hello,

I am not sure if it works but perhaps you could use two global k-variables for 
the amplitudes and call another instrument for the crossfade from your master 
instrument ( it is necessary to control what is the state of gkAmp1 in the 
current moment, it is the i-time of the isntr crossfade):


gkAmp1 init 1
gkAmp2 init 0

#define FADETIME #3# ; 3 seconds for crossfade?

instr master 
;...

	if (ktrigger==1) then
		event "i","crossfade",0,$FADETIME
	endif


endin

instr crossfade 
	if  ( i(gkAmp) == 0) then
			gkAmp1 line 0, p3 1 ; fade in
		 else
			gkAmp1 line 1, p3, 0 ; fade out
		gkAmp2=1-gkAmp1 ; amp2 is the opposite
endin


and use the gkAmps in the playing isntrument

I did not try it myself and I am sure there are more elegant ways to do it but 
this is one ide.

greetings,
tarmo


On Tuesday 24 April 2012 00:02:03 Alex Weiss wrote:
> Hi list
> 
> I'm having some difficulties implementing an idea in csound. Here's what I
> want to do: play one sound file, and at random intervals switch over to a
> different sound file with constant-power crossfades between the two. My
> plan was to have two instruments, each playing one sound file, and a third
> master instrument that controls the amplitudes of the other two
> instruments. But I'm not sure how to trigger the cross-fades. Any idea?
> 
> Thanks,
> Alex
> 
> Send bugs reports to the Sourceforge bug tracker
>             https://sourceforge.net/tracker/?group_id=81968&atid=564599
> Discussions of bugs and features can be posted here
> To unsubscribe, send email sympa@lists.bath.ac.uk with body "unsubscribe
> csound"

I was thinking that you could trigger two instruments with event that
would control the amplitude of the two sound files by means of global
variables. If you use the 'r' family of of envelopes you could also
have a fade out as well as fade in when you turn them on and off.
Sorry, I'm about to start work and don't ave time to explain what I
mean in code! Good luck!

On 24 April 2012 02:18, Tarmo Johannes  wrote:
> hello,
>
> I am not sure if it works but perhaps you could use two global k-variables for
> the amplitudes and call another instrument for the crossfade from your master
> instrument ( it is necessary to control what is the state of gkAmp1 in the
> current moment, it is the i-time of the isntr crossfade):
>
>
> gkAmp1 init 1
> gkAmp2 init 0
>
> #define FADETIME #3# ; 3 seconds for crossfade?
>
> instr master
> ;...
>
>        if (ktrigger==1) then
>                event "i","crossfade",0,$FADETIME
>        endif
>
>
> endin
>
> instr crossfade
>        if  ( i(gkAmp) == 0) then
>                        gkAmp1 line 0, p3 1 ; fade in
>                 else
>                        gkAmp1 line 1, p3, 0 ; fade out
>                gkAmp2=1-gkAmp1 ; amp2 is the opposite
> endin
>
>
> and use the gkAmps in the playing isntrument
>
> I did not try it myself and I am sure there are more elegant ways to do it but
> this is one ide.
>
> greetings,
> tarmo
>
>
> On Tuesday 24 April 2012 00:02:03 Alex Weiss wrote:
>> Hi list
>>
>> I'm having some difficulties implementing an idea in csound. Here's what I
>> want to do: play one sound file, and at random intervals switch over to a
>> different sound file with constant-power crossfades between the two. My
>> plan was to have two instruments, each playing one sound file, and a third
>> master instrument that controls the amplitudes of the other two
>> instruments. But I'm not sure how to trigger the cross-fades. Any idea?
>>
>> Thanks,
>> Alex
>>
>> Send bugs reports to the Sourceforge bug tracker
>>             https://sourceforge.net/tracker/?group_id=81968&atid=564599
>> Discussions of bugs and features can be posted here
>> To unsubscribe, send email sympa@lists.bath.ac.uk with body "unsubscribe
>> csound"
>
>
> Send bugs reports to the Sourceforge bug tracker
>            https://sourceforge.net/tracker/?group_id=81968&atid=564599
> Discussions of bugs and features can be posted here
> To unsubscribe, send email sympa@lists.bath.ac.uk with body "unsubscribe csound"
>