Author Topic: Difference between CPC 464 and 6128? (volume issue)  (Read 601 times)

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Offline 6128user

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For long time I thought this was just some minor technical issue (dirty contacts etc) until I faced this same difference in emulators too.

Basically, the sound volume is lower in some games when played in 6128. At worst the volume difference is so big that when you're used to 464, then suddenly some channel or sound effects are barely audible in 6128. I have no idea why. What can make such difference? The best example is the game "Chuckie egg". I played that in my old 464 until I decided to go into 6128 because having 3.5" floppy drive was big upgrade over cassette adapter. In Chuckie Egg I really loved that walking sound which changes occasionally in hilarious ways, but now in 6128 I can barely even hear the walking sound at all. I can't raise the volume because the other sound effects and tunes are way too loud then. I tested that it was the same in both disk and tape image. When testing emulator, as soon as I changed into CPC464 setting, the volume was pretty much back again.

Offline mr_lou

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Re: Difference between CPC 464 and 6128? (volume issue)
« Reply #1 on: 20:10, 18 March 18 »
As a musician, all I know is that if you call the SOUND command from BASIC, it behaves differently regarding volume on the CPC464 and CPC6128.

On the CPC6128, volume goes from 0 to 15. 0 is mute, and 15 is the loudest.
On the CPC464, volume goes from 0 to 7. 0 is mute, and 7 is the loudest. Then again from 8 to 15 where 8 is mute and 15 is loudest. So 0-7 is the same as 8-15.
I noticed this rather early because I did a lot of music in BASIC as a kid.

This means that if volume 10 is used, it'll be much lower on a CPC464 than on the CPC6128.

I don't know why it's like this. My best guess is a design flaw on the CPC464.

Don't know what it's like on the CPC664.

Offline DanyPPC

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Re: Difference between CPC 464 and 6128? (volume issue)
« Reply #2 on: 21:28, 18 March 18 »
I tested chuckie egg on classic CPC464 and 464+ and the walking sound is much lower on the Plus machine.
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Offline Shaun M. Neary

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Re: Difference between CPC 464 and 6128? (volume issue)
« Reply #3 on: 22:42, 18 March 18 »
I've noticed this too. My CPC464 is a lot lower than my 6128+


I've also noticed the same with Spectrums. My black +2a is significantly louder than my grey +2

Offline arnoldemu

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Re: Difference between CPC 464 and 6128? (volume issue)
« Reply #4 on: 10:56, 19 March 18 »
chuckie egg uses the firmware for sound.

cpc464 - v1.0
cpc6128, 464+,6128+ - v1.1

So there is probably a difference here just like in basic.

EDIT: Is it all games or some games that have this problem? Any more examples?
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Offline Shaun M. Neary

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Re: Difference between CPC 464 and 6128? (volume issue)
« Reply #5 on: 14:09, 19 March 18 »
chuckie egg uses the firmware for sound.

cpc464 - v1.0
cpc6128, 464+,6128+ - v1.1

So there is probably a difference here just like in basic.

EDIT: Is it all games or some games that have this problem? Any more examples?

You might be on to something here. What firmware was 664, Kev?
I was using 664 Firmware and BASIC 1.1 with the M4 and I think it may have improved it. I'm waiting for it to come back from repair so can't test it again right now, but now that you mention it, it fits.

Offline 6128user

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Re: Difference between CPC 464 and 6128? (volume issue)
« Reply #6 on: 04:03, 20 March 18 »
chuckie egg uses the firmware for sound.

cpc464 - v1.0
cpc6128, 464+,6128+ - v1.1

So there is probably a difference here just like in basic.

EDIT: Is it all games or some games that have this problem? Any more examples?


Yes there were also more of such games where I noticed the difference because I used 464 quite long time. Now I'm kicking myself that I sold my 464 because I thought 6128 alone would be fine... I can't belive the prices they are asking in ebay for these.

But also, my current 6128 contains some issues, maybe caps needs to be changed because it creates a lot of noise and interference sound, like it makes sounds regarding to screen content. It's possible that this might exaggrate the sound difference because the noise is so loud.
« Last Edit: 04:07, 20 March 18 by 6128user »

Offline chinnyhill10

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Re: Difference between CPC 464 and 6128? (volume issue)
« Reply #7 on: 08:43, 20 March 18 »

Yes there were also more of such games where I noticed the difference because I used 464 quite long time. Now I'm kicking myself that I sold my 464 because I thought 6128 alone would be fine... I can't belive the prices they are asking in ebay for these.


What people 'ask' and what you pay are two different things. Many collectors are like spoilt children who want it NOW and pay over the odds. Patience is the key. Picked up an AZERTY 464 with a couple of minor issues for 6 quid last week, and a perfectly working UK one for 15 at the tail end of last year. No monitor naturally. Both Ebay, both ignored by the dealers and the other bidders. The bargains are still out there.
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Offline angelcaio

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Re: Difference between CPC 464 and 6128? (volume issue)
« Reply #8 on: 13:59, 21 March 18 »
But in the CPC464 Firmware (soft 158), at the beginning of the chapter 7.2 Tone Periods and Amplitudes say:
   "The sound chip allows 16 different amplitudes in the range 0 .. 15. Amplitude O is no sound at all, amplitude 15 is maximum volume."
Therefore, even if there are such differences in the basic versions (range for the volume from 0 to 7 in Basic 1.0), it should not affect machine code programming and firmware calls, i think.
http://www.cpcwiki.eu/imgs/7/7b/S158se07.pdf