Clearing the mixer should be done only once and in the highest numbered 
instrument. The examples/CsoundAC.csd orchestra shows how it should be done, 
typically as the last opcode in a master output stage.

The new Signal Flow Graph opcodes can be used for mixing in a more flexible 
way, and do not require clearing (it is handled automatically). But they do 
not mimic the traditional mixer with busses.

Hope this helps,
Mike

----- Original Message ----- 
From: "UnUnUnium" 
To: 
Sent: Saturday, January 02, 2010 11:54 AM
Subject: [Csnd] Re: Re: Re: Strange channel dropout problem



Thank you Oeyvind. This makes sense to me - nothing is too obvious at this
stage in my Csound learning.

I think some of the problem may have been occurring because I was not
calling "MixerClear" inside the effect, just in the final instrument - I was
sending like this "Global instrument send -> individual effect -> Global
mixer(MixerClear).

I tried clearing the mixer inside each effect, but that caused gaps in
playback. Will get to the bottom of this at some point ;)

Best, Jeremy



Oeyvind Brandtsegg-2 wrote:
>
> ... so the next step is to write a simple version of the mixer setup,
> you could do this "bottom up" by implementing it from scratch,
> og "top down" by stripping down the big csd and leaving only one sound
> generator, one effect (maybe two), and one mixer/out instr.
>
> Sorry for giving such obvious advice...
>
> Oeyvind
>
> 2009/12/30 J :
>> Ok - taking out all mixer inputs and outputs DID solve the problem. No
>> dropouts or other unexpected behaviour - I'm using local variables for
>> the
>> audio in all instruments, input and output.
>> I'm still not sure why that might be the case however - using local
>> variables will work fine for this project, though I am curious as to why
>> using the mixer caused this behaviour.
>> Best, Jeremy
>>
>> On Wed, Dec 30, 2009 at 2:44 PM, J  wrote:
>>>
>>> Thank you for looking it over Oeyvind - it is just as I feared ;) I
>>> think
>>> the first thing I will try is to use direct i/o, as instinctively I
>>> think
>>> that may be a part of the problem - I also haven't tried that yet, only
>>> globals vs. mixer sends. Will report back when I get to the bottom of
>>> it!
>>> Best, Jeremy
>>>
>>> On Wed, Dec 30, 2009 at 11:19 AM, Oeyvind Brandtsegg
>>> 
>>> wrote:
>>>>
>>>> I can't see anything obvious errors in the code snippets you sent,
>>>> but since this is part of a large csd the error might lurk "anywhere".
>>>> The only sane method for finding errors like this in a large orchestra
>>>> is to strip it down until the error disappears. In your eaxmple,
>>>> perhaps limiting the number of different effects (taking away one by
>>>> one until you oly have one effect type, and see if the error still
>>>> occurs). If it's still there, try to use "direct out" audio routing
>>>> (audio out from each instrument instead of using globals and a mixer).
>>>> Then if it's still there, you probably have something quite small now,
>>>> one audio generating instr and one audio effect, and you isolate each
>>>> of those to see where the error is. You should be able to debug
>>>> anything by breaking it down into smaller pieces like this.
>>>>
>>>> it can take some time, sorry, but more often than not it's the way to
>>>> go
>>>> ;-)
>>>> Oeyvind
>>>>
>>>>
>>>> 2009/12/29 J :
>>>> > Hello.
>>>> > I am experiencing a strange, inexplicable (to me anyway ;) problem
>>>> > with a
>>>> > crossfading effects unit I'm building. The unit is designed to
>>>> > crossfade
>>>> > between effects which process a common input. I have tried sending
>>>> the
>>>> > input
>>>> > both via the mixer opcodes as well as just using a global signal.
>>>> > The problem that happens is this: randomly, after running the .csd
>>>> for
>>>> > awhile, one channel will go silent, and the other channel will get
>>>> > really
>>>> > loud. It doesn't seem to be happening on any particular DSP block -
>>>> it
>>>> > does
>>>> > seem to be happening only to the right channel. Any suggestions would
>>>> > be
>>>> > much appreciated, as this is a real head scratcher for me at this
>>>> > point, as
>>>> > I've tried everything I can think of and scoured the board archives.
>>>> I
>>>> > will
>>>> > include sections of my code just to show how I am doing things, the
>>>> > whole
>>>> > csd is too big to post and would clog the board a bit I think.
>>>> > Best, Jeremy
>>>> > I'm sending audio like this (as you can see, I first used mixer send,
>>>> > then
>>>> > tried a gasig solution)>
>>>> >
>>>> > ;GLOBALISED AUDIO INS
>>>> > gasig = asig * gkvolumefactor
>>>> > gasig2 = asig2 * gkvolumefactor
>>>> > gasig3= asig3 * gkvolumefactor
>>>> > gasig4 = asig4 * gkvolumefactor
>>>> > ;MIXER SENDS
>>>> > ;MixerSetLevel 1, 11, gkvolumefactor
>>>> > ;MixerSend asig, 1, 11, 0 ; change first number to be the
>>>> > instrument
>>>> > number
>>>> > ;MixerSend asig2, 1, 11, 1 ; change first number to be the
>>>> > instrument
>>>> > number
>>>> > ;MixerSetLevel 1, 12, gkvolumefactor
>>>> > ;MixerSend asig3, 1, 12, 0 ; change first number to be the
>>>> > instrument
>>>> > number
>>>> > ;MixerSend asig4, 1, 12, 1 ; change first number to be the
>>>> > instrument
>>>> > number
>>>> > endin
>>>> > The effects are scheduled like this:
>>>> > instr 2 ;Effects Scheduler
>>>> > ktrigger init 0 ;NO INITIAL TRIGGER
>>>> >
>>>> > gkeffect chnget "gkeffect" ; TURNS ON NEW EFFECT IF CHANGED
>>>> > ktrigger changed gkeffect ; IF gkeffect CHANGES GENERATE AN TRIGGER
>>>> > IMPULSE
>>>> > ;START NEW EFFECT
>>>> > kmintim = 0 ; MINIMUM TIME BETWEEN INSTANCE TRIGGERS
>>>> > kmaxnum = 3 ; MAX NUMBER OF SIMULTANEOUS INSTANCES (PER INSTRUMENT)
>>>> > kwhen = 0 ; TRIGGER TIME OFFSET
>>>> > kdur = 36000 ; DURATION OF INSTRUMENT
>>>> > schedkwhen ktrigger, kmintim, kmaxnum, gkeffect, kwhen, kdur
>>>> > endin
>>>> > Here's an effect:
>>>> > instr 6; PVADSYN
>>>> > ;TURNOFF CONDITION
>>>> > if gkeffect !=6 then ; REMEMBER TO SWITCH THIS TO INSTR NUMBER
>>>> > WHEN
>>>> > BUILDING NEW EFFECTS
>>>> > turnoff2 6, 0, 1 ; REMEMBER TO SWITCH THIS TO INSTR
>>>> > NUMBER
>>>> > WHEN BUILDING NEW EFFECTS
>>>> > endif
>>>> > ;FADING
>>>> > afade madsr i (gkattack), 0, 1, i (gkrelease)
>>>> >
>>>> > ;MAPPING
>>>> > kratL = gkrootNoteCps/gkglobrootNoteCps; DIVIDE DESIRED PITCH BY BASE
>>>> > PITCH
>>>> > TO GET RATIO
>>>> > kratR = gkrootNoteCps2/gkglobrootNoteCps ; DIVIDE DESIRED PITCH BY
>>>> BASE
>>>> > PITCH TO GET RATIO
>>>> > ;ROUTING
>>>> > ;asig MixerReceive 11, 0
>>>> > ;asig2 MixerReceive 11, 1
>>>> > asig = gasig
>>>> > asig2 = gasig2
>>>> > ;DSP
>>>> > fsig1 pvsanal asig, 1024, 256, 1024,
>>>> 1
>>>> > fsig2 pvsanal asig2, 1024, 256, 1024,
>>>> 1
>>>> >
>>>> > a1 pvsadsyn fsig1, 100,kratL ,1,2
>>>> > a2 pvsadsyn fsig2, 100,kratR ,1,2
>>>> > ;OUTPUT CALCULATIONS
>>>> > asigL = a1* afade; FADE
>>>> > asigR = a2* afade; FADE
>>>> > MixerSetLevel 6, 111, gkvolumefactor
>>>> > MixerSend asigL, 6, 111, 0 ; change first number to be the
>>>> > instrument
>>>> > number
>>>> > MixerSend asigR, 6, 111, 1 ; change first number to be the
>>>> > instrument
>>>> > number
>>>> >
>>>> > endin
>>>> > Then it goes to the mixer:
>>>> > ;OUTS AND POSTPROCESSING
>>>> > instr 111
>>>> > aOutL MixerReceive 111, 0
>>>> > aOutR MixerReceive 111, 1
>>>> > denorm aOutL, aOutR
>>>> > ;aOutL dcblock2 aOutL
>>>> > ;aOutR dcblock2 aOutR
>>>> > outq aOutL, aOutR, aOutL, aOutR
>>>> > MixerClear
>>>> > endin
>>>> >
>>>>
>>>>
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>>>> csound"
>>
>>
>
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