VOGONS


First post, by lordskylark

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I found a few topics on here, but I didn't come across anything specific (I may have missed it though).

SB Pro 1.0 uses two OPL2 chips, and 2.0 uses one OPL3 chip.

Some websites I have found claim that this causes no difference in the sound.
Does it really?
OPL2 and OPL3 seem to be different chips entirely.

I have some games that I want to record that were designed specifically for OPL2. If I get an OPL3 SBPro 2.0, it really will not sound any different at all?

I really would like to verify this beforehand.
Does anyone have recordings somewhere to specifically compare how each one sounds?

Andrew

Reply 1 of 16, by cyclone3d

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The only games that will sound different in regards to the OPL on the 1.0 vs 2.0 are the ones that were specifically written to take advantage of the dual OPL2 chips.

Yamaha modified setupds and drivers
Yamaha XG repository
YMF7x4 Guide
Aopen AW744L II SB-LINK

Reply 2 of 16, by bristlehog

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There is a difference in the sound: OPL2 is a 9-channel mono chip, while OPL3 is a 18-channel stereo chip. Thus, sound cards containing two OPL2 chips (SB Pro 1.0, Pro Audio Spectrum and few others) have to be programmed in a somewhat different way from OPL3 cards.

If you try to play OPL3 song on a dual OPL2 card, you will end up with mono sound. If you try to play dual OPL2 song on OPL3 - the result, I believe, depends on the engine delivering song data to the hardware. For AIL 2.0, right channel is missing, leaving us with only the left and center channel.

lordskylark wrote:

Some websites I have found claim that this causes no difference in the sound.

This is not true overall, but might be true in some specific cases.

lordskylark wrote:

OPL2 and OPL3 seem to be different chips entirely.

Not entirely: OPL3 is fully backwards compatible with OPL2. But it doesn't make an OPL3 card fully backwards compatible with _dual_ OPL2 cards.

lordskylark wrote:

I have some games that I want to record that were designed specifically for OPL2. If I get an OPL3 SBPro 2.0, it really will not sound any different at all?

If the games were designed for a single OPL2, you will not hear any differences related to the sound chip. However, there might be some sound quality differences caused by different sound path design and quality. E.g. Sound Blaster 2.0 is a very noisy card that is prone to coil whine and even mouse movements cause noise. Pro Audio Spectrum 16 is, on the other hand, very quiet card and its sound path is isolated from extraneous noises. So, if you move from SB 2.0 to a PAS16, there will be no differences caused by OPL3 itself, but there will be ones caused by overall build quality of the involved cards.

If the games were designed for a dual OPL2 card, you won't get right sound out of an OPL3 card.

lordskylark wrote:

I really would like to verify this beforehand.

This isn't hard, just play with DosBox, switching its sound engine between 'sb2' (single OPL2), 'sbpro1' (dual OPL2) and 'sbpro2' (OPL3) should show you the difference for any songs you want.

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Reply 3 of 16, by lordskylark

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So to summarize this regarding the Sound Blaster Pro:

A "Sound Blaster Pro 1.0 - Dual OPL2" will correctly play "single OPL2" but not single "SBPro2 OPL3"?
A "Sound Blaster Pro 2.0 - OPL3" will correctly play "single OPL2" but not "Sound Blaster Pro 1.0 Dual OPL2"?

Thanks,
Andrew

Reply 4 of 16, by Scali

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lordskylark wrote:

A "Sound Blaster Pro 1.0 - Dual OPL2" will correctly play "single OPL2" but not single "SBPro2 OPL3"?
A "Sound Blaster Pro 2.0 - OPL3" will correctly play "single OPL2" but not "Sound Blaster Pro 1.0 Dual OPL2"?

Yes, basically the stereo option between the two is not entirely compatible (you could set up the OPL3 to be mostly compatible with dual OPL2, but afaik nobody ever did that).
Also, there's an obscure feature of the OPL2, namely a sort of speech synthesis, which is not supported by the OPL3 either.
I don't know of any OPL2 software that uses it, but in theory, there could be software that uses this OPL2 feature, which would not work on OPL3 either.

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Reply 5 of 16, by bristlehog

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lordskylark wrote:

So to summarize this regarding the Sound Blaster Pro:

A "Sound Blaster Pro 1.0 - Dual OPL2" will correctly play "single OPL2" but not single "SBPro2 OPL3"?
A "Sound Blaster Pro 2.0 - OPL3" will correctly play "single OPL2" but not "Sound Blaster Pro 1.0 Dual OPL2"?

Yes.

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Reply 6 of 16, by lordskylark

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bristlehog wrote:

This isn't hard, just play with DosBox, switching its sound engine between 'sb2' (single OPL2), 'sbpro1' (dual OPL2) and 'sbpro2' (OPL3) should show you the difference for any songs you want.

I did some testing with this, and I'm not convinced that DOSBox accurately emulates these cards.

I tried every soundcard, and they all sounded exactly the same on DOSBox.

Also, when the SB16 is playing any SBPro stereo tracks, it should play it mono, but it plays it still plays it stereo.
Whereas my authentic SB16 card will not play any audio at all in that game if on the SBPro setting.

Andrew

Reply 7 of 16, by bristlehog

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What game it is?

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Reply 8 of 16, by lordskylark

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bristlehog wrote:

What game it is?

Might and Magic IV/V

I have SB16, but support for that is an afterthought as SB16 uses regular "SB" mode for music. (If you play the original demo, there's a note right at the beginning stating that the demo does not support OPL3 at all. And half of the music files from the demo go completely unchanged byte-for-byte in the final game, so I don't think the FM version of the music wasn't initially designed for OPL3.)

There is a specific Sound Blaster Pro mode though. I would guess it would have been optimized for the Dual OPL2 version, but I can't test.

Reply 9 of 16, by bristlehog

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MM IV and MM V don't support anything other than single OPL2. That is the reason you're hearing no differences.

Do not let 'Sound Blaster Pro' option in setup fool you. Hundreds of games support SB Pro, but just a couple dozens can do dual OPL2. You can find a list of such (not complete though) here: https://www.gog.com/forum/general/help_me_sor … _from_this_list

When I want to test something concerning dual OPL2, I usually go with Ultima Underworld, because it supports dual OPL2 and keeps its music files in XMI format which is easy to play. Note that Ultima Underworld 2 has dropped dual OPL2 support.

lordskylark wrote:

There is a specific Sound Blaster Pro mode though. I would guess it would have been optimized for the Dual OPL2 version, but I can't test.

It is not optimized so, and you actually can test: by switching sb2-sbpro1-sbpro2 in DosBox. You will not hear any differences, and that lack of differences is the result of the test. With Ultima Underworld, for example, you will hear the differences.

An example of a game that supports both dual OPL2 and OPL3 is Warcraft II. It has a separate set of MIDI files optimized for OPL, and compatibility with single OPL2, dual OPL2 and OPL3 is achieved by middleware Miles Sound System library.

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Reply 10 of 16, by lordskylark

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There must be some difference though...

If I select the "Sound Blaster" option, the audio is mono. (Using any card on DOSBox, and using my real SB16 OPL3 card.)
If I select the "Sound Blaster Pro" option (no matter what card in DOSBox), the audio is stereo, yet there are definitely instruments omitted from the song when compared to the "Sound Blaster" option.

Reply 11 of 16, by bristlehog

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lordskylark wrote:

There must be some difference though...

If I select the "Sound Blaster" option, the audio is mono. (Using any card on DOSBox, and using my real SB16 OPL3 card.)
If I select the "Sound Blaster Pro" option (no matter what card in DOSBox), the audio is stereo, yet there are definitely instruments omitted from the song when compared to the "Sound Blaster" option.

Is this all happening in MMIV/V?

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Reply 12 of 16, by lordskylark

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bristlehog wrote:
lordskylark wrote:

There must be some difference though...

If I select the "Sound Blaster" option, the audio is mono. (Using any card on DOSBox, and using my real SB16 OPL3 card.)
If I select the "Sound Blaster Pro" option (no matter what card in DOSBox), the audio is stereo, yet there are definitely instruments omitted from the song when compared to the "Sound Blaster" option.

Is this all happening in MMIV/V?

Yes. The best track I found to test this out on is the "end game" track in the ending. If you are not familiar with the game, there is a mirror in the very first town. If you type "showtime" you can view the endgame.

At 1:22 there is some sort of bassoon like instrument that plays in the "Sound Blaster" option. If you are using DosBox, no matter what soundcard, as well as my authentic SB16, this instrument plays here. (The output is also mono.)

If you use the Sound Blaster Pro cards in Dosbox and choose the "Sound Blaster Pro" option in the game configuration menu, it will play in stereo, but that instrument does not play. (My authentic SB16 only plays silence in the SBPro option.)

The music files themselves in the game are a uniquely designed format containing various soundcard configurations in the same file (so for example, in ENDGAME.M you would have all the instructions for playing that song with SB, SBPro, SC-55, MT-32, etc).

I'm not sure if the reason the bassoon instrument is not head at all in the "Sound Blaster Pro" option, is because the wrong soundcard is being used (I.e. Pro 1.0 vs 2.0, etc.), or whether the sound programmers programmed for it not to play in the "Sound Blaster Pro" setting in the game.

The game files contain different soundcard drivers... one for music and one for speech for each sound card. This is a list of the music drivers:

ADMUS(adlib)
BLASTMUS (sound blaster)
CANMUS (roland canvas SC-55)
IBMMUS
NULLMUS
PROMUS (Sound Blaster Pro)
ROLMUS (MT-32)
SPECMUS
TAPMUS
WAVEMUS (Wave Blaster)

Reply 13 of 16, by bristlehog

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I have no idea what music formats and driver system MMIV/V are using. Thus I'm going to be useless here. Your issues with missing instruments may come from DosBox possible inaccurate reproduction of SB family, or from other reasons.

If your goal is to verify whether you shall have issues with SBPro 2.0 and MMIV/V, you can try asking around to test that on a real card. Unlike SB Pro 1.0, SB Pro 2.0 cards are ubiquitous, thus you may succeed.

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Reply 14 of 16, by lordskylark

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Yes, that is basically what I am asking - is if someone could verify this or provide a recording. I would like to buy the appriopriate Sound Blaster Pro card, and wanted to make sure I should get 1.0 or 2.0.

Reply 16 of 16, by lordskylark

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cyclone3d wrote:

Gimme a few days and I can test both.

My guess is that DOSBOX is doing something that the real hardware would not do.

Any updates?