# SuperVP - generalized cross synthesis

Hi All

Could somebody may explain the order of the param file (amplitude scaling/frequency scaling … of sound 1 and 2)(s.screenshot I mean third slot)

the included file has this matrix
0 1 0 1 0 0
0.5 1 0 1 0 0
2 0 1 0 1 0
4 0 1 0 1 0

but unfortunately the example in the documentation is not working…

and how to change between different cross modes? t= constant cross? and the rest? (s screenshot: I mean 9. slot)

would be great

Thanks

best L

Hi MARIAROSE,

Well the parameters for the Generalized Cross Synthesis are as follow, according to my notes and this AudiosSculpt reference
http://support.ircam.fr/docs/AudioSculpt/2.8.3/co/cross-synthesis.html. :

If you consider `S1` is the fft spectrum of `sound1`, `S2`… of `sound2` and `Sout` the `result` then,

in mode <`add`> (just click on the mode slot, the 9th, and a menu will appear) :

`Sout = XS1 + xS2`
Where `X` is the amp coefficient “Amplitude Scaling” of `sound 1`
and `x` is the amp coefficient “Amplitude Scaling” of `sound 2`
so that’s an amp mix

whereas in mode :

Amp(Sout) = Xamp(S1) + xamp(S2) + qamp(S1)amp(S2)
Freq(Sout) = Y
freq(S1) + y
Freq(S2)

where
X and x as above
Y is the phase coefficient ("Phase Scaling”) of sound 1,
y is the phase coefficient (“Phase Scaling”) of sound 2,
q is the multiplication amplitudes coefficient “Q Factor”.

and at last the order of parameters for the OM SuperVp object is :

(time X x Y y q).

I Hope I’ve made no mistake typing all these params !

Bye,

N.

Thanks a lot for this very nice and detailled description!!
Now it is working

Is it also possible making a stretch factor or matching the second sound to the first if the files do not have the same length?

All the best

L

Hi MARIAROSE,

You’re welcome.

You may have noticed the ‘match’ and ‘stretch factor’ params in the Audiosculpt General Cross Synthesis Interface. You may also apply a time compression/dilation factor with the -D flag in supervp command line ((a code which is (very!) less explicit than the interface but there’s a full documentation : supervp -h in terminal, you need to install the command-line tools in the kernel folder within AS or shipped separately in the forum’s apps)).

I can’t find a way in OM supervp-cross-synthesis object (there’s no optional hidden slot for the compr/dilat parameter, in the code neither: select object and type “e”… ). So, you need to make that operation beforehand with supervp-timestretch to match the length of 1st sound (be aware that the duration of the sound include the silence within.)

N.

Yes… I did

the first soltion sounds complicated…

I think I will do it by hand before with timestretch…

Thank you!

All the best
L

You may use the OM sound-dur-ms object to get the duration of your sounds then some math to calculate your factor i.e.

S2_Duration * F = S1_Duration => F = S1_Durtation / S2_Duration

am I right ? Hold on…

Cool idea! That works nice.