Max Msp cv to Eurorack

R_Gol's icon

Hi there,
I'm a max user and also have eurorack system.
I'm about to purchase Motu interface and to use some of its out's to generate cv to my eurorack system.

I was wondering how it does - Lets say I want to send a sine LFO to control my filter cutoff that expect -5 to +5 v but the cycle~ in max is alternating between -1 and + 1

I dont understand how it goes. do I need to multiple it by 5 ? this doesnt make any sense. where and when the scaking masde between the 'digital world' of MAX and the 'electrical world' of eurorack

Can you please explain me this ?

Thanks

Martin Beck's icon

I use an Expert Sleepers ES-8. I use the scale object to scale the output voltage. This link also contains videos about Max and ES-8.
https://www.expert-sleepers.co.uk/es8.html

There is also a package available in the package manager called CV Tools....but I never used it
https://cycling74.com/articles/get-the-gen-cv-tools-package-by-spektro-audio/

R_Gol's icon

so basically max output between -1 and +1 is equivalent to -1 and +1 Volt in my eurorack ?
so if I want my lfo to cycle between -5 and + 5 v I need to scale it before sending to DAC ?

Martin Beck's icon

I don,t have my computer with me but as far as I remember it is as follows. Max objects like cycle output a normalized scale of -1 to 1. This is converted by my Expert Sleepers ES-8 to a range of -10V to 10V. The ES-8 appears as a normal dac object. If I want to have -5V to 5V I put a scale -1. 1. -0.5 0.5 object behind the cycle.

R_Gol's icon

OK thanks. now it is more clear!
Wondering if someone here use it with Motu ultralite and can tell if the Motu device does the same scaling ( from -1 +1 to -10V +10V

Source Audio's icon

Motu ultralite outputs -4.6 to +4.6 volts DC
for audio signal from -1. to +1.
on line outs, unbalanced.
If one takes balanced out DC between - phase and + phase it is
double, -9.2 to +9.2 dc.

On phones output it is -4.9 to + 4.9
P.S.
It is easier to measure voltage using sig~ that cycle...
If You need exact -5 to +5 volt could use balanced out,
and scale cycle output.
I am not sure if all hardware devices output same voltage

Ronald Nollet's icon

Use a joransloque Rx2 2 ch interface