard, speakers,...) is discarding the tiny SNR difference you may have. Maybe it would be interesting to post mp3s with the 3 quality level to see if someone can notice a difference. Beware of the placebo effect though ;-)

If you are interested, I got similar quality results using Blarrg's FIR resampler (which is also way faster) and from what I can tell, it sounds the same in term of quality than the mp3 you posted.

I tried out Blargs FIR filter and it has some small issues with some sounds, but the biggest issue was the interface isn't good enough for the amount of work I need it to do. I was also using his Blip Buffer for the SMS PSG before but it sounds a little muffled compared to how it is now (try it out in RC .720 and compare to previous when released). His stuff is certainly very fast though, and for the quality it can give at that speed it's a great library.

I just learnt the algorithms required, read some libraries and designed my own interface, until you do that it's like some magic black box that you have no idea what it's doing. Be warned though, it's some pretty technical stuff! I also had to rework a lot of my sound cores to work in floats/doubles instead of INT16's for increased speed (to stop translations back and forth).

You should release your emulator for Windows so I can compare RC to yours too :), I looked at the SDL release on your site but it doesn't work too well.

Mmm Good i downloaded and listened carefully all MP3 records, yes it sounds good, but it fast demo music and i can't say more about overall quality, if you make sound record from Sonic & Knuckles (intro) i completely appreciate it

I added S&K for you Sasha, hopefully that will do.

The game didn't work initually, I forgot that it checked for the other games in the place I was mirroring the game. Fixed it anyhow.

Strange it not have PSG at all, and sounds as Sega Magistr Drive 5.

It must be like this: http://www.megaupload.com/?d=XI9VQW5A

Do you remember what issues you had with Blargg filter ? I'm interested since it's actually very hard to track down every music in every games ;-)

If you coded you own resampling engine from scratch, that's indeed quite impressive, I still have my doubts it's so much worth the effort at the end regarding quality comparison with existing libraries but certainly an interesting & self-teaching challenge.

About releasing a better window port, well yeah, let's say the stability & usability of the program is the direct consequence of my poor Windows coding skills, sorry about that ;-)
I hope someday someone more skilled could make a real port, we are missing good & open-source emulators on computers.

Sasha is that a sample from a real MD? It sounds slightly echoey, maybe there isn't enough delay between YM2612/PSG in my emulator.

@Eke I can't name any Genesis games as none that I tested (about 40 or so) sounded too bad at all (fairly good), but when I started playing with SMS and NES which are much higher native sampling rates it began playing up. Personally I can definitely notice a difference in the emulator now even in Genesis in comparison to Blargs FIR filter, more with the cleanness of the sound, it's hard for me to explain.

It's also hard to notice a big difference compared to Kega which is the best sounding Genesis emulator in my opinion, but some sounds if you concentrate on it sound different in RC. The Kawasaki swoop part of the drum beat is a bit more scratchy in Fusion. I just need to get the mixing levels right between FM/PSG to finish it off. I've been digging into sound for two weeks now and I need a break from it.

This shows some small differences between Kega and RetroCopy v0.720 when playing Kawasaki . You can see in the highlights KEGA's phase filtering as it builds to certain levels whereas in RetroCopy it keeps them flat. Could be why KEGA sounds a little more scratchy in places.

I should probably determine if the PSG is in effect here because if it is you would likely see some voltage decay on the real machine that I'm not emulating yet. You rarely see straight lines like seen in the RC image on real machines.

Besides that the output looks pretty similar.

The effect you are seing seems to be some kind of DC offset removal (high-pass filtering) on square waves (I think those "drums" in Kawasaki intro music are using FM PCM channel, not PSG).

It definitively occurs on real machine as well (they deliberately placed capacitors on the output for that) so Kega is actually more accurate if it emulates this. Indeed, it will sound a little different, though I don't hear anything scratchy on my setup personnaly, drums sounds perfect to me.

This is sample is very accurate prototype of my real Sega MegaDrive2 (Europe version) emulated record from Regen 0.972.

Also i want show another records: http://www.megaupload.com/?d=1QCY7IYA

In some parts of music sometimes PSG sounds higher at 5%, my main task is show my console, she play music always at average volumes of FM, DAC and PSG...

In Kega 3.63 i hear very silent melodies, in Retrocopy 0.720 not hear PSG at all, and it currently close to my last console Sega Magistr Drive 5, she not have PSG too.

Eke doesn't really look like that to me, also the "Filter" option wasn't ticked (SuperHQ was though) which is I assume the high pass filter. Steve has said he compared output of his to a real system so maybe it's some kind of internal FM thing he is doing based on real tests. As to scratchy, that is just the word I put to the noise difference, I probably need a better audio vocab if I want to explain sounds.

Sasha, do you have any real samples from a Genesis connected through the headphone port?

About voltage of capacitors for real sega, my console have capacitors at 220uF 16V and automatically control average volume of PSG music, my console sounds as Model 1.01

I only have records from old VHS cassette, and i setup all volumes from these records, i can send you one MP3...

That's too many layers away for my liking Sasha. If you can manage to find any online (recorded on modern PCs with high SNR) it would be a good help.

Finally i found records, i connected VHS to TV tuner, and found side's of music for test's, sorry for bad quality, my cassette very old, 20% of VHS broken but most of records in safe...

http://www.megaupload.com/?d=ID39Z64W

This is my real third Mega Drive 2, sorry it only in PAL region record...

"Filter" option is actually a low-pass filter (you can notice how it sounds more muffled when enabled, my MD2 sounds even more muffled I'd say). I think Kega is either removing some low frequencies by default or it is reproducing square waves decay (I know it is doing it for PSG).

Next record with gameplay:

http://www.megaupload.com/?d=MFDYKCEA

Yeah Eke-Eke in your console it muffled, in my more weird only Mono signal from TV set and VHS, + 50Hz PAL with slow music, but i love my console, she more Retro than Sega Genesis

Next record with gameplay:

http://www.megaupload.com/?d=QIJME3LQ

Sonic the Hedgehog more than memory

And last records with cool music

Sonic 3D Blast:

http://www.megaupload.com/?d=KXMUTGOI

MUSHA:

http://www.megaupload.com/?d=C727TUMG

I found a small bug in the way I was doing my low/high amplication so the sound will probably be a bit better in 0.720. I also added a cutoff filter for removing low and high frequencies similar to real machines for those that want that (the specific high/low amount is tweakable in config.xml). This is done before resampling so that it isn't influenced by any noise introduced by it.

PSG now sounds OK? and next release will be on next day or two?

I'll know by end of tonight whether it's a tomorrow release or day after. Hopefully tomorrow. PSG sounds ok to my ear, but you can adjust level to suit.