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ST stereo upgrade!


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#26 jmetal88 OFFLINE  

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Posted Wed Mar 12, 2014 6:16 PM

So what exactly does this stereo mod do for sound in existing games?  Does it just arbitrarily split up the original mono notes or what?



#27 GadgetUK OFFLINE  

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Posted Thu Mar 13, 2014 9:14 AM

The YM chip has 3 channels (if you think left centre and right although the are A,B or C etc). So music on games basically stick one instrument or 'track' on one channel, another on the next and so on. As standard all 3 are just merged into one audio output, so you hear all 3 channels but all from one place. Once split to left, right and centre you can clearly hear the seperation of the channels. Eg. Drum in left ear, sax in right, piano centre etc. Watch my vid on page one and compare how those games sound on a standard ST. Edit: just don't watch on iPhone without headphones or iPhone is mono lol

Edited by GadgetUK, Thu Mar 13, 2014 9:16 AM.


#28 jmetal88 OFFLINE  

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Posted Thu Mar 13, 2014 3:03 PM

The YM chip has 3 channels (if you think left centre and right although the are A,B or C etc). So music on games basically stick one instrument or 'track' on one channel, another on the next and so on. As standard all 3 are just merged into one audio output, so you hear all 3 channels but all from one place. Once split to left, right and centre you can clearly hear the seperation of the channels. Eg. Drum in left ear, sax in right, piano centre etc. Watch my vid on page one and compare how those games sound on a standard ST. Edit: just don't watch on iPhone without headphones or iPhone is mono lol

 

I think I get it.  It sounds like there might be some 'novelty' to it, but I think I would rather the sounds just stay blended.



#29 GadgetUK OFFLINE  

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Posted Thu Mar 13, 2014 3:33 PM

 
I think I get it.  It sounds like there might be some 'novelty' to it, but I think I would rather the sounds just stay blended.

Each to their own! Stereo is not for everyone or Atari would have made it stereo to start with! Personally I love the definition that stereo provides. Same with the Mega Drive and Lynx - sounds so much better in stereo IMO but that's just my opinion at the end of the day!

Edited by GadgetUK, Thu Mar 13, 2014 3:35 PM.


#30 MrMaddog OFFLINE  

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Posted Thu Mar 13, 2014 8:55 PM

Wow, wish I knew about this Tweety board! I had my STe hooked up to a boom box and the chiptunes does sound better, but it's still all coming out of both speakers as mono sound while only the DMA audio is true stereo. Would be nice if this could be an option on ST emulators (hint, hint...)

#31 Umberto OFFLINE  

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Posted Thu Mar 13, 2014 9:16 PM

You can do a simple mod (and the original Tweety board I think had it?) to

disable the new stereo sound for when you are doing sound/speech samples.

 

IIRC....

Don't remember that on the tweety, but its was probably 20 plus years ago that I installed it on my mega 2, and then pulled it for what ever reason. Was digging through some boxes the other day and found my old tweety, Would be interesting to find a pdf of the manual to see if this was true. I do remember the sound was pretty cool pumped through my stereo.



#32 fedepede04 OFFLINE  

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Posted Fri Mar 14, 2014 12:16 AM

the AY 8912 sound on Amstrad CPC 464 was split

channel A is right

channel B is both

channel C is left



#33 GadgetUK OFFLINE  

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Posted Fri Mar 14, 2014 3:10 AM

the AY 8912 sound on Amstrad CPC 464 was split

channel A is right

channel B is both

channel C is left

I was wondering about the +2 as well (same chip I think you said!)  So it's possible to have cool stereo on the Amstrad and Speccy +2 as well =)



#34 fedepede04 OFFLINE  

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Posted Fri Mar 14, 2014 3:37 AM

the Ym2149 was built under licence from general instrument.

there was some minor changes, don't recall them the only one i recall is that the envelope volume had 0-15 step, on the AY and 0-31 on the YM.

 

the stereo on the Amstrad was hardware made,

and yes i can be made on the +2.

http://www.benopheti...description.pdf



#35 GadgetUK OFFLINE  

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Posted Fri Mar 14, 2014 3:46 AM

the Ym2149 was built under licence from general instrument.

there was some minor changes, don't recall them the only one i recall is that the envelope volume had 0-15 step, on the AY and 0-31 on the YM.

 

the stereo on the Amstrad was hardware made,

and yes i can be made on the +2.

http://www.benopheti...description.pdf

 

Thanks, i've saved a copy of that.  Interesting little board.  I wonder what the effect of swapping a YM2149 and AY chip around would be?  If it just about envelope volume I guess they might be almost compatible with each other.



#36 fedepede04 OFFLINE  

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Posted Fri Mar 14, 2014 5:05 AM

i also think that the DAC output is not quite the same, but i don't think that you will hear the big difference.
Maybe if you play sample music, because the combine the volume of the 3 channel, to raising the Bits,
but then again that won't work in stereo mode anyway :D



#37 Muzz73 OFFLINE  

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Posted Fri Mar 14, 2014 1:51 PM

I may have the manual to my Tweety Board, but I'm not sure. If I do, I'll scan and post it on Monday.



#38 Umberto OFFLINE  

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Posted Fri Mar 14, 2014 9:00 PM

I may have the manual to my Tweety Board, but I'm not sure. If I do, I'll scan and post it on Monday.

that would be great



#39 Ayreon OFFLINE  

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Posted Mon Mar 17, 2014 8:42 AM

On http://rdemming.home...Atari/index.htm you'll find a way to make your own stereo upgrade on your plain ST without the need for a tweety board.It is basicly doing the same thing for a fraction of the costs. Just need a bit of soldering, cutting and drilling holes skills.



#40 GadgetUK OFFLINE  

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Posted Mon Mar 17, 2014 6:11 PM

Yep,

 

On http://rdemming.home...Atari/index.htm you'll find a way to make your own stereo upgrade on your plain ST without the need for a tweety board.It is basicly doing the same thing for a fraction of the costs. Just need a bit of soldering, cutting and drilling holes skills.

Yes, that's why I bumped this post to start with.  Internal MIDI synth going in there next =)



#41 DarkLord OFFLINE  

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Posted Tue Mar 18, 2014 9:35 AM

Ah, maybe that was the version I was thinking of - it will allow you to switch back to mono

for digitized voices/samples, right?



#42 Bryan OFFLINE  

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Posted Tue Mar 18, 2014 9:56 AM

Each to their own! Stereo is not for everyone or Atari would have made it stereo to start with!

I doubt they would have. They used that chip because it was cheap not because they cared what the ST would sound like. I think if they were going to do stereo on the cheap, they could have at least used two chips to get 3 voices per channel.

 

When I had an ST, I made my own version of Tweety Board which had channel 1 mixed to the middle so you had L, R, and Center with standard stereo cables.



#43 Muzz73 OFFLINE  

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Posted Tue Mar 18, 2014 2:22 PM

I have always wished and hoped that someone would have come out with a STereo upgrade, like running dual SIDs in a Commodore 8-bit or dual POKEYs on an Atari 8-bit. Sure, the synthesis might still be cheesy, but 6 voices in stereo would still be better than 3 in mono.

 

OK, maybe not "better", but fun to play around with.



#44 GadgetUK OFFLINE  

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Posted Wed Mar 19, 2014 3:54 AM

I installed that SAM2195 internal MIDI synth last night! Link in my signature. Instrument mapping isn't ideal due to GM vs Roland MT-32 but overall I am pleased with it.

#45 Master Phruby OFFLINE  

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Posted Wed Mar 19, 2014 8:48 AM

I remember installing a Tweety Board back in the day for my 1040stfm. Worked like a charm!



#46 Muzz73 OFFLINE  

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Posted Fri Mar 21, 2014 2:31 PM

OK, I have scanned the entire Tweety Board manual in B&W, 150dpi. I'm sorry this took so long, but it's a surprisingly long manual for such a simple product.

 

Please note: There were a few blank pages in the original manual that were inserted for print pagination. I have left these out (no point in having them in a PDF). There was also a four page addendum included regarding newer model ST's that came out after the original manual was printed. I have included all four pages of the addendum at the end of the manual (after page 29).

 

You may download it here:

 

https://www.dropbox....weety_Board.pdf

 

I hope this helps for anyone who might have needed it.



#47 DarkLord OFFLINE  

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Posted Sat Mar 22, 2014 3:47 PM

Thanks for that - I've scanned and posted several items like this,

I know what hard (and b o r i n g) work it is.  :)



#48 Muzz73 OFFLINE  

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Posted Sat Mar 22, 2014 10:32 PM

Absolutely. I was going to scan it at 300dpi in grayscale, but I thought it'd probably end up too large to be practical, so I went with dithered B&W, 150dpi and it still came out to almost 15MB. Whew!

#49 Lynxpro OFFLINE  

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Posted Fri Apr 18, 2014 7:02 PM

I doubt they would have. They used that chip because it was cheap not because they cared what the ST would sound like. I think if they were going to do stereo on the cheap, they could have at least used two chips to get 3 voices per channel.
 
When I had an ST, I made my own version of Tweety Board which had channel 1 mixed to the middle so you had L, R, and Center with standard stereo cables.



Not exactly true. They went with the YM2149 not only because it was cheap but also because the AMY wasn't finished.

The Tweety Board is cheap but I'm curious why nobody has made a Dual YM2149 adapter like the Dual POKEY adapters available for the A8 line...

#50 misterdid OFFLINE  

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Posted Fri Sep 14, 2018 5:03 PM

I know it's an old topic...Do anyone has the PDF of the tweety board manual ? I found one of this old board, but no box, no manual :(

I'd like to test it in my 520ST, but I don't want to mess up...






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