Audio quality of 1Chip and Zemmix?

Page 1/2
| 2

By selios2000

Champion (421)

selios2000's picture

16-09-2015, 11:29

Hello all!
I've been listening some musics (FM+SCC) with the OpenMSX emulator for MAC and comparing them with a real MSX.
The result is that the sound quality in MSX is far better!!
So my question is if the "emulated" FM and SCC of the 1Chip and Zemmix has good quality or it is the same as the originals.
Thank you!

Login or register to post comments

By Grauw

Ascended (8192)

Grauw's picture

16-09-2015, 12:57

The 1chipMSX’s SCC implementation is quite ok as far as I know. I’ve done a few side-by-side comparisons in the past focusing on the small click you get from changing frequency (FPGA implementations don’t have it, real SCC and openMSX do, my verdict is that it’s better without). Although I wasn’t looking specifically into the similarity of the waveform characteristics (high harmonics, especially), I don’t recall any large differences standing out to me. Though I should do another listening test sometime. Nevertheless, because the SCC is also a relatively simple sound chip, it is fairly easy to emulate.

FM is quite a different story though. For one thing the exact ROM tone settings aren’t known, also I think there are imperfections in the FM emulation. Wouter from team openMSX is doing research into improving the emulation, but for now it’s a good approximation but there are some problems. As a result, FM music can have some noticeable differences, e.g. the swirly sound and the bassline in the 2nd Illusion City opening sound much better on a real MSX compared to an emulator (haven’t tried that one on 1chipMSX).

And of course there are also differences caused by different analog audio circuitry between the SCC/FM and the MSX audio output, this analog circuitry is different for each MSX so it can change the characteristics of the sound (e.g. a different filter can result in brighter / more dampened audio). And the PC output is typically generated by a DSP-based DAC which is quite different from the resistor-array of the SCC. Let’s also not forget the absence of that lovely interference hum on the PC Smile, it’s got a much lower noise floor. Also MSX-MUSIC uses a quite typical way to mix the channels which would be hard to emulate exactly on a PC. I think FPGA emulations are more comparable to the real thing in that regard.

By AxelStone

Prophet (2662)

AxelStone's picture

16-09-2015, 13:32

I have not played too much with Fm games in 1Chip, but I've played some SCC games and the quality is very high. I'll try some FM games and will comment impressions.

By Manuel

Ascended (15531)

Manuel's picture

16-09-2015, 14:24

selios2000: can you be a bit more specific what kind of differences you heard?

By selios2000

Champion (421)

selios2000's picture

16-09-2015, 14:27

Thank you guys.
I'm afraid I'm not so perfectionist to distinguish among different MSX audio outputs, so I assume that average good real quality is played Smile. I think that 1Chip and Zemmix do not have interference hum, but the MSX audio output is high enough to not take notice of it while listening to the melodies.
The point is that I'm thinking of buying the Zemmix Neo, (no sound interference at all and VGA output) but I'm afraid if real sound hardware is far from being reached or it is just emulated at a 90% exact quality, for example. In that case, would be a good decision to buy it, because I think that it is impossible to be 100% the same.

By Grauw

Ascended (8192)

Grauw's picture

16-09-2015, 15:03

selios2000 wrote:

I think that 1Chip and Zemmix do not have interference hum

Oh, they do, quite a lot. It’s not unacceptable for playing games etc., but for audio production it can be annoying. Interference from the video output is strongest, using a dark colour scheme (like COLOR 0,0,0) eliminates most of it.

selios2000 wrote:

but I'm afraid if real sound hardware is far from being reached or it is just emulated at a 90% exact quality, for example. In that case, would be a good decision to buy it, because I think that it is impossible to be 100% the same.

I don’t think the FM and SCC emulation quality is a reason not to buy a Zemmix Neo, it’s good enough and quite convenient to have built-in. If needed you can always plug in an external FM or SCC cartridge, external audio is output separately on (I believe) the red audio channel.

I would not use the Zemmix Neo’s built-in FM to compose music with MoonBlaster though, I’d make sure to use a real OPLL FM cartridge for that.

By selios2000

Champion (421)

selios2000's picture

16-09-2015, 17:59

Graw, but, if you use the audio output and the video only for image display (turning off sound of tv), it also has interferences? I don't understand... VGA do not have audio signal doesn't it?
You mean that Zemmix or 1Chip connected via VGA and RCA audio output has got sound interferences? Sad
I have a FM PAQ Cartridge. But I'm afraid that the internal one and this will be mixed and maybe the sound would be rare??
OMG!

Manuel: the difference is in depth, overall quality. It seems that the emulated ones sound like a very compressed mp3 compared to a CD, loosing nuances.

By Grauw

Ascended (8192)

Grauw's picture

16-09-2015, 19:14

selios2000 wrote:

You mean that Zemmix or 1Chip connected via VGA and RCA audio output has got sound interferences? Sad

Yes, due to crosstalk on the main board.

The same applies to many MSX computers btw. Some are better than others.

By tvalenca

Paladin (728)

tvalenca's picture

16-09-2015, 19:45

If I'm not mistaken, @Parn found some issues in PSG sound quality on both Zemmix Neo and OCM. He promissed more tests, because he found the issue at MSX-Campinas meeting. (Sept-05 trhu 07).

By selios2000

Champion (421)

selios2000's picture

16-09-2015, 19:35

What a pity Sad
So it seems that our "old" MSX computers must live for more years as new hardware has the same "errors"...

By Meits

Scribe (5439)

Meits's picture

16-09-2015, 22:00

I decided to buy an OCM because of the video noise in the audio... I was very disappointed when I heard it... OCM is not at all an improvement on audio output...

Page 1/2
| 2