Opened 19 years ago

Closed 19 years ago

Last modified 6 years ago

#1947 closed defect (fixed)

DOTT/SAM: GM Instrument Chorus Level Improperly Set

Reported by: SF/tbcarey Owned by: eriktorbjorn
Priority: normal Component: Engine: SCUMM
Version: Keywords:
Cc: Game: Day of the Tentacle


While investigating bug #1159518 [], I discovered that the instrument chorus levels for the two SCUMM games that use General MIDI natively [Day Of The Tentacle + Sam'n'Max Hit The Road] are improperly set to 64 for every single instrument, while the original interpreters for both games set every instrument to chorus level 0 consistently throughout the game. Global chorus level remains at 64 in the originals as well, so that doesn't need to be changed. I was able to easily track these differences via the display on my SC-88.

Ticket imported from: #1159734. Ticket imported from: bugs/1947.

Change History (14)

comment:1 by eriktorbjorn, 19 years ago

Since that old bug is in danger of being closed as invalid (since it was primarily about the tweeting bird in the DOTT intro), I'd better add this comment here as well:

The Part::sendAll() function in scumm/imuse.cpp calls _mc->chorusLevel(_effect_level). I wonder if it's supposed to be _mc->chorusLevel(_chorus) instead.

I guess the MIDI device I'm listening to at the moment doesn't implement chorus, because I can't tell the difference between chorus 0 and chorus 64.

comment:2 by SF/tbcarey, 19 years ago

That sounds about right, especially given the following in Part::setup(Player *player):

_effect_level = 64; _chorus = 0;

The difference is really noticeable on a device capable of chorus. I'm using an SC-88 in SC-55 mode [i.e. the original device the music was written on for the game] and I could always hear the difference between playing the games under DOSBox and ScummVM, but had never bothered to investigate what it actually was. If you can make this change, I'll be more than happy to test it and let you know if it sounds correct.

comment:3 by eriktorbjorn, 19 years ago

Ok, I've made the change. The more I look at it the more sense it makes to me, even if I'm still not 100% sure.

I don't know how long it takes for the change to propagate from developer CVS to anonymous CVS, and I don't remember which of them the daily snapshots are based on.

If it goes spectacularly wrong, at least it's an easy change to revert. :-)

comment:4 by eriktorbjorn, 19 years ago

I just wanted to point out that if this indeed turns out to be a bug, like I suspect it is, it goes all the way back to revision 1.1 of the imuse.cpp that was committed on November 14 the year 2001. See

That has to be some sort of record...

comment:5 by SF/tbcarey, 19 years ago

It appears to be fixed. Chorus level is set to 0 on all instruments and the music finally sounds identical to the original interpreter's output. Thanks for your help.

comment:6 by SF/tbcarey, 19 years ago

Status: newclosed

comment:7 by eriktorbjorn, 19 years ago

Owner: set to eriktorbjorn
Resolution: fixed

comment:8 by eriktorbjorn, 19 years ago

Ok, good. It would, of course, have been interesting to know if there's any music that's supposed to change the chorus setting, and compare that to the original.

But either way I guess it's going to be right more often than wrong now, and most users probably don't have fancy enough MIDI hardware to tell the difference. :-)

comment:9 by SF/tbcarey, 19 years ago

SAM + DOTT are the only SCUMM games that support General MIDI natively, and thus the only ones that should be affected by chorus levels (the MT-32 has no chorus capability, only reverb). I've checked both and they both set all instruments' chorus levels to 0.

However, I'll do a check on the non-SCUMM games I have as well that use MIDI [BASS, FOTAQ, Simon the Sorcerer 1]. BS1 + BS2 both use sampled music, as you know; I'm not sure about the HE games since I don't own any, but the two Freddi Fish demos I have both use digital music. Are there are other games you can think of that use MIDI? Let me know and I'll see if I can find any candidates to test them for me.

comment:10 by SF/tbcarey, 19 years ago

Actually, forget that.. the non-SCUMM games should be outside of the iMuse framework, correct? Not that I won't check on them anyway.. I've just noticed some inconsistencies and unset parameters in BASS right now anyway :)

comment:11 by sev-, 19 years ago

Speaking of HE games. MIDI music have these demos (all available from our demos page):

Fatty Bear's Birthday Surprise (DOS demo) Putt-Putt Goes to the Moon (DOS demo) Putt-Putt Joins the Parade (DOS demo)

Also full versions of these games and their Win32 versions use MIDI too, and both funpacks use it as well. Later games switch to digitized music.

comment:12 by sev-, 19 years ago

Ah, forgot that Win32 version of Inherit the Earth also uses MIDI. There was demo which used MIDI but it's not downloadable now, ask me or eriktorbjorn on IRC to send it to you.

comment:13 by SF/tbcarey, 19 years ago

Okay, I've basically analyzed every single non-SCUMM game that uses MIDI and come up with the following discrepencies/info:

1. All games originally designed for MT-32 but remapped as General MIDI [SIMON1, BASS, FOTAQ] must receive a 'GM System On' message upon start-up of the game (SysEx: F0 7E 7F 09 01 F7) to reset reverb, chorus, panning, and volume levels among others. As it is now, they can inherit settings from previous games/MIDI files which could drastically alter the way they sound. Additionally, BASS and FOTAQ should send a MIDI Controller 123 message (All Notes Off) when exiting to turn off all hanging notes, which they seem to have problems with. None of the other games' music hangs upon exit, so if you're using a different method for them, it should be mirrored in BASS and FOTAQ.

2. SIMON1DEMO's tempo is incorrect; it's about 25% too fast. Didn't notice the same behaviour in SIMON1TALKIE, and I don't have SIMON1DOS to test.

3. ITE-DEMO's original interpreter sends the 'GM System On' message at start-up, but ScummVM doesn't, so this should be fixed also. Music also hangs on exit, so Controller 123 or appropriate fix is needed.

4. Simon the Sorcerer II Demo's original interpreter does not send a 'GM System On' message, even though it supports GM devices natively via Miles Drivers. I suspect the music was originally written for an MT-32 since selecting either device in setup yields the same instrument mapping, so this was probably an oversight. It's my opinion the message should be sent on start-up in ScummVM. I did not have any other version (SIMON2TALKIE or SIMON2DOS full) to test.

5. I did not manage to get MIDI working with the original interpreters for any of the HE games (if someone can help me do it, that'd be great - there were no setup programs, and modifying the .ini file manually to include the .drv file did nothing). They all sounded fine under ScummVM and channel parameters were all cleared as instruments were assigned to channels.

6. As for DOTT + SAM, I noticed a few small differences, but nothing that would affect playback. For example, SAM does not set channel volumes to 0 upon pauses but instead issues a Controller 120 message (All Sound Off). They both also initialize every channel to certain parameters upon loading, but since ScummVM properly sets parameters when instruments are actually assigned, I can't think of an instance when this would matter.

I'll look into implementing some of the above changes, but if anyone else gets the urge, feel free :)

comment:14 by digitall, 6 years ago

Component: Engine: SCUMM
Game: Day of the Tentacle
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