digital 8-bit audio via AY

I was thinking about the subject... After all, it’s very easy to implement.
After all, it is necessary that the low nibble be twice as quiet as the high one.
This means that the most significant nibble must be simultaneously output to two outer channels,
and the lowest one - to one central one.

The disadvantage of this method is that on the scorpion there is A in the center, on GRM - B, and on
some 'branded' ones - C.
I remember that some newspaper wrote about a similar subject called 'MCC' -
maybe I have it 'their' method ?

;
;Player for AY-8-8910/12 or YM2149F
;For real output 8bit samples !
;
; (C) EVP
;
ORG #8000,0

AYDELAY EQU 10 ;delay

CALL AYCLEAR

AYPLAY EXX
LD BC,#FFFD
LD DE,#080A ;outer channels (A,C)
LD L,#09 ;central (B)
EXX
LD BC,#BFFD
LD HL,SAMP_S
LD DE,SAMP_E-SAMP_S

AYLOOP PUSH DE
LD A,(HL)
AND #F
LD E,A
LD A,(HL)
RRCA
RRCA
RRCA
RRCA
AND #F
LD D,A

EXX
OUT (C),E
EXX
OUT (C),D
EXX
OUT (C),D
EXX
OUT (C),D
EXX
OUT (C),L
EXX
OUT (C),E

LDB,AYDELAY
AYLP DJNZ AYLP
INC HL
POP DE
DEC DE
LD A,D
OR E
JP NZ,AYLOOP
RET
;
; Preparing registers AY.
;
AYCLEAR EXX
LD DE,#BFFF
LD BC,#FFFD
LD A,7
OUT (C),A
LD B,D
LD A,#38
OUT (C),A
LD A,5
AYCLR LD B,E
OUT (C),A
LD B,D
OUT (C),0 ; #ED,#79 - not doc.
DEC A
CP #FF
JR NZ,AYCLR
EXX
RET
DS 3
SAMP_S INCBIN "SAMPLE.I" ; 8-bit sample
SAMP_E DS 1

PS. this is all now written in LC, without testing the theory ;)
but in general here for ALASM teams meet...

With respect, Evgeniy aka EVP.

on 11 Feb 99 (01:09) Eudgine Palenock wrote to All about digital 8-bit
sound via AY:

EP> I was thinking about the subject... After all, it’s very easy to implement.
EP> After all, it is necessary that the low-order nibble be twice as quiet as the high-order nibble.
2^4=16 times. Otherwise, your volumes #40 and #08 will be the same.
So your method does not give 8 bits, but less:(

EP> This means that you need to simultaneously output the high-order nibble into the two outermost
EP> channels, and the low-order nibble into one central one.
What if it’s mono? ;)

EP> The disadvantage of this method is that on the scorpion in the center A, on the GRM -
EP> B, and on some 'branded' ones - C. I remember in some newspaper
I'm generally used to mono on Spec, but imho, the most correct thing is ACB, i.e. with
average C. So there will be more support. Well, B also has the right to life.
But A... =8-[ ] Again on the scorps they tried to do everything their own way...

──────════════════════════ ═════════════════════════[ have a nice day ]════─┘

Dmitry Rekman aka RCL

DR> I’m generally used to mono on Spec, but imho, the most correct thing is ACB, i.e. with
DR> average C. This way there will be more support.
WRONG ANSWER! You, like the stepovians, are mistaken. I remember that STEP also
said that they declared ACB their standard... Then they were inundated with letters... It turned out that the majority had ABC.
Now with the arrival of Scorps with their BAC, the situation has changed... But not in favor
ACB. ACB - for the Poles, on Western cars.

Screw you, Dmitry... That's it... Bye!
Alexey||Rain

There was nothing to do, and 13 Feb 99 at 16:53:00
Alex Baskakov wrote a letter to Dmitry Rekman on the topic: "Re: digital 8-bit sound
via AY"
I saw this and decided to answer.

AB> WRONG ANSWER! You, like the stepovians, are mistaken. I remember STEP also
AB> said that they declared ACB as their standard... Then they were inundated with letters
AB>... It turned out that the majority had ABC.
So it is. ------^^^^^
But I have a knob that switches ABC <-> ACB (this is me because of the Poles)

AB> Now with the arrival of Scorps with their BAC, the situation has changed... But not in favor

But Scorpov's BAC is IMHO a perversion. I wonder how they explain their choice?
Or did they just decide to show off? After all, everyone has either ABC or ACB.

With that said, let me take my leave. Sincerely, Andrey Khoroshilov.

... The mind is stronger than the chest. Hippies are people too.
... What were you going to see there? Glass fabric? And thought from electrons?

Once, 15 Feb 99 at 22:11:00, someone Aleksandr Majorov wrote to Eudgine
Palenock, on the topic 'digital 8-bit sound through AY'...

AM> can I find out where this information comes from?
AM> I brought up the scorpion diagrams, so both on the "yellow" and
AM> "green" ABC is used!!!

Look for example at ZX.SPECTRUM - now they have put music for scorpion under BAC
... Yes, I myself have seen such a scorpion... It’s just that many people have corrected this glitch...

AK> But Skorpovskoe BAC is IMHO a perversion. I wonder how they explain their
AK> choice?
AK> Or did they just decide to show off? After all, everyone has either ABC or ACB.
IMHO, design inattention.

Screw you, Andrey... That's it... Bye!
Alexey.

AK> your choice? Or did they just decide to show off? After all, everyone has either
AK> ABC or ACB.
They did what God intended. We just didn’t think about this issue,
IMHO...
P.S. The same situation happened in Peters-256. Even now I don’t know what the channel layout is.. A according to the ABC scheme.

Wow! The Protoss are attacking my Zerlings! It's time to get going. Ivan.

- Break up the scheme, big and small..

... E-mail: ivan...@neva.spb.ru