#1 2007-03-28 18:46:56
Sustained sounds
Hello all
This is my first post ever so please excuse me if I come across like an idiot!
I have noticed that when using the Drummer, if i hit one of the main keys to trigger a drum sound, the sound is sustained constantly (at a low volume) until i trigger a new sound. Is this normal?
Or is it an indication that my SID chip is frazzeled?
I also noticed that it does not happen when I use the Bassline or the Monosynth. And when I run the demo song in the sequencer it sounds great, no apparent problems.
Any advice is much appreciated.
Thanks
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#2 2007-03-28 19:47:59
Re: Sustained sounds
Hi! You do not seem like much of an idiot to me - and I have made a complete prick of myself here more than once so I should know.
The C64 tends to 'bleed' a lot (it's one of the SIDs unique quirks). I think it has something to do with the oscs still generating the last sound they were ordered to with the amp envelope never quite closing combined with the physical input and outputs bleeding. There are some dead simple mods to 'fix' the 'problem' such as earthing (grounding) the sound input pin on the video port... Do a search of this forum, there is a lot of good info here.
Also, just using the video output instead of the RF TV output kills a lot of the fuzz (which I assume is down to crosstalk between the video and audio signals and inacuracies in the tuning of the tv set)....
Drummer is quite noisey because of the colour scheme - which could explain why youre hearing something lingering in that app. Maybe. If you make a recording any issues could probably be instantly identified by some of the serious C64 geeks here. 
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#3 2007-03-28 23:11:06
Re: Sustained sounds
Yeah, the SID got some sound memory 
I think Tristan is right with his 'bleeding explanation', Drummer doesn't use the filter so the hizz goes always through...
Actually I kind of like that behaviour (which is still there on my "denoised" commodores). Cynthcart always creates huge fragments after playing a lot of synthlines or chords. Pure Ambient scapes!
I aggree it might come annoying on drumsounds but this is what noise gates are for 
. Since the artefacts are still there when the gates open the whole sound is becoming quite spatial, almost like early reflections.. My 6581 has little more hizz-artefacts than my 8580, btw.
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#4 2007-03-29 01:49:24
Re: Sustained sounds
Excellent!
Thank you both very much for the advice. I feel reassured.
I'll get some samples recorded tomorrow. Just for interests sake really, its nice to know the whys and wherefores of this lovely little chip. I think its a 6581 by the way, not sure yet though as I havnt opened it up to look at the guts yet (I'm a bit scared to as its the only working c64 out of 3 that I recently perchased from separate people who all claimed that the machines where in good working order!). But its an old 'breadbin' if thats any kind of indicator?
Anyway, I love it and look forward to the hours of fun/stress turning it into a duel SID Beast
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#5 2007-03-29 13:56:51
Re: Sustained sounds
Headloc wrote:
But its an old 'breadbin' if thats any kind of indicator?
Not really. Chances are good it's a 6581 but you never know if there's still the original board inside or if it's some late model breadbox that came with a short newschool board. You don't have the P64 cartridge but just the free versions? The cart shows the SID model in the bootscreen (99% trustworthy). If you don't have the cart but able to transfer .PRGs to your C64 there's a detection routine somebody posted at forum64.de, too. However, opening the breadbox is not that dangerous unless you don't touch anything inside, and something you really should get familiar with - A short glimpse at the SID won't hurt
Last edited by ron (2007-03-29 14:40:58)
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#6 2007-03-30 13:48:59
Re: Sustained sounds
ron wrote:
You don't have the P64 cartridge but just the free versions?
Yes I'm happy to say I have the P64 cartridge. It reports that my system is PAL and my SID revision is 6581.
I know im probably jumping the gun a bit as my knowledge of electronics is pretty thin, but I have been collecting any c64s that I find, at the moment I have 2 old breadbins and 2 C64Cs and another 2 C64C's on the way.
I intend to create 2 different duel SID machines, One running 2 6581 chips and the other running 2 8580 chips.
I was offered a C128 the other day but wasnt sure if the SID would be useful, am I right in thinking it may have a 8580 chip inside?
I have lots of other questions but I think they would probably be better posted in a different section of the forum.
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#7 2007-03-30 14:18:59
Re: Sustained sounds
Headloc wrote:
I was offered a C128 the other day but wasnt sure if the SID would be useful, am I right in thinking it may have a 8580 chip inside?
AFAIR there're early C128 equipped with 6581s, too. But you're right, we're getting right away from the "drummer" topic here
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