How do I get PSG instruments?

Master (177)

26-07-2004, 05:00

I've been trying to get some decent tunes out of my PSG lately, and all I get are square waves.
So I've been wondering how instruments/drums/etc are simulated?

(Hope I'm not annoying yer ppls out there )

Por ro

Scribe (5063)

26-07-2004, 08:45

'Dunno if ya've read any specs concerning PSG? But it's e.z. as 1, 2 .. euh. 4.
If ya got square waves (sure it wasn't sin wave?) you prolly have some envelope set on the volume channels (bit 4=1)

With PSG it's hard to actually 'simulate' instruments since the color of the sound is always the same old one we've grown to love so much. Drums can be achieved by adding some extra noise to it.

Por Sousuke

Master (177)

26-07-2004, 13:04

Well I did read the specs of the PSG, and already tried to play w/ the envelopes, but couldn't produce useful sounds or different :-/

I dunno whether 'simulate' is understood correctly.. I meant changing the tone color:
My tunes are all sounding very similar (to be exact: the same ) now.
I'm not aiming to acheive ~100% preproduction of real instruments (don't really like that anyway), but looking for some cool sounding synthetic ones

Por ro

Scribe (5063)

26-07-2004, 14:30

tip: DON'T use the standard envelope things.. they suck. period.
and no, changin the 'color' of PSG isn't possible... thaz what I was trying to tell ya earlier (yeah I know, I suck at communication: schism dude, schism)

The PSG is a very basic sound processor, but with some fitling you can end up with some cool tunes. The Atari computer also had a simular sound chip. As a matter of fact, and this is a scoop, I'm busy at the moment converting the ever popular Atari sc68 replayer (also 3 channels of PSG)

Por NYYRIKKI

Enlighted (6094)

26-07-2004, 14:47

Well... PSG can play only square waves and white noice. Drums are typically made by changeing noice volume and noise perioid. Only way to make "instruments" is to change wave volume.

Envelope shapes have only effect to volume, but you can get more usefull sounds by changeing volume on Z80. If you change volume quick enough, you can even play samples.

Por wolf_

Ambassador_ (10135)

26-07-2004, 15:06

There's the M & S commands in basic MML ..

By applying some of those envelopes on your squares you can come up with saw-style stuff.. I tried it yeeeeeeeears ago, it was work for a monk, really! iirc the 20th aniversary demo by Magoo features that stuff.. and iirc the small MSX1 shooter Desolator also has a sound like that.

Por flyguille

Prophet (3031)

26-07-2004, 15:37

I REMEBER, the &H0D envelope sound like a SHOT... so, short the expo time, then add another sound shot of a second channel but with different sound TONE... and volume and voala!!!.

Por hap

Paragon (2043)

26-07-2004, 16:44

I just messed around in Basic... How's this for changing the colour ?

10 CLEAR: DEFINTA-Z: PLAY"v10o1l4cccv12c","v6o2l4rcv7cv8g","v4o3l4rrgv5g": PLAY"l64o1v10cv9cv8cv7cv6cv5cv4cv3c2cv1c","l64o2v1cv2cv3cv4cv5cv6cv7cv8cv9cv10c": GOSUB80
20 A=62: B=0: C=0: SOUND1,14: SOUND3,14: SOUND5,0: SOUND0,200: W=20: FORI=1TO12: SOUND8,I: GOSUB70: NEXT: SOUND10,10: SOUND9,14
30 SOUND1,14: SOUND3,14: SOUND0,200: SOUND2,208: SOUND7,A: A=A-1: IFA=55THENA=56: SOUND8,14: SOUND10,11: C=C+1: IFC=5THENSOUND7,55: W=300: GOSUB70: BEEP: CLEAR: END
40 W=40: FORI=1TO3: S=70: GOSUB70: S=255: GOSUB70: S=70: GOSUB70: S=180: GOSUB70: S=100: GOSUB70: S=250: GOSUB70: S=100: GOSUB70: S=250: GOSUB70: NEXT
50 IFB=0THENW=5: SOUND0,30: SOUND2,50: FORI=70TO210STEP5: S=I: GOSUB70: NEXT: FORI=210TO70STEP-5: S=I: GOSUB70: NEXT: IFA=56THENB=1: W=60: FORI=1TO8: SOUND7,52: SOUND6,I+10: GOSUB70: NEXT: SOUND7,56: SOUND6,0: S=0: SOUND9,0: SOUND8,0: W=300: GOSUB70: SOUND9,14: GOTO30ELSE30
60 SOUND1,15: SOUND3,15: SOUND2,160: SOUND0,255: W=3: O=0: P=0: FORH=1TO3: FORI=50+OTO100+O+PSTEP5: S=I: GOSUB70: NEXT: O=O+20: P=P+10: NEXT: O=30: FORH=1TO3: FORI=50+OTO85+OSTEP5: S=I: GOSUB70: NEXT: O=O+10: NEXT: GOTO30
70 FORJ=0TOW: SOUND4,S: SOUND4,200: SOUND4,170: NEXT: RETURN
80 IFPLAY(0)THEN80ELSERETURN

Por ro

Scribe (5063)

26-07-2004, 17:10

for changing the screen layout you mean?! darn

Por hap

Paragon (2043)

26-07-2004, 17:25

whoa, sorry about that..
I'll provide a temporary download link instead:
members.chello.nl/~s.morsink/crap/flang2.zip

Could a moderator please remove or edit my above message ? The forum doesn't let me edit that post.

Por wolf_

Ambassador_ (10135)

26-07-2004, 17:30

hm.. I was about to write something about code-boxes and word-wrap .. until I realised there are no spaces in that code