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TmEE co.(TM)
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Joined: 05 Dec 2006
Posts: 1954
Location: Estonia, Mahtra village
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 Posted: Sun Jun 24, 2007 8:51 pm Post subject: My attempt at 2ch Z80 mixer |
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www.hot.ee/tmeeco/DWNLOADS/MSETEST.RAR
It can play 1ch @ 110KHz, and 2ch @ 52KHz.
This demo plays @ 22KHz or so.
2ch playback is little distorted because of extra jitter, and it sounds faster than 1ch on real HW (LDIR instruction executed faster ?) than on emulator where it sounds slower than 1ch.
A and B buttons make sound.
Thing is not finished though, need to work out sound effect stuff, and music part.
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Last edited by TmEE co.(TM) on Sun Jun 24, 2007 9:10 pm; edited 1 time in total |
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evildragon
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Joined: 12 Mar 2007
Posts: 326
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| Posted: Sun Jun 24, 2007 9:07 pm Post subject: |
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| this is awesome :p i never thought this was even possible... |
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TmEE co.(TM)
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Joined: 05 Dec 2006
Posts: 1954
Location: Estonia, Mahtra village
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| Posted: Sun Jun 24, 2007 9:12 pm Post subject: |
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It is, and it sounds lot better on real HW, than on emulators (Fusion sounds nice though). 110KHz is achieved thanks to Stef's idea which he came quite some time ago (see the "How can I do music on MegaDrive" topic on MD stuff forum).
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TmEE co.(TM)
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Joined: 05 Dec 2006
Posts: 1954
Location: Estonia, Mahtra village
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| Posted: Mon Jun 25, 2007 12:28 pm Post subject: |
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Updated the thing, now it sounds much more nicer.
A=Snare drum (ch1)
B=Bass drum (ch0)
C=Crash cymbal(ch1)
There is a weird pop when 2ch are playing, I couldn't get rid of it... any ideas anyone ?
I was drumming whole night yesterday...
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Shiru
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Joined: 07 Apr 2007
Posts: 786
Location: Russia, Moscow
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| Posted: Mon Jun 25, 2007 3:23 pm Post subject: |
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| TmEE co.(TM) wrote: | | There is a weird pop when 2ch are playing, I couldn't get rid of it... any ideas anyone ? |
Record sound output from emulator to wav and look it in any sound editor, you understand this problem. It's a incorrect DC offset. |
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TmEE co.(TM)
Very interested
Joined: 05 Dec 2006
Posts: 1954
Location: Estonia, Mahtra village
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| Posted: Tue Jun 26, 2007 8:14 am Post subject: |
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Yes it was... I lowered the volume of one channel playback (so it is as loud as 2ch) but I forgot to add 64 to get "silence" position (128), it was 64, and when 2ch played, jump from 64 to 128 caused a pop. Now it is fixed and works great !!!
Upadated again.
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Stef
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Joined: 30 Nov 2006
Posts: 1290
Location: France - Sevres
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| Posted: Sun Jul 01, 2007 8:51 pm Post subject: |
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It's awesome to see how we progressed from our first attempt 
just need to continu in this way and we will do our 4 ch MOD player on Z80 |
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Fonzie
Genny lover
Joined: 29 Aug 2006
Posts: 318
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| Posted: Mon Jul 02, 2007 6:22 am Post subject: |
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yeah ^^ Very impressive dudes 
May i recall that the official sega driver supported "delta compressed samples" (ADPCM?) in top of FM/PSG Haha  I'm insane, I know
Anyway, nowadays, you may have 8Megabytes cartridges, so it is fine |
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Shiru
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Joined: 07 Apr 2007
Posts: 786
Location: Russia, Moscow
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| Posted: Mon Jul 02, 2007 6:59 am Post subject: |
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| DPCM and ADPCM is different things, DPCM is much simpler, it has fixed delta. |
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TmEE co.(TM)
Very interested
Joined: 05 Dec 2006
Posts: 1954
Location: Estonia, Mahtra village
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| Posted: Mon Jul 02, 2007 3:20 pm Post subject: |
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For a while, I was thinking about creating my own brand of ADPCM, but as Fonz said, size is no problem today
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